PSI-CELP SPEECH CODING DOUBLES THE CAPACITY OF RADIO-WAVES

The digital cellular mobile radio system introduced in Japan in March 1993 (a full bit-rate system) is likely to run short of radio bandwidt h within a few years because the number of subscribers is quickly incr easing. We have therefore developed a speech coding method that operat es at half the bit-rate but still has almost the same quality as the f ull bit-rate system. This new method is called PSI-CELP (pitch synchro nous innovation code excited linear prediction); it has been adopted a s the half-rate PDC (personal digital cellular) standard in Japan. The PSI-CELP system is expected to be used in the next digital cellular m obile radio system.