Maximising spectral-efficiency in 3rd generation radio-access-networks using low-complexity multiple-access-control protocols

One approach to maximising the spectral efficiency on the uplink in a WCDMA based 3rd generation radio-access-network (3GRAN) is to employ an efficient multiple-access control (MAC) protocol. However, the proper design of resource allocation algorithms in 3GRAN has been limited by the absence of a metric that measures true resource and capacity in the 3GRAN environment, where different users may have different signal-to-interference ratio (SIR) requirements. This paper presents a novel resource metric as a solution to this fundamental problem. Subsequently, the resource metric is put to use in order to design, develop and evaluate new multiple-access control algorithms, based on distributed-scheduling-control (DSC), which offer the benefit of low complexity. However, a major problem when using DSC is quality-of-service (QoS) support for services with delay-constraints in the absence of a centralised scheduler. This problem is addressed here by using a deadline-driven-backoff (DDB) procedure that is based on a ´probabilistic´ earliest-deadline-first (EDF) scheduling principle. The main conclusion is that a low complexity DSC strategy can be designed using the proposed resource metric to give near optimal performance and thus maintain a high spectral-efficiency in 3GRAN.