Differential Overlap Decoding: Combating hidden terminals in OFDM systems

In this paper, we propose a Differential Overlap Decoding (DOD) algorithm to solve the hidden-terminal problems in OFDM based WLAN systems. DOD exploits the retransmission and random-jitter features of WLAN to decode the collided packets as a whole. DOD provides with new methods and views to jointly separate and decode collided packets in OFDM based system. In DOD, we formulate IFFT/FFT, channel influence and packet collision as linear processes. Thus we can express the received collided packets as linear equations, and simplify this problem into solving linear equations. We evaluate the performance of DOD through simulation, and results show that when DOD is applied, hidden-terminal problems can be viewed as a 3-5 dB BER performance degradation rather than network contention.