CDMA versus dynamic TDMA for access control in an integrated voice/data PCN

The authors present a comparative evaluation of dynamic TDMA and spread spectrum CDMA approaches to medium access control (MAC) in an integrated voice/data PCN environment. After a brief discussion of general technological issues related to the selection of a MAC approach for PCN, dynamic TDMA and packet CDMA protocols appropriate for the support of integrated voice/data traffic are described. Performance evaluation methodologies for determining the system capacities of these competing MAC techniques are described. System-level performance measures such as channel utilization, voice blocking probability and data delay are obtained from a detailed simulation model for the D-TDMA case, and compared with a preliminary set of corresponding results for asynchronous packet CDMA. Overall, the results show that while CDMA does achieve a higher normalized capacity than TDMA, the gains are very sensitive to the propagation loss constant, and must be balanced against higher message transfer delay for certain data services