 be used on the DPCHs. However, even in this case, Layer 1 control information is transmitted only on the first DPCH, while DTX bits are transmitted during the corresponding time period on the additional DPCHs. DPDCH DPDCH Pilot Transmission Power Physical Channel 1 Transmission Power Physical Channel 2 Transmission Power Physical Channel L One Slot (2560 chips) Figure 4.17 Downlink slot format in case of multi-code transmission. The UMTS Network and Radio Access Technology 4.3.8.3 STTD in the DPCH In the following we describe how antenna diversity occurs using the pilot bit pattern for the DPCH channel transmitted on antenna 2 illustrated in Table 4.19: Npilot = 2 diversity antenna pilot pattern results from STTD encoding the two pilot bits defined in Table 4.17 with the last two bits (data or DTX) of the second data field (data 2) of the slot. Hence, for Npilot = 2 the last two bits of the second data field (data 2) after STTD encoding, follow the diversity antenna pilot bits defined in Table 4.19. Npilot = 4 diversity antenna pilot bit pattern results from STTD encoding both the shadowed and non-shadowed pilot bits in Table 4.17. Npilot = 8, 16 diversity antenna pilot bit pattern shown in Table 4.19 results from STTD encoding the corresponding (shadowed) bits in Table 4.17. The non- shadowed pilot bit pattern is orthogonal to the corresponding (non-shadowed) pilot bit pattern in Table 4.17. Pilot bit patterns Npilot > 4 in compressed mode with the 'spreading factor reduc- tion' method will get symbol repetition for the pilot bit patterns of Table 4.19. Table 4.19 Pilot Bit Patterns of Downlink DPCCH for Antenna 2 using STTD Slot 0 Npilot2a Npilot Npilot = 8c Npilot==16d a The pilot bits precede the last two bits of the data 2 field. Bit pattern does not apply to slot formats 2B and 3B. Bit pattern does not apply to slot formats OB, 1B, 4B, 5B, 8B, and 9B. Bit pattern does not apply to slot formats 6B, 7B, 10B, 11B, 12B, and 13B. e Bit pattern applies also to slot formats 2B and 3B. In other slot formats we app