KUAR WiMAX 802.16a OFDM Jordan Guffey

1. KUAR WiMAX 802.16a OFDMJordan Guffey WiMAX OFDM • Worldwide Interoperability for Microwave Access • Designed to provide Metropolitan Area Access. Provides for wireless networking access at distances up to 50 km, rather than hundreds of meters with WiFi. MAN ( Metropolitan Area Network) rather than LAN ( Local Area Network ). • Used as “last-mile” connection for broadband access. • Operates at 10-66 GHz licensed frequencies and 2-11 GHz unlicensed frequencies. • The WiMAX standard 802.16a (2-11 GHz) supports an OFDM (Orthogonal Frequency Division Multiplexing) physical layer. OFDM allows much higher data rates over non-line-of-sight connections. • One high-rate data stream is broken up into many lower-rate data streams. Each stream is assigned to a OFDM sub-carrier. This scheme mitigates frequency selective fading, a major bottleneck to wireless communications. • Frequency selective fading with a single carrier system must be corrected by equalization. At very high data rates, equalization can become prohibitively complicated. OFDM Spectrum KUAR Implementation • Frequency domain view of a 4 carrier OFDM signal. Under ideal conditions, there is zero inter-carrier interference. • Goal: Implement an adjustable OFDM transceiver in the KUAR (KUAgile Radio) that complies with the 802.16a OFDM PHY specifications. • Challenges: • Fitting all the required logic in the Virtex II FPGA. • Complex error control coding scheme. • OFDM extremely sensitive to timing and frequency offsets. • Strategy: Implement the OFDM model in Simulink, then synthesize each block in VHDL. Each block will then be extensively tested in the FPGA with data generated from the Simulink model.