A New MAC Protocol for Supporting Differentiated QoS in IEEE 802.11 Multihop Wireless Networks

Abstract

In IEEE 802.11 multihop wireless networks, each node uses DCF to randomly contend for the medium access to transmit their packets. There is multimedia transmission that needs QoS guarantee. Even that the IEEE 802.11e provides differentiations of MAC access (EDCF), it still remains random manner and can not guarantee the end-to-end QoS in this access network to meet requirements like delays, jitters, or even bandwidth. Furthermore the hidden terminal problems is more serious in the multihop networks. The IEEE 802.11 PCF provides central coordination to meet QoS requirement but it requires an infrastructure. So it can’t be used in multihop wireless networks. Here we propose a new MAC scheme which can provide QoS guarantee in multihop wireless networks. We propose the global coordinator to gather the information about conflict links and the requests for scheduling contention-free access. We also provide an adaptive approach for new coming request to avoid global re-scheduling to reduce overhead and to improve the performance.