A Distributed Polling Service-Based Medium Access Control Protocol: Prototyping and Experimental Validation

Mobile ad hoc networks and its variations such as wireless mesh networks and wireless LANs (WLAN) have become the ubiquitous connectivity solution in public as well as residential access networks, due to their cost efficiency, reliability and flexibility of deployment and operation. The rapidly proliferation of such wireless access networks are greatly advanced by the distributed multiple access control (MAC) protocols, which is based on random access techniques such as ALOHA, slotted ALOHA, carrier sense multiple access (CSMA) and CSMA with collision avoidance (CSMA/CA). The most important standards for these applications are the protocols in the IEEE 802.11 [1] series, which are widely used as the solution for the “last mile” access problem and become a de facto standard for various wireless access networks. The IEEE 802.11 protocol family defines physical layer (PHY) and medium access control (MAC) functions for wireless communication in the ISM bands of 2.4GHz and 5GHz. There are various amendments for the standard 802.11, such as 802.11a/b/g/e/n and the currently working draft of 802.11ac. Most of these amendments focus on the enhancement in PHY, which provides higher link capacity. For example, 802.11g adopts OFDM to leverage the data rate up to 54Mbps in 2.4GHz band. 802.11n [2] further improves the previous standards by adding multiple-input multiple-output (MIMO) antennas and the link capacity is boosted up to 600 Mbps. Although various PHY techniques are added to improve the link capacity, the MAC’s they are based on almost remains same, which is based on CSMA/CA.