This thesis focuses on advanced multi-antenna receiver and transmission techniques to improvethe utilization efficiencies of radio resources in broadband single carrier communications. Specialfocus is devoted to the development of computationally efficient frequency domain (FD) turboequalization techniques for single and multiuser MIMO frequency selective channels. Anotherspecial emphasis is given to transmission power optimization for single user MIMOcommunications, which takes into account the convergence properties of the iterative equalizer.
A new iterative FD soft cancellation (SC) and minimum mean square error (MMSE) filteringbased joint-over-antenna (JA) multiuser MIMO signal detection technique for multiuser MIMOuplink transmission in frequency-selective channels is proposed. The proposed FD multiuserMIMO detection technique requires significantly lower computational complexity than its time-domain counterpart. Furthermore, significant performance gains can be achieved with theproposed JA turbo receiver compared to an antenna-by-antenna (AA) turbo receiver when the totalnumber of transmitter antennas and users is larger than the number of receiver antennas, as wellas in the presence of spatial correlation.
The impact of existing linear precoding techniques, e.g, maximum information rate (MaxRate)and minimum sum mean square error (MinSumMSE), on the performance of frequency domainturbo equalization is investigated by utilizing extrinsic information transfer (EXIT) chart analysis.
A novel transmission power minimization framework based on an EXIT analysis of singlecarrier MIMO transmission with iterative FD SC-MMSE equalization is then proposed. Theproposed optimization framework explicitly takes into account the convergence properties of theiterative equalizer. The proposed convergence constrained power allocation (CCPA) techniquedecouples the spatial interference between streams using singular value decomposition (SVD),and minimizes the transmission power while achieving the mutual information target for eachstream after iterations at the receiver side. The transmission power allocation can be formulatedas a convex optimization problem. A special case having only two mutual information constraintsis considered, for which the Lagrange dual function is derived and its dual problem is solved.Inspired by the Lagrange duality, two CCPA based heuristic schemes are developed. Thenumerical results demonstrate that the proposed CCPA schemes outperform the existing powerallocation schemes.
