Provisioning Link Layer Proportional Service Differentiation in Wireless Ad Hoc Networks with MIMO links

In this paper, we present a collision free MAC protocol for wireless ad-hoc networks with multiple input multiple output (MIMO) links. The proposed MAC protocol provides proportional service differentiation to various classes of traffic based on their respective bandwidth demands. It exploits the spatial multiplexing and interference suppression capability of MIMO links in order to activate multiple links in the same collision domain. Simulation results show that the proposed MAC protocol achieves strict fairness in maintaining the proportional service differentiation among contending links. Then we introduce the concept of proportional fairness deviation which can be used as a tuning knob for assigning the leftover bandwidth to different traffic classes in proportion to their differentiation parameters. This tuning knob will adjust the quality of service assigned to users in a particular traffic class for a specific cost.