7Downlink Physical Channels

7.1. PBCH physical channel

The Physical Broadcast Channel (PBCH) transmits the BCH transport channel that contains the system information corresponding to the Master Information Block (MIB) message.

The processing associated with the PBCH physical channel is summarized in Figure 7.1.

Figure 7.1. Processing associated with the PBCH physical channel

7.1.1. Error detection code

The error detection is obtained with a Cyclic Redundancy Check (CRC) code.

The CRC structure is the remainder when the transport block a0, a1, a2, a3,..., aA–1 (A = 24 bits) is divided by a generator polynomial, whose remainder p0, p1, p2, p3,..., pL–1 (L=16) constitutes the cyclic redundancy bits.

The 16 cyclic redundancy bits p0, p1, p2, p3,..., pL–1 are scrambled by the sequence xant, 0, xant, 1,..., xant, 15, then are concatenated to the transport block to constitute the sequence c0, c1, c2, c3,..., cK–1.

The sequence xant, 0, xant, 1,..., xant, 15 determines the number of antenna ports (Table 7.1).

Table 7.1. Mask of the cyclic redundancy sequence

Number of antenna ports Sequence xant,0, xant,1,...,xant,15
1 <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0>
2 <1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1>
4 <0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1>

7.1.2. Error correction code

The error correction code is a convolutional code that produces three ...

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