Throughput of TCP over Cognitive Radio Channels

We study TCP performance over ON-OFF channels, i.e., channels which are busy/unavailable for transmissions intermittently. The data may also be subject to random errors. Such situations arise in cognitive radio networks when secondary users opportunistically use the channel when the licensed user is not using it. We use a Markov model to evaluate the TCP throughput and probability of retransmission timeout when the ON-OFF periods are exponentially distributed and then extend it to phase-type ON and phase-type OFF periods. We then generalize the Markovian model to more general ON-OFF duration distributions and also to multiple TCP connections.