A joint subcarrier and power allocation technique with pro-rata fairness and unequal error protection for video transmission over OFDMA downlink

In this paper, we investigate the video quality fairness issue experienced during the transmission of video traffic from base station (BS) to users in orthogonal frequency division multiple access (OFDMA) networks. Assurance of video quality fairness is a cross-layer optimization problem when fairness is required among users in the application layer and it is achieved through resource optimization in the physical layer. For this we develop a non-iterative joint subcarrier assignment and power allocation algorithm for downlink transmission. Also we define pro-rata video quality fairness, where users are assigned video quality proportional to their demand and formulate a pro-rata fairness index to measure the fairness of the proposed algorithm. The rate compatible punctured codes (RCPC) used in the proposed work compliments video quality fairness through unequal error protection (UEP) of users based on their priority at the physical layer. The physical layer channel state information (CSI) and application layer rate distortion (RD) information of each user are used to allocate power and spectrum resources. Extensive simulation studies show that in comparison with methods which utilize only the physical layer information available at the BS, the proposed algorithm ensures significantly better video quality fairness and spectral efficiency.