Qaja, W. M.; Chambers, J. A. (Advanced Signal Processing Group, Electronic and Electrical Engineering Department, Loughborough University, Leicestershire, LE11 3TU, UK)
In this paper, closed-loop extended orthogonal space-time-frequency-block coding (CL-EO-STFBC) is proposed for use within cognitive wireless relay networks. To exploit the available spectrum opportunities within the EO-STFBC, a spectrum indicator matrix is used in the development of the relay transmission scheme. The approach has the flexibility to dynamically adapt the code matrix to the number of available relays. The performance of the scheme is evaluated in terms of end-to-end frame error rate.