MDP-based fast handoff with reducing waste rate method for management radio resource in 3GPP cellular networks

The 3G wideband CDMA systems (WCDMA) adopt the orthogonal variable spreading factor (OVSF) code tree as the channelization codes management for achieving high data rate transmission in mobile communications. It assigns a single channelization code for each accepted connection. Nevertheless, the data rate of traffic classes should be powers of two of the basic rate, which is impractical and wastes the system capacity when the required rate is not powers of two of the basic rate. One good solution to reduce the waste rate is to assign multiple codes for each accepted connection but it causes two inevitable drawbacks: long handoff delay and new call setup delay due to high complexity of processing with multiple channelization codes, and high cost of using more number of rake combiners at both of the base stations and the mobile nodes. Therefore, we propose herein an adaptive efficient partition algorithm with the Markov decision process (MDP) analysis approach to provide fast handoff while reducing the waste rate significantly. Numerical results show that the proposed approach outperforms the single code assignment scheme in GOS and waste rate. Meanwhile, the optimal number of rake combiners is also analyzed in this paper.