Joo Rak Kang and Tae-Jin Lee, Sungkyunkwan University, Korea

In a dense Machine-to-Machine (M2M) network, a large number of stations contend to achieve transmission opportunity and it creates a critical congestion problem. To solve this issue, a group-based contention Medium Access Control (MAC) protocol is introduced. Stations are divided into small numbers of groups and only one station in each group will contend as a group leader to achieve the reserved time interval dedicated to a winner group. It can reduce the contention overhead and lessen the congestion problem. In this paper, we propose Scheduled Group Contention MAC (SGCMAC) protocol to enhance the group-based contention MAC. The proposed SGCMAC protocol divides groups based on the traffic categories of stations and schedules the contention groups to reduce the contention overhead. We also propose an efficient resource management mechanism in the group grant time to prevent the waste of time caused by idle stations. Simulations with IEEE 802.11ah parameters demonstrate that our proposed SGCMAC has performance gains over other group-based contention MAC protocols.

Medium Access Control (MAC), Machine-to-Machine, Grouping, Wireless LAN, Random Access Protocols