| 摘要 |
A cellular radio system, having a mobile services switching center (MSC) coupled to a base station by means of a pulse code modulation (PCM) link, has an apparatus comprising, in the MSC, a transcoder and rate adaptor (TRA) that generates a PCM frame from a plurality of user data blocks, each user data block corresponding to one of a plurality of users and each user data block comprising an integer number of bytes of data. In the PCM frame, each of the plurality of user data blocks occupies an integer number of consecutive bytes of the generated PCM frame, which is then output to the PCM link. The base station includes a channel encoder that generates an air interface frame from a plurality of user data blocks contained in a received PCM frame. The base station may also generate a timing control signal which is received by the MSC. A timing controller in the MSC is responsive to the received timing control signal, and causes the TRA to synchronize output of a generated PCM frame with generation of an air interface frame such that the generated PCM frame will arrive at the base station channel encoder substantially just at a moment when the generated PCM frame is needed by the channel encoder in order to generate the air interface frame without waiting for the generated PCM frame.
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