Improving the quality of Service of EDCF over DCF For Real Time Applications Using Probability Algorithm

Abstract: IEEE 802.11 (802.11) WLAN standard is being accepted widely and rapidly for many different environments today Main characteristics of the 802.11 networks are their simplicity and robustness against failures due to the distributed approach. They are created and maintained by the IEEE LAN/MAN Standards Committee (IEEE 802). Quality of Service (QoS) support is the key for multimedia applications over WLAN. So, since the demand for QoS is nowadays is a topic of great concern for the transmission of the different services like video, voice, best-effort services controlling the maximum network applications, background services for which the priority assigned is lower than the one assigned to the standard. So in order to get the better Qos at our desired application we need to control the network parameters in such a way that we get a certain output and according to the output we will see that at which station we are getting the maximum output. And at that station we will send the access category at which we want the best output Qos. So, we have resolved this problem of attaining the good Qos at our desired station by giving the random values for the contention window and the arbitrary interframe spaces is done by calculating the probability of winning and the probability of collisions. Due to the increasing demand of high rates WLANS in the applications like video streaming and voice over IP. It's mandatory to improve its performance in every possible way for the ease of the user. To calculate the probability of winning of a station for random values of AIFS and CW using the proposed algorithm and to find out the probability of the collisions in a station for the random values of AIFS and CW using the proposed algorithm and also to analyze the result and check where the output coming better. Then the station at which we are getting the maximum output we will send that data for which we want the best QOS.

Keywords: QoS, SINR, MAC delay, RSSI downlink (DL) and uplink (UL), handoff, cellular communications