Experimental Performance Evaluation of a MAC Protocol for Cooperative ARQ Scenarios

This paper provides details and performance evaluation of the implementation of the Persistent Relay Carrier Sensing Multiple Access (PRCSMA) protocol for Cooperative ARQ (C-ARQ) scenarios using off-the-shelf wireless cards. The underlying idea of PRCSMA is to modify the basic rules of the IEEE 802.11 MAC protocol to execute a distributed C-ARQ scheme in wireless networks in order to enhance their performance and to extend coverage. For the implementation, we modify the HostAP driver for off-the-shelf air-interfaces. HostAP is a Linux based driver for 802.11b WLAN cards based on Intersil´s Prism 2.5. Performance evaluation tests provide proof-of-concept of the efficiency, in terms of mean delay, of the PRCSMA in realistic conditions.