Reservation code multiple access with control code for voice terminal

For local wireless communication, the reservation code multiple access (RCMA) protocol has been proposed as a promising protocol, which allows all terminals to share a group of spreading codes on a contention basis and facilitates introducing voice/data integrated services into spread-spectrum systems. However, the voice packet dropping probability of RCMA is degraded in the heavy load condition because of the contention mechanism of random access. We propose the use of the control code for the voice terminal with the RCMA protocol to improve the voice packet dropping probability. In the proposed model, by assigning a minislot in the call set-up for each voice terminal, a voice terminal can reserve a spreading code efficiently without the packet collision by transmitting a mini-packet to a minislot while a data terminal has to contend for a code for each packet transmission. We show that the proposed model attains lower voice packet dropping probability than the conventional RCMA while the data packet average delay is almost the same as that of conventional RCMA by theoretical analysis and the computer simulation.