Multiple-Symbol Joint Signal Processing for Differentially Encoded Single- and Multi-Carrier Communications: Principles, Designs and Applications

Abstract

Abstract-Bypassing the potentially excessive-complexity and yet inaccurate channel estimation, differentially encoded modulation in conjunction with low-complexity non-coherent detection constitutes a viable candidate for future multiple-antenna aided systems, where estimating all the links may become unrealistic, especially in high-speed environments. Upon exploiting the correlation between the phase distortions experienced by the consecutively transmitted symbols and/or based on mutually and iteratively utilizing the increasingly improved bit reliability information among the associated multiple symbols in the context of differentially modulated systems using channel code aided iterative receivers, the joint processing on consecutively received multiple symbols improves the system's performance. For example, an increased robustness against rapid channel fluctuation, improved flexibility in the system's performancecomplexity compromise as well as a reduced performance loss is achieved in comparison to its coherent detection aided counterpart. In order to stimulate further research on differentially modulated systems and on the associated multiple-symbol signal processing based advanced receiver design, a comprehensive review on their related concepts and fundamental principles is carried out in this treatise, followed by a number of potential challenges encountered in their practical implementations in future high-spectral-efficiency wireless transmissions, such as their applications in high-order differentially modulated systems and in differential interference suppression of spatial-division multiplexing/multiple access scenarios.

Differential Space-Time Coding Dispensing With Channel Estimation Approaches the Performance of Its Coherent Counterpart in the Open-Loop Massive MIMO-OFDM Downlink

“…should compare the proposed scheme to the family of stateof-the-art training-based channel estimation schemes [50][51][52] or the S-DSTC scheme designed for time-varying channels [22,23,35,[53][54][55]. All the existing studies have indicated that the coherent counterpart of a non-coherent scheme having perfect channel state information (PCSI) can be regarded as a performance upper-bound.…”

“…Different from Fig. 8, we considered the normalized Doppler frequencies of F d T s = 10 −3 and 10 −2 [55]. As shown in Fig.…”

Distributed Differential Quasi-Orthogonal Space-Time Block Coded System for Multiple-Relay Networks

“…Figure 2 depicts the bit-error-rate (BER) performances of various QOSTBC systems as a function of signal-to-noise (SNR), when E sr =r n;R ¼ 20 dB. It is firstly observed that the DC-QOSTBC systems outperform the DD-QOSTBC systems, of which result can be expected from a traditional communication system [3]. It is found that the DD-QOSTBC (P1) systems outperform the DD-QOSTBC (P3) systems as SNR increases because Protocol I provides additional information during Time-slot 1.…”

“…In particular, the advantages of MIMO systems, such as capacity and diversity improvements are compared with singleinput single-output (SISO) system adopting the combination of the differential modulation and an orthogonal space time block code (STBC) [3][4][5]. Unfortunately, however, employing a large number of antennas has been considered as an impractical direction for small mobile terminals due to its limited physical hardware size.…”

UAV-Aided Two-Way Multi-User Relaying

“…The benefit of fractional time allocations in terms of improving the capacity of single-user and singleinput single output HD decode-and-forward systems has been shown earlier e.g. in [38], [39]. To sum up, we provide a brief comparison of the related literature in Table I.…”