| We consider flow control in the downlink direction for a microcellular CDMA system carrying integrated packet level-data and voice services with the objective of providing maximum traffic capacity without service degradation due to overload. The goal of this research is to develop flow control techniques that regulates the admitted calls based on the prediction of the total transmitted power requirements over the next packet transmission interval. If the probability of exceeding the maximum power value is sufficiently low, the extra power required to accommodate the data transmission is unlikely to result in outage and, therefore, data flow is permitted. The autocovariance function of the transmitted power under maximally loaded traffic conditions allows such predictions.; With packet-level flow control, one can potentially transmit useful volumes of packet data even when no fixed mean data transmission rate can be guaranteed. The traffic admitted to any cell is increased if the traffic in the neighboring cells happens to be low. Using constant bit rate (CBR) speech transmission with 100% activity, the system can accommodate about 67 mobiles. With available bit rate (ABR), we can accommodate up to 82 data mobiles receiving data at the same average rate of 8 Kb/sec. |
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