International Journal of Engineering and Technology

The IEEE 802.11 MAC protocol cannot support quality of service (QoS) requirements. In order to provide QoS in the IEEE 802.11 MAC protocol, the IEEE 802.11e has been standardized. These standards provide multiple transmission rates, which can be changed dynamically according to the channel condition. When using multiple transmission rates, the capacity of wireless LAN improves, but the performance anomaly problem may occur. Cooperative communications were introduced to alleviate the performance anomaly problem with the help of relay nodes with higher transmission rates. Previous cooperative communications protocols are based on the IEEE 802.11 DCF MAC protocol. That is, none of them takes the IEEE 802.11e EDCA into consideration. In this paper, we apply the EDCA features such as TXOP and block ACK for cooperative communications. Simulation results show that the proposed protocol works well and improves network performance.