Abstract:
The IEEE 802.11 Wireless Local Area Network (WLAN) standard was able to ease the communication difficulty by providing mobility and low cost of system deployment for its users. On the other hand, the WLAN has difficulty in meeting the optimum Quality of Service (QoS)demand for data applications. Consequently, a later variant of the amendment standard, IEEE 802.11n, came with improvement strategies. The introduction of frame aggregation, block acknowledgment and reverse direction protocol techniques at the Media Access Control (MAC) sub-layer of the Datalink layer reduced the overhead cost to an optimum value. This work analyzed the performance of MAC Service Data Unit (MSDU) frame aggregation technique at variable aggregation sizes and number of contending stations in an error-prone WLAN channel. The frame aggregation technique was selected for analysis based on its popularity as compared to other MAC improvement techniques. Firstly, an analytical approach that models the network based on discrete time Markov chain (DTMC) was developed and then simulated in MATLAB environment. The values of the MSDU frame aggregation sizes, the variable number of contending stations and variable bit-error-rate (BER) values of the WLAN channel were chosen arbitrarily but within the practical range for a number of simulation cycles. Based on the generated results, it was observed that the MSDU aggregation size should not be increased beyond 46 for the various BER values of the channel considered for this work else the performance throughput would depreciate. This performance information is very resourceful for optimal design and implementation of frame aggregation technique in the WLAN network.
