International Journal of Electrical, Electronics and Computer Engineering (IJEECE)
The IEEE 802.22 stands for Wireless Regional Area Network (WRAN). WRAN uses the white spaces & unused VHF & UHF TV bands. Cognitive Radio (CR) is a key to develop such a wireless standard. It is based on time division multiplexing and orthogonal frequency division multiple access. WRAN is developed for rural areas where utilization can be very low. In this paper, the authors provide a detail overview of IEEE 802.22 WRANs & mainly PHY layer. The WRAN physical layer is fundamentally based on the IEEE 802.16e system, but the OFDMA parameters including preamble structure and pilot pattern are newly designed by considering the WRAN channel environments.