Some Low Cost Error Control Coding Techniques for Computer Systems

项目编号：0701452 PI姓名：Bella BosePI机构：俄勒冈州州立大学项目名称：计算机系统的低成本差错控制编码技术摘要：在数据通信系统中，当二进制数据从源传输到目的地时，由于信道噪声，数据位可能被破坏.可以使用差错控制码来检测和/或校正数据位中的这些差错。差错控制码的主要思想是在发送端给信息比特附加一些适当的冗余校验比特，以便在接收端利用这些多余的冗余比特来检测/纠正信息比特和校验比特中的错误，数据错误可以大致分为对称错误、非对称错误和单向错误。在对称错误中，1到0和0到1错误都可能出现在接收的字中。在非对称错误情况下，只有一种类型，例如1到0错误可能发生。最后，在单向情况下，在一个数据字内的错误是相同的类型，要么都是1到0或都是0到1，但错误的类型是不知道的先验。此外，还研究了采用自动重传请求（ARQ）方法的一些新的差错控制技术。在ARQ协议中，系统中使用了检错码。每当接收器接收到一个字时，它会检查这个字中是否有错误。如果没有，它接受这个字，并向发射机发送一个肯定的确认;发射机然后发送下一个字。然而，如果存在一些错误，则接收器拒绝该字并向发送器发送否定确认;然后发送器再次发送相同的字。这个过程一直持续到接收者得到正确的单词。当错误为非对称或单向错误时，提出了一些新的码合并方案。这里，不是在接收器端丢弃损坏的字，而是使用逐位OR或AND操作将其与下一个传输的（相同）字组合。这些方法的性能分析将进行调查。这些低成本的错误控制方案的应用程序，许多计算机和通信系统将进行评估。

Project ID: 0701452PI name: Bella BosePI Institution: Oregon State University Project Title: Some low cost error control coding techniques for computer systemsAbstract:In data communication systems, while transferring binary data from the source to destination the data bits may be corrupted due to the channel noise. These errors in the data bits can be detected and/or corrected using error control codes . The main idea of error control codes is to append some appropriate redundant check bits to the information bits at the transmitter so that at the receiver, the errors in the information and check bits can be detected/corrected using these extra redundant bits.The data errors can be broadly classified as symmetric, asymmetric and unidirectional. In symmetric errors both 1 to 0 and 0 to 1 errors can occur in a received word. In asymmetric error case only one type, say 1 to 0 errors can occur. Finally, in the case of unidirectional case, the errors within a data word are of same type, either all 1 to 0 or all 0 to 1, but the error type is not known a priori.In this proposal, some efficient design of error control codes for asymmetric and unidirectional errors are investigated. Furthermore, some novel error control techniques using automatic repeat request (ARQ) method are also studied. In ARQ protocol, error detecting codes are used in the system. Whenever a receiver receives a word, it checks whether there are some errors in the word. If none, it accepts the word and sends a positive acknowledgement to the transmitter; the transmitter then sends the next word. However, if there are some errors then the receiver rejects the word and sends a negative acknowledgement to the transmitter; the transmitter then sends the same word again. This process continues till the receiver gets the correct word. When the errors are of asymmetric or unidirectional type, some novel schemes of code combing are proposed. Here, instead of discarding the corrupted word at the receiver end, it is combined with the next transmitted (same) word using bit-by-bit OR or AND operation. The performance analysis of these methods will be investigated. The applications of these low cost error control schemes for many computer and communication systems will be evaluated.