Adaptive time diversity for TDMA/TDD personal communication systems

The adaptive time diversity of multibearer connections is investigated in a Rayleigh fading channel. A scheme is proposed that adaptively increases the time diversity branch number, up to some predetermined limit, when a negative acknowledgment is sent from the receiver and the order of transmission slots is continually changed. The receiver sorts and combines all the transmitted messages of single data block using maximal ratio combining. The performance of the proposed scheme is assessed in terms BER performance, throughput, and message delay distribution. The results show that the proposed scheme offers better performance than the conventional scheme because it realizes both time diversity and frequency diversity