This paper presents a sparse representation method for direction of arrival (DOA) estimation of coherent signals in the presence of unknown mutual coupling. Making use of the special structure of the mutual coupling matrix for uniform linear arrays (ULAs), we formulate the problem of DOA estimation of coherent signals with mutual coupling as anâ€¦ (More)

This paper presents a real-valued sparse representation method for direction of arrival (DOA) estimation with uniform linear arrays (ULAs). Applying a unitary transformation, we convert the complex optimization problem into a real one, thereby reducing the computational complexity at least by a factor of four without sacrificing its accuracy. Simulationâ€¦ (More)

In an attempt to admit new users into Code-Division-Multiple-Access (CDMA) communication systems in the case of overload, we investigate an optimal proportional quality of service (QoS) reduction method subject to a weighted sum power constraint in this paper. Based on the Perron-Frobenius theorem, we are able to derive an optimal closed-form solution.â€¦ (More)

This paper considers linear precoder optimization problems for minimizing the mean-square error (MSE) with multiple-input multiple-output (MIMO) systems. In contrast to the conventional sum-power constraint on transmit antennas, a more realistic power constraint, which is the joint constraint of sum-power and maximum eigenvalue, are adopted in this paper.â€¦ (More)