 for uplink and downlink. HSPDSCH (high speed physical downlink shared channel). This transfers actual HSDPA data of the transport HSDSCH and can use 1 to 15 code channels, with a spreading factor (SF) of 16. All these associated physical channels should be adjacent, as shown in Figure B.2. QPSK or 16-QAM modulation is supported over 2 ms TTI slots. No power control is supported. In addition, the HSDSCH does not support soft handover due to the complexity of synchronising the transmission and scheduling from different cells. Instead, cell reselection through a normal DCH would be implemented; i.e. the HSDPA user is given a DCH in the SHO area, and is then moved to the new cell, where it would get an HSDPA channel again after the procedure is completed. HSSCCH (high speed shared control channel). This includes information to tell the UE how to decode the next HSPDSCH frame. It uses QPSK modulation and a fixed SF of 128. It shares the downlink power with the HSPDSCH, but may support power control in order to maximise the available power for the data channel. More than one HSSCCHs are required when code multiplexing is used, but a maximum of four is supported by the UE. Soft handover is not supported. HSDPCCH (high speed dedicated physical control channel). This channel carries the ACK/NACK (not acknowledged) (repetition encoded) and channel quality indicator transmitted from the UE in the uplink direction, which is needed for L1 procedures. The primary modulation is BPSK (binary phase-shift keying) with an SF of 256 (15 kbps). The transmission power used is typically the same as that used for the uplink DPCH plus additional offset to provide higher protection. The HSDPCCH may be received by two different sectors in the same Node B, but in general soft handover is not supported. Associated DPCH (dedicated physical channel). Two DPCHs are needed for each HSDPA UE, one in the downlink and another in the uplink. While the downlink DPCH is only used for signalling purposes, the uplink DPCH is the complementary data chan