Mitigating Co-Channel Interference in CSMA/CA Networks via a Cell-Delimited Payload Retention Scheme

Besides the occurrence of frame corruption when nodes from nearby cells transmit in parallel, CSMA/CA-based networks also suffer another form of co-channel interference known as the ´exposed node´ problem. Here, nodes are unnecessarily blocked from spatially reusing the channel although parallel transmissions would have most likely been successful had they occurred. For mitigating this well-known problem, transmit power control schemes have been at the forefront of solutions. In this paper, we propose another scheme: By the assignment of a ´cell number´ selected by the coordinating node to all other nodes in each cell, nodes only retain the payload portion of frames with headers indicating the same number while their long-term fail rates do not exceed a limit. With the aid of a realistic IEEE 802.11b simulator as our evaluation platform, we show that this scheme provides comparable results to as well as enhances the performance of a conventional open loop transmit power control scheme.