Dynamic power optimization of pilot and data for downlink OFDMA systems

In this paper, we investigate the power allocation prob lem in downlink orthogonal frequency-division multiple access(OFDMA) networks. Different from previous researches on powerallocation, we take into account various practical factors, such asthe stochastic traffic arrival, the time-varying channel, the queuestability requirements of all users, the channel estimation cost andthe corresponding effect of imperfect channel state information(CSI) on data transmission rate. The power allocation problemis formulated as maximizing the time-averaged data transmissionrate by optimizing pilot and data power allocation subject to thequeue stability and the maximum transmit power constraints. Thedata transmission rate is defined in terms of the pilot transmitpower, the data transmit power and the channel estimation er ror, which is non-concave. To solve the non-concave and stochas tic optimization problem, a dynamic pilot and data power alloca tion (DPDPA) algorithm is proposed with the aids of approximatetransformation, Lyapunov optimization and Lagrange dual formu lation. Moreover, we derive the bounds of performances, in termsof the time-averaged data transmission rate and queue length. KCI Citation Count: 2