H-ARQ技术在第三代移动通信系统中的应用

首先介绍了H-ARQ技术的原理及其分类,然后简述了H-ARQ技术在3G各个标准,如WCDMAR99、HSDPA和cdma20001xEV中的应用,并与以往移动通信标准中的H-ARQ技术的运用进行了对比,最后展望了H-ARQ在未来通信系统中的发展和演化。     

移动通信中基于Turbo码的H-ARQ技术

重点介绍了两种最近在3GPP和3GPP2中得到一定应用的H-ARQ技术:基于速率匹配短截Turbo码的H-ARQ技术,基于准互补Turbo码的H-ARQ技术等,主要分析了它们的基本原理和准则及实施方案;概述了基于其他编码的H-ARQ技术的研究情况.     

采用Ⅲ型H-ARQ的BICM-ID系统研究

本文提出了采用Ⅲ型H-ARQ的BICM-ID系统实现方案.给出了传输协议及组合译码算法,从理论上分析了系统通过率.在Awgn信道和Bayleigh衰落信道下,对分别采用Ⅰ型,Ⅱ型,Ⅲ型H-ARQ的BICM-ID系统通过率进行了仿真比较.结果表明,与采用其他两种类型H-ARQ的BICM-ID系统相比,采用Ⅲ型H-ARQ的BICM-ID系统性能最优.而且,在低信噪比和Rayleigh信道下的优势更加突出.     

H-ARQ信道上高性能全分集LDPC码的构造与性能分析

为了提高混合自动重传请求(H-ARQ)系统的通信性能,研究了H-ARQ块衰落信道上全分集低密度奇偶校验(LDPC)码的构造与性能.首先分析了H-ARQ块衰落信道的中断概率及其固有分集,然后构造了在H-ARQ块衰落信道上能取得全分集的LDPC码,新构造的码字采用根校验节点把每次传输联系起来,从而获得全分集.在此基础上,分析了全分集LDPC码的结构,提出了通过提高全分集校验比特的比例,改善全分集LDPC码在H-ARQ信道上编码增益的方法.仿真结果表明,所提算法在H-ARQ信道上不仅能取得全分集,而且具有较高的编码增益     

朗讯全新HSDPA技术及其在Cingular网络的成功应用

1朗讯HSDPA技术的优点 朗讯科技贝尔实验室在HSDPA(高速下行分组接入)技术领域进行了多年的研发,其推出的HSDPA芯片采用了Turbo编码,实现了峰值数据速率24 Mbit/s的无线传输,领先于3GPP的R5标准和正在发展的R6标准.朗讯科技已经实现了HSDPA的主要关键技术,包括自适应编码调制(AMC)、快速混合自动重传(H-ARQ)、MAC调度、多入多出天线处理(MIM0)等.     

基于G.hn标准协议的PLC混合ARQ方案研究与改进

现代电力线通信(PLC)系统为了可靠地传输数据并提高系统传输量,自动重传请求(ARQ)技术必不可少.然而ARQ技术已经很好地解决了现有通信的数据传输问题,但由于PLC信道不稳定、强干扰以及衰减非常快等缺点造成误码率极高、吞吐量低.针对PLC家庭网络提出能够适应PLC信道的H-ARQ技术来满足未来PLC通信网络的需求.改进ARQ和低密度奇偶校验(LDPC)技术相结合来提高传输率、降低误码率.最后通过仿真实验对改进的H-ARQ协议算法验证,从仿真结果可以看出误码率降低、吞吐量较高,能适应环境极其差的电力线通信.     

基于II型H-ARQ系统速率可变低密度校验码的设计与研究

构造了一类用于II型H-ARQ系统、具有Z字形结构校验矩阵、性能优良的速率可变低密度校验码(RC-LDPC)。将渐进边增长(progressiveedgegrowth)算法推广应用到RC-LDPC码的构造中,扩大了码率动态变化范围,提高了码的性能。仿真结果表明将此类RC-LDPC码应用于II型H-ARQ系统,可获得较高的吞吐量,且其校验矩阵的Z字形结构极大地降低了系统实现的复杂度。     

基于II型H-ARQ系统速率可变低密度校验码的设计与研究

构造了一类用于Ⅱ型H-ARQ系统、具有Z字形结构校验矩阵、性能优良的速率可变低密度校验码（RC-LDPC）。将渐进边增长（progressive edge growth）算法推广应用到RC-LDPC码的构造中，扩大了码率动态变化范围，提高了码的性能。仿真结果表明将此类RC-LDPC码应用于Ⅱ型H-ARQ系统，可获得较高的吞吐量，且其校验矩阵的Z字形结构极大地降低了系统实现的复杂度。     

在不同移动速度下的无线链路自适应的实现分析

首先简单介绍了两种直接链路自适应技术AMC，H-ARQ，讨认弛不同的用户移动速度对信道估计的影响，说明用户移动速度差别很大时应采用不同的链路自适应技术；然后提出了一种在用户高速移动时的间接链路自适应技术并对其进行了分析，分析结果表明这种间接链路自适应技术在用户高速移动时的性能优于现在的通用的直接链路自适应技术。     

《电子科技》2006年总目录

综述1-56大功率激光二极管阵列光束整形技术综述………………孔媛媛1-60H-ARQ技术在第三代移动通信系统中的应用……牛昱,罗青全1-65并行数据挖掘算法综述…………………刘华元,袁琴琴,王保保1-69MPLS组播流量工程综述…………………………姜少杰,吕光宏1-74网格技术应用漫谈………………………韩毅娜,刘守义,秦莲2-74基于GIS的电信管线资源系统设计………………章媛,沈永珞3-64高校校园网安全整体解决方案研究………………张武军,李雪安3-68采用DS-CDMA方式的超宽带技术研究与应用……李浩,曾兴雯3-74综合网络管理系统中抽象网元模…     

OFDMA-CDM performance enhancement by combining H-ARQ and interference cancellation

In this paper, superimposed packet allocation for orthogonal frequency-division multiple-access code-division multiplexing (OFDMA-CDM) is presented, where each transmitted packet is associated with one spreading code. An iterative algorithm which is a combination of parallel interference cancellation and hybrid automatic repeat request (H-ARQ) based on soft value combining (SVC) is proposed, and its performance is studied and compared with other existing H-ARQ schemes. The proposed algorithm exploits the reliability information of erroneously received copies of the same data packet to improve the performance of interference cancellation. The interference of correctly received packets is ideally reconstructed and subtracted. Thus, the overall system performance improves iteratively. As a result, the proposed algorithm outperforms conventional H-ARQ based on SVC, as well as H-ARQ based on maximum ratio combining.     

HSDPA中的H-ARQ技术分析

HSDPA（High Speed Downlink Packet Access）即高速下行分组接入技术是3G中的一项重要技术。它作为一种无线增强技术极大的提高了系统的下行数率，而且同时适用于WCDMA和TD—SCDMA系统。HSDPA中引入了自适应调制和编码技术（AMC）、混合自动请求重发（H—ARQ）、快速小区选择（FCSS）、MIMO技术等关键技术。主要研究其中的H—ARQ（Hybrid Automatic Repeat reQuest）技术。首先介绍H—ARQ的起源及三种不同类型H—ARQ的特点，其次研究了H—ARQ在HSDPA中的应用，最后对不同H—ARQ方案的性能进行了分析。     

Delivering QoS in the next generation network — a standards perspective

The next generation network (NGN) is envisaged as being an IP-based network which supports a wide variety of applications in an increasingly converged fixed-mobile environment. This paper looks at the key standards which are available as enablers to the building and operating of an NGN that delivers appropriate levels of quality of service for end-user applications.The paper starts by looking at a general framework for quality of service (QoS) standards, including the necessary terminology to distinguish between the performance of the network and the requirements of applications. It goes on to look at the key standards that address the application requirements, the performance of the IP layer and the behaviour of its bearer. In addition the paper discusses several concepts designed to allow the control of QoS levels in IP-based networks. Although it also discusses published standards, there is much ongoing standardisation activity in the technical areas of QoS and network performance that is outside the scope of this paper.     

Hybrid ARQ with Cross-Packet Channel Coding

We describe hybrid automatic repeat request/forward error correction (H-ARQ) with cross-packet channel coding which extends current H-ARQ schemes for point-to-point communications. In contrast to current H-ARQ schemes, the transmission of two consecutive packets of information bits is considered jointly. If a retransmission for the first packet is necessary, we encode the first and a second packet jointly. For fading channels, this allows diversity gain from retransmissions without decreasing the total code rate. We describe an encoder and a decoder which can be decoded iteratively for a system with H-ARQ with cross-packet channel coding     

Performance Analysis of Hybrid-ARQ Characteristics in HSDPA

This paper describes network level simulation results for Enhanced UMTS. High-Speed Downlink Packet Access (HSDPA) enhances both the capacity and the peak rate of WCDMA-based systems. Link adaptation and Hybrid-Automatic Repeat reQuest (H-ARQ) are two key functions creating these enhancements. This paper considers the results of different aspects of the H-ARQ process. This process is considered from two viewpoints. The results are mainly gathered from the ns-2 based network level simulator Enhanced UMTS Radio Access Networks Extension (EURANE). This is a network level simulator with realistic traffic and user scenarios. Also results from a more fundamental analysis of H-ARQ characteristics based on link-level results will be included. In this more fundamental point of view, only the underlying channel conditions are used for a preliminary study of new ideas. The rounding down and delaying of the CQI reporting both have a significant impact on throughput and transfer delay of the HSDPA channel. The analysis of the link-level results provides a first insight how different parts of the WCDMA system interact with each other and impact the end-to-end performance as experienced by the user. Both viewpoints show that the H-ARQ functionality indeed enhances the capacity and peak rate of the WCDMA system.     

A Soft Combining Hybrid-ARQ Technique Applied to Throughput Maximization Within 3G Satellite IP Networks

This paper deals with the application of Hybrid-Automatic-Repeat-reQuest (H-ARQ) techniques to reliable end-to-end data communications in satellite networks, whose applications have to cope with accurate Quality-of-Service (QoS) requirements. Particularly, we face this problem by introducing a modified H-ARQ scheme based on the use of the turbo codes' error-correction capabilities. According to our scheme, each packet is turbo coded, and packet retransmissions are lowered by keeping track of previous erroneous packet-decoding results. Moreover, two kinds of these techniques are proposed and applied, respectively, to consecutive received packet replicas or to decoding algorithm outputs. The benefits achieved through this approach have a positive effect both on the error-recovery strategies and, above all, on the congestion-control protocols, since they rely on a retransmission scheme. By means of analytical derivations carried out under the assumption of a wideband-code-division multiple-access communications, it has been possible to highlight noticeable performance improvements in terms of bit- and frame-error rates and link throughput. Computer simulations performed focusing on a typical satellite-universal-mobile-telecommunication-system environment validate analytical predictions and point out a remarkable gain without requiring a significant hardware-complexity increase. As a result, it has been possible to allow active users a better QoS, in terms of error rate, throughput, and delivery delay, or to increase access-network capacity, besides avoiding transmitted-power wasting     

Power controlled H-ARQ in cdma2000 1/spl times/EV-DV

The newly applied H-ARQ technique in the reverse link of a cdma2000/spl reg/ 1/spl times/EV-DV system is shown to be similar in nature to the fast power control technique such that the two techniques both reduce interference to other users. In order to balance the H-ARQ gain and packet delay time, four modes of operation are defined: normal, reduction, boost, and boost reduction. The four modes are defined according to the way the channel gain is set for the H-ARQ operation. Simulation results show that the reduction modes have better performance in terms of both PER and packet delay time. It is also shown that the boost modes have lower PER and packet delay time than the non-boost modes, but at the expense of more energy.