发明名称 |
Line terminating equipment in SDH networks, using forward error correcting codes. |
摘要 |
<p>In an optical transmission system applicable to a SDH network, communication between two line terminating equipments is performed in a form of a STM frame composed of a SOH field and a payload, which is determined by CCITT recommendations. The line terminating equipment provides a FEC circuit which is preferably arranged at a location between MSP and MST function blocks. The FEC circuit is designed to perform coding/decoding operations, using a cyclic Hamming code, directly on each AU-4 message derived from the STM frame. Otherwise, the FEC circuit performs operations on each k-bit interleaved AU-4 message (where 'k' is an integer larger than 1). Check bits generated by a FEC coding circuit are written into undefined byte areas in a MSOH field, and error correcting is performed at a decoder circuit on the basis of embedded check bits, therefore FEC operations are performed within a multiplex-section layer. A FEC processing circuit is constituted by shift registers each of which is connected by exclusive-or logic so as to execute FEC processing calculation generating a remainder by a generator polynomial. For a FEC code on direct AU-4 message, the FEC processing circuit in parallel configuration for lowering an operational clock rate is determined by a matrix form calculation, which creates an output vector indicating a set of shift registers' data in a future clock timing from an input vector consisting of data stream in message and initial shift registers' values. <IMAGE></p> |
申请公布号 |
EP0684712(A2) |
申请公布日期 |
1995.11.29 |
申请号 |
EP19950401132 |
申请日期 |
1995.05.16 |
申请人 |
NIPPON TELEGRAPH AND TELEPHONE CORPORATION |
发明人 |
TOMIZAWA, MASAHITO;YAMABAYASHI, YOSHIAKI;KOBAYASHI, YUKIO;NAKAGAWA, KIYOSHI;YAGISAWA, KEN-ICHI |
分类号 |
H03M13/00;H03M13/15;H04J3/14;H04Q11/04;(IPC1-7):H04J3/14 |
主分类号 |
H03M13/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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