An adaptive retransmission scheme of SIMO FM-DCSK UWB system

In this paper, an adaptive retransmission mechanism of single-input frequency-modulated differential chaos shift keying Ultra-wideband (SIMO FM-DCSK UWB) system with automatic repeat request (ARQ) protocol has been investigated, in which scheme adaptive unit delay (T
_d
) is used to control transmission. Unlike the previous work based on optimal assignment of number of pulses per symbol or frame duration, the adaptive unit delay (T
_d
) will not change the data rate or bandwidth, only can change the position of the pulses. Through simulation it is shown that bit error rate (BER) and throughput performances of the proposed scheme are better than normal retransmission mechanism when it is applied to two-user or multi-user systems over indoor channel, it reflects that our proposed scheme can enhance performance of chaotic UWB systems.