Rate Compatible Punctured Codes, Their Use in Military Satellite Communication Systems.

摘要

The problem of interfacing older military terminal equipments, which work exclusively from an internal timing source, into a communication system that requires all terminals to synchronize to the network clock is addressed in this paper. These data communication systems would typically operate with a fixed symbol transmission rate and employ end-to-end convolutional coding for channel errors. A scheme is proposed which would allow a clock discrepancy of up to + or - 4% between the terminal clock and the network clock. The method proposed is to add control bits to the information stream between terminals. The control bits would allow the effective information rate to be either increased or decreased by + or - 4%. The overall symbol rate of the communication link is held constant by selecting a higher rate convolutional code from the set of rate compatible punctured codes (RCPCs). This paper describes the methodology used to select an optimal RCPC and presents some examples. The probability of error for a selected code is compared with that of a convolutional code for an application typical of a satellite communication system. The conclusion is that the increase in signal to noise required to sustain the same probability of error is minimal. Keywords: Rate compatible punctured codes; Military communication; Satellite communication; Jamming; Computer simulation; Canada. (jhd)