up to Pass t 1 Sample Clauses

up to Pass t 1. ≤ ≤ − After Pass i (1 i t 1), the remaining bits are mutually independent and have the same bit error probability, so the average bit error rate is just equal to any individual bit error probability. After Pass t− 1, a retained bit is related to a parity check matrix H(2t−1 —1)×2t−1 (like H7×8 in (2.29)). A corresponding belief network like Figure 2.4 can also be

up to Pass t 1. For Pass 1, the initial bit error probability is given by p (= p(0)). Since the bit error probability does not change with the pass going on, the optimal weight deter- mined by (2.28) remains constant during the whole pass. As shown in Figure 2.3 in Subsection 2.5.1, w = 2 as long as the bit error probability is at least 0.20. Pass 1 up to Pass t − 1 are described in the following algorithm.