Admission control of integrated voice/data traffic for networks of LEO satellites using CDMA

Abstract

In this paper, we consider a network of low-earthorbit (LEO) satellites with integrated voice and data traffic. The uplinks and downlinks of all satellites use code-division multiple-access (CDMA) with directsequence spread-spectrum (DS/SS) signaling. The satellites act as bent-pipes; no on-board processing or intersatellite links are present. The network performance is analyzed in terms of the average blocking probability and the average throughput of the voice calls as well as the average packet error probability and the average throughput of data messages. An optimal distributed admission control scheme for the integrated voice and data traffic is derived for this multiple-satellite network. This admission scheme determines the number of newly arrived voice users that are accepted so that the blocking probability of voice calls is minimized over a longer period. 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. Moreover, we present the admission policy of data traffic under threshold model. We also compare the performance over both threshold model and graceful degradation model.