Medium Access Control Protocols With Memory
Jaeok Park, Mihaela van der Schaar · IEEE/ACM Transactions on Networking · 2010
Many existing medium access control (MAC) protocols utilize past information (e.g., the results of transmission attempts) to adjust the transmission parameters of users. This paper provides a general framework to express and evaluate distributed MAC protocols utilizing a finite length of memory for a given form of feedback information. We define protocols with memory in the context of a slotted random access network with saturated arrivals. We introduce two performance metrics, throughput and average delay, and formulate the problem of finding an optimal protocol. We first show that a time-division multiple access (TDMA) outcome, which is the best outcome in the considered scenario, can be obtained after a transient period by using a protocol with -slot memory, where is the total number of users. Next, we analyze the performance of protocols with one-slot memory using a Markov chain and numerical methods. Protocols with one-slot memory can achieve throughput arbitrarily close to 1 (i.e., 100% channel utilization) at the expense of large average delay by correlating successful users in two consecutive slots. Finally, we apply our framework to wireless local area networks (WLANs).