Resource optimization to achieve hard delay constraints in OFDMA systems

In this paper we propose an algorithm to achieve hard delay constraints in OFDMA systems. The resource scheduler has to ensure that delay deadlines of the packets get achieved and the resources are also not under utilized. This is a very difficult task since the channel and packet arrival in user queues are time varying in nature. The instantaneous decisions of scheduler depend on current as well as future channel and packet arrival considerations. In this paper we represent hard delay deadlines of packets in the form of various constraints. We then develop a constrained optimization problem and propose an efficient algorithm. This algorithm allocates subcarriers and powers to different users in such a way that the objective of sum rate maximization and hard delay constraint achievement are simultaneously attained.