A robust hybrid-MAC protocol for M2M communications

In M2M communications, there is a critical requirement of a robust MAC protocol to enable multiple M2M devices to access the channel. For this purpose, reservation or contention based MAC protocols can be used, but with multiple M2M devices, adaptability, and scalability become bottlenecks. Therefore, a frame based hybrid-MAC scheme, consisting of a CSMA-based contention period, and a TDMA-based transmission period has been proposed here. During contention period, the devices compete for the channel access. The successful devices during this period will strive to transmit data, using IEEE 802.11 DCF mechanism within each TDMA slot. The aim is to make sure that in case of TDMA clock synchronization failure, there is no communication failure between M2M devices. Extensive simulation results in ns-2 environment show that the proposed time frame scheme for hybrid-MAC protocol performs better than slotted-ALOHA and TDMA in terms of aggregate throughput and average end-to-end delay.