A BEB-Based Admission Control for VoIP Calls in WLAN with Coexisting Elastic TCP Flows
VoIP service over WLAN networks is a promising alternative to provide mobile voice communications to compete with cellular systems. However, several performance problems appear due to i) heavy protocol overheads, ii) unfairness and asymmetry between the uplink and downlink flows and iii) the coexistence with other traffic flows. This paper addresses the performance of VoIP communications with simultaneous presence of bidirectional TCP traffic, showing how the presence of elastic flows drastically reduces the capacity of the system. To solve this limitation we propose a simple solution using an adaptive Admission and Rate Control algorithm which tunes the BEB (Binary Exponential Backoff) parameters as is defined in the IEEE 802.11e standard. The results show the improvement achieved on the overall system performance (in terms of number of simultaneous voice calls with QoS guarantees).
KeywordsMobile Node Medium Access Control Access Point Admission Control Medium Access Control Protocol
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