A new measure of index assignment in dynamic channels

In dynamic noisy communication channels, a channel bit error rate (BER) varies with time. When channel distortion measure Dc is a function of bit error rate, an optimal index assignment to minimize Dc is not as uniformly optimal as BER varies. The paper presents a new distortion measure called expected channel distortion (ECD). It is independent of the bit error rate by two proposed beta-type distributions in a multiple-error pattern. Additionally, any index assignment algorithm with ECD measure is mismatch-free. In other words, index assignment algorithms can be against channel mismatch even though BER varies with time in dynamic channels. The voice digitization in North American Telephone Systems (CCITT) is adopted to demonstrate the usefulness of the proposed measure.