An integrated parking information system is disclosed. The system includes a collection system and a means for collection of parking data, and an information provision system and a method for the provision of parking information, for instance, enabling a driver to know exactly which city parking rules and fines apply for any given street parking space, as well as other associated information. The system can notify members about available parking spots through a GPS application that is integrated with phones & in dash navigation systems. The system can provide alerts to protect members against parking violations.

Parking tickets are a major problem and expense for private and commercial vehicle operators worldwide. Parking rules are unclear, opaque, ambiguous, inconsistent and confusing, leaving operators in the dark as to their compliance with applicable parking rules. As a result, more than $5 billion is spent on parking violations in the top 50 urban areas. Vehicles get an average of four tickets per year. Significant time and money is lost driving around trying to find the best parking option. Significant fuel is consumed in merely trying to locate a parking spot. This excess traffic attributable to locating a parking spot translates into excess fuel consumption, wasted time, traffic congestion, and emissions pollution.
Circling streets around a destination in search of nearby parking wastes precious time and creates frustration. The frustration is even greater when returning to a parking space to discover that a car has been towed because of a violation such as the street cleaning schedule. Finally, ambiguous or missing signage leads many drivers to simply pay parking tickets even when they were, in fact, legally parked. Parking complaints are commonplace among people living in or visiting cities.
Commercial drivers also experience difficulties with parking. Delivery services, cleaning companies, contractors and other local businesses often view parking tickets as just a cost of business. In the US alone, over six million mobile resource management (MRM) systems have been deployed, with the number expected to double in the next five years.
There are a number of local providers in certain markets that provide information regarding street parking and public garages. There are several providers that provide auctions for parking spots (which is difficult due to the short time constraints of finding parking). A few providers use outdoor sensors to determine whether a parking spot is vacant.
Existing efforts at addressing the problem of parking spot information fall short in several aspects. Collecting and maintaining current parking sign data on a global scale has not successfully been accomplished. The only way to collect the parking sign data is to travel down every street of every city to capture the parking sign data. This is because cities do not actually possess the parking sign data in enough detail regarding location of parking meters, valet parking signs, loading zones, etc.; however, knowing exactly where these parking zones exist is critical information to the end-user.
What is needed is a system for capturing the parking sign data directly at the point of application—the street level. This is because there exists no accurate, central repository of parking rule information for each street and city. For the most part, cities do not possess or maintain this information in any reliable way, and assembling such a database based on an intentional planned methodology—in other words, keeping track of each sign placed and where and when it was emplaced—is simply impractical, especially in an enormous municipality where construction, vandalism, weather storms, accidents, etc., make any such effort a rapidly moving target.
Indeed, parking enforcement is performed according to what the posted parking rules are for a given alleged violation—no database can be checked; rather, the test is what was posted at the time and place of the alleged violation. Therefore, directly capturing the rules and tagging their locations is the only way to address this problem.
Additionally, there simply exists no central database of available parking spots. The only way to create such a database is to manually assemble it through actual data collection, and then continuously maintain it. This is because vehicles are continuously occupying and vacating spots all over with no central repository of tracking this data. Some smartphone parking applications exist, but nearly all of them focus on either garage parking locations or parking meter timers. None provide comprehensive information and advice about street parking in combination with recommendations on the optimal parking options.
Some companies provide parking information online, ranging from simple attempted directories of parking garages to attempted databases of on-street and off-street parking in a handful of cities. Existing online parking information systems fall short because their data is limited, stale, and does not account for dynamic changes in available parking spots, nor catalog the parking rules, nor provide location based parking rule information in real time, among other shortcomings.
Some companies attempt to deliver parking information to GPS units. Generally, these vendors focus on commercial parking garages rather than on-street parking.
Some companies provide parking applications for handheld mobile devices. These generally attempt to address only one part of the parking problem, such as meter timers, commercial parking garages, etc.
Further, all existing parking information technologies provide data that is stale, old, and frequently out-of-date. Such solutions do not provide a means for continuously updating and refreshing parking data according to a useful and effective frequency, i.e., continuously. Existing parking spot information solutions are limited geographically due to collection methodology. Further, there is no commercial user solution. There is no product or service that provides a comprehensive parking spot solution. Therefore, there is a need for a distributed, continuous parking data collection solution that can rapidly and efficiently collect and aggregate parking data. There is also a need for a convenient, timely, and accurate parking information distribution solution across multiple access points and mobile and integrated delivery means. Therefore, a system is needed that provides this data and also over various channels—online, through GPS systems, and via smartphones. There is also a further need for a contemporary, dynamically adaptive database of parking rule information for urban, suburban, and rural areas worldwide. There is also a need for parking solutions for the unique needs of commercial users.
It is against this background that various embodiments of the present invention were developed.

Parking information collection system and method


A system and method are provided for displaying video surveillance fields of view limitations. The system and method perform video surveillance of a given area and then geo-locate any obstacles within the area, including measuring their overall size and shape. The system and method map the size, location and shape of the objects into a database and then identify where there are video surveillance coverage gaps from each vantage point where video surveillance is being performed on the area. The system and method then determine where there are overlapping locations of blocked video surveillance (i.e., locations that are “invisible” to video surveillance). The system and method create a simulated image of the area from an orientation above the area which indentifies locations within the area that may not be seen by video surveillance from any of the vantage points where video surveillance is being performed.

One of the drawbacks with using video surveillance to monitor a location is that it can be difficult to determine where there are coverage gaps in the surveillance. This difficulty is exacerbated when reconciling surveillance coverage from multiple viewpoints (i.e., when several video cameras are used to cover an area from multiple locations).
The video cameras in a typical security system are usually placed such that all of the scenes which are viewed by the cameras overlap to some extent. However, there are often areas where one or more obstacles block a portion of the field of view of one camera and the remaining cameras are unable to provide adequate surveillance of the blocked area. These gaps in the video surveillance may not be readily apparent when camera data is viewed by security personnel.
One method that is used to minimize the size and number of blocked video coverage areas is to place surveillance cameras at optimal locations such that the effect of obstacles is minimized. The placement of cameras in these desired positions can often be problematic because there may be no infrastructure or supporting structures that exist at these locations making it difficult and/or expensive to adequately mount the video cameras. In addition, even if special arrangements are made to place cameras at these locations, there are typically unforeseen areas of blocked coverage.
Another of the current methods that is used to minimize the size and number of blocked video coverage areas is to place multiple cameras in an area and use rotating field of views for each of the cameras. One of the shortcomings associated with using rotating field of views for each of the cameras is that events in the field of view of the camera can transpire when the camera is not pointing where the events occur. Security personal monitoring multiple screens, and particularly screens with rotating fields of view, frequently fail to detect activity on those screens. In addition, even when rotating field of views are used for each of the cameras, there are typically unforeseen areas of blocked coverage.

System and method for displaying video surveillance fields of view limitations


The optimization of two technologies (CMOS and CCD) wherein a pinned photodiode is integrated into the image sensing element of an active pixel sensor. Pinned photodiodes are fabricated with CCD process steps into the active pixel architecture. Charge integrated within the active pixel pinned photodiode is transferred into the charge sensing node by a transfer gate. The floating diffusion is coupled CMOS circuitry that can provide the addressing capabilities of individual pixels. Alternatively, a buried channel photocapacitor can be used in place of the pinned photodiode.

Active pixel sensors refer to electronic image sensors within active devices, such as transistors, that are associated with each pixel. An active pixel sensor has the advantage of being able to easily incorporate signal processing and decision making circuitry on the same chip. Conventional active pixel sensors typically employ polysilicon photocapacitors or photodiodes as the active image sensing elements. These conventional active pixel sensors suffer from poor blue color response, high dark current and image lag.
Pinned photodiodes have been employed within charge coupled devices and have shown advantages in the area of color response for blue light, dark current density and image lag. For this reason pinned photodiodes are normally associated with high performance image sensors. Heretofore, pinned photodiodes have typically been employed as photoelements for charge coupled devices. An example of such a use of a pinned photodiode can be seen in THE PINNED PHOTODIODE FOR AN INTERLINE-TRANSFER CCD IMAGE SENSOR, by Burkey et al., IEDM 84, 1984, pages 28-31. However, charge coupled device technology lacks in the amount and type of circuitry elements that can be placed on a device.
From the foregoing discussion it should be apparent that there remains a need within the art of semiconductors for a pinned photodiode employed within a semiconductor technology that can provide advanced circuitry elements.

Active pixel sensor integrated with a pinned photodiode


An otoplastic for production of behind-the-ear hearing aids. The hearing aid includes a preferably flexible signal conductor, such as an acoustic tube positioned in the auditory canal, whereby the otoplastic matches the individual anatomy of the patient and its locating part is in the form of a clip, which, at least partly arched, follows the outer edge of the cavum conchae. A branch following the edge of the cavum conchae transforms, above the antitragus, into a bent crosspiece traversing the cavum conchae and extending in the direction of the porous acusticus externus. The end section of the crosspiece lies in the upper section of the auditory canal and widens to accept the signal conductor (42).

1. Field of the Invention
The invention relates to an ear fitting piece, i.e. an earpiece for behind-the-ear (BTE) devices in the field of hearing acoustics.
2. Discussion of the Related Art
BTE devices are also frequently referred to as BTE secret ears (SE). In this connection, a relatively short sound tube is used, making it possible to noticeably reduce friction losses, particularly in the high-frequency sonic range.
However, the sound tube must be precisely positioned in or on the auditory canal, and for this purpose, an ear fitting piece, i.e. an earpiece is regularly used, which is individually adapted to the human anatomy of the ear of the patient to be treated. Up to the present date, various forms of earpieces have become common, with some, namely the so-called "open" BTE earpieces, being particularly preferred, in order to have the minimum possible effect on the auditory canal, caused by partially covering or closing it off in some regions, with a "foreign body." These "open" BTE devices have the further advantage that the hearing capacity that still exists is impaired as little as possible in terms of its natural effect.
Known relevant earpieces are known as "SE shell shape, SE clip shape, or SE claw shape" (See Ulrich Voogdt: Otoplastik—Die individually Otoplastik zur Horgerate-Versorgung . . . [Earpieces—Individual earpieces for hearing aids . . . ], Volume 2 of the scientific series "Akademie für Hörgeräte-Akustik" [Academy for hearing device acoustics], Median-Verlag of Killisch-Horn GmbH, 1993). A modified version of these common earpieces is the "open" solution. However, all of the variants have the common feature that it is frequently not possible to make the hearing correction as natural as possible.
It is therefore the task of the invention to create an earpiece for an "open" BTE hearing aids, for CI components (cochlear implant microphone systems and CI BTE processors), or BTE tinnitus systems, which are characterized not only by a minimal feeling of wearing a foreign body, and good wearing comfort, but primarily in that natural sound processing in the human ear can be utilized with as little distortion as possible, in order to ensure a maximum degree of hearing correction and sense of natural hearing.

Otoplasty for behind-the-ear (BTE) hearing aids


To produce pulses in a cyclically repetitive mode while modifying the production frequency, a counter looped on itself is used. The outputs of this counter are connected to the address inputs of a memory. The signals read in the memory represent pulses to be produced. When it is sought to increase the period of reading the totality of the memory gradually, some of the words of this memory are read for a greater period of time. In the invention, words are chosen for which this addressing will be maintained by comparing the reverse of the reading address with a given value and by deciding, as a function of the result of this comparison, whether the word read at this address must be read for a longer duration or not. It is shown that this circuit is very easy to make and requires but few components. The circuit made can be used particularly in the field of the control of three-phase synchronous motors.

1. Field of the Invention
The present invention relates generally to pulse production circuits and, more particularly, to a circuit for producing width-modulated pulses. The invention can be used especially in the field of electrical motor control and, more particularly, for the control of three-phase asynchronous or synchronous controllable motors.
2. Discussion of the Related Art
In industry, there are many uses for three-phase synchronous or asynchronous motors. For example, such motors are commonly used in pump motors. In domestic applications, household appliances are already beginning to be configured to include three-phase motors. Indeed, these motors have the advantage of not requiring switch-over devices and are therefore not subject to the wearing out of brushes experienced in conventional motors.
However, in domestic applications, as well as sometimes in industry, three-phase motors cannot be used because of the unavailability of a mains electrical current in three-phase form. It has therefore been necessary to devise electronic circuits to produce three-phase electrical current from the rectified single-phase AC mains supply. FIG. 1 is a schematic block diagram of an exemplary circuit that performs such a conversion.
A single-phase AC mains supply 1 lets current into a transformer 2 connected to a diode-based full-wave rectifier bridge 3. The rectifier bridge 3 is parallel connected to the terminals of a capacitive circuit 4 comprising, in the illustrated example, two capacitors 5 and 6 and giving a high DC voltage. In one example, this high DC voltage is in the range of 400 volts. A midpoint 7 of the transformer 2 is connected to a midpoint 8 of the capacitors 5 and 6. If it is sought to economize on one of the capacitors 5 or 6, the midpoint 8 no longer exists and, of course, it is no longer connected to the midpoint 7. The midpoint 7 is furthermore connected to an electrical ground 9 of the system.
The capacitors 5 and 6 are series-connected between a high-voltage node 10 and a low-voltage node 11. In the above example, the node 10 is taken to +200 volts with respect to the ground 9 while the node 11 is at -200 volts.
A three-phase motor 12 has three primary windings 13, 14, 15 series-connected with one another by means of connection terminals 16, 17, 18. The terminals 16, 17, 18 are supplied electrically by a switch-over circuit 19. The circuit 19 is itself controlled by a processing circuit 20. The processing circuit 20, in one example, may be supplied from the rectifier circuit 3 in such a way that this set forms a compact device that can easily be positioned against the motor 12. The motor 12 has a rotor 21 with corresponding coils to rotationally drive mechanical loads.
The circuit 19 schematically has three cells that are parallel-connected to one another between the terminals 10 and 11. Each cell has two series-connected transistors that are connected to each other by a midpoint. The midpoints, respectively 22, 23, 24 of each cell, are connected to the terminals 16, 17, 18. The six transistors of the three cells receive, at their gates, control signals produced by the circuit 20. These control signals are typically pulse-width modulated signals.
FIGS. 2a to 2c give a view, in an example, of particular features of production and use of pulse-width modulated control signals. FIG. 2a shows the principle of this production. A first signal generator is used to produce a saw-toothed signal A. Another signal generator is also used to produce a signal B. In the example, the signal B is a sinusoidal signal. It is ensured that the peak-to-peak amplitude of the signals A and B are the same. The frequencies of the signals A and B are substantially different. In one example, the frequency of the signal A will be in the range of 10 KHz while the frequency of the signal B will be in the range of 200 Hz.
In a comparison circuit 27 (FIG. 1), the value of the signal A is permanently compared with the value of the signal B and a pulse C is provided (FIG. 2a) when the signal A is greater than the signal B. It can clearly be seen in FIG. 2a that the pulses C produced in this way are short-duration signals when the signal B is at its maximum and are long-duration signals when signal B is at its minimum. In this way, a modulation of pulses is produced, referred to as a width modulation.
The circuit 20 includes three circuits of this type, only one of which is illustrated to simplify the Figure. Each of these circuits is therefore capable of producing a signal such as the one shown in FIG. 2a. The circuit 20 also has inverter circuits to produce complementary signals of the three signals thus produced. The six resultant signals are applied to the three cells of the circuit 19. Each signal is applied to a transistor of a cell while the complementary signal of that signal is applied to the other transistor of the same cell. It is known that this mode of action makes it possible, by phase-shifting the signals applied to the different cells with respect to one another, to provide a pulsed supply to the terminals 16 to 18 AC voltages of +200 volts to -200 volts. The phase shift leads to the three-phase supply of the motor 12.
The production of the signals A and B in the circuit 20 is generally done by cyclical readings of tables 25, 26 comprising sets of values that are stored in memory. There may be several sets of such tables. At each cycle period of a clock whose pace is set at a frequency f1 or f0 respectively, a new value of the table is read at an address of a word. The address increases gradually from one cycle period to another. When the reading of a last word of the table is arrived at, a loop is set up with the first word and so on and so forth. In one example, the table 25 used to produce the signal B will have 48 values and the table 26 used to produce the saw-toothed signal A will have 256 values.
In practice, rather than returning to an initial reading address when the final reading address of the table has been reached, it is possible to continue the reading by making the address values decrease so that the table is read backwards until the initial value. Then the reading is started again in the original direction and so on and so forth. Consequently, when the signals are symmetrical, the tables may take up less space.
In the example, the frequency f0 of the reading of the table producing the signal A is in the range of 10 MHz. As a result of this, the frequency of the signal A is also in the range of 10 KHz. Indeed, it is necessary to read 256 values upwards and 256 values downwards, giving about 500 values per period of the signal A. In order that the distribution of the pulses of the signal A during a period of the signal B may have sufficient resolution, the number of the signal A pulses is preferably in the range of 50:48 (which is a multiple of two). This naturally leads to an upper limit frequency for the signal B equal to 200 Hz (10,000/50=200). In view of the fact that it is sought to create signals which are phase shifted by 120.degree., the table 25 is read at each time with two shifts for the reading, each time, of three values to be compared with the value read in the table 26.
FIG. 2b shows the same elements as FIG. 2a, the only difference being that in FIG. 2b the frequency of the signal B is greater than that of FIG. 2a. The mode of comparison of the signals A and B in the comparator 27 is shown on the bottom of FIG. 2b.
FIG. 2c shows what could happen if the instant of the change of state of the signal B is not synchronized with the instants of the changes of state of the signal A. FIG. 2c gives an enlarged view of the part of FIG. 2a surrounded by dashes. In FIG. 2c, the growth of the signal A is faster than the growth of the signal B owing to the difference in frequency referred to here above. Rather than having only one instant when the signal A becomes greater than the signal B, in certain cases, signal B may, for a very short duration in the range of one or two cycle periods at the frequency f0, be smaller than the signal A. After this period, signal B may then be greater during one more cycle period before again becoming smaller than signal A for a longer duration. The presence of stray pulses such as a pulse 28 shown in FIG. 2c has led those skilled in the art to synchronize the signals with the frequencies f0 and f1 for controlling the reading of the tables 25 and 26.
For three-phase synchronous motors, the only way to change the speed of rotation of the motor is to modify the frequency of the signal B. However, to meet the conditions of synchronization dictated by the disorderly conditions described above and illustrated in FIG. 2c, it has been accepted as a necessity that the signals must be synchronized with the frequency f0 and f1 that enable the production of the signals A and B. In practice, this leads to a situation where f1 is a sub-multiple of f0. This leads to a situation where the modification of the frequency f1 can progress only by operations of division by integers. In the illustrated example, it is thus possible to make f1 vary by 200 Hz to 100 Hz and then 66 Hz and then 50 Hz, etc. However, these frequency jumps are far too great if it is sought to regulate the speed of the motors more precisely. Indeed, if it is arranged that the signal at 200 Hz leads to a motor speed of the order of 1,000 rpm, then the passage to 100 Hz will lead to a modification of this speed into a speed of 500 rpm, without any possibility of obtaining intermediate speeds at 825 rpm, 790 rpm, etc.
One conventional approach has been to duplicate the reading of certain words in the memory table that enables the production of the signal B. By reading the same word twice, for example, the period of the signal B lasts one more cycle period, namely 49 cycle periods instead of 48 cycle periods. This period is modified by about 2%, which is an acceptable adjustment. The problem, however, is to choose those memory words of the memory that must be read several times. Indeed, if the operation is limited to the reading of the first words of the tables several times (namely those words whose address is close to the beginning of the table), a distortion of the equivalent alternating signal produced for the signal B is prompted. This distortion leads to advances and delays of phases of the supply of the windings 13, 14, 15 which are ultimately very poorly supported by the motor 12. This in turn leads to an irregular wearing-out of its rotation bearings. Furthermore, these distortions reverberate as electrical parasites are reinjected into the network 1.
There are known ways, however, of distributing the addresses of the words to be read several times among the possible addresses of the words of the memory 25. However, this distribution implies the use of a microprocessor and of a recorded microprogram whose power, and hence cost, have no relation to the expected cost of the motor 12 and its electronic control circuit. Indeed, for motors for domestic use, the cost of the motor coil and control circuit should be minimal. It is therefore impossible to control a motor of this kind with a microprocessor-based circuit whose cost is significant.


A chemical mechanical polishing apparatus has a platen with a cavity with an opening to the top surface of the platen. A polishing pad is located at an upper surface of the platen. A flexible membrane is positioned in the cavity to define a first and a second volume. A pressure source is connected to the second volume to flex the membrane, and a lifting member is positioned in the first volume so that flexing of the membrane extends the lifting member through the opening to lift the substrate off the polishing pad. Alternately, de-ionized water may be forced through a passage in the platen and an aperture in the polishing pad to lift the substrate.

The present invention relates generally to chemical mechanical polishing of substrates, and more particularly to a method and apparatus for removing a substrate from the surface of a polishing pad in a chemical mechanical polishing system.
Integrated circuits are typically formed on substrates, particularly silicon wafers, by the sequential deposition of conductive, semiconductive or insulative layers. After each layer is deposited, the layer is etched to create circuitry features. As a series of layers are sequentially deposited and etched, the outer or uppermost surface of the substrate, i.e., the exposed surface of the substrate, becomes increasingly non-planar. This non-planar outer surface presents a problem for the integrated circuit manufacturer. If the outer surface of the substrate is non-planar, then a photo-resist layer placed thereon is also non-planar. A photo-resist layer is typically patterned by a photolithographic apparatus that focuses a light image onto the photoresist. If the outer surface of the substrate is sufficiently non-planar, the maximum height difference between the peaks and valleys of the outer surface may exceed the depth of focus of the imaging apparatus. Then it will be impossible to properly focus the light image onto the entire outer surface. Therefore, there is a need to periodically planarize the substrate surface to provide a flat surface for photolithography.
Chemical mechanical polishing (CMP) is one accepted method of planarization. This planarization method typically requires that the substrate be mounted on a carrier or polishing head. The exposed surface of the substrate is then placed against a rotating polishing pad. The carrier head provides a controllable load, i.e., pressure, on the substrate to push it against the polishing pad. In addition, the carrier head may rotate to provide additional motion between the substrate and polishing surface.
A polishing slurry, including an abrasive and at least one chemically-reactive agent, may be supplied to the polishing pad to provide an abrasive chemical solution at the interface between the pad and the substrate. CMP is a fairly complex process, and it differs from simple wet sanding. In a CMP process, the reactive agent in the slurry reacts with the outer surface of the substrate to form reactive sites. The interaction of the polishing pad and abrasive particles with the reactive sites on the substrate results in polishing.
An effective CMP process has a high polishing rate and generates a substrate surface which is finished (lacks small-scale roughness) and flat (lacks large-scale topography). The polishing rate, finish and flatness are determined by the pad and slurry combination, the relative speed between the substrate and pad, and the force pressing the substrate against the pad. The polishing rate sets the time needed to polish a layer. Because inadequate flatness and finish can create defective substrates, the selection of a polishing pad and slurry combination is usually dictated by the required finish and flatness. Given these constraints, the polishing time needed to achieve the required finish and flatness sets the maximum throughput of the CMP apparatus.
One problem encountered in the CMP process is the difficulty in removing the substrate from the polishing pad surface once polishing has been completed. As mentioned above, a thin layer of slurry is supplied to the surface of the polishing pad. When the substrate is placed in contact with the polishing pad, the surface tension of the slurry generates an adhesive force which binds the substrate to the polishing pad. The adhesive force makes it difficult to remove the substrate from the pad at the end of the polishing operation.
Typically, the carrier head is used to remove the substrate from the polishing pad. The substrate is vacuum-chucked to the underside of the carrier head. When the carrier head is retracted from the polishing pad, the substrate is lifted off of the polishing pad. However, if the surface tension holding the substrate on the polishing pad is greater than the force holding the substrate on the carrier head, then when the carrier head retracts, the substrate will remain on the polishing pad. This may cause the substrate to fracture or chip. In addition, failure to remove the substrate can cause a machine fault requiring manual intervention by the integrated circuit manufacturer. This requires shutting down the polishing apparatus, decreasing throughput. To achieve reliable operation from the polishing apparatus, the substrate removal operation should be essentially flawless.
Several techniques have been employed to reduce the surface tension between the substrate to the polishing pad. One such technique is to slide the substrate horizontally off of the polishing pad to break the surface tension before vertically retracting the carrier head. This technique may, however, damage the substrate as the substrate may detach from the carrier head as it slides off the edge of the polishing pad. The mechanical configuration of the CMP apparatus may also prohibit this technique.
Another technique is to treat the surface of the polishing pad to reduce the surface tension. However, this technique is not always successful, and the alteration of the pad surface may adversely affect the finish and flatness of the substrate, and reduce the polishing rate.
In view of the foregoing, there is a need for a chemical mechanical polishing apparatus which reliably removes the substrate from the polishing pad surface.

Method and apparatus for removing a substrate from a polishing pad in a chemical mechanical polishing system


The present invention relates to a terminal and a base station, and to a receiving and transmitting method to be performed at the terminal and the base station, respectively. In particular, the present invention relates to power consumption reduction by providing two operation bandwidths for a terminal, one being a cell-bandwidth, a bandwidth in which the cell may operate and the other one is a bandwidth, lower than the cell-bandwidth and called power-saving bandwidth. The terminal may perform the initial cell search including reception of the system information in the cell bandwidth and perform other reception/transmission/monitoring operation(s) in the power-saving bandwidth. Accordingly, a low-cost terminal implementation is enabled, which is particularly advantageous for the machine communication terminals.

Third generation (3G) mobile systems, such as, for instance, universal mobile telecommunication systems (UMTS) standardized within the third generation partnership project (3GPP) have been based on wideband code division multiple access (WCDMA) radio access technology. Today, 3G systems are being deployed on a broad scale all around the world. After enhancing this technology by introducing high-speed downlink packet access (HSDPA) and an enhanced uplink, also referred to as high-speed uplink packet access (HSUPA), the next major step in evolution of the UMTS standard has brought the combination of orthogonal frequency division multiplexing (OFDM) for the downlink and single carrier frequency division multiplexing access (SC-FDMA) for the uplink. This system has been named long term evolution (LTE) since it has been intended to cope with future technology evolutions.
The LTE system represents efficient packet based radio access and radio access networks that provide full IP-based functionalities with low latency and low cost. The detailed system requirements are given in 3GPP TR 25.913, "Requirements for evolved UTRA (E-UTRA) and evolved UTRAN (E-UTRAN)," v8.0.0, January 2009, (available at http://www.3gpp.org/ and incorporated herein by reference). The Downlink will support data modulation schemes QPSK, 16QAM, and 64QAM and the Uplink will support BPSK, QPSK, 8PSK and 16QAM.
LTE's network access is to be extremely flexible, using a number of defined channel bandwidths between 1.25 and 20 MHz, contrasted with UMTS terrestrial radio access (UTRA) fixed 5 MHz channels. Spectral efficiency is increased by up to four-fold compared with UTRA, and improvements in architecture and signaling reduce round-trip latency. Multiple Input/Multiple Output (MIMO) antenna technology should enable 10 times as many users per cell as 3GPP's original WCDMA radio access technology. To suit as many frequency band allocation arrangements as possible, both paired (frequency division duplex FDD) and unpaired (time division duplex TDD) band operation is supported. LTE can co-exist with earlier 3GPP radio technologies, even in adjacent channels, and calls can be handed over to and from all 3GPP's previous radio access technologies.
FIG. 1 illustrates structure of a component carrier in LTE Release 8. The downlink component carrier of the 3GPP LTE Release 8 is sub-divided in the time-frequency domain in so-called sub-frames 100, each of which is divided into two downlink slots, one of which is shown in FIG. 1 as 120 corresponding to a time period Tslot. The first downlink slot comprises a control channel region within the first OFDM symbol(s). Each sub-frame consists of a given number of OFDM symbols in the time domain, each OFDM symbol spanning over the entire bandwidth of the component carrier.
In particular, the smallest unit of resources that can be assigned by a scheduler is a resource block also called physical resource block (PRB). A PRB 130 is defined as NsymbDL consecutive OFDM symbols in the time domain and NscRB consecutive sub-carriers in the frequency domain. In practice, the downlink resources are assigned in resource block pairs. A resource block pair consists of two resource blocks. It spans NscRB consecutive sub-carriers in the frequency domain and the entire 2·NsymbDL modulation symbols of the sub-frame in the time domain. NsymbDL may be either 6 or 7 resulting in either 12 or 14 OFDM symbols in total. Consequently, a physical resource block 130 consists of NsymbDL×NscRB resource elements corresponding to one slot in the time domain and 180 kHz in the frequency domain (further details on the downlink resource grid can be found, for example, in 3GPP TS 36.211, "Evolved universal terrestrial radio access (E-UTRA); physical channels and modulations (Release 8)", version 8.9.0, December 2009, Section 6.2, freely available at www.3gpp.org. which is incorporated herein by reference). While it can happen that some resource elements within a resource block or resource block pair are not used even though it has been scheduled, for simplicity of the used terminology still the whole resource block or resource block pair is assigned. Examples for resource elements that are actually not assigned by a scheduler include reference signals, broadcast signals, synchronization signals, and resource elements used for various control signal or channel transmissions, as also illustrated in FIG. 3.
The number of physical resource blocks NRBDL in downlink depends on the downlink transmission bandwidth configured in the cell and is at present defined in LTE as being from the interval of 6 to 110 (P)RBs. It is common practice in LTE to denote the bandwidth either in units of Hz (e.g. 10 MHz) or in units of resource blocks, for the downlink case the cell bandwidth can equivalently expressed as 10 MHz or NRBDL=50 RB.
Before a UE can access an LTE cell, it performs a cell search procedure. This procedure enables the UE to determine the time and frequency parameters which are necessary to demodulate the downlink and to transmit uplink signals with the correct timing.
The first phase of the cell search includes an initial synchronization. Accordingly, the UE detects an LTE cell and decodes all the information required for registering to the detected cell. The procedure makes use of two physical signals which are broadcast in the central 62 subcarriers of each cell, the primary and secondary synchronization signals (PSS and SSS, respectively). These signals enable time and frequency synchronization. Their successful detection provides a UE with the physical cell-ID, cyclic prefix length, and information as to whether FDD or TDD is employed. In particular, in LTE, when a terminal is switched on, it detects the primary synchronization signal which for FDD is transmitted in the last OFDM symbol of the first time slot of the first subframe (subframe 0) in a radio frame (for TDD the location is slightly different, but still well-determined). This enables the terminal to acquire the slot boundary independently of the chosen cyclic prefix selected for the cell. After the mobile terminal has found the 5 millisecond timing (slot boundaries), the secondary synchronization signal is looked for. Both the PSS and SSS are transmitted on 62 of the 72 reserved subcarriers around the DC carrier. In the next step, the UE shall detect a physical broadcast channel (PBCH) which, similarly to the PSS and SSS is mapped only to the central 72 subcarriers of a cell. The PBCH contains the Master Information Block (MIB) including information about the system resources. In LTE up to Release 10, MIB had a length of 24 bits (14 bits of which are currently used and 10 bits are spare). MIB includes the following parameters:                Downlink system bandwidth,        Physical HARQ Indicator Channel (PHICH) structure, and        8 most significant bits of the System Frame Number (SFN)
After successful detection of the master information block (MIB) which includes a limited number of the most frequently transmitted parameters essential for initial access to the cell, the terminal activates the system bandwidth, meaning that it has to be able to receive and detect signals across the indicated downlink system bandwidth. After acquiring the downlink system bandwidth, the UE may proceed with receiving further required system information on the so-called System Information Blocks (SIB). In LTE Release 10, SIB Type 1 to SIB Type 13 are defined, carrying different information elements required for certain operations. For instance, in case of FDD the SIB Type 2 (SIB2) includes the UL carrier frequency and the UL bandwidth.
The various SIBs are transmitted on a Physical Downlink Shared Channel (PDSCH) and thus (cf. details to PDSCH and PDCCH below) the respective allocations are assigned by a Physical Downlink Control Channel (PDCCH). Before the terminal (UE) is able to correctly detect such (or any) PDCCH, it needs to know the downlink system bandwidth from the MIB.
The data are mapped onto physical resource blocks by means of pairs of virtual resource blocks. A pair of virtual resource blocks is mapped onto a pair of physical resource blocks. The following two types of virtual resource blocks are defined according to their mapping on the physical resource blocks in LTE downlink:                Localised Virtual Resource Block (LVRB)        Distributed Virtual Resource Block (DVRB)
In the localised transmission mode using the localised VRBs, the eNB has full control which and how many resource blocks are used, and should use this control usually to pick resource blocks that result in a large spectral efficiency. In most mobile communication systems, this results in adjacent physical resource blocks or multiple clusters of adjacent physical resource blocks for the transmission to a single user equipment, because the radio channel is coherent in the frequency domain, implying that if one physical resource block offers a large spectral efficiency, then it is very likely that an adjacent physical resource block offers a similarly large spectral efficiency. In the distributed transmission mode using the distributed VRBs, the physical resource blocks carrying data for the same UE are distributed across the frequency band in order to hit at least some physical resource blocks that offer a sufficiently large spectral efficiency, thereby obtaining frequency diversity. It may be noted that data that is targeting multiple receivers at the same time is usually mapped in the distributed fashion, as the probability that all receivers provide a sufficiently large spectral efficiency on the same localized resource blocks generally decreases with an increasing number of receivers.
In 3GPP LTE Release 8 there is only one component carrier in uplink and downlink. Within one DL subframe, the first 1 to 4 OFDM symbols are used for downlink control channel and downlink signal transmission (LTE control region). Downlink control signaling is basically carried by the following three physical channels:                Physical control format indicator channel (PCFICH) for indicating the number of OFDM symbols used for control signaling in a sub-frame (the size of the control channel region). For NRBDL>10, the PCFICH carries the control format indicator (CFI), which indicates a length of either 1, 2, or 3 OFDM symbols, while for NRbDL≦10, the CFI indicates a length of either 2, 3, or 4 OFDM symbols.        Physical hybrid ARQ indicator channel (PHICH) for carrying the downlink ACK/NACK associated with uplink data transmission. The duration of PHICH, the number of OFDM symbols used for PHICH, is configured by higher layer. For normal PHICH, the duration is 1 OFDM symbol. For extended PHICH, the duration is 2 to 3 OFDM symbols. The duration of PHICH puts a lower limit on the size of the DL control region determined from the PCFICH value.        Cell-specific reference signals (CRS) are transmitted on one or several of antenna ports 0 to 3. In a normal subframe, CRS is distributed within the subframe across the whole bandwidth. In an MBSFN subframe, CRS shall only be transmitted in the non-MBSFN region, DL control region, of the MBSFN subframe.        Physical downlink control channel (PDCCH) for carrying downlink scheduling assignments and uplink scheduling assignments.
The PCFICH is sent from a known position that depends on the downlink system bandwidth value within the control signaling region of a downlink sub-frame using a known pre-defined modulation and coding scheme. The user equipment decodes the PCFICH in order to obtain information about a size of the control signaling region in a sub-frame, for instance, the number of OFDM symbols. If the user equipment (UE) is unable to decode the PCFICH or if it obtains an erroneous PCFICH value, it will not be able to correctly decode the L1/L2 control signaling (PDCCH) comprised in the control signaling region, which may result in losing all resource assignments contained therein.
The PDCCH carries control information, such as, for instance, scheduling grants for allocating resources for downlink or uplink data transmission. A physical control channel is transmitted on an aggregation of one or several consecutive control channel elements (CCEs). Each CCE corresponds to a set of resource elements grouped to so-called resource element groups (REG). A control channel element typically corresponds to 9 resource element groups. A scheduling grant on PDCCH is defined based on control channel elements (CCE). Resource element groups are used for defining the mapping of control channels to resource elements. Each REG consists of four consecutive resource elements excluding reference signals within the same OFDM symbol. REGs exist in the first one to four OFDM symbols within one sub-frame. The PDCCH for the user equipment is transmitted within the OFDM symbols according to the CFI value that is usually indicated by PCFICH in the sub-frame.
Another logical unit used in mapping of data onto physical resources in 3GPP LTE Release 8 (and later releases) is a resource block group (RBG). A resource block group is a set of consecutive (in frequency) physical resource blocks. The concept of RBG provides a possibility of addressing particular RBGs for the purpose of indicating a position of resources allocated for a receiving node (e.g. UE), in order to minimize the overhead for such an indication, thereby decreasing the control overhead to data ratio for a transmission. The size of RBG is currently specified to be 1, 2, 3, or 4 resource blocks, depending on the system bandwidth, in particular, on NRBDL. Further details of RBG mapping for PDSCH in LTE Release 8 may be found in 3GPP TS 36.213 "Evolved Universal terrestrial Radio Access (E-UTRA); Physical layer procedures", v8.8.0, September 2009, Section 126.96.36.199, freely available at www.3gpp.org and incorporated herein by reference.
The UE shall monitor a set of PDCCH candidates on the serving cell for control information in every non-DRX subframe, where monitoring implies attempting to decode each of the PDCCHs in the set according to all the monitored downlink control information (DCI) formats. A DCI represents the required L1/L2 control information, for which more information can be found in 3GPP TS 36.212, "Evolved Universal terrestrial Radio Access (E-UTRA); Multiplexing and Channel Coding", ver. 8.8.0, December 2009, Section 5.3.3, freely available at www.3gpp.org and incorporated herein by reference. The set of PDCCH candidates to monitor are defined in terms of search spaces.
UE monitors two types of search space: UE specific search space and common search space. Both UE specific search space and common search space consist of a generally different number of candidates for different aggregation levels defined by aggregating generally different CCEs.
PDCCH for system information is transmitted in common search space, so that all the UEs can receive system information by monitoring common search space.
Physical downlink shared channel (PDSCH) is used to transport user data. PDSCH is mapped to the remaining OFDM symbols within one sub-frame after PDCCH (with the possible exception of a limited number of resource elements, as indicated previously). The PDSCH resources allocated for one UE are in the units of resource block for each sub-frame. In LTE, DL data region starts after the DL control region within one subframe. In DL data region, CRS, PDSCH and—if configured—corresponding UE-specific or demodulation reference signals (DM-RS) are transmitted.
FIG. 3 shows an exemplary mapping of PDCCH 331-333 and PDSCH 350 within a sub-frame. The first three (in this example) OFDM symbols form a control channel region 390 (PDCCH region) and are used for L1/L2 control signaling. The remaining eleven OFDM symbols form data channel region (PDSCH region, in FIG. 3 only first 4 are shown, belonging to the first slot) and are used for transport of physical layer data (which may be control information of higher layers or user data). Within a resource block pairs of all sub-frames, cell-specific reference signals, so-called common reference signals 340 (CRS), are transmitted on one or several antenna ports 0 to 3.
Moreover, the sub-frame also includes UE-specific reference signals, so-called demodulation reference signals 380 (DM-RS) used by the user equipment for demodulating the PDSCH. The DM-RS are only transmitted within the resource blocks in which the PDSCH is allocated for a certain user equipment. In order to support downlink multiple input/multiple output (MIMO) with DM-RS, up to eight DM-RS layers are defined meaning that at most, MIMO of eight layers is supported in LTE Release 10. FIG. 4 shows only the case of 4 simultaneous employed DM-RS layers.
In September 2009 the 3GPP Partners made a formal submission to the ITU proposing that LTE Release 10 & beyond (LTE-Advanced) be evaluated as a candidate for IMT-Advanced. The ITU has coined the term IMT Advanced to identify mobile systems whose capabilities go beyond those of IMT 2000. In order to meet this new challenge, 3GPPs Organizational Partners have agreed to widen 3GPP's scope to include systems beyond 3G. In 3GPP, further advancements for E-UTRA (LTE-Advanced) should be studied in accordance with: 3GPP operator requirements for the evolution of E-UTRA and the need to meet/exceed the IMT-Advanced capabilities. The expectancy is that Advanced E-UTRA should provide substantially higher performance compared to what is expected to be the IMT-Advanced requirements in ITU-R.
LTE-A Rel.10 work started from March 2010 and was already stable in June 2011. The major features included in LTE-A Rel.10 included Carrier Aggregation, enhanced DL MIMO, UL MIMO, relay and etc.
According to 3GPP TS 36.300 v.10.2.0, "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description", December 2010, Section 5.5, in Carrier Aggregation (CA), two or more Component Carriers (CCs) are aggregated in order to support wider transmission bandwidths up to a total of 100 MHz. A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities. It is possible to configure a UE to aggregate a different number of CCs in the UL and the DL.                The number of DL CCs that can be configured depends on the DL aggregation capability of the UE;        The number of UL CCs that can be configured depends on the UL aggregation capability of the UE;        It is not possible to configure a UE with more UL CCs than DL CCs.
When CA is configured, a UE only has one RRC connection with the network. At RRC connection reestablishment/handover, one serving cell provides the NAS mobility information and the security input. The serving cell is referred to as Primary Cell (PCell). In the downlink, the carrier corresponding to the PCell is Downlink Primary Component Carrier (DL PCC) while in the uplink it is Uplink Primary Component Carrier (UL PCC).
Another key feature of the LTE-A is providing relaying functionality by means of introducing relay nodes to the UTRAN architecture of 3GPP LTE-A. Relaying is considered for LTE-A as a tool for improving the coverage of high data rates, group mobility, temporary network deployment, the cell edge throughput and/or to provide coverage in new areas. A relay node is wirelessly connected to radio access network via a donor cell. Depending on the relaying strategy, a relay node may be part of the donor cell or, alternatively, may control the cells on its own. In case the relay node is a part of the donor cell, the relay node does not have a cell identity on its own, however, may still have a relay ID. In the case the relay node controls cells on its own, it controls one or several cells and a unique physical layer cell identity is provided in each of the cells controlled by the relay.
LTE-A Release 11 work started from September 2011. The major features of LTE-A Release 11 include LTE carrier aggregation enhancements, Further Enhanced Non CA-based ICIC (inter-cell interference coordination) for LTE, Coordinated Multi-Point Operation (COMP) for LTE—Downlink and etc. Besides, LTE-A Release 11 also includes studies on Coordinated Multi-Point operation (CoMP) for LTE, Enhanced Uplink Transmission for LTE, further Downlink MIMO enhancements for LTE-Advanced.
During the study on CA enhancement, CoMP and DL MIMO, current PDCCH defined in Releases 8-10 shows some disadvantages: Beamforming or spatial multiplexing is not possible, frequency scheduling gain with localized allocation is not possible, because of only distributed DCI transmission is supported and frequency ICIC (Inter-Cell Interference Coordination) is not possible, because of random REG allocation among cells. In order to improve the situation, an enhanced PDCCH (E-PDCCH) is worked on, which would avoid the above problems.
A possibility provided by the LTE in order to improve battery lifetime is the discontinuous transmission (DTX) and reception (DRX). In order to provide a reasonable battery consumption of the terminal (UE), LTE Rel-8/9 as well as Rel-10 provide a concept of discontinuous reception (DRX). Accordingly, the terminal does not have to regularly monitor the control channels but rather can switch off the transmission and the reception over long periods and needs to activate the transceiver only at predefined or required time instances.
The following terms (parameters) describe the way DRX works:                "on-duration": duration in downlink subframes that the UE waits for after waking up from DRX to receive PDCCHs. If the UE successfully decodes a PDCCH, the UE stays awake and starts the inactivity timer;        "inactivity-timer": duration in downlink subframes that the UE waits to successfully decode a PDCCH, from the last successful decoding of a PDCCH. When PDCCH is not successfully decoded without the inactivity period, the UE re-enters DRX. The UE shall restart the inactivity timer following a single successful decoding of a PDCCH for a first transmission only (not for retransmissions); and        "active-time": total duration that the UE is awake. This includes the "on-duration" of the DRX cycle, the time UE is performing continuous reception while the inactivity timer has not expired and the time UE is performing continuous reception while waiting for a DL retransmission after one hybrid ARQ (HARQ) round trip time (RTT). Based on the above, the minimum Active Time (here also called "active-time") is of length equal to on-duration, and the maximum is undefined (infinite);
There is only one DRX cycle per UE. All aggregated component carriers follow this DRX pattern.
In order to allow for further battery saving optimization, activation and deactivation of component carriers is introduced. Accordingly, a DL CC could be in one of the following three states: non-configured, configured but deactivated or active. When a DL CC is configured but deactivated, the UE does not need to receive the corresponding PDCCH or PDSCH and is also not required to perform CQI measurements for that CC. Conversely, when a downlink CC is active, the UE shall receive PDSCH and PDCCH (if present, transmitted), and is expected to be able to perform CQI measurements. After the configuration of the component carriers, in order to have PDCCH and PDSCH reception on the DL component as described above, the DL CC needs to be transitioned from the configured but deactivated state to the active state.
In the uplink however, a UE is always required to be able to transmit on PUSCH on any configured uplink CC when scheduled on the corresponding PDCCH (there is no explicit activation of uplink CCs).
In the past releases, semi-persistent scheduling (SPS) was introduced in order to reduce control channel overheads for applications that require persistent radio resource allocation such as voice over IP. SPS therefore introduces a persistent allocation of the physical resource blocks which a user should decode on the downlink or which he can transmit on the uplink. Up to now, however, the SPS feature is not very widely used.
Without SPS, in the downlink and uplink, eNB dynamically allocates resources to UEs at each TTI via the L1/L2 (layer 1/layer 2) control channel(s) (PDCCH) where the UEs are addressed via their specific C-RNTIs. TTI is a transmission time interval which is a basic timing unit of the transmission. C-RNTI is a cell radio network temporal identity, which uniquely identifies a UE. The cyclical error check (CRC) of a PDCCH is masked with the addressed UE's C-RNTI. Only a UE with a matching C-RNTI can decode the PDCCH content correctly resulting in a positive CRC check. This kind of PDCCH signaling is also referred to as "dynamic grant". A UE monitors at each TTI the L1/L2 control channel(s) for a dynamic grant in order to find a possible allocation (DL and UL) it is assigned to.
In addition, E-UTRAN can allocate uplink/downlink resources semi-persistently. When required, retransmissions are explicitly signaled via the L1/L2 control channel(s). Since retransmissions are scheduled, this kind of operation is referred to as semi-persistent scheduling (SPS). The benefit is that PDCCH resources for initial HARQ transmissions are saved. One example for a service, which might be scheduled by semi-persistent scheduling is voice over IP (VoIP). Every 20 ms a VoIP packets is generated by the speech codec during a talk-spurt. Therefore the eNB could allocate uplink or respectively downlink resources persistently every 20 ms, which could be then used for the transmission of the VoIP packets. In general, SPS is beneficial for services with a predictable traffic behavior, such as services with a constant bit rate, where the packet arrival time is periodic.
A UE also monitors the PDCCHs in subframe where it has been allocated resources persistently. A dynamic grant, PDCCH with a C-RNTI masked CRC, can override a semi-persistent allocation. In case the UE finds its C-RNTI on the L1/L2 control channel(s) in the sub-frames where the UE has a persistent resource(s) assigned, this L1/L2 control channel allocation overrides the persistent allocation for that TTI and the UE does follow the dynamic grant. When UE does not find a dynamic grant it will transmit and/or receive according to the persistent allocation.
The configuration of SPS is performed by RRC signaling. For example, the periodicity of the semi-persistent allocation is signaled within RRC. The activation of a semi-persistent allocation and also the exact timing as well as the physical resources and transport format parameters are sent via PDCCH signaling. Once SPS is activated, UE follows the semi-persistent allocation according to the activation PDCCH with the configured periodicity.
In order to distinguish a dynamic PDCCH from a PDCCH that activates SPS, also referred to as SPS activation PDCCH, a separate identity is introduced. Basically the CRC of an SPS activation PDCCH is masked with this additional identity which is referred to as SPS C-RNTI. The size of the SPS C-RNTI is 16 bits, which is the same as the normal C-RNTI. Furthermore, the SPS C-RNTI is also UE specific, each UE configured for SPS is allocated a unique SPS C-RNTI. In case UE detects an SPS activation PDCCH, it will store the PDCCH content and apply it every SPS interval, periodicity signaled via RRC. Retransmissions of an SPS allocation are also signaled using the SPS C-RNTI.
Similarly to the activation of SPS, eNB can also deactivate the semi-persistent scheduling. As for the activation, also the deactivation of SPS resource (also denoted SPS resource release), is signaled by using a PDCCH.
Another improvement of Release 11 has been agreed as a working item for standardization and relates to providing low cost machine type communication (MTC) terminals based on LTE. Moreover, LTE RAN enhancements for diverse data applications are under study. The machine type communication traffic profiles include sporadic data access for exchange of relatively small data amounts. Such a type of communication is particularly relevant for applications which require always-on connectivity, such as smart phones, sporadic access for the purpose of checking e-mails or social network updates. The aim of the working item is to identify and specify mechanisms at the radio access network level that enable enhancing the ability of the LTE to handle diverse traffic profiles. In particular, the aim is to reduce the costs and complexity of terminals in order to extend the battery life. The machine type communication traffic is in general delay insensitive data traffic in which the terminals and/or eNodeB can wait for some time until the data is delivered. Such traffic may be, for instance, the planned data traffic including regular updates such as measurements or other reports. The amount of data exchange is typically rather small and can be delivered in few subframes. For instance, such data may be SMS type messages for controlling or reporting by a machine.
It is suggested that the MTC terminals shall only operate in the 1.4 MHz band only and shall be only addressable by E-PDCCH since the PDCCH is incompatible for different bandwidths. Addressing by E-PDCCH means that the DCI is transmitted in the PDSCH region. E-PDCCH is an enhanced PDCCH channel under study for release 11, which should provide more efficient and robust transmission.
The current initial synchronization procedure works only for all possible downlink system bandwidth sizes if the UE is capable of processing all the possible downlink system bandwidths. Up to the PBCH detection and reception it would be sufficient for the UE to support only a 1.4 MHz cell since the mapping of PSS/SSS to the central 62 subcarriers and the mapping of PBCH to the central 72 subcarriers enables the detection of these signals and channel independent of the actual downlink bandwidth of the cell. However, this bandwidth is neither sufficient to complete the synchronization procedure (for instance, receiving the various SIB Type messages (on PDSCH)) nor to commence the regular operation in the cell (for instance, by completing the connection setup and starting monitoring the PDCCH and possibly receive data on PDSCH), nor to initiate a random access procedure.
In other words, at the latest after the detection of the PBCH, the UE needs to enable the full downlink system bandwidth processing chain, in a case without carrier aggregation up to 20 MHz (or 100-110 PRBs) need to be operable and within the capability of the UE hardware and software.
3GPP contribution R1-112669, "On support of low-cost MTC terminals with reduced Tx/Rx bandwidths", August 2011, RAN1 meeting no. 66, freely available on www.3gpp.org suggests continuous (permanent) operation of the terminal at using a small operational bandwidth in a larger system bandwidth cell. In particular, it is proposed to define a UE with a narrower receiving (Rx)/transmitting (Tx) bandwidth than the eNodeB's Tx/Rx bandwidth. The following features are envisaged to support a 1.4 MHz capable MTC UE to access an eNodeB with a wider bandwidth:                Special PDCCHs are introduced and used for MTC UEs. The PDCCHs are transmitted within the central 1.4 MHz-wide part of DL carrier. E-PDCCH on PUSCH region may be used for MTC UEs.        System Information Block of the eNodeB for MTC UEs are separately transmitted from those for legacy UEs and within the central 1.4 MHz wide part. Paging signals for MTC UEs are also transmitted within the central part.        Some of the reserved bits in PBCH may be used for MTC UEs, or X-PBCH might be transmitted within the central 1.4 MHz-wide part.        As located on the both edges of UL carrier, legacy PUCCHs are not used for transmission of UCI from MTC UEs. Alternatively, PUSCH is used for the UCI transmission.        All PRACH slots are located in the central 1.4 MHz-wide part. Alternatively, different PRACH configurations are configured for legacy UEs and MTC UEs.
As can be seen, each of these points is introducing a new functionality for the UE and requires the corresponding support at the eNodeB side as well. Furthermore, the eNodeB would be tasked to manage the collision-free operation of channels and signals between such proposed MTC UEs and "regular" UEs.
According to R1-112669, the PDCCH is transmitted within the central 1.4 MHz-wide part of the downlink carrier. E-PDCCH or PDSCH region may be used for MTC UEs. Shared channel is only transmitted within the central 1.4 MHz wide part of the downlink carrier. Thus, the eNodeB scheduling and link adaptation has to manage coexistence of different bandwidth capabilities. The frequency scheduling flexibility for an MTC PDSCH and PUSCH is extremely limited, since only central 1.4 MHz are available. This may cause congestion of the central bandwidth in the case of simultaneous access by multiple MTC UEs on the PDCCH as well as PDSCH. The relative control signaling overhead is also substantial, since large packets need to be segmented and transmitted and consequently indicated by control signaling in multiple subframes.
The main task of the present invention is to enable an operation of a low-power-consumption device that is capable of integrating into the existing radio access network without major modifications, particularly for existing start-up and device attachment/registration procedures, while still able to operate at low power consumption during times of little or no data activity. At the same time, the target is to simplify the eNodeB's job of handling and coordinating the resources and transmissions to and from "regular" UEs and low-cost UEs.

Active bandwidth indicator for power-saving UEs

PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA


In a non-contact IC card system which transmits and receives signals between an interrogator and a transponder, a transmitter-receiver used for the interrogator includes a carrier wave oscillator capable of sweeping an oscillation frequency, a resonant wave detector for detecting the resonant frequency of the transponder among carrier waves generated by the carrier wave oscillator, and a carrier frequency holder for maintaining the oscillation frequency of the carrier wave oscillator to the frequency detected by the resonant wave detector. The system is driven with a high transmission efficiency by bring the carrier wave frequency of the interrogator into agreement with the resonant frequency of the transponder, without lowering the Q value of the resonant circuit of the transponder and without any special adjustment for controlling the resonant frequency of the transponder to the desired frequency.

1. Field of the Invention
This invention relates to a non-contact integrated circuit (hereinafter "IC") card system which transmits and receives signals between an interrogator (a reader-writer) and a transponder (a card), in particular, to a transmitter-receiver used for the interrogator.
2. Description of the Related Art
Non-contact IC card systems are well known which transmit and receive signals between an interrogator (a reader-writer) and a transponder (a card) by the electromagnetic coupling method or electromagnetic induction method.
FIG. 3 is a block diagram commonly used in such an electromagnetic coupling type non-contact IC card system. In the non-contact IC card system shown in FIG. 3, the interrogator modulates a carrier wave generated in an OSC (oscillator) 1, through a modulating circuit 3 in accordance with signals from a data-processing circuit 2, and the modulated wave is amplified in a constant-current driver circuit 4 and then transmitted to the transponder through constant-current drive of an antenna coil 5. The transponder receives signals from the interrogator through an antenna coil 11, whereupon the received signals are demodulated in a demodulating circuit 13 and are sent to a data-processing circuit 14. The data are processed in the data-processing circuit 14, and the preset data are sent to a modulating circuit 15 and then sent out to the interrogator through the antenna coil 11. The interrogator receives the signals sent from the transponder through the antenna coil 5, whereupon the signals are demodulated in a demodulating circuit 6 and then sent to the data-processing circuit 2 to process the data to make judgement or the like.
Now, in order to enhance the selectivity of signals sent from the interrogator, the transponder is provided with a tuned resonant circuit A comprised of the antenna coil 11 and a capacitor 12. The resonant frequency f.sub.0 of this resonant circuit A depends on inductance L of the antenna coil 11 and capacitance C, and is determined by the formula: ##EQU1## where f.sub.0 is in hertz, L is in henrys, and C in farads. Thus, in order to obtain a desired resonant frequency, the antenna coil 11 and the capacitor 12 are required to have the desired inductance and capacitance.
However, the precision of capacitance of the capacitor 12 is about plus-minus 5% at best. Also, as the form of the antenna coil 11, it can be roughly grouped into two types, one of which is of the type of a wound wire and the other of which is of the type of an etched copper-clad plate. Of these, the precision of inductance of the wound wire type is about plus-minus 5%. Hence, there is a limit on the improvement in the precision of the resonant frequency f.sub.0 and an error of about plus-minus 5% usually occurs between the carrier wave frequency of the interrogator and the resonant frequency of the transponder.
Meanwhile, in order to efficiently convert into voltage the magnetic field induced in the antenna coil 11, it is more preferable for the resonant circuit to have a higher Q (quality factor). However, making the Q of the resonant circuit A higher results in a narrow frequency bandwidth selected in the resonant circuit A. Hence, if the Q is made too high, the frequency selected in the resonant circuit A turns outside the range of the tolerance between the carrier wave frequency of the interrogator and the resonant frequency of the transponder, thereby causing the problems that the signals from the interrogator can not be received.
Accordingly, the Q of the resonant circuit A is intentionally lowered to the extent that the error between the carrier wave frequency of the interrogator and the resonant frequency of the transponder does not come into question.
Alternatively, in order to set the resonant frequency of the transponder to have the desired frequency, a special adjustment is made when the transponder is manufactured. That is, a plurality of capacitors are provisionally provided as the capacitor 12 of the resonant circuit A, and some unnecessary capacitors are removed at the time of the adjustment so that the desired resonant frequency F.sub.0 can be obtained, or a troublesome operation is made, e.g., the antenna coil 11 is unwound at the time of the adjustment.

Transmitter-receiver for non-contact IC card system


A system for rendering available a stream of identical random processes to at least two seperate and remote parties is disclosed. The system includes a multiple random process source which makes available a preferably large number of independent random processes. The system further includes a device available to the parties and which serves for selecting for use by each of the parties, at the same time, an identical one of said plurality of random processes.

Randomness is used in many disciplines of science and technology and even economics, and finds application in fields such as communications, computing, data security, access control, experimentation and forecasting—e.g. weather forcasting—and like processes and in simulations, particularly of processes involving chaos theory.
In some systems, there is a need for identical and simultaneous randomness at different remote locations. Furthermore, random data employed at the remote locations is preferably confidential and unknown to an unauthorised party. Examples include                (i) secret key data encryption methods, in which both communicating parties need to have the same secret key, which is typically a random key;        (ii) remote access control in which a distant operator needs to have the same password as that installed in a 'machine' to be accessed—this passsword is preferably a random passsword;        (iii) weather forecasting,        (iv) remote computing applications requiring identical random parameters,        (v) chaos processes which are executed remotely,        (vi) frequency hopping systems, and        (vii) data hiding or steganography.
Encryption, for example, is one of a series of useful tools that allow secure electronic communications, wherein data of highly sensitive content is propagated through public networks. Ideal secure electronic communication should comprise the following three features:
1) protection of data from unauthorized tampering,
2) identification and authentication of the data source, and
3) prevention of unauthorized access to the data.
Keys or key systems for encrypted data as described above often rely on random processes for their creation. Authorized parties to a given communication need compatible keys. However it is preferable to avoid sending keys, both in order to avoid interception, and also to make the encryption process simpler and faster. Preferably, therefore, authorised parties to a communication should be able to produce the same random key independently. Unfortunately, however, the definition of randomness does not permit replication, which is to say no process that can be repeated may be truly random. Current approaches for dealing with this issue are addressed by two general families of solutions:
(i) generating randomness at one party, and sending the outcome—for example random data forming key(s)—to the other party; and
(ii) using a pseodo random process at both parties, e.g., a PRNG (Pseudo Random Number Generator) which gives the same (apparently random) bit stream as an output at both parties if fed by the same input seed.
These approaches are limited because they both involve sending data from one party to the other, and the data, whether the random data itself in the first instance or the seed in the second instance, may be intercepted by an unauthorized party.
The problem thus remains of having identical randomness at separate and even remote parties. One possibility, involves separately and independently to safely supply each party with an identical list of random numbers. Another approach is to supply each party with the same semi-random or pseudo-random algorithm and somehow synchronize their starting points. Synchronization may typically be by means of a clock or by a signal sent to the two parties or from one of the parties to the other.
Clock synchronization is problematic in that there will always be a time difference, however small, between the two parties. Signal synchronization is subject to the so-called "Byzantine agreement problem" which may be stated as follows:
Two separate and remote allied armies, A and B, approach to besiege a powerful city. Neither army alone is powerful enough to overcome the city and should it appear on the battlefield alone it will be destroyed. Only if both armies appear simultaneously and from opposite directions, is there any chance of success.
The overall commander, located with army A, has to co-ordinate an attack, but has at his disposal dispatch riders as his only means of communication.
The overall commander thus sends a message to the commander of Army B, by dispatch rider, which conveys the time and directions of the intended simultaneous attack. However, having sent the message by a courier, the sender—the commander of army A—cannot be certain that the message has reached its destination, (and if it has, that it has not been tampered with on the way). Thus logic dictates that he will not attack, due to his instinct for self-preservation.
Having received the message, the commander of Army B is faced with the same problem, he cannot be certain that the content of the message is real and that it indeed comes from his ally. It could be a false message sent by the enemy and intended to lure him to his destruction. Furthermore, and most importantly, he knows that commander A has an instinct for self-preservation which is no less real than his own and he knows for sure that the logic of commander A tells him not to attack. Thus he must assume that A will not attack and hence he too, does not attack.
For solving the agreement issue one may suggest that commander B can send back to army A an acknowledgment message, acknowledging the receipt of the first message (of the time and direction of the attack). Nonetheless, the two allies remain with the same dilemma, and commander B, who has sent the acknowledgment message cannot be sure it has reached army A untouched—thus B's instinct for self-preservation leads him not to attack. Furthermore, the commander of army A, will be faced with the same dilemma when receiving his acknowledgement and is unlikely to launch an attack on the basis of this information. Army A receives the acknowledgement but also cannot be sure that the acknowledgement is genuine and has not been sent by the enemy to lure him to his destruction. Furthermore, A knows of B's instinct for self-preservation. Bearing this in mind, army A must assume that army B will not attack. The situation is not improved however many further rounds of acknowledgement or confirmation are carried out. That is to say, having sent the acknowledgment message, both army A and army B keep facing the same dilema of not being able to assume that the other will attack and, as a result, an attack will never be launched.
The "Byzantine Agreement Problem", is a logical dilemma that is relevant when translated into modem communications, especially when considering for example, open communication modes such as the Internet, which are exposed to hackers, imposters etc. and to errors, cuts and breaks in communications.
The issues that this logical dilemma presents, and which must be solved are (i) synchronization; (ii) simultaneity; (iii) identification; and (iiii) authentication.
At the basis of the problem lies the fact that at any given step, one party knows less than the other, and there is a lag between the knowledge of the parties (about the situation of one party in regard to the other party, and in their mutual understanding).
There is thus a widely recognized need for, and it would be highly advantageous to have, a simple way to produce identical ongoing randomness at seperate and remote locations, that is confidential by nature and which enables a mode of communication, synchronization or authentication between two parties that is not vulnerable to the logical dilemmas of the Byzantine agreement problem.
A limited solution and for the limited application of encryption, is to be found in U.S. Pat. No. 5,703,948 which uses state machines to produce pseudo-random keys for the encryption of messages between parties.

System and method for making available identical random data to seperate and remote parties


In a method for detecting a maintenance situation on a two-wheeled vehicle having a motor provided in order to assist forward motion of the two-wheeled vehicle at least at times, a maintenance situation is detected by sensing the position of the two-wheeled vehicle by way of a first sensor variable. Control is then applied to the motor either as a reduction in the applied drive power output, e.g. in the form of the motor speed or torque, or as a complete shutoff or immobilization of the motor.

1. Field of the Invention
The invention relates to a method and an apparatus for assisting maintenance in the context of a motor-driven two-wheeled vehicle.
2. Description of the Related Art
In the context of maintenance of a two-wheeled vehicle it is sometimes necessary to turn the bicycle upside down in order to gain better access to the parts requiring repair. When repairing a flat tire, for example, it is usual firstly to invert the bicycle in order to place it on the saddle and the handlebars, before removing the front or rear wheel. This facilitates removal of the wheel for replacement of the tire.
In such a situation it can happen, however, that the motor of a driven two-wheeled vehicle unintentionally becomes activated, so that a rotation of the pedal cranks, or a rotation of the rear wheel via the chain, occurs. If the rider is working on the rear wheel in this situation, undesirable injuries can occur.
The published German patent application document DE 10 2012 201 881 A1, discloses a control assemblage for an electric bicycle in which an electric motor for driving the electric bicycle is enabled as a function of signals of an acceleration sensor. The drive system is thus enabled when the signals of the acceleration sensor suggest the presumption that the electric bicycle is moving. It is additionally possible to ascertain whether a pressure is being exerted on the pedals.

Method and device for detecting a maintenance situation in a two-wheeled vehicle


A spring contact component for a plug socket of an electromedical implant, with a coil surrounding the outer periphery of a plug opening. A simpler, more cost effective and automatable design of a plug socket module can be achieved in that at least one end of the coil is electrically and mechanically connected directly to a connector pin via a wire-shaped and/or strip-shaped element. The invention also relates to a corresponding plug socket module, a modular header, and a method for producing a spring contact component of this type.

A wide range of medical implants are known from the prior art. In conjunction with the present invention, an electromedical implant is understood to be an active implant, which, besides a power supply (for example, a battery), also comprises further electrical and/or electronic components (for example, capacitors), which are arranged in a housing that is hermetically sealed. Electromedical implants of this type include, for example, cardiac pacemakers, defibrillators or neurostimulators. These implants are used to excite the biological tissue by means of electrical pulses, which are generated by a pulse generator provided in the housing.
Implants of this type are often connected to electrode lines, which, after implantation in a body, are used to treat said body, for example, to transmit and/or deliver stimulation pulses and/or defibrillator shocks to specific points of the body, or are used to detect electric potentials of points of the body. To this end, an electrical connection has to be produced between the electrical and/or electronic components arranged inside the housing and the electrode line. This electrical connection is generally produced by means of a bushing, and what is known as a terminal housing. Here, a bushing ensures an electrical connection between the interior of the housing and the external environment, and is responsible at the same time for the hermetic seal of the housing. The terminal housing fastened via the bushing further guides the electrical connection of the bushing to a contact point, which is often formed as a plug contact socket. The connector piece (e.g., plug) of the electrode line is introduced after implantation into the generally standardized plug contact socket. Electrical contact is thus produced at the contact points of the plug contact socket between the electronic components of the implant, for example, a pulse generator, and the contact points of the connector piece of the electrode line and, therefore, of the electrode fastened thereto.
The interface between the implant and the electrode line is normally designed as a detachable multipoint connection and is defined in terms of its geometry via ISO standards. A coaxially stepped, double pug connection with sealing lips is defined in Standard ISO 5841-3 (IS-1 Standard) for pulse generators with cardiac pacemaker function, that is to say for pulse generators that operate with low-voltage pulses. A coaxially stepped, quadruple plug connection (of which three are in-line and smooth) with sealing lip systems integrated in the socket opening is defined in Standard ISO 27186 (DF4/IS4 Standard) for pulse generators with cardiac pacemaker function and/or defibrillator function, that is to say with high-voltage and low-voltage pulses. By contrast, there are no standard guidelines for a plug/socket geometry of neurostimulators. In products known at the time of filing of the present application, plug/socket systems with eight coaxial-smooth plug connections with sealing lip systems integrated into the socket opening are used, for example.
In the mentioned plug systems, all contactings can be formed in principle via spring contacts, provided specific demands in terms of the plug-in force, retention force and pull-out force, and also the electrical contact stability, are met.
In the known plug contact sockets, the sealing lip systems in life-sustaining implants (cardiac pacemakers, defibrillators, etc.) are normally designed redundantly, that is to say sealing lip pairs are used on either side of the individual electrical contact regions in order to keep bodily fluid away from the contact point, and also to electrically insulate the contact points from one another. In the case of implants that are not life-sustaining (for example, neurostimulators), a deviation is made from this rule.
From document International Publication No. WO 2006/026186, an implant with a plug contact socket for a multipoint plug connection is known, which has a plurality of electrically conductive, toroidal contact springs (spring coils). Here, each spring coil is arranged in a corresponding metal spring ring in such a way that the spring coil surrounds the outer periphery of the opening for the introduction of the plug at the respective point. Furthermore, on each spring ring, a wire feed line fastened thereto is provided and produces the electrical contact with the interior of the implant housing. The unit formed from a spring coil, the associated spring ring and the wire feed line fastened thereto is also referred to as a spring contact component. Together with the plastic housing likewise disclosed in the above document, a contact socket component is formed.
In other known solutions, the spring ring is omitted and the toroidal contact spring is mounted in a spring cage made of electrically conductive material. Here, the spring cage is often produced as a metal form-milled part. The contact socket component is assembled manually from the spring coil and spring cage. In a further manual method step, plug contact sockets are produced by stringing together contact socket components and sealing socket components alternately. Automated production of plug contact sockets is not possible due to design constraints. The known solution is additionally overstressed with consideration of the process-induced shape and position tolerance of its individual components and, therefore, non-uniform forces may act on a real electrode plug fitted into such a plug contact socket and could consequently lead to malfunctions. It has also proven to be disadvantageous with such a known solution that the occupied installation space is comparatively bulky and does not allow any further volume reduction. The seal between the modularly constructed metal-conductive contact socket components and the intermediate electrically insulating sealing socket components additionally appears to be problematic.
An object is therefore to create a plug contact socket for a terminal housing that avoids the above disadvantages and, in particular, can be produced in a simple manner in terms of the equipment involved and, therefore, cost effectively. The plug contact socket should also conform to the above-specified standards.
The present invention is directed toward overcoming one or more of the above-identified problems.

Spring contact component, plug contact socket, and contact socket component


A method, system and service for a data center computer network. A core network switches data using a first protocol layer. A first access switch is in electrical communication with the core network. The first access switch communicates the data to the core network using the first protocol layer. A second redundant access switch forms a first access switch pair with the first access switch. The second access switch is in electrical communication with the core network and communicates the data using the first protocol layer. The second access switch is in electrical communication with first access switch and communicates with the first access switch using a second protocol layer. The second protocol layer is at lower OSI level than the first protocol layer. The first access switch and the second access switch are configured to form a first VLAN. A first edge device is in electrical communication with the first access switch and the second access switch. The first edge device is part of the first VLAN.

Service providers of data center computing resources provide a centralized arrangement which allows network and infrastructure resources to be shared among separate customers. This is typically accomplished by providing each customer its own virtual network within the data center. Such may be useful, for example, in an "ecommerce" environment where a service provider implements a data center to provide web server and data server computing resources to multiple customers. As used herein, the term "data center" refers to a facility that is typically secured and is used to provide computing resources, such as web hosting, to different communities of users.
As the need for shared and scalable network computing resources increases, so too does the need for solutions which facilitate scalability in a manner is not disruptive to customers. For example, if the growth of Customer A necessitates the installation of a new web server, current technology may require that data center services for Customers B & C be disrupted or taken off line while the new server for Customer A is installed and the data center network configured to include the new server.
A network can be divided into seven layers according to the known Open System Interconnect ("OSI") model. A Physical layer 1 defines all the electrical and physical specifications for devices. This includes the layout of pins, voltages, and cable specifications. Network adapters and cables are physical-layer devices. A Data link layer 2 provides the functional and procedural means to transfer data between network entities on a LAN (or Virtual LAN) and detect and possibly correct errors that may occur in the Physical layer. Data link layer 2 is the layer at which bridges and switches operate. Connectivity is provided among locally attached network nodes forming Data link layer 2 domains for unicast or broadcast forwarding. A Network layer 3 provides functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks. Network layer 3 performs network routing functions, and might also perform segmentation and desegmentation, and report delivery errors. Routers operate at Network layer 3, routing data throughout an extended network such as the Internet. Network layer 3 also provides logical addressing and provides end-to-end data transport from the source machine to the destination machine across multiple Data link layer 2 instances. Other OSI Layers transfer data transparently between end users (layer 4), control connections between computers (layer 5), transform data to provide a standard interface (layer 6), and allow a user to access information on the network through an application (layer 7).
A Virtual LAN ("VLAN") is well known today and is implemented by one or more programmed switches such as one or more access switches. A switch is a device that performs transparent bridging, i.e., connection of multiple network segments with forwarding based on MAC addresses. A MAC address is a unique identifier of a respective computing device, and can be "burned-in" to a network interface card of the computing device. Communication of message packets within a VLAN uses OSI Model Data link layer 2 protocol. Data link layer 2 is implemented by hardware and software functions within the switch. To implement a VLAN, the access switch includes a MAC address table for each VLAN which lists which computing device(s) (by MAC address) are logically resident on which interface. An incoming message specifies the MAC address of the target device and is associated with a particular VLAN based on the interface from which it was received. Typically, the switch will look up the address in the MAC address table. If the address is found, the switch will forward the message to the destination through the identified interface. Otherwise, the switch will forward the message through all interfaces associated with the VLAN. All computing devices on the VLAN continually monitor all message packets on their subnet and "listen" for message packets bearing their own MAC address. When a computing device on the VLAN detects a message packet bearing its own MAC address as a destination device, the computing device receives and processes the message packet. Otherwise, the computing device ignores the remainder of the message packet.
Current arrangements and methods for securely and virtually separating multiple customers from their computing resources over a shared local area network (LAN) Ethernet infrastructure has been primarily accomplished through the use of layer 2 and VLAN technologies. Though layer 2 technologies are intended to maintain a loop-free environment (such as through the implementation of spanning-tree algorithms) and offer a flexible stable and secure connectivity approach, layer 2 technologies are limited by their inability to scale as the network infrastructure continues to grow over time. This makes the entire data center network design vulnerable, threatening the overall infrastructure, customer and their resources, and making it less cost effective to support and manage as changes and problems occur. For example, adding a server to a switch and reconfiguring the switch to accommodate the new server as part of a customer's virtual private network ("VPN") can trigger spanning-tree recalculations that impacts other customers. It is therefore desirable to have a data center system that allows for the implementation and expansion of a customer's VPN in a manner that is secure but is not disruptive to other customers. VPNs allow multiple customers to share the same physical network infrastructure while each customer's traffic remains logically separate.
In computer networking and telecommunications, a known Multi Protocol Label Switching ("MPLS") function is a data-carrying function which emulates some properties of a circuit-switched network over a packet-switched network. MPLS operates at an OSI layer that lies between traditional definitions of Data link layer 2 and Network layer 3, but closer to Network layer 3 than Data link layer 2, and therefore, will be considered Network layer 3. MPLS networks benefit from the advantages of OSI layer 3 routing and re-routing in the event of network changes and reconfiguration. However, because of the complexities of configuration and network management, MPLS networks are typically implemented in large-scale wide area networks to provide campus to campus VPNs where changes to customer's networks that would necessitate configuration changes are infrequent. However, the use of a strictly MPLS network in a shared data center environment is expensive and inefficient, and requires a disproportionate amount of personnel because of the frequency of changes in customers' data center requirements. For example, holiday periods may necessitate that customers in the on-line retail business add servers, and then remove those servers when the holiday period is over. Such may also be the case where a web or data server experiences a failure, and a replacement server must be quickly brought on-line. It is therefore desirable to have a data center network system and method that allows the use of OSI layer 3 devices in a manner that does not require frequent configuration and re-configuration of these devices, yet provides the robust routing and VPN environment characteristic of OSI layer 3 networks.

Data center virtual local area network system and method

International Business Machines Corporation