Introducing quiet period to wireless LAN over TV white space

摘要

In the use of temporally and geographically unused frequency spectrum, so-called “white space,” frequency band in operation is necessary to be monitored periodically. This paper proposes a method to place a “quiet period” to conduct periodical spectrum sensing for the operating band in wireless LAN (WLAN). Impact of transmission-error and presence of hidden-node are considered. A promising approach for monitoring the operating channel is placing “quiet period” in which all network nodes cease transmission. However, it seems difficult to place such quiet periods in WLAN that has a contention-based protocol. We propose a method for introducing the quiet period by using contention-free period based on the IEEE802.11 wireless LAN. In this paper, throughput and response time performance considering hidden-node and transmission-error is evaluated through computer simulation. It is found that the degradation of throughput performance by the presence of hidden-node and transmission-error is recovered by using quiet period.