Admission Policies for Integrated Voice and Data Traffic in CDMA Packet Radio Networks

Abstract

In this report, we derive optimal admission policies for integrated voice and data traffic in packet radio networks employing code-division multiple-access (CDMA) with direct- sequence spread-spectrum (DS/SS) signaling. The network performance is measured in terms of the average blocking probability of voice calls and the average delay and packet loss probability of data messages. Our admission scheme determines the number of newly arrived voice users that are accepted in the network so that the long-term blocking probability of voice calls is minimized in longer-term. In addition, new data arrivals are rejected, if the mean delay or the packet loss probability of data exceeds a desirable prespecified level. A semi-Markov decision process (SMDP) is used to model the system operation. Then a value-iteration algorithm is used to derive the optimal admission control. Two models for the other-user interference of the CDMA system are considered: one based on thresholds and another based on the graceful degradation of the CDMA system performance, and their performance is compared. These admission policies can be employed by either terrestrial or satellite CDMA networks and are currently being extended to networks of LEO satellites and multi-rate multi-media CDMA communications.