Soft Decision Strategy Design for Signal Demodulation in IEEE 802.11 Protocol Suite Based Wireless Communication Process

摘要

Orthogonal frequency division multiplexing (OFDM) technique has now been widely used as the core algorithms in various communication protocols which support high bit rate transmission, such as IEEE 802.11 protocol suite, for it has many advantages including higher efficiency in bandwidth utilization, stronger ability in anti multipath fading, and higher effectiveness in mitigating interference between narrow-band signal. Moreover, as all kinds of communication technologies are always in a fast developing process nowadays, OFDM has also been integrated with many other techniques, including soft decision, interleaving, trellis coded modulation (TCM), etc. To be specific, soft decision has been recognized as the most suitable technique in signal demodulation process, especially in those systems with higher integrated design complexity and higher data coding or modulating complexity. However, reports on soft decision applied wireless communication system based on IEEE 802.11 protocol suite cannot be easily found, even if wireless fidelity (WiFi) and dedicated short range communication (DSRC) based on IEEE 802.11a, b, g, n, or even p have been discussed so much in networking and performance analysis. In this paper, an effort has been tried to introduce soft decision strategy into the signal demodulation process for IEEE 802.11 protocol suite, the soft decision algorithm for quadrature amplitude modulation orthogonal frequency division multiplexing (QAM-OFDM) signal demodulation process has been designed and discussed in detail, and the feasibility of such design has been confirmed.