| 摘要 |
Methods and apparatus for providing automatic retransmission query (ARQ) functions in a communication system. A transmitter in the system applies an inpu t data packet to a first convolutional encoder operating at a first rate to generate an inner code including multiple encoded packets. The encoded packets are interleaved an d applied to a second convolutional encoder operating at a second rate which gener ates an outer code including a transmit packet generated from each of the encoded pac kets. A first transmit packet is sent to a receiver, which decodes the transmit packet in a Viterbi decoder operating at the second rate to generate a decoded version of th e first transmit packet. The decoded version is inverted to provide a first provisional decoding of the input packet. If a cyclic redundancy code (CRC) check of the fi rst provisional decoding is passed, the receiver sends an ACK signal to the transmit ter and no retransmission is required. If the check is not passed, the transmitter send s one or more additional transmit packets, which are processed in a manner similar to the first transmit packet to generate one or more additional provisional decodings of the input data packet. If a CRC check of a given one of these additional provisional deco dings is passed, the receiver accepts it as the input packet and sends an ACK signal to t he transmitter. If non pass the CRC check, the receiver may combine decoded versio ns of the transmit packets, and apply the result to a Viterbi decoded operating at the first rate to generate another provisional decoding of the input packet. This provisi onal decoding is accepted as the input packet if it passes a CRC check.
|
