密集WiFi网络环境网络分配矢量优化与性能分析

Optimized network allocation vector setting and performance analysis in dense WiFi networks

IEEE 802.11协议利用RTS/CTS帧交换来设置设备的网络分配矢量(NAV)。现有NAV方案未考虑密集部署场景,可能存在误清除的情况。提出一种简便可行的可计数NAV(C-NAV)设置方案,通过统计NAV设置信息的个数并进行实时更新以防止误清除,从而更有效地利用传输机会。对所提C-NAV方案进行了理论分析和仿真验证,证明在密集部署WiFi场景中,该方案能有效避免现有设置方案NAV时长浪费和错误清除等问题,提升网络的整体吞吐量。

IEEE 802. 11 defines a virtual carrier sense mechanism, via RTS/CTS handshaking, to adjust channel access. AP and STAs overhearing either RTS or CTS set their network allocation vector( NAV) and defer the channel access. However, conventional NAV setting may causes the channel waste. Some literatures resolve the problem by clearing redundant time, though, they rarely fo-cus on dense WiFi networks involving multiple overlapping BSS, and may lead to incorrect clearing. This paper proposes a simple and feasible scheme named countable-NAV( C-NAV), which can more effectively utilize transmission opportunity by introducing a counter of NAV setting message and updating it in real time to avoiding incorrect clearing. Both theoretical analysis and simulation results show that the proposed scheme is feasible by more accurately setting and clearing NAV. It can avoid channel waste and in-correct clearing result from the existed NAV setting schemes, and then improve the network throughput.