Orthogonal frequency division multiple access downlink physical layer communication for IEEE 802.16-2009 standard

Abstract

Worldwide interoperability for microwave access (WiMAX) is a wireless broadband technology, which supports point to multi-point (PMP) broadband wireless access. WiMAX is basically a new shorthand term for IEEE Standard 802.16. This standard determines the air interface, including the medium access control layer and physical layer (PHY), of consolidated fixed and mobile point to-multipoint broadband wireless access frameworks offering numerous services. WiMAX PHY incorporates orthogonal frequency division multiplexing/orthogonal frequency division multiple access (OFDM/OFDMA) as the modulation technique in uplink as well as downlink. Hence, this study addresses OFDMA basics, OFDMA frame structure, OFDMA symbol, OFDMA PHY as per IEEE 802.16e-2009 standard. It also explains OFDMA time-division duplexing frame which consists of partial usage of subchannels and adaptive modulation and coding zones in the downlink from base station to two mobile stations (MS). The author analysed the system performance by reconfiguring different channels such as additive white Gaussian noise (AWGN), flat fading channel and multipath fading or frequency-selective channels. The impact of each channel on received signals (MS 1 and MS 2) is shown in figures and the corresponding values are noted in a table.