Low chip rate: 3.84 Mchip/s 1.28 Mchip/s Data modulation Spreading characteristics Orthogonal Orthogonal Q chips/symbol, Q chips/symbol, where Q=2P,0<p<4 = where Q=2p,0<ps4 In this section we use Q for the spreading, while SF denotes spreading in the FDD mode. The symbol duration Ts depends on the spreading factor Q and the chip duration Tc: Ts=QxTc, where Tc = 1/chip rate. The UTRA Physical Layer Design 4.5.2 Mapping of Bits onto Signal Point Constellation 4.5.2.1 Mapping for Burst Type 1 and 2 We perform data modulation on the bits from the output of the physical channel map- ping procedure in [20] and combine always two consecutive binary bits to a complex valued data symbol. Each user burst has two data carrying parts, termed data blocks: i=1,2; k = 1,...,K. (4.47) Nk corresponds to the number of symbols per data field for the user k. We link this number to the spreading factor Qk as described in Table 1 of [6]. Data block d(k,1) gets transmitted before the midamble and data block d(k,2) after the midamble. Each of the Nk data symbols d(k,1) ; i = 1,2; k = 1, ,K; n = 1, ,Nk; of equa- tion (4.47) has the symbol duration T) =QT as already given. The data modulation is QPSK, thus the data symbols d(k,1) are generated from two con- secutive data bits from the output of the physical channel mapping procedure in [20]: e{0,1}, l = 1,2; k = 1,..., K; = i =1,2 (4.48) using the following the mapping to complex symbols illustrated in Table 4.38. Table 4.38 Mapping Complex Symbols Consecutive binary bit pattern Complex symbol d(k,1) The mapping corresponds to a QPSK modulation of the interleaved and encoded data bits of equation (4.48). 4.5.2.2 Mapping for PRACH Burst Type When mapping the PRACH burst type the preceding logic applies with a modified number of symbols in the second data block. Thus, for the PRACH burst type, the num- ber of symbols in the second data block d(k,2) is decreased by 96/Qk symbols. 4.5.3 Spreading Parameters and Channelization Codes Data spreading includes two steps, i.e. channelization and sc