WCDMA下行链路干扰抑制接收机研究和低功耗ASIC设计方法探讨

【作者】 朱劲松；

【导师】 赵春明；

【作者基本信息】 东南大学 ， 通信与信息系统， 2005， 硕士

【摘要】 本文首先概述了DS/CDMA系统中的干扰抑制技术,最直接有效的是多用户检测技术。然后介绍了多用户检测技术的分类和发展历史,以及几种经典多用户检测算法的原理。接着重点分析了WCDMA下行链路多址干扰抑制技术:线性均衡和干扰抵消。首先针对WCDMA下行链路多码传输的特点给出了多址干扰抑制接收机的一般结构。然后针对这个结构分析了LMMSE自适应均衡和干扰抵消的原理和各自的优、缺点,讨论了干扰抵消和线性均衡技术相结合的可行性。最终得到一个适用于WCDMA下行链路的干扰抑制接收机结构。该接收机在LMMSE自适应均衡器前面和后面分别串接串行干扰抵消器和两级并行部分干扰抵消器来分别抵消多码传输时的多码道干扰和单码传输时的多用户干扰,采用快速哈达码变换估计干扰用户的等效扩频码,经解扩得到等效干扰符号,再重构和抵消多用户干扰。然后依据WCDMA平台,采用计算机仿真的方法研究多码传输、LMMSE自适应码片均衡、干扰抵消以及本文建议接收机的整体性能。通过仿真进一步说明采用LMMSE自适应码片均衡和干扰抵消技术相结合的下行链路干扰抑制接收机的性能优势,并确定了影响该接收机性能的主要参数。验证了该接收机能够工作在很多环境中并获得稳定的性能增益,具备一定的实用价值。由于手持终端对功耗的严格要求,论文最后探讨了低功耗ASIC设计和功耗分析技术。结合作者的设计经验介绍了CDMA2000-1x移动终端基带处理芯片的低功耗设计和功耗分析过程,主要讨论了门控时钟技术对改善集成电路功耗的影响。更多还原

【Abstract】 The paper firstly introduces the Multiple Access Interference(MAI) suppression techniques used in DS/CDMA and the most effective one is the Multi-User-Detection(MUD) technique. Then it introduces the classification and evolution history of MUD and the principals of several classical MUD algorithms.The paper secondly analyses MAI suppression techniques used in WCDMA downlink, that is LMMSE adaptive equalization and Interference Cancellation(IC). It gives out the general structure of MAI suppression receiver according to the feature of WCDMA downlink. Then It analyses the principals, advantages and disadvantages of LMMSE and ICs, and discusses the feasibility of combining these two techniques together. At last, It gives out the detail structure of MAI suppression receiver which is applicable to be used in WCDMA downlink. The suggested receiver uses Successive Interference Cancellation (SIC) and Parallel Interference Cancellation (PIC) placed before and after LMMSE adaptive chip equalizer to cancel Multiple Code Interference(MCI) in multiple code transmission and MAI in single code transmission. It estimates the effective spreading code of interference users using Fast Hadamard Transformation, then achieves effective interference symbols after de-spreading, at last re-constructs and cancels the MAI.The paper thirdly researches the performance of multiple code transmission, LMMSE, IC, and the suggested receiver by computer simulations in WCDMA system. The simulations further demonstrate that the performance gain of the suggested receiver by using LMMSE and IC techniques together, and make certain the parameters of the receiver that affect performance much. The simulations also demonstrate that the suggested receiver can work in many environments to get stable gain, and have much applicable value.Because of the strict requirements of power consumption in Mobile Terminal, the paper introduces the low power ASIC design and estimation techniques at last. It mainly introduces the low power design and power estimation procedure of the base-band processor chip of CDMA2000-1x MT, and mainly discusses the clock gating techniques to improve the power comsumption of integrated circuit.更多还原