A medium access protocol for interconnecting ATM and wireless networks

This paper describes a medium access protocol for wireless ATM systems using time division multiple access with frequency division duplex. Voice and data mobiles are supported. In order to utilize the resource efficiently, information slots are allocated to mobiles that are in talkspurt only. When a mobile changes its state from silent to talkspurt, it has to request for an information slot. Real-time service is required for voice mobiles and so queueing is not allowed. The medium access scheme for voice mobiles is based on the non-collision packet reservation multiple access (NC-PRMA) which will ensure prompt delivery of voice packets. Data mobiles are considered as services that are delay-insensitive. Available bit rate services can be provided for (delay-insensitive) data mobiles. The scheme for data mobiles is based on the distributed queueing request update multiple access (DQRUMA). Numerical results are obtained through simulations and the performance of the proposed hybrid protocol is compared with that of PRMA and reservation TDMA. The results obtained show that the proposed protocol performs better in the sense of having smaller voice and data dropping probabilities under similar system conditions. Additional advantages are that optimization of the system throughput is easier and that the performance of voice mobiles is unaffected by instability in the data portion of the protocol