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

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... y 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.