Optimal energy assignment for frequency selective fading channels

This paper describes a method to minimize the total energy necessary to communicate data over a frequency selective fading channel using multicarrier data transmission. The energy is minimized given a desired average bit error rate at a fixed gross bit rate. For a number of configurations, the optimal energy distribution is calculated analytically. For other configurations, we present a generic numerical approach. To evaluate the performance, a comparison is made with two other commonly used energy assignment schemes. The advantage of this scheme is most apparent when the channel suffers from deep fades, as is the case in mobile wireless communications.