Service curve assurances versus uplink throughput in CDMA networks

The scheme proposed in this paper balances the partly conflicting objectives of meeting the diverse quality of service (QoS) needs of mobile hosts (MHs) and achieving high uplink throughput in a Direct Sequence Code Division Multiple Access (DS-CDMA) based cellular network. The QoS needs of the MHs are modeled using the notion of a service curve, which is a function characterizing the minimum number of bits a MH must transmit in any given time interval in order to meet its QoS requirement. Each MH is also assumed to have a specified bound on the acceptable bit error rate.The technique proposed in this paper maximizes the uplink throughput subject to the service curve constraints by jointly adapting the transmitted power and the number of spreading codes used by each MH in relaying its data bits. During this joint adaptation, the technique also imposes specified bounds on the transmitted power and the number of spreading codes that a MH can handle. The proposed technique is evaluated using a discrete-event simulation. The evaluation shows that the proposed scheme can effectively balance the two above-mentioned objectives.