Hybrid SR ARQ Scheme Using Trellis Coded Modulation for Point-To-Multipoint Communication Over Nonstationary Channels

In this paper, a type-I hybrid SR ARQ scheme using trellis coded modulation (TCM) for point-tomultipoint communication was analyzed on nonstationary broadcast channels where the channel bit error rate (BER) varies over time. A nonstationary channel is modelled as a two-state Markov chain. In the numerical calculations, it is found that, for a given p 1 and ε̄ , the values of the average burst length b̄ have a very small influence on the throughput. Numerical results show that the throughput is better for values between 10−6 and 10−4 of average bit error rate ε̄ if the errors occur in bursts. However, the scheme performs better for the stationary channel when the average bit error rate becomes large. For medium and high values of ε̄ , the throughput decreases when the number of receivers increases.