IDLE-SIGNAL CASTING MULTIPLE-ACCESS WITH PARTIAL ECHO (ICMA-PE) FOR MOBILE PACKET COMMUNICATIONS

A highly efficient random access scheme ICMA-PE (Idle-Signal Casting M ultiple Access with Partial Echo) is proposed for digital mobile commu nications. In this scheme, partial echo (PE) bits are broadcast with i dle busy bits and receive nonreceive indicating bits as collision cont rol bits to control mobile transmission, thus improving the random acc ess efficiency. First, frame formats, behavior of mobile and base stat ions, and the transmission procedure are explained. Next, the packet f ailure rate and throughput are evaluated with both theoretical analysi s and computer simulations. As a result it is clarified that about 20 percent improvement in maximum throughput is achieved compared to conv entional schemes. The improvements achieved with transmissions also ar e mentioned and the transmission characteristic when various message l ength signals coexist is clarified. Finally, the effect of the coincid ence of a PE with one from another station is evaluated, and it is sho wn that the PE bit length of about 7 bit is necessary to maintain the characteristic.