Research And Implementation For Key Technologies Of TD-Hspa+Downlink

TD-HSPA+is based on TD-SCDMA, and at the same time introduces other key technologies to improve the system performance. In the physical layer, MIMO and high order modulation are introduced in TD-HSPA+. Joint detection is the key algorithm of TD-HSPA+in physical layer, it differentiates between interference and noise to eliminate multiple access interference and multipath interference, so it can improve system performance and expand the area coverage. Signal to noise and interface ratio is the important parameter to reflect the channel quality, and its estimation accuracy will significantly affect the performance of the system. In addition, the software defined radio as the currently widely used real-time signal processing structure have attached significant development and attention in the last ten years, and more and more communication algorithms and standards are implemented based on it. In this paper, the physical key algorithms are improved and simulated, and they are implemented on the software radio platform. The theoretical research and the hardware implement have important guidance values and practical significance.In this paper, we first introduce the basic theory of joint detection algorithm, and discuss the high operation complexity problem of the existing joint detection algorithms, then the principle and realization process of Block-FFT algorithm are described in detail, finally performance and the complexity of the algorithms are compared through simulation. The existing SINR algorithm is simple, but its accuracy is low, and it will greatly influence the performance of the system. In this paper, a novel SINR estimation algorithm is put forward, and the simulation results indicate that the performance of the new algorithm is close to the theoretical method.Based on the theoretical analysis, we discuss the realization of the single antenna TD-HSPA+system physical layer algorithms in the software defined radio platform. Software defined radio platform chooses the high performance DSP digital processor as the baseband processing chip, so we first finish the fix-point of the programs based on DSP processing capacity and the bit width of the D/A and A/D module in RF, then with the aid of CCS BIOS tools, we design data communication function between different modules. At the same time, considering the whole processing delay and precision of the link, we optimize the fixed point division, CRC code, channel estimation, joint detection and other modules. Finally, we summarize the DSP program optimization methods, and it will improve further program optimization work.Based on the physical layer simulation and implementation, we discuss the link-level to system-level interface, and we mainly introduce three kinds of L2S methods which are suitable for the TD-HSPA+system. The work is helpful for the possible system simulation.