Adaptive power allocation with user prioritization fr downlink orthogonal frequency division multiple access systems

Maximizing the capacity of a downlink orthogonal frequency division multiple access (OFDMA) system with prioritization of user-services is investigated. An iterative algorithm is proposed to determine the capacity of individual user from a limited and varying power budget when the channel is subjected to fading, shadowing and propagation path loss. Simulation shows that the proposed algorithm not only can obtain achievable capacity of the users' requested services but also conserve excess transmit power if a lesser power budget is adequate to achieve the desired capacity