ormation, control information mapping, and channel interleaver. In the physical layer processing of the BCH transport channel, the information arrives at the coding module in the form of one transport block every 40 ms and the coding steps include addition of CRC to the transport block, channel coding, and rate matching. The 16-bit parity is calculated and attached to the BCH transport block. After the attachment, the CRC bits are scrambled according to the eNB transmit antenna configuration, i.e., the CRC bits of the PBCH are masked with the cell identifier. The permissible modulation schemes for various physical channels in the downlink and uplink of LTE are shown in Table 9-20 [116]. 9.15.5 Physical Channel Processing Figure 9-70 illustrates different stages of 3GPP LTE physical channel processing in the downlink and uplink. In the downlink, the coded bits in each of the codewords are scrambled for transmission on a physical channel. The scrambled bits are modulated to generate complex-valued modulation symbols 9.15 3GPP LTE physical layer protocols Table 9-20 Physical Channels, Signals, and their Corresponding Modulation Schemes for 3GPP LTE Downlink and Uplink [107,108] Downlink Physical Channels Physical Broadcast Channel (PBCH) Physical Downlink Control Channel (PDCCH) Physical Downlink Shared QPSK, 16 QAM, 64 QAM Channel (PDSCH) Physical Multicast Channel QPSK, 16 QAM, 64 QAM (PMCH) Physical Control Format Indicator Channel (PCFICH) Physical HARQ Indicator BPSK modulated on I and Q Channel (PHICH) with the spreading factor 2 or 4 orthogonal codes Physical Signals Reference Signals (RS) Complex I+jQ pseudo-random sequence of length 31 Gold sequence derived from cell ID Primary Synchronization Signal One of 3 Zadoff-Chu sequences Secondary Synchronization Two 31-bit BPSK M-sequence Signal Uplink Physical Channels Physical Uplink Shared QPSK, 16QAM, 64QAM Channel (PUSCH) Physical Uplink Control Channel BPSK, QPSK (PUCCH) Physical Random Access u root Zadoff-Chu sequence Channel (PRACH) Physical Signals Demod