Optimum transmit filter for Single-Carrier FDMA with Frequency-Domain Linear Equalization

Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been selected as the uplink transmission scheme in the 3GPP Long Term Evolution standard. SC-FDMA is a form of Single-Carrier Frequency Domain Equalization (SC-FDE) with a flexibility in resource allocation, thus it has reduced sensitivity to phase noise and a lower Peak-to-Average Power Ratio (PAPR) compared to Orthogonal Frequency Division Multiple Access. This, consequently, makes it more attractive for low cost devices with limited transmit power. In this paper we propose an optimum power allocation scheme for SC-FDMA transmission considering Frequency-Domain Linear Equalization (FD-LE). We derive the optimum power allocation for the SC-FDMA transmission for both a Zero-Forcing (ZF) and a Minimum Mean-Square Error (MMSE) receiver in order to maximize the achievable rate subject to a constant transmit power. Results show that the optimum power allocation for the MMSE FD-LE results in greater improvement in the achievable transmission rate compared to ZF FD-LE.