Optimum real-time data transmission scheduling for channel searching in IEEE 802.11 wireless LANs

In transmitting real-time data over IEEE 802.11 wireless local area networks (WLANs), interference considerably degrades the quality of service (QoS). To minimize this damage, the radio channel should be switched to an unused new channel as soon as interference is detected on the current channel. For that purpose, the system has to know in advance,which channels are in use and which are not. The paper proposes an efficient method to search in advance for channels that are not in use by downlink real-time data transmission scheduling. The proposed method enables all stations (STAs) belonging to the basic service set (BSS) to perform fair and time-randomized other channel measurement. Therefore, the probability of detecting packets in other channel measurement becomes higher, and the BSS can select a channel that is not in use if interference is detected on the current channel. Adopting the proposed method, the BSS can successfully obtain stable throughput for real-time data transmission. The simulated throughput (video streaming) and packet detection probability in other channel measurements confirms the effectiveness of the proposed method.