New PAPR-Preserving Mapping Methods for Single-Carrier FDMA with Space-Frequency Block Codes

Innovative mapping schemes for Space-Frequency Block Codes (SFBC) which are compatible with the structure of Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems are introduced. We first show that existing space-time and space-frequency block codes lack flexibility in terms of framing or cause a degradation of the signal envelope properties when combined with SC-FDMA. Then, we present an Alamouti-based orthogonal code designed for 2 transmit antennas that makes use of an innovative mapping in the frequency domain to preserve the low envelope properties of SC-FDMA. Next, an extension of this concept to a quasi-orthogonal code for 4 transmit antennas is presented and analyzed. We prove the good performance of the proposed schemes over multiple-input multiple-output (MIMO) channels both in static and in high-mobility scenarios.