The Joint Design Of Generalized Differential Space-Time Coding And Sphere Decoding

In recent years, the explosion of smart devices with the help of ubiquitous mobile Internet services are intertwined with our daily lives on much deeper level. As a result, the mobile internet data services have to be fast and reliable on a large scale. In fact, the deployment of modern cellular network is becoming a national policy worldwide. However, there are still many barriers which limit the effectiveness of our modern network, such as the ever-changing wireless channel states and the hardware limitation imposed by our mobile equipment. Therefore, in this thesis, we focus on these challenges and propose feasible solutions to these questions.Firstly, since Space-Time Coding technology can utilize both temporal and spatial channel resources to improve the transmission data rate and/or reliability, three classical space-time coding techniques were introduced, namely, Linear Dispersion Code (LDC), Spatial Modulation (SM), Space-Time Shift Keying (STSK). Secondly, in order to remove the channel estimation overhead as well as to reduce the channel estimation complexity, we did a thorough investigation on differential space-time coding schemes for RF systems, from Differential Phase-Shift Keying (DPSK), Differential Linear Dispersion Code (DLDC) to Differential Space Time Shift Keying(DSTSK). Furthermore, a novel low-complexity DSTSK scheme was proposed, which can avoid the complexity of Cayley Transform required by conventional DSTSK schemes. Thirdly, in order to reduce the complexity of the Maximum Likelihood (ML) detector, Sphere Decoding (SD) algorithms were studied carefully in both SISO and MIMO systems. Moreover, the SD algorithm was combined with SM in order to achieve high-rate low-complexity system performance. Finally, numerous simulation results were given to demonstrate the complexity reduction as well as BER performance of the above-mentioned systems.