| 摘要 |
<p>A method for encoding and decoding the digital information sequence uses a combination of two block codes to simultaneously correct and detect errors. The reliability of the data decoded by an error correcting block code is checked by comparing the result of the decoding operation using either the raw parity or a corrected parity determined by using a second error correcting block code, as follows: the information sequence is encoded by a first stage of the encoder to produce an information code word including an information vector and a primary redundancy vector. The primary redundancy vector is encoded in a second stage of the encoder to obtain a redundancy code word. The information code word and redundancy code word are interleaved and transmitted to the receiver. At the receiver, the information code word and redundancy code word are decoded in a first stage of the decoder to obtain a first estimate of the information code word. The first estimate of the information code word is decoded in the second stage of the decoder to produce a second estimate of the information code word. The distance between the first and second estimates of the information code word is evaluated. If the distance is more than one, the received code word is erased. In another embodiment, the information sequence is repeated at the receiver. Each repetition includes a parity check resulting from the same code or from different codes. The received information vectors are selectively combined and then individually decoded using the individual parity vectors to generate multiple estimates of the information sequence. The estimates are then combined using hard or soft combining techniques.</p> |
