An efficient and decentralised user association scheme for multiple technology networks

Wireless networks have emerged as the most popular access technologies. Multiple technologies like WiFi, WiMAX, LTE, along with traditional cellular networks augmented with pico and femto base stations, are available for a user to access the Internet. Many emerging user devices, e.g. smart phones, allow for Internet connectivity using most of the available technologies. Thus, at a given point in time, a user can be in the communication range of many base stations, potentially using different access technologies. This naturally gives a user a choice as to which base station he should select for network access. The association chosen by a user determines not only his own performance, but also the performance perceived by other users. Though user performances are coupled, association decisions can seldom be taken in a centralised manner. This is because different access technologies may not share the required control information and cooperate. Also, different user devices may not want to divulge their own information, for privacy or security reasons, and also on account of additional power requirement for control message exchange. Thus, one needs to devise distributed association schemes that do not require any message passing. In this paper, we consider the problem of maximising network utility subject to constraints on user requirements. To this end, we propose a distributed association scheme in which a user chooses his association based only on his own past association and the utility he obtained. We prove that it is indeed possible to achieve maximum network utility while satisfying individual user requirements in a completely distributed manner. We also evaluate the performance of the proposed scheme using simulations.