Anti-multipath Interference Technology In WCDMA System

In order to improve the WCDMA uplink data transmission rate and system capacity,3 GPP R6 version hsupaare wireless access technology is introduced.Hsupaare increased in an enhanced dedicated uplink,allowing a minimum of 2 spread spectrum factor.When using small spreading factor,because of the effect of multipath fading,more physical channel code orthogonality,and multi-user interference,uplink receiver performance will be worse.Processing gain of the traditional RAKE receiver is not enough to reduce multipath interference caused by intersymbol interference(ISI),therefore,this kind of situation,this paper puts forward an improved uplink receiver,to restore more code channel orthogonality,eliminate intersymbol interference in order to achieve high receiving performance.The main research work of this paper are as follows:(1)study the traditional RAKE receiver implemented in a WCDMA R99 version.According to the radio channel multipath propagation characteristics leads to the RAKE receiver and multipath searcher,channel estimation and multipath combined key technologies were discussed in detail,including formulas related algorithms analysis and simulation analysis.(2)for the HSUPA spreading gain in the low case,an improved RAKE receiver.Based on the traditional RAKE receiver on the introduction of interference cancellation module,designed an improved interference cancellation RAKE receiver.It gives a detailed block diagram of the design and research of algorithm design of key modules.(3)simulation compares the performance of several uplink receiver algorithms.The simulation link design and environmental parameters set MATLAB simulation platform,and traditional RAKE receiver,a RAKE receiver interference cancellation order,second order of several interference cancellation algorithm RAKE receiver,etc.were simulated and compared.Simulation results show that the improved interference cancellation after the RAKE receiver has about 2.5d B gain than the conventional RAKE receiver performance,performance has been significantly improved.