CSMA/CA with RTS/CTS overhead reduction for M2M Communication with Finite Retransmission Strategy

The number of Machine to Machine (M2M) applications is increasing rapidly especially in cellular communication systems. These applications should support a very high number of stations (STAs) and facilitate communication without any human intervention. To fulfill these requirements random access protocols are a possible choice. Carrier sense multiple access collision avoidance (CSMA/CA) protocol with request to send and clear to send (RTS/CTS) mechanism presents high degradation of the throughput and packet drop probability performance especially when the packets size are small. The medium access control (MAC) overhead caused by the RTS and CTS messages is high comparing to the total duration of successful transmission. In order to reduce the MAC overhead we propose in this work a new strategy to serve many users successively. This strategy consists on sending many RTS in parallel by different stations on different frequency sub-bands. Once the RTS messages do not collide with each other, there will be no need to resend the RTS and wait for a CTS to gain the channel access. In this paper, this proposed strategy is investigated and we demonstrate that it reaches better saturation throughput and packet drop probability especially in loaded networks.