A speech packet protocol for mobile radio using idle-signal casting multiple access

A medium access control protocol has been described that can support both speech and data packets over mobile radio channels. The logical TDMA protocol utilised a frequency-division ,multiplexing approach for voice station reservations. Both voice and data stations used the R-channel for this purpose. The base station maintained the queue order by implementing a scheme of access-tokens on the D-channel. Mobile stations retained a queue position after their packet transmissions by appending continuation-tokens. The variable length packet scheme was found to support more conversations than the fixed length packet version. Also, the total delay with variable length packets is bound to two frame times, whereas the delay for fixed length packets has an upper limit of three frame times. However, in the region of operation (voice loss<2%), the fixed length packer version has an upper speech clip of one frame time, whereas the varible length packets can significantly exceed this limit. It is therefore necessary to examine further the subjective quality of the speech loss using variable length packets