More and more devices are becoming wirelessly connected. Many of these devices are operating in crowded\r\nunlicensed bands, where different wireless technologies compete for the same spectrum. A typical example is the\r\nunlicensed ISM band at 2.4 GHz, which is used by IEEE 802.11bgn, IEEE 802.15.4, and IEEE 802.15.1, among others.\r\nEach of these technologies implements appropriate Media Access Control (MAC) mechanisms to avoid packet\r\ncollisions and optimize Quality of Service. Although different technologies use similar MAC mechanisms, they are\r\nnot always compatible. For example, all CSMA/CA-based technologies use Clear Channel Assessment (CCA) to\r\ndetect when the channel is free; however, in each case it is specifically designed to improve detection reliability of\r\nthe specific technology. Unfortunately, this approach decreases the detection probability of other technologies,\r\nincreasing the amount of cross-technology collisions. In this article, we introduce the concept of coexistence aware\r\nCCA (CACCA), which enables a node operating in one technology to backoff for other coexisting technologies as\r\nwell. As a proof of concept, we analyze the Packet Error Rate(PER) incurred by an IEEE 802.15.4 network in the\r\npresence of IEEE 802.11bg interference, and assess the PER reduction that is achieved by using CACCA.
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