Mining Publication: Technical Services for Mine Communications Research: Task A, Task Order No. 1 - Applicability of State-Of-The-Art Voice Bandwidth Compression Techniques for Wireless Mine Communication

The applicability of voice bandwidth compression techniques to mine wireless communication systems is examined. Promise has been attached to such techniques because the lessened bandwidth gave hope for lessened received noise and hence increased operating range or reduced transmitter power requirements. Analog vocoders and digital adaptive predictive coders are examples of real-time techniques. For these techniques, as the bandwidth gets narrower, the signal-to- noise ratio required rises, so that expected benefits of reduced transmitter power are not fully achieved. Benefits are achieved only through the use of sophisticated and costly equipment deemed impractical for most mine applications. However, non-real-time bandwidth compression achieved by stretching out the transmission time for a voice signal to several times its original duration can provide a savings in transmitter power but with an attendant time delay.