sions use two different radio frequencies separated, e.g. by 190 MHz. The TDD mode is a duplex method where uplink and downlink transmissions occur over the same radio frequency by using synchronized time intervals. In the TDD, time slots in a physi- cal channel are divided into transmission and reception parts. Information on uplink and downlink are transmitted reciprocally. The UTRA has QPSK as modulation scheme. In the WCDMA or FDD mode the spreading (and scrambling) process is closely associ- ated with modulation. The different UTRA families of codes are: channelization codes derived with a code tree structure to separate channels from same the source, and codes to separate different cells; Table 4.2 illustrates the harmonized parameters of the two UTRA modes. A 10 ms radio frame divided into 15 slots (2560 chip/slot at the chip rate 3.84 Mcps) applies to two modes. A physical channel is therefore defined as a code (or number of codes) and additionally in TDD mode the sequence of time slots completes the defini- tion of a physical channel. The information rate of the channel varies with the symbol rate being derived from the 3.84 Mcps chip rate and the spreading factor. We derive the symbol rate from the 3.84 Mcps chip rate and the spreading factor to ob- tain a variable rate in the channel. The information rate of the channel, e.g. varies with The UTRA Physical Layer Design spreading factors from 256 to 4 for FDD uplink, from 512 to 4 for FDD downlink; and from 16 to 1 for TDD uplink and downlink. Consequently, modulation symbol rates vary from 960 k symbols/s to 15 k symbols/s (7.5 k symbols/s) for FDD uplink (down- link) respectively, and for TDD the momentary modulation symbol rates varies from 3.84 M symbols/s to 240 k symbols/s. The UTRA has QPSK as modulation scheme. In the WCDMA or FDD mode the spreading (and scrambling) process is closely associated with modulation. The different UTRA families of codes are: Table 4.2 UTRA FDD and TDD Harmonized Parameters Parameters UTRA TDD UTRA FDD Multiple access 