Phase rotation‐based precoding for spatial modulation systems

Abstract

In this study, the authors investigate the benefits of phase-rotation-assisted precoding (PRP) technique in spatial modulation (SM) systems, which are based on maximum free distance d min . First, a closed-form solution of the maximumd min PRP matrix is derived for the scenario of having two transmit antennas (N t = 2). Moreover, two numerical methods are proposed for dealing with the case of N t > 2. The complexity of the proposed algorithms is presented. The authors simulation results show that the proposed PRP algorithms provide beneficial bit error ratio performance improvements compared with both the conventional SM and with the existing adaptive SM.

Performance Improvement of Space Shift Keying MIMO Systems with Orthogonal Codebook-Based Phase-Rotation Precoding

“…First, it is shown in [16] that amplitude precoding may require a large dynamic range in the precoding gain, which requires high cost linear power amplifier at the transmitter. This was also noted as the reason for phase-only precoding in [15]. Second, we find in the numerical results that four phases are sufficient for performance improvement.…”

“…This approach develops algorithms to find the TPC codeword that realizes a design objective for the given CSI [12][13][14][15][16][17][18][19][20]. This algorithm should be used in the transmitter and receiver to yield the same codeword, and it requires full knowledge of the CSI at both sides.…”

“…Another utilized design objective is the transmit power minimization subject to Guaranteed Euclidean distance (GED), which is utilized as the second method in [12,13]. Other design objectives include Signalto-Noise Ratio (SNR) maximization [14], direct BER minimization [15], and phase alignment [16]. In [12-14, 17, 18], the designed codeword involves amplitude scaling, while, in [15,16], it is based on phase rotation only.…”

“…Other design objectives include Signalto-Noise Ratio (SNR) maximization [14], direct BER minimization [15], and phase alignment [16]. In [12-14, 17, 18], the designed codeword involves amplitude scaling, while, in [15,16], it is based on phase rotation only. Therefore, this approach yields a codeword matching the instantaneous channel, leading to a significant reduction in BER.…”

“…For example, in [13], the max-min algorithm is approximated by a convex function that is iteratively solved using an optimization tool. In [15], a precoder formulation Wireless Communications and Mobile Computing 7 for the simple case of = 2 is first found. This formulation is iteratively used for the case of > 2.…”