Utility function maximization problems for two cross-layer optimization algorithms in OFDM wireless networks

One of the main problems in wireless networks is optimization of radio resources allocation in down-link channel. Different traffic types transmitted over the network suggest a dynamic resource allocation in order to provide a better quality of service (QoS). There are radio resource management modules, called schedulers, which are engaged in resource planning and access priority assignment depending on the types of traffic with the specified requirements for QoS. Schedulers are developed based on algorithms derived from solving various radio resources optimization problems. Cross-layer optimization problems such as the problem of minimizing the transmission power or the problem of maximizing the transmission rate [1], in fact involve the optimization of a utility function, that describe a certain level of user satisfaction for a particular resources allocation scheme under certain restrictions. In this paper we study two cross-layer optimization algorithms that are intended to maximize the utility function under different conditions - dynamic subcarrier assignment (DSA) algorithm and adaptive power allocation (APA) algorithm.