uded. Furthermore, co-existence of TDD and FDD in the same bands (now under study) may be possible. The UMTS Terrestrial Radio Access. The UMTS Network and Radio Access Technology Table 5.1 UTRA Frequency Bands in the MS and BS Side FDD (MHz) TDD (MHz) up- and downlink User equip- Base station User equip- Base station Uplink (MS to BS) 1920-1980 1920-1980 1900-1920 1900-1920 Downlink (BS to MS) 2110-2170 2110-2170 2010-2025 2010-2025 Region 2 - e.g. Europe Uplink (MS to BS) 1850-1910 1850-1910 1850-1910 1850-1910 Downlink (BS to MS) 1930-1990 1930-1990 1930-1990 1930-1990 1910-1930 1910-1930 RADIO TRANSMISSION AND RECEPTION ASPECTS After the allocation of the frequency ranges for the UTRA modes in the preceding sec- tion, in the following we present the transceiver parameters from the technical specifications, [1-4]. These parameters will set the necessary background to consider equipment and network design, including traffic engineering issues. 5.2.1 Transmit to Receive (TX-RX) Frequency Separation While the TDD mode does not need Frequency Separation (FS), the FDD mode does in both the EU and the BS. Table 5.2 UTRA TX-RX Frequency Separation User Equipment (UE) and Base Station (BS) UE and BS Minimum value = 134.8 MHz No TX-RX frequency separation is Maximum value = 245.2 MHz required All UE(s) shall support 190 MHz FS in case (a)¹ All UE(s) shall support 80 MHz FS in case (b)¹ Each TDMA frame has 15 time slots FDD Can support both fixed and variable Each time slot can be allocated to TX-RX FSs either transit (TX) or receive (RX) Use of other TX-RX FSs in existing or other frequency bands shall not be precluded When operating within spectrum allocations of cases (a) and (b) Table 5.1, respectively. 5.2.2 Channel Configuration The channel spacing, raster and numbering arrangements aim to synchronize in both FDD and TDD modes as well as keep certain compatibility with GSM, in order to facilitate multi-mode system designs. This applies, e.g. to the raster distribution where 200 kHz corresponds to all (UE and BS in