Power allocation method based on the channel statistics for combined positioning and communications OFDM systems

The design of pilot and data power allocations for multicarrier OFDM signals is a key aspect in the development of combined positioning and high-data-rate communications systems. In this paper, we investigate capacity-maximizing pilot and data power allocations when a certain positioning accuracy is required. We consider a formulation based on the Expected Crámer-Rao Bound of the joint time-delay and channel estimation and the ergodic capacity, modeling the channel impulse response as a random vector. We compare the performance of capacity-maximizing pilot and data power distributions with respect to distributions that use equi-spaced and equi-powered pilot structures, shown by previous work to be optimal in terms of channel estimation. Numerical results show that the restriction to the use of equi-spaced and equi-powered pilot structures has an important impact on both the achievable capacity and the positioning capabilities of the designed signals.