Asynchronous cooperative transmission mechanism using distributed Orthogonal Frequency Division Multiplexing for mobile ad hoc networks

Abstract

In this article, we propose an asynchronous cooperative transmission mechanism for Mobile ad hoc Networks (MANETs). The proposed cooperative transmission mechanism employs distributed Unitary Space-Frequency Coded-Orthogonal Frequency Division Multiplexing (USFC-OFDM), which does not require any channel estimation and has a lower decoding complexity, and therefore can provide better reliability and robustness when mobile nodes move fast. Moreover, it can achieve a larger diversity gain and multiplexing gain, and can thus combat fast time-varying and frequency-selective channel fading, and tolerate imperfect synchronisation among mobile nodes. To support USFC-OFDM, a Time Division Multiple Access-based Cooperative Medium Access Control protocol and an on-demand Cooperative Dynamic Source Routing protocol are also proposed. Through simulation results, we show that the proposed USFC-OFDM-based cooperative transmission mechanism can significantly improve the network performance in terms of packet delivery ratio and bit error rate in highly dynamic mobile environments.