A Practical Computationally Efficient Power and Bit Allocation Algorithm for Wireless OFDM Systems

A new practical computationally efficient power and bit allocation algorithm for wireless OFDM communication systems is proposed aiming at minimization of transmit power under the constraints of data rate and bit error rate. The proposed algorithm exploits the relationship between the water-filling level and the system data rate, and the differences between the bit allocations of two consecutive water-filling iterations in order to derive an efficient adaptive water-filling level searching method without need of preset parameters and a simplified greedy search method to allocate final bits, respectively. By combining them effectively, the proposed algorithm converges faster to the optimal solution than existing techniques. Computer simulation demonstrates the computational efficiency of the proposed algorithm in frequency selective fading environments.