An analysis of three multiple access techniques for the uplink of future cellular mobile systems

Orthogonal Frequency Division Multiple Access (OFDMA) is today a part of many standard specifications. Despite its attractive features, it has two main drawbacks when employed in the uplink: The high peak-to-average power ratio inherited from Orthogonal Frequency Division Multiplexing (OFDM) and the inherent frequency diversity loss. The loss of frequency diversity can be alleviated by precoding. Variants of Precoded OFDMA include Spread Spectrum Multi-Carrier Multiple Access (SS-MC-MA) and the frequency-domain implementation of single-carrier (SC) FDMA. The latter transforms OFDMA into a SC transmission system, avoiding the PAPR problem. This paper analyzes OFDMA, several variants of Precoded OFDMA and SC-FDMA in its frequency-domain implementations and compares them for uplink transmission.1