Effectiveness of the Limited Retransmission on the WLANs Using Error-Prone Channel

Abstract

IEEE 802.11 based wireless local area networks (WLANs) is one of the most popular protocols for interconnecting portable communication devices. All the stations communicating over WLANs share a common wireless channel. Many conscious studies have been devoted to utilize this precious medium efficiently. However, most of these studies have been done either under assumption of idealistic channel condition or with unlimited retransmitting number. This paper is devoted to investigate influence of limited retransmissions and error level in the utilizing channel on the network throughput, probability of packet dropping and time to drop a packet. The results show that the networks using four-way handshaking mechanism has a good immunity against the error over the available range of retry limits, also the throughput is unchangeable with size of the network over the range of retransmission limits. On the other side, for the networks using basic access mechanism, the throughput is suppressed with increasing amount of errors in the transmitting channel over all the range of the retry limit as well as it is quite sensitive to the size of the network. However, the throughput does not change with retry limits when it exceeds the maximum number of the backoff stage in both DCF's mechanisms. In the both mechanisms the probability of dropping a packet is a decreasing function with number of retransmissions and the time to drop a packet in the queue of a station is a strong function to the number of retry limit, size of the network, the utilizing medium access mechanism and amount of errors in the channel