Research And Realization Of Receiving Algorithm With High Performance In WCDMA/HSPA+

With the development of mobile communication technology, HSPA+has been widely promoted and applied because of the broad-based WCDMA networks. To enhance the data transfer rate, HSPA+introduces a higher order modulation techniques and MIMO technology while reducing the spreading factor of the system. The introduction of MIMO technology leads to the enhancement of the signal interference when the signal transmitting in the multipath fading channel, however, the higher order modulation is more sensitive to the interference of the signal and small spreading factor can lead to the reduce of the spreading gain and the noise immunity. The performance of traditional RAKE receiver can’t meet the system requirements. This paper studies a novel GRAKE receiver algorithm based on the traditional RAKE receiver algorithms. GRAKE receiver algorithm can effectively cancel the interference and improve the performance, which meets the requirement of HSPA+system.First, this paper introduces the high-order modulation technology and MIMO technology. Then this paper describes the basic principle of RAKE receiver algorithm, on the bases of RAKE receiver algorithms. Furthermore, GRAKE receiver algorithm is introduced, and the principle of interference suppression is studied. The superiority of GRAKE receiver algorithms is demonstrated through performance simulation of the two receiver algorithms, then this paper focus on the specific method of GRAKE receiver in the engineering practice of HSPA+system. The further studies about the key technologies of GRAKE develops a method for the calculating of equivalent channel response and proposes a low complexity parameter estimation method in this paper. Finally, according to the engineering implementation method, this paper sets up the HSPA+downlink simulation platform and the performance of GRAKE is simulated.The simulation results show that, the GRAKE receiver has improved performance than traditional RAKE receiver. The performance of GRAKE receiver based on parameter estimation has a narrow gap with the ideal GRAKE algorithm, just about six db less under high SNR. The GRAKE receiver algorithm can be applied to the engineering realization of HSPA+systems.