Methods and apparatuses are described for a User Equipment (UE) to receive enhanced Control CHannels (eCCHs), including enhanced Physical Downlink Control CHannels (ePDCCHs), transmitted in a set of Resource Blocks (RBs) over a Transmission Time Interval (TTI). A method includes transmitting a first control signal to a first UE over a first number of Resource Elements (Res) in a subset of the RBs and over a first number of the transmission symbols in the TTI; transmitting a second control signal to a second UE over a second number of the REs in the subset of the RBs and over a second number of the transmission symbols in the TTI; and transmitting a reference signal of the first type over a third number of the REs in the subset of the RBs and over a third number of the transmission symbols in the TTI.

1. Field of the Invention
The present invention relates generally to wireless communication systems, and more particularly, to transmitting physical downlink control channels.
2. Description of the Art
A communication system includes a DownLink (DL) that conveys transmission signals from transmission points such as Base Stations (BSs) (or NodeBs) to User Equipments (UEs), and an UpLink (UL) that conveys transmission signals from UEs to reception points such as NodeBs. A UE, which is also commonly referred to as a terminal or a Mobile Station (MS), may be fixed or mobile and may be a cellular phone, a personal computer device, etc. A NodeB is generally a fixed station and may also be referred to as an Access Point (AP) or some other equivalent terminology.
DL signals include data signals, which carry information content, control signals, and Reference Signals (RSs), which are also known as pilot signals. A NodeB transmits data signals through respective Physical Downlink Shared CHannels (PDSCHs) and transmits control signals through respective Physical Downlink Control CHannels (PDCCHs). UL signals also include data signals, control signals, and RSs. UEs transmit data signals through respective Physical Uplink Shared CHannels (PUSCHs) and transmit control signals through respective Physical Uplink Control CHannels (PUCCHs). It is possible for a UE having transmission of data information to also transmit control information through the PUSCH.
Downlink Control Information (DCI), which serves several purposes, is conveyed through DCI formats transmitted in respective PDCCHs. For example, DCI includes DL Scheduling Assignments (SAs) for respective PDSCH receptions by UEs and UL SAs for respective PUSCH transmissions from UEs. As PDCCHs are a major part of the total DL signaling overhead, their resource requirements directly affect DL throughput.
Accordingly, one method for reducing PDCCH overhead is to scale its size according to the resources required to transmit the DCI formats during a DL Transmission Time Interval (TTI).
Assuming Orthogonal Frequency Division Multiplexing (OFDM) as the DL transmission method, a Control Format Indicator (CFI) parameter transmitted through a Physical Control Format Indicator CHannel (PCFICH) can be used to indicate a number of OFDM symbols for a DL control region in a DL TTI.
A frequency resource unit, which is also referred to as a Resource Block (RB), includes a number of sub-carriers or Resource Elements (REs), e.g., 12 REs. A PDSCH transmission can occur over a number of RBs and over a number of OFDM symbols, e.g., over all OFDM symbols in a DL TTI, after a DL control region.
FIG. 1 illustrates a conventional structure for PDCCH transmissions in a DL TTI.
Referring to FIG. 1, a DL TTI includes a subframe having N=14 OFDM symbols. A DL control region occupies a first M OFDM symbols 110. A remaining N−M OFDM symbols are used primarily for PDSCH transmissions 120, and a PCFICH 130 is transmitted in some REs of a first OFDM symbol and provides 2 CFI bits indicating a DL control region size of M=1, M=2, or M=3 OFDM symbols.
Some OFDM symbols also include RS REs 140 and 150, which assumes that there are two NodeB antenna ports. These RS REs 140 and 150 are transmitted over substantially an entire DL operating BandWidth (BW) and are referred to as Common RSs (CRSs), as they can be used by each UE for performing channel measurements and for demodulating control or data signals. A CRS is transmitted without precoding, i.e., without applying a phase to its transmission, or with a same precoding (phase) as for all control or data signals for which a UE uses the CRS for demodulation.
In addition to a CRS, other RS types for a DL subframe include a DeModulation RS (DMRS) that is transmitted only in RBs used for PDSCH transmission to a UE (the DMRS uses UE-specific precoding and is associated with a data signal using a same precoding), and a Channel State Information (CSI) RS that is periodically transmitted in some subframes, without UE-specific precoding, and is intended to primarily serve for measurement.
Additional control channels may be transmitted in a DL control region but are not shown for brevity. For example, when using a Hybrid Automatic Repeat reQuest (HARQ) process for data transmission in a PUSCH, a NodeB may transmit a Physical Hybrid-HARQ Indicator CHannel (PHICH) to indicate to a UE whether a previous transmission of data Transport Blocks (TBs) in a PUSCH was correctly received, i.e., an ACKnowledgement (ACK), or incorrectly received, i.e., a Negative ACK (HACK).
Each Control CHannel (CCH) transmitted with the conventional structure illustrated in FIG. 1 will be referred to herein as a conventional CCH (cCCH) including a cPDCCH, a cPCFICH, and a cPHICH.
FIG. 2 illustrates a conventional encoding process for a DCI format.
Referring to FIG. 2, a NodeB separately codes and transmits each DCI format in a respective cPDCCH. A Radio Network Temporary Identifier (RNTI) for a UE for which a DCI format is intended for masks a Cyclic Redundancy Check (CRC) of a DCI format codeword in order to enable a UE to identify that a particular DCI format is intended for it. Alternatively, a DCI-type RNTI may mask a CRC, if a DCI format provides UE-common information. The CRC 220 of (non-coded) DCI format bits 210 is computed and it is subsequently masked 230 using an eXclusive OR (XOR) operation between CRC and RNTI bits 240. For example, the XOR operation is XOR(0,0)=0, XOR(0,1)=1, XOR(1,0)=1, XOR(1,1)=0, and both a CRC and an RNTI have 16 bits.
The masked CRC bits are appended to DCI format information bits 250, followed by channel coding 260, e.g., using a convolutional code, by rate matching 270 to allocated resources, interleaving and modulating 280, and transmitting a control signal 290.
FIG. 3 illustrates a conventional decoding process for a DCI format.
Referring to FIG. 3, a received control signal 310 is demodulated and de-interleaved 320, a rate matching applied in a NodeB transmitter is restored 330, and data is subsequently decoded 340. After decoding, DCI format information bits 360 are obtained after extracting CRC bits 350, which are then de-masked 370 by applying an XOR operation with a UE RNTI 380 (or a DCI-type RNTI). Finally, a UE performs a CRC test 390.
If the CRC test passes, a UE considers a DCI format as valid and determines parameters for signal reception or signal transmission. If the CRC test does not pass, a UE disregards a presumed DCI format.
To avoid a cPDCCH transmission to a UE blocking a cPDCCH transmission to another UE, a location of each cPDCCH transmission in the time-frequency domain of a DL control region is not unique. Consequently, a UE must perform multiple decoding operations to determine whether there are cPDCCHs intended for it in a DL subframe.
The REs carrying each cPDCCH are grouped into conventional Control Channel Elements (cCCEs) in the logical domain. For a given number of DCI format bits, a number of cCCEs for a respective cPDCCH depends on a channel coding rate, e.g., Quadrature Phase Shift Keying (QPSK)).
A NodeB may use a lower channel coding rate and more cCCEs for a cPDCCH transmission to a UE experiencing a lower DL Signal-to-Interference and Noise Ratio (SINR) than to a UE experiencing a higher DL SINR. The possible cCCE aggregation levels for a cPDCCH transmission may be, for example, 1, 2, 4, and 8 cCCEs.
For a cPDCCH detection process, a UE may determine a search space for candidate cPDCCH transmissions after it restores cCCEs in the logical domain according to a common set of cCCEs for all UEs (i.e., a Common Search Space (CSS)) and according to a UE-dedicated set of cCCEs (i.e., a UE-Dedicated Search Space (UE-DSS)). For example, a CSS includes the first C cCCEs in the logical domain, and a UE-DSS may be determined according to a pseudo-random function having as inputs UE-common parameters, such as the subframe number or the total number of cCCEs in a DL subframe, and UE-specific parameters such as a RNTI. For example, for cCCE aggregation levels Lε{1,2,4,8}, cCCEs corresponding to a cPDCCH candidate in are given in Equation (1).cCCEs for cPDCCH candidate m=L·{(Yk+m)mod └NCCE,k/L┘}+i  (1)
In Equation (1), NCCE,k is a total number of cCCEs in subframe k, i=0, . . . , L−1, m=0, . . . , MC(L)−1, and MC(L) is a number of cPDCCH candidates to monitor in a search space. Exemplary values of MC(L) for Lε{1,2,4,8} are, respectively, {6, 6, 2, 2}. For a CSS, Yk=0. For a UE-DSS, Yk=(A·Yk 1)mod D, where Y−1=RNTI≠0, A=39827 and D=65537.
If enough cCCEs remain after transmissions of DCI formats conveying UE-common information, a CSS may also convey some DCI formats for DL SAs or UL SAs. A UE-DSS exclusively conveys DCI formats for DL SAs or UL SAs. For example, a CSS may include 16 cCCEs and support 2 DCI formats with L=8 cCCEs, or 4 DCI formats with L=4 cCCEs, or 1 DCI format with L=8 cCCEs and 2 DCI formats with L=4 cCCEs. The cCCEs for a CSS are placed first in the logical domain (prior to interleaving).
FIG. 4 illustrates a conventional transmission process for cPDCCHs.
Referring to FIG. 4, after channel coding and rate matching, as illustrated in FIG. 2, the encoded DCI format bits are mapped in the logical domain to cCCEs of a cPDCCH. The first 4 cCCEs (L=4), cCCE1 401, cCCE2 402, cCCE3 403, and cCCE4 404 are used for cPDCCH transmission to UE1. The next 2 cCCEs (L=2), cCCE5 411 and cCCE6 412, are used for cPDCCH transmission to UE2. The next 2 cCCEs (L=2), cCCE7 421 and cCCE8 422, are used for cPDCCH transmission to UE3, and the last cCCE (L=1), cCCE9 431, is used for cPDCCH transmission to UE4.
DCI format bits are scrambled 440 by a binary scrambling code and are subsequently modulated 450. Each cCCE is divided into conventional Resource Element Groups (cREGs). For example, a cCCE having 36 REs can be divided into 9 cREGs, each having 4 REs.
Interleaving 460 is applied among cREGs (blocks of 4 QPSK symbols). For example, a block interleaver may be used where interleaving is performed on symbol-quadruplets (4 QPSK symbols corresponding to the 4 REs of a cREG) instead of on individual bits.
After interleaving the cREGs, a resulting series of QPSK symbols is shifted by J symbols 470, and each QPSK symbol is mapped to an RE 480 in a DL control region.
Therefore, in addition to a CRS from NodeB transmitter antenna ports 491 and 492, and other control channels such as a PCFICH 493 and a PHICH (not shown), REs in a DL control region include QPSK symbols for cPDCCHs corresponding to DCI formats for UE1 494, UE2 495, UE3 496, and UE4 497.
FIG. 5 illustrates a conventional transmission process for a CFI.
Referring to FIG. 5, a NodeB transmitter generates CFI bits 510, e.g., 2 CFI bits, encodes the CFI bits and performs a number of repetitions 520 to obtain a sequence of encoded CFI bits. For example, a (3, 2) Hamming code and 11 repetitions of the encoded CFI bits may apply to obtain sequences of 32 encoded bits, after puncturing the last repeated encoded bit. The sequences of encoded bits are modulated using QPSK 530 and the output is mapped to frequency disperse cREGs 540 and transmitted in a cPCFICH 550.
FIG. 6 illustrates a conventional reception process for a CFI.
Referring to FIG. 6, a UE receiver receives a cPCFICH 610, accumulates repeated transmissions of encoded CFI bits over respective cREGs 620, demodulates an accumulated output 630, decodes resulting bits 640, and obtains an estimate of the transmitted CFI bits 650.
The cPHICH cREGs is placed only in a first OFDM symbol or over a maximum of three OFDM symbols of a DL control region. A cPHICH transmission in each cREG is not confined in only one RE, but in order to provide interference randomization, it is spread over all REs in each cREG. To avoid reducing a cPHICH multiplexing capacity (by a factor of 4 for a cREG of 4 REs), orthogonal multiplexing of cPHICH transmissions may apply within each cREG using orthogonal codes with a Spreading Factor (SF) equal to NSF,freqcPHICH. For a cREG of 4 REs, the orthogonal codes are Walsh-Hadamard (WH) codes with NSF,freqcPHICH. For QPSK modulation and 1-bit HARQ-ACK for each data TB received by a NodeB, each cPHICH may be placed on the In-phase (I) or the Quadrature (Q) component of a QPSK constellation and may be modulated with a WH code over each cREG.
For NSF,freqcPHICH, the 1-bit HARQ-ACK multiplexing capacity of each cPHICH is 2NSF,freqcPHICH=8 (obtained from the 2 dimensions of QPSK (I/Q and from NSF,freqcPHICH=4). Therefore, multiple cPHICHs separated by I/Q multiplexing and by different WH codes are mapped to a same set of REs in one or more cREGs and constitute a cPHICH group.
FIG. 7 illustrates a conventional transmission of a HARQ-ACK bit in a cPHICH.
Referring to FIG. 7, a HARQ-ACK bit 710 is multiplied 722, 724, 726, and 728, by each element of the WH code 732, 734, 736, 738 and a resulting output is placed on the I-branch of a QPSK modulated RE 742, 744, 746, and 748 (the Q-branch may be used to transmit another HARQ-ACK bit). The WH code may be one of 4 WH codes 750. With I/Q multiplexing and orthogonal sequence multiplexing with NSF,freqcPHICH=4, 8 cPHICHs are provided within one cREG. As for a CFI transmission, a transmission in each cPHICH group may be repeated over multiple cREGs to obtain frequency diversity and improve the effective SINR of each HARQ-ACK signal.
A UE receiver for a cPHICH only performs the conventional functions of QPSK demodulation and WH code despreading (and averaging over repeated cPHICH group transmissions as discussed below), which is similar to the cPFCICH UE receiver functions illustrated in FIG. 6 (with the exception of WH code dispreading).
A cPHICH resource is identified by a pair (ncPHICHgroup, ncPHICHseq), where ncPHICHgroup is a cPHICH group number and ncPHICHseq is a WH code index within a cPHICH group. A number of cPHICH groups is ncPHICHgroup=┌Ng(NRBDL/8)┐, where Ngε{⅙,½,1,2} is a parameter informed to UEs through a broadcast channel, NRBDL is a total number of RBs in a DL BW, and ┌ ┐ is a "ceiling" operation rounding a number to its next integer.
A UE is normally informed of NRBDL prior to a cPHICH reception, but this may not be possible for the total number of UL RBs, NRBUL, in an UL BW. Accordingly, NRBDL (not NRBUL) is used to specify NcPHICHgroup. A cPHICH group number is determined as shown in Equation (2).ncPHICHgroup=(IRB—RAlowest—index+CSI)mod NcPHICHgroup  (2)
Further, a WH code index within a group is determined as shown in Equation (3).ncPHICHseq=(└IRB—RAlowest—index/NcPHICHgroup┘+CSI)mod 2NSF,freqcPHICH  (3)
In Equations (2) and (3) IRB—RAlowest—index represents a smallest RB index of a PUSCH transmitting a data TB corresponding to a HARQ-ACK bit transmitted in a cPHICH, CSI represents a CSI of a Zadoff-Chu (ZC) sequence used for DMRS transmission in a PUSCH, and └ ┘ is a "floor" operation rounding a number to its previous integer.
cPHICH resources corresponding to consecutive UL RBs are mapped to different cPHICH groups. For simplicity, one data TB per PUSCH is assumed herein, but the above expressions can be generalized for multiple data TBs per PUSCH.
A DL control region for transmitting cCCHs uses a maximum of M=3 OFDM symbols and each cCCH is transmitted over substantially an entire DL BW. Consequently, the DL control has limited capacity and cannot achieve interference co-ordination in the frequency domain.
There are several cases where expanded capacity or interference co-ordination in the frequency domain is used for transmitting CCHs. For example, one such case is a communication system with cell aggregation, where DL SAs or UL SAs for UEs in multiple cells are transmitted in a single cell. Another case is an extensive use of spatial multiplexing, where multiple DL SAs or UL SAs schedule respective PDSCHs or PUSCHs in same respective resources. Another case is when DL transmissions in one cell experience strong interference from DL transmissions in another cell and DL interference co-ordination in the frequency domain between the two cells is needed.
However, due to the cREG-based transmission and interleaving of the cCCHs, a conventional DL control region cannot be expanded to include more OFDM symbols while maintaining compatible operation with existing UEs, which will not be aware of such expansion.
An alternative is to extend a DL control region in the PDSCH region and use individual RBs over a number of subframe symbols for transmitting enhanced CCHs (eCCHs) and include ePDCCH, ePCFICH, and ePHICH.
FIG. 8 illustrates a conventional structure for eCCH transmissions.
Referring to FIG. 8, although eCCH transmissions start immediately after cCCH transmissions 810 and are over all remaining subframe symbols, alternatively, they may start at a fixed location, such as the fourth OFDM symbol, and extend over a part of the remaining subframe symbols. In FIG. 8, eCCH transmissions occur in four RBs, 820, 830, 840, and 850, while the remaining RBs are used for PDSCH transmissions 860, 862, 864, 866, and 868.
However, several aspects for an eCCH operation in FIG. 8 still need to be defined in order to provide a functional design.
One aspect is the RS used for demodulation of eCCHs. A CRS transmitted over an entire DL BW may not always exist or may not always be received by all UEs without significant interference. Therefore, the CRS may not be generally relied upon for demodulating eCCHs. A DMRS is associated with UE-specific precoding and although UE-specific DMRS can be associated with an eCCH transmission to a UE, the UE-specific DMRS cannot be associated with multiple eCCH transmissions to respectively multiple UEs.
Another aspect is the multiplexing and transmission of an ePCFICH and the functionality for a respective eCFI indicating a size of an enhanced control region in a respective DL subframe.
Another aspect is the multiplexing and transmission structure for an ePHICH in an enhanced control region.
Another aspect is the multiplexing and support for a CSS and for a UE-DSS for ePDCCH transmissions and detections.
Therefore, there is a need to define an operation for an enhanced DL control region.
There is another need to define an RS used by multiple UEs for demodulating respective eCCHs transmitted over multiple RBs.
There is another need to define a multiplexing and transmission structure for an ePCFICH and an operation for a respective eCFI.
There is another need to define a multiplexing and transmission structure for ePHICHs.
Finally, there is another need to define a multiplexing and transmission process for an ePDCCH in an enhanced CSS or an enhanced UE-DSS and a UE operation for detecting this ePDCCH.

Extension of physical downlink control channels in a communication system


A multirotor aircraft that includes a chassis, three or more vertical rotors, one or more free wings and one or more fixed horizontal rotor. The free wing is attached to the chassis by an axial connection so that the angle of the free wing is changed relative to the chassis according the flow of air over the free wing. The fixed horizontal rotor enables the multirotor aircraft to lower and climb while flying forward at a stable horizontal pitch of the chassis.

The inventor and applicant of the invention subject matter of the present patent application is also the inventor and applicant of PCT/IL2015/050874 which was published as WO2016/035068 and claims priority from Israeli patent application 234443, which describes a multirotor that includes chassis, three or more vertical rotors, and a free wing that can rotate freely around its longitudinal axis, thus providing the aircraft with lift during horizontal flight. The present invention refers to such multirotor that further includes a fixed horizontal rotor and unique control system. The contents of the above PCT/IL2015/050874 are all incorporated by reference as if fully set forth herein in their entirety. This invention deals with the substance and control of aircraft with a free wing, having the ability of vertical take-off and landing. It flies horizontally in a constant pitch angle by using a wing which moves freely around a vertical axis and driven by vertical and horizontal engines. By using a constant wing at least two thirds of the energy needed for the flight is saved.
Aircrafts with a constant wing are usually built from a chassis, wings and engines which are joined together rigidly. This forces the aircraft to adjust to the direction of the air flow so that air flows around the wing to produce lift. In order to climb or lower the vehicle has to change its pitch angle. The pitch angle is a nuisance for several reasons. First, it makes it uncomfortable for people to walk inside the aircraft when the angle is too sharp or changed. Second, when a camera or a baggage are installed then some stabilizing devices are needed, like engines and mechanisms with some degrees of freedom which will stabilize them in order to keep the camera in a constant horizontal angle. These stabilizing devices are complicated, expensive and add extra weight to the aircraft. The present invention combines a unique structure and a unique flight control algorithm which enable the aircraft to fly horizontally at a fixed pitch angle both while climbing and lowering as long as no turns are needed. This removes one important degree of freedom, because during aerial photographing the aircraft flies straight but has to change its altitude according to the physical features. If a vertical Photograph of the ground is needed, it can be done without a use of stabilization gimbal or other stabilization means of the camera.
An industry has recent emerged, that is engaged in the development, manufacture, and use of aircraft able to take off and/or land vertically and to fly horizontally. These aircraft may be either manned or unmanned vehicles and have employ of variety of configurations with respect to the wings, propulsion and lift systems, payload areas, and the like. Such aircraft are often characterized by having a propulsion system that enables vertical takeoff and landing of the aircraft. Once the aircraft is airborne, the orientation of the propulsion system (e.g., including propellers or jet engines) may be adjusted in order to propel the aircraft forward in horizontal flight. Accordingly, such aircraft are able to take off and land vertically, hover, and fly horizontally using the propulsion system. The aircraft is controlled and stabilized using sensors and a flight control system that controls and transmits commands to the aircraft's propulsion system.
One of the disadvantages of such known aircraft configuration is the limitation in which the aircraft can remain airborne. This limitation stems from the fact that when the aircraft is in horizontal flight, some of the energy from the propulsion system is utilized for horizontal, forward movement. Therefore, certain aircraft configurations include wings to enhance energy efficiency in horizontal flight. In certain aircraft configurations equipped with wings, part or all of propulsion system is attached to the wings by a fixed connection, so that the angle there between is fixed and rotary movement of the propulsion system occurs simultaneously with wing rotation.
In other configurations, the wing and propulsion system are fixed in relation to the chassis. A disadvantage of the aforementioned configuration in which propulsion and wing have a fixed connection, relates to losses and inefficiencies during takeoff, landing, and hover. For example, when the wings are vertical relative to the earth (e.g., with engines facing upwards, functioning like a helicopter) and conditions are windy, drag and instability ensue. Similarly, in an aircraft configuration in which both engines and the wing are connected to the chassis by a fixed connection, a negative lift and/or drag is created on the wing during takeoff, landing, or hover with either a rear wind or a side wind.
The above disadvantages result in energy losses (and therefore also increased engine operation) or even a deviation from a designated vertical landing line or hovering point. This may be especially problematic when the aircraft is to be landed on the roof of a building, in which case a side wind at the precise moment of landing may divert the aircraft from its landing point.
Using actuators and various mechanical mechanisms to stabilize the aircraft may reduce reliability, which is particularly hazardous when the components are critical for flight. Furthermore, such mechanisms are heavy and thus reduce the maximum flight time or freight-carrying capacity of the aircraft.
Prior art solutions for vertical takeoff and landing (VTOL) vehicles have not resolved the need for an approach to perform one or more of the above actions without drawbacks, e.g., mechanical/electrical complexity, efficiency losses, reliability losses, size and weight constraints, and/or cost-prohibitive. Therefore, there is a need for systems and methods that address one or more of the deficiencies described above amongst others. Accordingly, there remains a need to provide aerodynamic and efficient vehicle that overcomes one or more of the above noted deficiencies.

Free wing multirotor with vertical and horizontal rotors


A constant current LED driver with adaptive startup voltage control is generally configured to provide output current to an LED load. A controller is configured to sense the output current, and to provide driving control signals as a function thereof to maintain the sensed current at a target current. During startup operation, the controller provides driving control signals further as a function of a first defined maximum output voltage value. During steady state operation, the driving control signals are provided as a function of a second defined maximum output voltage value. The maximum values may be set according to forward voltage drop values for the LED load in association with first and second temperatures, respectively. During transition operations, the maximum output voltage value is continuously adjusted between the first and second maximum output voltage values, such that the LED load exceeds its warm up time prior to steady state operation.

The present invention relates generally to circuitry and methods for providing constant current to a light source such as an LED load. More particularly, the present invention relates to an adaptive startup voltage control for a constant current LED driver.
Light emitting diode ("LED") lighting is growing in popularity due to decreasing costs and long life compared to incandescent lighting and fluorescent lighting. LED lighting can also be dimmed without impairing the useful life of the LED light source, and is generally effective in extremely cold environments, such as for example −40 degrees Celsius (° C.).
Generally speaking, LED lighting applications are designed to control the output current in the load and not the voltage, as the forward voltage of an LED load can vary dramatically, for example as a function of temperature, and a fixed voltage output would likewise produce varying output current and lighting output levels. Conventional LED drivers therefore sense an output current provided to the load and a feedback circuit implemented by the controller maintains the output current to a substantially constant value.
However, as the current flow through the LED load may vary as a function of temperature, the brightness of the LED lighting output may change along with the temperature of the LED load even while the current supplied from the LED driver remains substantially constant. Therefore, at least for certain temperature variations, the output current from the driver circuit to the LED load must vary as a function of temperature in order to maintain appropriately constant lighting output.
A typical representation of forward voltage drop characteristics for an LED load versus temperature is shown in FIG. 1. As represented in FIG. 1, the incremental forward voltage drop for an LED load is relatively flat, or in other words substantially unchanging, after the temperature of the load exceeds about 20 degrees Celsius. However, the load voltage may be dramatically higher at −40 degrees Celsius than a voltage for the same LED load at a temperature such as 20 degrees Celsius, and typically it could approach levels 30% higher or more.
This forward drop voltage differential for loads at such different temperatures is a challenge for LED driver designers. When an LED load reaches steady state operation at full bright lighting output, it is generally hot enough to maintain a reasonably high temperature (for example >20 degrees Celsius) because LEDs generate heat after a relatively short warm up time. LED driver designs typically include a maximum output voltage to limit the output power of the driver. This maximum output voltage limit typically is designed around the forward voltage drop at the steady state temperature (e.g., around 20° C.).
However, again with reference to the characteristic curve in FIG. 1, if the temperature at startup is around −40° C. the forward voltage of the LED load will be much greater than the voltage at 20° C. The driver circuit might not be able to start the LED load at −40° C. or otherwise maintain full current if the driver output voltage limit is set around Vf+20 (i.e., forward drop at +20° C.). If the LED driver design is accordingly modified to force the maximum output voltage limit to be the forward drop at −40° C., the LED driver output voltage will by necessity be over-designed for steady state operation, with a power limit substantially 30% higher or even more with respect to a desired configuration. This over-voltage design is highly undesirable, as it would typically increase the product cost and size dramatically.

This patent is subject to a terminal disclaimer.

Adaptive startup method for constant current LED drivers


A method of providing near simultaneous night vision and communication including directing a narrow voice modulated IR laser beam at a distant receiver/demodulator during communication periods, causing the IR laser beam to diverge substantially during scene viewing periods, other than the data communication periods, for illuminating a darkened scene which includes the laser beam receiver, and viewing the darkened scene with an IR viewing device.

The present invention relates to the field of laser communication devices.
The concept of laser communications is fairly mature. It is known to modulate laser beams with various types of data in order to transmit the data over substantial distances. U.S. Pat. No. 4,959,827 to Grotzinger et al. teaches voice modulation of a laser beam for secure voice communication, while U.S. Pat. No. 4,823,401 to Gammarino teaches modulation of a laser beam with binary data to be transmitted to a distant receiver for recovery of the data.
It is deemed desirable to provide devices for secure voice communication over one or two kilometers by modulation of a laser beam. The devices should be compact, light weight and portable in order to minimize adverse impact on the effectiveness of military ground combatants. It is also desirable to provide civilian police with a capability to operate in a dangerous night time mission such as attempting to arrest an armed criminal. Since police departments have limited budgets, cost is an important factor.
It is also deemed desirable to be able to give the police or military combatants the ability to see in the dark in order to determine the location and behavior of an armed person who may be occupying the darkened scene. Since cost is an important factor, what is really needed is the ability to provide secure voice communication along with the ability to see in the dark through the use of essentially the same piece of equipment which is not costly.

Pocket laser communicator and illuminator

The United States of America as represented by the Secretary of the Air Force


The present invention relates to an SDH transmission technique. In an SDH transmission system including a plurality of SDH transmission units for multiplex relay and one SDH transmission unit for relay, with a desired network formed by the respective SDH transmission units, the SDH transmission system is provided with a relay section for a communication carried out between the SDH transmission unit and the SDH transmission unit, or between the SDH transmission units, a multiplexing section for a communication carried out between the transmission units, and a network section for a desired communication carried out irrespective of the multiplexing section and the relay section in the above network. It is thereby possible to freely carry out a desired communication in the network irrespective of the relay section and the multiplexing section which are defined in an SDH transmission mode.

(1) Field of the Invention
The present invention relates to an SDH (Synchronous Digital Hierarchy) transmission system, and a frame transmission method in an SDH transmission system and an SDH transmission unit, and more particularly to a transmission method suitable for use in a SONET in accordance with an SDH transmission mode.
(2) Description of the Related Art
(A) Description of Transmission Frame Handled in SONET (SDH) Transmission Mode
FIG. 9 is a diagram showing a format of a basic transmission frame handled in a SONET (Synchronous Optical Network). As shown in FIG. 9, the basic transmission frame for the SONET has 9xc3x973 bytes of overhead 10 containing various operation and maintenance (supervisory control) information such as frame synchronization signal, or parity check signal, and 9xc3x9787 bytes of payload 20 containing actually transmitted data, resulting in information of 9xc3x9790 bytes in total. In the SONET, the 90xc3x979 bytes (=810 bytes) of frame is transmitted 8000 times per second, thereby generating a signal [referred to as STS-1 (Synchronous Transport Signal Level 1) , or STM-0 (Synchronous Transfer Module Level 0) in the SDH] having a transmission rate of 51.84M (=90xc3x979xc3x978xc3x978000) b/s. As used herein, xe2x80x9cSONETxe2x80x9d means a network currently used in North America in accordance with an SDH transmission mode.
Further, as is well known, the overhead 10 is provided with a section overhead [(R-) SOH] 11 which, in communication between a line terminal multiplex relay transmission unit (LTE) and a regenerator unit (REG), or between the regenerator units (REG) (referred to as xe2x80x9csectionxe2x80x9d in the SONET, or xe2x80x9cregenerator (R-) sectionxe2x80x9d in the SDH: see reference numeral 11A in FIG. 13) , is terminated and replaced at the LTE and the REG, and a line overhead [LOH (M-SOH)] 12 which, in communication between the LTE (referred to as xe2x80x9clinexe2x80x9d in the SONET, or xe2x80x9cmultiplex (M-)sectionxe2x80x9d in the SDH: see reference numeral 12A in FIG. 13), is terminated and replaced at the pieces of LTE.
Additionally, the overhead 10 is provided with the various operation and maintenance information. For example, as shown in FIG. 10, in the SOH 11 are defined A1, A2 bytes used to establish frame synchronization, a digital error supervising [BIP (Bit Interleaved Parity] byte B1 used on the section 11A, and data communication channel (DCC) bytes D1 to D3 (data link of 192 k b/s) for communication for a supervisory control in the section 11A. In the LOH 12 are defined a BIP byte B2 over a line 12A, APS (Automatic Protection Switch) bytes K1, K2, and DCC bytes D4 to D12 (data link of 576 k b/s) over the line 12A.
Moreover, in FIGS. 9 and 10, pointer bytes (AU [administrative unit] pointer) 13 shows, by using an address, a difference between a phase of a transmission frame and a frame phase of an administrative data unit (VT: Virtual Tributary Unit) contained in the payload 20. The pointer bytes 13 can rapidly establish frame synchronization of the VT.
Further, in the SONET, the basic transmission frame (STS-1) having the above-mentioned format is processed through byte multiplexing by n frames (where n=3, 12, 48, 192, and so forth), thereby forming an STS-n frame as shown in FIG. 11. It is possible to generate a high-speed signal with, for example, an STS-3 (of 155.52M b/s=51.84M b/sxc3x973) if the STS-1 frame is processed through the byte multiplexing by 3 frames, an STS-12 (of 622.08 M b/s) if processed through the byte multiplexing by 12 frames, anSTS-48 (of 2.488 G b/s) if processed through the byte multiplexing by 48 frames, and an STS-192 (of 9.953 G b/s) if processed through the byte multiplexing by 192 frames. Moreover, in the SDH, STM-N (N=n/3) respectively correspond to signals having the same transmission rates as those of the above STS-n.
Here, in the case of the STS-192, as shown in FIG. 12, the frame includes 9xc3x97576 (3xc3x97192) bytes of overhead 10 and 9xc3x9716704 (87xc3x97192) bytes of payload 20. However, all the bytes of the overhead 10 are not used. As shown in FIG. 12, only one byte is used for each area for operation and maintenance information (such as B1, E1, and F1) except special signals (such as A1, A2 bytes, and BIP byte B2). Hence, under the present circumstances, almost the entire area of the overhead 10 is left free.
(B) Description of SONET
FIG. 14 is a block diagram showing an illustrative SONET (transmission system). In the SONET 100 shown in FIG. 14, a 10 G ring network 200 for handling a transmission frame (STS-192) of about 10 G b/s, 2.4 G ring networks 300, 400 for handling a transmission frame (STS-48) of about 2.4 G b/s, and a 622 M ring network 500 for handling a transmission frame (STS-12) of about 622 M b/s are interconnected through transmission units serving as gateways which will respectively be described infra.
Further, as shown in FIG. 14, for example, in the 10 G ring network 200 (hereinafter briefly referred to as 10 G ring 200), a plurality of 10 G b/s line terminal multiplex relay transmission units (LTE) 110-1 to 110-4 and a plurality of 10 G b/s regenerator units (REG) 111 are connected in a ring manner. Similarly, in the 2.4 G ring networks 300, 400 (hereinafter briefly referred to as 2.4 G rings 300, 400), 2.4 G b/s LTE 120-1 to 120-4, and 130-1 to 130-4 are connected in the ring manner. In the 622M ring network 500 (hereinafter briefly referred to as 622M ring 500), 622M b/s LTE 140-1 to 140-4 are connected in the ring manner.
Moreover, in the 10 G ring network 200, according to a maximum transmittable distance of the line terminal multiplex relay transmission unit 110-i (where i=1 to 4), a proper number of regenerator units (REG) 111 are mounted between the line terminal multiplex relay transmission units 110-i to form the section 11A. It is to be noted that the regenerator unit 111 may be mounted in the 2.4 G rings 300, 400, or in the 622M ring 500.
Here, the transmission units (LTE) 110-i, 120-i, 130-i, and 140-i, and the transmission units 111 [hereinafter referred to as xe2x80x9ctransmission unit 100Axe2x80x9d or xe2x80x9cnode unit 100Axe2x80x9d unless the transmission units 110-i, 120-i, 130-i, 140-i, and 111 (LTE, REG) are individually shown] forming the rings 200 to 500 respectively have the function of performing replacement (termination/insertion) processing of the overhead 10 of the received transmission frame STS-n (STM-N). With attention to the function, as shown in FIG. 15, the transmission unit includes interface portions 171 to 173 according to a transmission frame to be handled (a speed of an accommodated line), a HUB circuit portion 174, a HED circuit portion 175, optical fibers 176, a CPU circuit portion 177, and so forth.
Further, each of the above interface portions 171 to 173 terminates a corresponding optical signal frame among, for example, an OC-192 (Optical Carrier-level 192) serving as an optical signal frame of the STS-192, an OC-48 serving as an optical signal frame of the STS-48, and an OC-12 serving as an optical signal frame of the STS-12, and extracts OH information in the overhead 10 to output the OH information to the HUB circuit portion 174, while inserting (storing) the OH information output from the HUB circuit portion 174 in the overhead 10 at a predetermined position.
However, the overhead 10 serving as a candidate for the termination/insertion processing varies depending upon whether it is processed in the interface portions 171 to 173 in the LTE 110-i, 120-i, 130-i, and 140-i, or in those in the REG 111. That is, both the SOH 11 and the LOH 12 are terminated in each of the LTE 110-i, 120-i, 130-i, and 140-i, and only the SOH 11 is terminated in each of the REG 111.
Moreover, all the interface portions 171 to 173 are not always used. For example, in the REG 111 shown in FIG. 14, the only type of interface portion, i.e., the interface portion 171 for the OC-192 is used.
Further, the HUB circuit portion 174 feeds the OH information from the interface portions 171 to 173 to the CPU circuit portion 177 through the HED circuit portion 175, while feeding to the corresponding interface portions 171 to 173 the OH information fed from the CPU circuit through the HED circuit portion 175. Here, the optical fibers 176 are used for connection with the HED circuit portion 175. It is thereby possible to perform high-speed OH information transmission processing between the HUB circuit portion 174 and the HED circuit portion 175 by using an ATM (Asynchronous Transfer Mode) cell-based optical signal.
Hence, as shown in FIG. 15, the HUB circuit portion 174 has a HUB portion 174A having the function of ATM cell generating (splitting)/multiplexing of the OH information from the interface portions 171 to 173, and an optical repeating regenerator (OR/OS: Optical Receiver/Optical Sender) 174B functioning as an electro/optical interface with the optical fibers 176.
Further, the above HED circuit portion 175 outputs to the CPU circuit portion 177 OH information input as an ATM cell through the optical fiber 176, while splitting into ATM cells and outputting to the HUB circuit portion 174 through the optical fiber 176 the OH information generated in the CPU circuit portion 175. For this purpose, the HED circuit portion includes an optical repeating regenerator (OS/OR) 175B functioning as an electro/optical interface with the optical fiber 176, and an overhead matrix portion 175B to make a routing control such that the ATM cell (OH information) from the HUB circuit portion 174 can be output to any one of a plurality of SCC (Serial Communication Channel) ports 178 of the CPU circuit portion 177. Moreover, the overhead matrix portion 175B also has the function of splitting into ATM cells the OH information generated in the CPU circuit portion 177.
Further, the CPU circuit portion 177 analyzes the OH information fed from the HED circuit portion 175, and generates OH information to be transmitted after being inserted in an overhead 10 of a transmission frame sent to an additional transmission unit 110, thereby making a supervisory control of the system 100. In the CPU circuit portion 177, the plurality of SCC ports 178 are connected to a CPU 180 through a bus 179.
According to the above configuration, in the above SONET transmission network 100, the termination/insertion processing of the overhead 10 is performed through the CPU 180 for each of the transmission units 100A, thus appropriately performing the transmission processing of the supervisory control information for the transmission network 100. This enables a network control unit 150 (see FIG. 14) to make a centralized supervisory control (such as construction of a communication path, or a network control (in operation) after the communication path construction) of the transmission network 100.
Specifically, the centralized supervisory control is typically made by communication between the CPUs 180 of the respective node units 100A by using the above D1 to D3 bytes or the D4 to D12 bytes for the DCC in the overhead 10.
Here, the communication path for communication is automatically constructed (set) by the network control unit 150 when, for example, the node unit 100A is turned on. That is, the network control unit 150 instructs, by using the DCC, one node unit 100A to set the communication path. The CPU 180 of the node unit 100A receives the instruction, and automatically and concurrently calls the CPUs 180 of all the other node units 100A by using the DCC [see FIG. 16(a)].
Further, the network control unit 150 determines a path (route) used for an actual communication (supervisory control) depending upon directions in which answers come back from the node units, and identification information (node ID) of the respective node units 10A, set to the answers [see FIG. 16(b)].
This enables the network control unit 150 to automatically set the communication (supervisory control) path irrespective of a network configuration. Moreover, when answers from the same node unit 100A come back from a plurality of directions, the network control unit 150 sets the path in a direction from which the first answer comes back.
Further, after setting the path as described above, the network control unit 150 communicates with the CPU 180 of a desired node unit 100A by using the DCC (through the set path), thereby making the centralized supervisory control of the transmission network 100 (for example, canceling an alarm generated in one node unit 100A). Moreover, after the communication path is set, the communication path may become unavailable due to, for example, a line trouble. In such a case, the network control unit 150 reconstructs a communication path as in the above discussion after the elapse of a desired time period (after, for example, about ten minutes).
However, in the system 100 using such a DCC, the centralized supervisory control requires a significantly complex protocol. Thus, it becomes difficult under the present circumstances to continuously obtain a stable operation. For example, when a large amount of alarms are given in one node unit 100A at the same time, the load on the CPU 180 of the node unit 100A rapidly increases, and a system down may be caused.
Further, when the communication path become unavailable due to a failure of the node unit 100A on the communication path in use, the line trouble, and so forth, the communication path can not be restored before, for example, the elapse of ten minutes as described above. Consequently, the restoration of the communication path takes a long time, resulting in a problem of reduced reliability of the centralized supervisory control.
Further, in the above system 100, a normal communication can be carried out with networks 160A, 160B (see FIG. 14) of other companies (other makers) since a recommendation provides a part concerning transmission of main signal, such as the frame synchronization establishment, parity operation, and handling of the payload 20. However, the companies have their own specifications for specifying another part concerning the communication between the CPUs 180, such as DCC. For example, in some cases, supervisory control information in the network 160A, 160B of the other companies can not directly pass through the 10 G ring 200.
Hence, in recent years, in the network (10 G ring 200) providing lines additionally connected to the network 160A, 160B of the other companies as shown in FIG. 14, it has been desired to perform no processing for supervisory control information other than own supervisory control information, and transparently pass the information to the other companies"" networks 160A, 160B (see FIG. 17).
In order to realize such a transparent transmission, there is one possible method in that a special byte for the purpose is additionally prepared (defined) in a space area (undefined byte) of the overhead 10, and the supervisory control information in the other companies"" networks 160A, 160B are set thereto (inserted therein).
However, the additional definition of the special byte causes a complicated control (handling) of the termination/insertion processing in the respective node units 100A, resulting in, for example, excessive load on hardware (mainly on the above interface portions 171 to 173), or an increase in hardware scale itself. Further, it becomes very difficult to control, for example, between which node unit 100A and which node unit 100A a certain byte should be transmitted.
In addition, in the system 100 of the same maker, though clock synchronization can basically be maintained at a time of termination/insertion of the overhead 10 in the node unit 100A, there may generally be left a slight difference. Consequently, little guarantee can be given that complete clock synchronization can be maintained when connected to the other companies"" networks 160A, 160B. Hence, when passing the supervisory control information received from the other companies"" networks 160A, 160B, data slip (loss or rereading) may occur in the node unit 100A due to a slight difference in clock.
That is, in the conventional system 100, the OH information of the overhead 10 is terminated in the respective node units 100A forming the section 11A or the line 12A, thereby continuously carrying out the communication about the supervisory control information through the CPUs 180 of the respective node units 100A. Hence, it is impossible to carry out a free communication for a supervisory control irrespective of the section 11A and the line 12A in the system 100. As a result, there are caused phenomena in that, for example, a stable supervisory control can not be made due to a rapid variation in load on the CPU 180, and OH information in conformance with specifications different from those of the own network can not be transmitted.
In view of the foregoing problems, it is an object of the present invention to provide an SDH transmission system, a frame transmission method in an SDH transmission system and an SDH transmission unit in which a desired communication can freely be carried out in a network irrespective of a relay section and a multiplexing section defined in an SDH transmission mode.
According to the present invention, for achieving the above-mentioned object, there is provided an SDH transmission system including a plurality of SDH transmission units for multiplex relay to carry out a multiplex relay transmission of a transmission frame in an SDH transmission mode, and at least one SDH transmission unit for relay to-carry out a relay transmission of the transmission frame between the SDH transmission units for multiplex relay, with a desired network formed by the plurality of SDH transmission units. Further, the SDH transmission system is provided with a relay section for a communication carried out by transmitting the transmission frame between the SDH transmission unit for multiplex relay and the SDH transmission unit for relay, or between the SDH transmission units for relay, a multiplexing section for a communication carried out by transmitting the transmission frame between the SDH transmission units for multiplex relay, and a network section for a desired communication carried out irrespective of the multiplexing section and the relay section in the network.
Therefore, it is possible to carry out a free communication in the network without much concern for the multiplexing section and the relay section, thereby providing the following advantages:
(1) It is possible to reduce the load of communication processing in the SDH transmission unit so as to stabilize the communication in the entire system.
(2) It is possible to make a normal connection through the network section to a network having specifications different from those of communication processing in the own network.
Here, in the SDH transmission system, an area for asynchronous communication may be reserved on an overhead portion of the above transmission frame, thereby carrying out the asynchronous communication in the above network section.
It is thereby possible to normally carry out the communication in the network without much concern for a clock of the transmission frame, resulting in a more simplified and higher-speed communication control in the network section.
Further, in the SDH transmission system, the area for asynchronous communication may be reserved on, in the above overhead portion, an overhead portion for a multiplexing section terminated in the SDH transmission unit for multiplex relay, thereby carrying out the asynchronous communication between the SDH transmission units for multiplex relay in the network section.
Further, in the SDH transmission system, the area for asynchronous communication may be reserved on, in the above overhead portion, at least an overhead portion for a relay section terminated in the SDH transmission unit for relay, thereby carrying out the asynchronous communication through the SDH transmission unit for multiplex relay and the SDH transmission unit for relay in the above network section.
It is thereby possible to carry out a communication with the desired SDH transmission unit for multiplex relay or relay in the network section, resulting in a contribution to flexibility of the communication in the network section.
Besides, in the SDH transmission system, an asynchronous communication cell having a communication control information portion and a data portion may be inserted in the above area for asynchronous communication, and the above SDH transmission unit may be provided with an asynchronous communication control portion capable of transmitting the asynchronous communication cell to the additional SDH transmission unit for multiplexing relay depending upon the communication control information portion of the asynchronous communication cell.
In the SDH transmission system, in the network section, the asynchronous communication cell is transmitted to the desired SDH transmission unit depending upon the communication control information portion thereof. Consequently, an extremely easy control can realize a high-speed communication in the network section. Additionally, it is possible to control a transmission destination (that is, a communication partner) of the above cell by simply controlling only the above communication control information portion, resulting in a very simplified control of the transmission destination.
Moreover, the communication in the network section may be made redundant. Thereby, it is possible to normally continue the communication in the network section even when the communication in the partial network section becomes unavailable due to occurrence of a failure or the like, resulting in significantly enhanced reliability of the system.
In this case, for example, two communication routes may be set in the above network section to carry out a communication by using, when one of the communication routes becomes unavailable, the other communication route. It is possible to extremely easily realize redundancy of the above network section.
Further, in the SDH transmission system, the above SDH transmission units may be connected in a ring manner to form a ring network as the above network, and communication routes respectively extending to the right and the left with respect to the above ring network may be set as the above two communication routes in the network section of the ring network. Thereby, it is also possible to extremely easily realize redundancy of the network section in the ring network.
Moreover, when any one of the above communication routes respectively extending to the right and the left is previously set to an unavailable state, only any one of the communication routes is used. Consequently, in the SDH transmission unit to terminate the communication routes, it is unnecessary to select the communication route, and continuously supervise in which of the communication routes the trouble occurs. Thus, it is possible to simplify, at least, the SDH transmission unit to terminate the communication routes.
Further, in this case, when the communication route different from the communication route set to the unavailable state becomes unavailable, the communication route set to the unavailable state may be set to an available state. In this case, it is also possible to normally continue the communication in the network section, resulting in significantly enhanced reliability of the system.
Besides, in the communication control information portion of the asynchronous communication cell may be set at least identification information of an SDH transmission unit serving as a transmission destination of the asynchronous communication cell. The above cell can thereby be transmitted to pass through intermediate SDH transmission units (a relay section, a multiplexing section) until the cell reaches the corresponding transmission unit in the network section. As a result, it is possible to extremely easily realize an asynchronous communication with a desired SDH transmission unit in the network section.
Moreover, in the communication control information portion of the asynchronous communication cell may be set both identification information of an SDH transmission unit serving as a transmission destination of the asynchronous communication cell, and identification information of an SDH transmission unit serving as a source of the asynchronous communication cell. In this case, the above SDH transmission unit serving as the transmission destination can identify that signals, even with the same transmission destination identification information, respectively contain different data as long as source identification information are different. As a result, even when signals with the same transmission destination identification information are transmitted from a plurality of transmission units, it is possible to continuously carry out a normal communication.
Besides, when two communication routes are set in the network section of the ring network, in the communication control information of the above asynchronous communication cell may be set identification information of the SDH transmission unit serving as a transmission destination of the asynchronous communication cell, identification information of the SDH transmission unit serving as a source of the asynchronous communication cell, and flag information used to identify through which of the respective communication routes the asynchronous communication cell is transmitted. Even when the respective communication routes are multiplexed in one SDH transmission unit, the communication route of the asynchronous communication cell can be identified depending upon the flag information. As a result, it is possible to surely perform selection of the communication route.
Further, when in the communication control information of a received asynchronous communication cell is set own identification information as the above identification information of the SDH transmission unit serving as the source, the above SDH transmission unit may discard the asynchronous communication cell. It is thereby possible to avoid a phenomenon in that, for example, a cell has no fixed destination by erroneously setting identification information which can not be found in the network section, and is left unerased indefinitely in the network, resulting in more enhanced reliability of the system.
Besides, as long as a received asynchronous communication cell can be transmitted to a network other than the above network, the above SDH transmission unit for multiplex relay can transmit the received asynchronous communication cell to the additional network as required. Thus, the above asynchronous communication can be applied to any type of network topology.
Next, in an SDH transmission system to transmit a transmission frame in an SDH transmission mode, a frame transmission method in the SDH transmission mode of the present invention includes the steps of inserting an asynchronous communication cell in a space area of an overhead portion of the transmission frame, and transmitting the transmission frame.
Thus, according to a frame transmission method in the SDH transmission mode of the present invention, it is possible to provide the following advantages:
(1) It is possible to make a supervisory control of the SDH transmission system by using the asynchronous communication, reduce the load of communication processing for the supervisory control, and make the above communication processing higher.
(2) Since the space area of the overhead portion is not fixedly used, it is possible to considerably enhance versatility and expandability of the communication processing for the above supervisory control.
(3) Since the asynchronous communication cell enables asynchronous transmission for the supervisory control without much concern for a clock of the transmission frame, resulting in an extremely easy communication control.
(4) It is possible to apply the existing asynchronous communication technique, resulting in very high practicability.
In addition, an SDH transmission unit of the present invention transmits a transmission frame in an SDH transmission mode. The SDH transmission unit includes a first overhead information extracting portion to extract first overhead information inserted in a space area of an overhead portion of a received transmission frame, a second overhead information extracting portion to extract second overhead information set in an area other than the above space area of the overhead portion, a main communication control portion to perform desired communication processing about the SDH transmission system depending upon the second overhead information extracted in the second overhead information extracting portion, an overhead inserting portion to insert a result of processing in the main communication control portion as an overhead portion of a transmission frame for an additional SDH transmission unit, and a distribution control portion to distribute to the overhead inserting portion at least first overhead information other than self-addressed information among the first overhead information extracted in the above first overhead information extracting portion so as to insert in a space area of the overhead portion for the additional SDH transmission unit.
Thus, according to the SDH transmission unit of the present invention, it is possible to provide the following advantages:
(1) Since the first overhead information other than the self-addressed information is transmitted after being inserted in the space area of the overhead portion of the transmission frame for the additional SDH transmission unit, it is possible to reduce the load of communication processing for the supervisory control.
(2) Since the space area of the overhead portion is not fixedly used, it is possible to considerably enhance versatility and expandability of the communication processing for the above supervisory control.
Here, the above first overhead information extracting portion may be configured as an asynchronous communication cell extracting portion to extract an asynchronous communication cell having a communication control information portion and a communication data portion, and the above distribution control portion may be configured as an asynchronous communication control portion to perform the above distribution processing depending upon communication control information set in the communication control information portion of the above asynchronous communication cell.
In this case, according to the SDH transmission unit, it is possible to provide the following advantages:
(1) The above communication processing can be made higher.
(2) Since the asynchronous communication cell enables asynchronous transmission for the supervisory control without much concern for a clock of the transmission frame, resulting in an extremely easy communication control.
(3) It is possible to apply the existing asynchronous communication technique, resulting in very high practicability.
Here, the above asynchronous communication control portion may include a switching mechanism portion to output, when communication control information of the received asynchronous communication cell is self-addressed information, the asynchronous communication cell to the above main communication processing portion, while outputting, when the communication control information of the received asynchronous communication cell is information other than the self-addressed information, the asynchronous communication cell to the above overhead inserting portion. It is thereby possible to realize the above distribution function in a simplified configuration.
Further, the above asynchronous communication control portion may include an asynchronous communication cell generating portion to generate an asynchronous communication cell addressed to an additional SDH transmission unit. In this case, the above switching mechanism portion may be set to output to the above overhead inserting portion the asynchronous communication cell generated in the asynchronous communication cell generating portion so as to insert in a space area of the overhead portion for the additional SDH transmission unit. It is thereby possible to transmit with a simple setting at a high speed a cell which needs to be posted to the additional SDH transmission unit.
Besides, the above asynchronous communication cell generating portion may set in the communication control information portion of the above asynchronous communication cell identification information of the additional SDH transmission unit serving as a transmission destination of the asynchronous communication cell. The above cell can thereby be transmitted to pass through intermediate SDH transmission units until the cell reaches the corresponding transmission unit. As a result, it is possible to extremely easily realize an asynchronous communication with the SDH transmission unit.
Further, the asynchronous communication cell generating portion may set in the communication control information portion of the above asynchronous communication cell both identification information of the additional SDH transmission unit serving as a transmission destination of the asynchronous communication cell, and own identification information. The SDH transmission unit serving as the transmission destination can identify that signals (cells), even with the same transmission destination identification information, respectively contain different data as long as source identification information are different. As a result, even when cells with the same transmission destination identification information are transmitted from a plurality of transmission units, it is possible to continuously carry out a normal communication.
Further, the above switching mechanism portion may discard, when own identification information is set in a communication control information portion of an asynchronous communication cell received from an additional SDH transmission unit, the asynchronous communication cell. It is thereby possible to avoid a phenomenon in that, for example, a cell has no fixed destination by erroneously setting identification information of an SDH transmission unit which does not exist, and is left unerased indefinitely in the network, thus greatly contributing to enhancement of reliability of the SDH system.
In addition, the switching mechanism portion may transmit, when in the communication control information portion of the above asynchronous communication cell is set transmission instruction information showing as a destination an SDH transmission unit in an additional SDH transmission system, the asynchronous communication cell to the SDH transmission unit in the additional SDH transmission system. Since it is thereby possible to transmit the received asynchronous communication cell to the additional network as required, the asynchronous communication can flexibly be applied to any type of network topology.

SDH transmission system, and frame transmission method in SDH transmission system and SDH transmission unit


A method and apparatus for reducing the loading impact between a sealing element in a suction valve of a piston compressor with a valve stop, wherein the sealing element is forcibly opened using a control device shortly before attaining pressure balance between cylinder and suction chambers of the compressor.

1. Field of the Invention
The present invention generally relates to compressor valves in a piston compressor. In particular, the invention relates to a method and apparatus for controlling the movement of a sealing element of a suction valve within a piston compressor by means of a control device.
2. Description of the Conventional Art
The useful life of an automatic compressor valve used mostly on the suction and pressure side is influenced primarily by the impact loading during the alternating impacting of an actual sealing element on a valve seat and/or valve stop. In particular, the sealing element is in a closed position when the pressure inside a cylinder chamber is greater than or equal to the counter-pressure of a suction chamber. When the counter-pressure of the suction chamber exceeds the falling pressure of the cylinder chamber (i.e., underpressure in the cylinder chamber), the sealing element is forced into an open position. Due to the rapid underpressure produced in the cylinder chamber, the sealing element, when moving toward an open position, accelerates at high speed in the direction of the valve stop. This rapid acceleration creates an undesirable loading impact on the sealing element which in turn adversely diminishes the useful life of the compressor valve.
In the case of a suction valve, by corresponding choice of the spring system, the closing speed can be kept sufficiently low to reduce the closing impact. For instance, to reduce the opening impact, a system of so-called double damping is used, which, after overcoming part of a stroke, the sealing element impacts on a damping plate or the like, movable in the direction of opening, is thereby braked and then, together with the damping plate, overcomes the remaining stroke, whereby the clearly enlarged moving mass causes a further decrease in the acceleration of the sealing element, resulting in a clearly reduced impact speed of the sealing element at the valve stop, compared with the simple valve of this kind.
Furthermore, compressor arrangements have become known in which, with the aid of so-called lift lugs (unloaders), on the one hand a capacity adjustment, continuously variable within certain limits, is brought about by partial holding open of the suction valve during the compression stroke, and in which, on the other hand, by corresponding dimensioning of the mass of the lift lug as well as the arrangement of motion damper, a lowering of the impact speed of the sealing element during closing is achieved.
To some extent the aforementioned arrangements also can be used to reduce the impact speed of the sealing element during opening: the lift lug is pressed by means of a spring against the sealing element or valve plate and, in any case, is already sitting there for a while before the pressure balance is attained. The additional opening force caused by this pressure spring may also open the sealing element under certain circumstances already before the pressure balance is attained. In this regard, however, the mass of the lift lug must be accelerated by the spring force against the overpressure in the cylinder chamber. Since the mass of such lift lugs is necessarily relatively great compared with the mass of the sealing elements used, in any case only a slight acceleration results and the premature opening of the sealing element caused by this under certain circumstances is minor.

Method and apparatus for controlling compressor valves in a piston compressor


A page zooming method for an electronic device includes the following steps. Displaying a page on the touch screen. Generating operation signals in response to a touch operation applied on the displayed page. Determining the touch operation as a page zoom gesture if one or more points on the displayed page is touched. Determining a quantity of the touched points of the touch operation, and determining the page zoom gesture is a zoom in gesture or a zoom out gesture and a zoom ratio according to the determined quantity of the touched points. Creating a zoomed page according to the displayed page, the determined zoom ratio and the determined type of the page zoom gesture. Displaying the zoomed page on the touch screen. An electronic device using the page zooming method is also provided.

1. Technical Field
The present disclosure relates to electronic devices and page zooming methods thereof, and particularly to, an electronic device having a touch screen and a page zooming method for the electronic device.
2. Description of Related Art
Electronic devices with touch screens, e.g., mobile phones, digital photo frames, electronic readers (e-reader), are capable of zooming the page displayed on the touch screen by manipulating the touch screen. For example, to zoom out the displayed page, the user uses two fingers sliding towards each other, and to zoom in the displayed page, the user uses two fingers sliding away from each other. However, both two fingers slide when applying the zooming method, which cannot satisfy various demands of different users.
Therefore, what is needed is an electronic device and a page zooming method thereof to alleviate the limitations described above.

Electronic device and page zooming method thereof

HONG FU JIN PRECISION INDUSTRY (ShenZhen) CO., LTD.


The invention relates to a method for purifying recombinant human FSH or an FSH variant starting from crude FSH, comprising the following steps: 1) dye-affinity chromatography; 2) hydrophobic interaction chromatography; and 3) reverse phase chromatography.

Follicle-stimulating hormone (FSH) is an injectable protein falling into the class of gonadotrophins. FSH is used in the treatment of infertility and reproductive disorders in both female and male patients.
In nature, FSH is produced by the pituitary gland. For pharmaceutical use, FSH may be produced recombinantly (rFSH), or it may be isolated from the urine of postmenopausal females (uFSH).
FSH is used in female patients in ovulation induction (OI) and in controlled ovarian hyperstimulation (COH) for assisted reproductive technologies (ART). In a typical treatment regimen for ovulation induction, a patient is administered daily injections of FSH or a variant (about 75 to 300 IU FSH/day) for a period of from about 6 to about 12 days. In a typical treatment regimen for controlled ovarian hyperstimulation, a patient is administered daily injections of FSH or a variant (about 150-600 IU FSH/day) for a period of from about 6 to about 12 days.
FSH is also used to induce spermatogenesis in men suffering from oligospermia. A regimen using 150 IU FSH 3 times weekly in combination with 2′500 IU hCG twice weekly has been successful in achieving an improvement in sperm count in men suffering from hypogonadotrophic hypogonadism [Burgues et al.; Subcutaneous self-administration of highly purified follicle stimulating hormone and human chorionic gonadotrophin for the treatment of male hypogonadotrophic hypogonadism. Spanish Collaborative Group on Male Hypogonadotrophic Hypogonadism; Hum. Reprod.; 1997, 12, 980-6].
Because of the importance of FSH in the treatment of fertility disorders, the provision of FSH of high purity and high specific activity is desirable. FSH treatment requires repeated injections. Highly purified FSH preparations can be administered subcutaneously, permitting self-administration by the patient, thus increasing patient convenience and compliance.
Lynch et al. [The extraction and purification of human pituitary follicle-stimulating hormone and luteinising hormone; Acta Endocrinologica, 1988, 288, 12-19] describe a method for purifying human pituitary FSH. The method involves anion and cation exchange chromatography, immunoaffinity extraction and size exclusion chromatography. The method is said to result in pituitary FSH having a specific activity of 4,990 IU (immunoassay)/mg, with 16 IU/mg of LH. Protein content was determined either by dry weight or in solution by absorption at 280 nm (assuming that A1 cm280 for 1 g/l is equal to 1).
WO 98/20039 (IBSA Institut Biochimique SA) describes a process for the purification of human urinary FSH starting with urinary extracts called human menopausal gonadotrophins (hMG). The process uses ion-exchange chromatography on weakly basic anionic exchange resins of the DEAE type followed by affinity chromatography on resin having an anthraquinone derivative as a ligand. The process is said to yield urinary FSH free from LH and having a specific activity of 6,870 IU (immunoassay)/mg. Protein content was determined by assuming that a water solution of 1 mg/ml of protein has an optical density of 0.62 at 277 nm, in quartz cuvettes with a 1 cm path length.
WO 00/63248 (Instituto Massone SA) describes a process for the purification of gonadotrophins, including FSH, from human urine. The process involves the following steps: ion exchange chromatography with a strong cationic resin of the type sulphopropyl, ion exchange chromatography with a strong anionic resin, and hydrophobic interaction chromatography (HIC). A FSH preparation having a specific activity of 8,400 IU/mg (Steelman-Pohley method: Assay of the follicle stimulating hormone based on the augmentation with human chorionic gonadotrophin; Endocrinology; 1953, 53, 604-616) and less than 1 IU LH (rat seminal vesicle weight gain method: Van Hell H, Matthijsen R & G A Overbeek; Acta Endocrinol, 1964, 47, 409) biological activity per 75 IU FSH is reportedly obtained. Protein content was performed by the Lowry method [O. H. Lowry et al., J. Biol. Chem., 1951, 193, 265].
U.S. Pat. No. 5,990,288 (Musick et al.) describes a method for purifying FSH from biological samples, such as human pituitary glands or human post-menopausal urine. The process uses cation exchange chromatography on Fractogel EMD SO3-650M, followed by dye affinity chromatography on Mimetic Orange 1 resin, followed by a step of hydrophobic interaction chromatography on Bakerbond Wide Pore HI-Propyl resin. The process is said to result in human pituitary FSH having a specific activity of 7,066 IU (immunoassay)/mg and less than 1 IU (immunoassay)/mg of LH, and a urinary FSH having a specific activity of 6,298 IU (immunoassay)/mg and less than 3 IU (immunoassay)/mg of LH. Protein content was determined by absorption at 280 nm (assuming that A1 cm280 for 1 g/l is equal to 1).
Chiba et al. [Isolation and partial characterisation of LH, FSH and TSH from canine pituitary gland; Endocrinol. J., 1997, 44, 205-218] describe a technique for purifying canine pituitary gonadotrophins, including FSH, using Concanavalin (Con) A affinity chromatography, hydrophobic interaction chromatography (HIC) and immobilized metal ion chromatography with Cu++. The resulting FSH is reported to have a specific activity of 2.17 IU/g protein using a radioreceptor assay for FSH for measuring biological activity and the BioRad protein assay kit (BioRad Laboratories CA USA) for determining protein content.
WO 88/10270 (Instituto di Ricerca Cesare Serono SPA) describes a method for purifying human FSH from urine. The process involves immunochromatography with FSH-specific immobilized monoclonal antibodies bound to Sepharose 4B by divinyl sulphone, followed by reverse phase HPLC. The resulting FSH is free of LH and other urinary proteins and has a specific activity of 6,200 IU/mg of lyophilised powder (Steelman-Pohley method). The preparation was the first FSH preparation to be suitable for subcutaneous administration, due to its purity.
An ongoing need remains for new methods for purifying FSH and FSH variants. In particular, there is a need for purification methods that avoid the use of the cost-intensive immunoaffinity chromatography steps.


A jaw crusher capable of stable angle detection is provided. For this purpose, the jaw crusher includes a fixed jaw (35), a swing jaw (36) provided to oppose the fixed jaw, a frame (34) for supporting the fixed jaw and the swing jaw, and an outlet clearance adjusting mechanism (62) for adjusting an outlet clearance between the fixed jaw and the swing jaw, and the outlet clearance adjusting mechanism includes a connecting member (61) of which one end is made abut to or connected to the swing jaw, a rotatable rotary member (64) which is made abut to or connected to the other end of the connecting member, a driving mechanism (65) for rotating the rotary member, and angle detecting equipment (69) which is mounted to the frame and detects a rotation angle of the rotary member.

A jaw crusher, which crushes raw materials by moving a swing jaw close to and away from a stationary jaw, has been conventionally known (for example, Japanese Patent Publication No. 5-45300, especially, pages 1 to 3, and FIG. 1 and FIG. 2). In this jaw crusher, the grain size of a crushed product is determined by an outlet clearance between lower ends of the stationary jaw and the swing jaw, and an outlet clearance adjustment mechanism is provided so as to make the outlet clearance adjustable. The outlet clearance adjustment mechanism includes a toggle plate of which one end is made abut to the swing jaw, and a toggle block to which the other end of the toggle plate is made abut, and the outlet clearance adjustment mechanism is constituted by constituting the toggle block in a link shape and rotatably supporting it. When the toggle block is rotated, the swing jaw is moved close to and away from the fixed jaw via the toggle plate, and the outlet clearance between the lower ends of the swing jaw and the stationary jaw can be adjusted. In this outlet clearance adjustment mechanism, an angular sensor or the like is provided at a rotary shaft of the toggle block so that the outlet clearance can be detected according to an amount of rotation of the toggle block.
However, the outlet clearance adjustment mechanism including the toggle block usually also plays the role of a reaction force receiving mechanism which receives a reaction force from the swing jaw which is crushing. Consequently, the angle sensor, which is mounted to the toggle block, causes the problem that the angle sensor is vibrated by a reaction force which is repeatedly exerted on the toggle plate and the toggle block from the swing jaw, an impact at the time of crushing and the like, and thus it cannot detect the angle with stability. In addition, there exists the problem that a sensor with high resolution is expensive.