On the effect of smart antennas on error statistics and TCP performance

We present some results on the statistics of the packet error process and on the resulting throughput of TCP when a smart antenna system is used to transmit signals from a base station to wireless users. Multiple users are assumed to be present, and the propagation environment considered includes frequency selective fading. The main results presented involve the tradeoffs between various systems parameters. It is shown that smart antennas have the potential to improve the wireless channel adequately, thereby essentially solving the performance problems which affect TCP. It is also shown that the whole complexity of these scenarios can be essentially summarized by the fading rate (Doppler frequency) and by the average packet error rate, thereby allowing the introduction of the concept of an "equivalent single-antenna system" and the scalability of the many available results for the latter case