A homotopy method for call admission control employing different user and service classes

This paper addresses power controlled call admission for interference limited mobile communication networks that controls user classes with different priorities as well as service classes with different quality-of-service constraints. The idea is to mathematically formulate the power controlled admission as a homotopy method. This novel and generic approach enables network operators to flexible define a user/service-specific admission policy in order to handle users with different access priorities and/or different service classes. As an example, we can interactively control the access of high priority users by dynamically adjusting the service quality of already active users with low priority. On the other hand, the proposed approach also allows for safe and soft call admission. That is, to prevent a QoS deterioration in the active links and to assure acceptance of new users, if and only if all users can be supported at their required QoS. Due its generic character the proposed method gains new insight in power control and admission theory. Beside describing the admission approach we also study the existence of power solutions and show results for different pre-defined admission control functions when applied in a CDMA based cellular system