Circuit-Energy Aware Discrete Bit Loading

Two fundamental problems related to multi-carrier modulation are considered in this paper. The first is finding the best modulation schemes in all subcarriers to minimize the total energy consumption required to send a given number of bits between two wireless nodes. The second is finding the best modulation schemes to maximize the number of bits transmitted between two nodes under total energy constraint. Discrete bit loading algorithms have been used to solve both problems over frequency selective channels. None of these algorithms takes the circuit energy into consideration. In this paper, we introduce new discrete bit loading algorithms to solve both problems with total energy defined as the sum of transmission energy and circuit energy. Compared to the conventional discrete bit loading algorithms, the new algorithms can achieve savings in the order of 9 dB in the energy minimization problem. 180% increase in the number of transmitted bits can also be achieved with the same total energy when compared to the existing algorithms.