High-Efficient InterActive Pair Scheduling (IAPS) Scheme for IEEE 802.11 Infrastructure WLAN

WLAN is becoming a promising system for future mobile ubiquitous network. However, the performance is largely restricted by MAC inefficiency, and AP remains as a bottleneck in infrastructure WLAN. A high efficient MAC, which decreases frame collision and balances the performance between AP and stations, is desirable. Therefore, we proposed an interactive pair scheduling (IAPS) scheme compatible with IEEE 802.11. IAPS uses ACK/CTS exchange to extend channel reservation for reverse data frames, hence achieving contention-free access and performance balance between uplink and downlink. Moreover, we defined MPT, the maximum pair scheduling times, to combat the unfairness due to long-term pair scheduling in LAPS and also benefit the service differentiation. The performance of LAPS is evaluated in an IEEE 802.11 based infrastructure WLAN. Simulation results show that LAPS increases the total throughput and benefits the performance balance especially when hidden terminals exist. Moreover, LAPS efficiently improves the throughput of VoLP in presence of mixed VoLP and best effort traffic.