Patent Document ID: 8873654
Application ID: 13514346
Patent Flag: 1

Claim One:
1. A method for improving channel estimation performance in a dynamic spectrum access multicarrier system that utilizes a pattern of pilot symbols to be included in transmitted signals sent from a sender to a receiver through an interference-affected propagation environment, the method comprising adaptively determining the pattern of pilot symbols to be included in the transmitted signals by carrying out the following steps: a) explicitly characterizing the interference-affected propagation environment by defining a covariance matrix of interference and white Gaussian noise based on external measurements of the propagation environment; b) determining placement positions of a predetermined number of equally powered pilot symbols by computing the placement positions that result in a minimum sum of square errors of a maximum likelihood channel estimation performed based on the covariance matrix, and c) with the pilot symbols in the placement positions, determining a relative power distribution between the placed pilot symbols by computing the power distribution that results in a minimum sum of square errors of a maximum likelihood channel estimation performed based on the covariance matrix, wherein the external measurements of the propagation environment, the determination of the placement positions of the pilot symbols and the determination of the relative power distribution between the placed pilot symbols are carried out by the receiver, the determined placement positions and relative power distribution constituting the pattern of pilot symbols, and wherein the receiver sends the pattern of pilot symbols to the sender so that the sender can include the pilot symbols in its transmitted signals.