AP-assisted CTS-blocking for WiFi-ZigBee Coexistence

WiFi interference is one of the big problems in ZigBee-based sensor networks. In this paper, we present a new WiFi-ZigBee coexistence scheme named AP-assisted CTS-blocking (AA CTS-blocking). The AA CTS-blocking uses an RTS/CTS (request to send, clear to send) mechanism to prevent WiFi transmissions during ZigBee communications. An RTS/CTS mechanism is defined in the IEEE 802.11 standard and is supported by off-the-shelf WiFi devices. We present the design and implementation of AA CTS-blocking utilizing an off-the-shelf WiFi device as it is. The experimental evaluations revealed that AA CTS-blocking reduced frame error rate (FER) by approximately 5% compared to an existing WiFi-ZigBee coexistence scheme.