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.