Some new technologies are introduced in hsdpa , including a shorter transimission time interval ( tti ) 、 adaptive modulation and coding ( amc ) scheme and a fast physical layer hybrid arq mechanism 在该系统中采用了以下技术:更短的传输时间间隔,物理层的混合自动重传,自适应编码调制等。
In communication systems , there are mainly two methods for controlling transmission errors , one of which is forward - error - correction ( fec ) and the other is automatic - repeat - request ( arq ) 数据传输系统中有两种技术被用来控制传输错误：即前向差错控制技术( fec )和自动要求重传技术( arq ) 。
Firstly , a syndrome - based type - i nonbinary hybrid arq ( harq ) is proposed , which makes full use of the powerful error - detection and - correction capacity of reed - solomon ( rs ) codes , and can be combined with the existing rs decoder easily 首先，提出了基于校正子( syndrome )的第一类多进制harq ，它充分利用了reed - solonmon ( rs )码强大的纠错和检错功能，并可直接结合到已有的rs译码器中。
Arq ( auto repeat on request ) is used in data communication to garauntee error - free transmission , but it is not suitable for video communication because video communication has stringent delay requirement and limitless retransmission is not allowed 传统的数据通信通过出错重传的方法保证数据的无差错传输，但是这种方法不适合实时视频通信。因为视频通信对延迟有严格的要求，不可能使用无限制的重传。
A new h - arq scheme that uses progressively decodable serially concatenated codes for retransmission is proposed with its design guidelines . theoretical bounds on total number of transmitted bits and throughput performance are derived . finally , the simulation results are given 提出了基于累进可译串行级连码的h - arq体制，论述了其设计原则，推导了重传比特数和通过率的理论限，给出了性能仿真结果。
Simulation results show that both objective gains measured in psnr ( peak signal - to - noise ratio ) and visual improvements of reconstructed video can be achieved by utilizing introduced methods . chapter 5 gives the implementation of jvt - based nwarq technique 实验结果表明，各改进算法能不同程度地提高和改善重建图像的峰值信噪比( psnr )和主观质量；第五章研究、实现并测试了基于jvt视频编码标准的无等待arq技术。
This experiment adopts the theory of similarity as theory foundation , adopts arq number as criteria of similarity , designs and makes physical model according that geometric scale is , selects experiment instrument and setting 标准机组段分层空调模型试验以相似理论为理论基础，采用热量阿基米德数arq作为该试验的相似准则。按照的几何比例尺以及其他制约条件设计并制作其物理模型，同时完成测试仪器选配和测试辅助装置的建立。
Secondly , the ipos is introduced on the whole , including network architecture , protocol reference mode , and two key technologies : the hybrid arq error control and adaptive coding modulation . meanwhile , the qos standard specifically used in the dissertation is presented 之后从总体上对ipos协议进行介绍,分析了其网络结构,协议模型,混合arq控制机制、自适应编码调制这两项ipos协议的主要技术组成等内容,并提出了本课题采用的qos指标。
Hsdpa is a good improvement and evolvement in the wireless part of wcdma . acm is one of the key technologies in hsdpa , and h - arq is a recessive technology of acm . in the end of this thesis , the basic principle of h - arq and its class are briefly discussed 自适应编码调制是hsdpa中的关键技术, h - arq是acm的一项隐含技术,本文最后介绍了h - arq的基本原理及其分类,研究了采用acm技术hsdpa性能的提升,讨论了采用acm技术可能增加的设备复杂性的问题。
Simulation results based on modified jm1 . 4 codec show that implemented nwarq can stop error propagation at decoder and completely recover damaged video without introducing any additional playout delay , comparing to ec and conventional arq ( automatic repeat request ) technique 测试结果表明：本文实现的无等待arq算法相对于传统的arq技术和差错掩盖技术而言，能在不影响解码器端重建图像正常回放的情况下，阻止差错的扩散，实现图像的完全彻底恢复。
