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In this paper, a closed-form expression for Bit Error rate (BER) of a Multiple-Input Multiple-Output (MIMO) system employing the Minimum Mean Square Error MMSE channel estimation method is derived. The numerical results show that when the Channel State Information (CSI) is free of estimation errors BER decreases when the number of receive antennas increases. However under imperfect CSI, BER is getting...
This paper investigates a Slotted ALOHA protocol for a multi-user wireless system operating under partial Line of Sight (LOS) conditions in which both the base station and mobile users are equipped with multiple element antennas. The investigations focus on how physical layer parameters such as spatial correlation, mutual coupling and Rician factor K affect the system capacity. Probability model for...
This paper reports the performance of Block Diagonalization (BD) scheme for different array antenna structures used in a multiuser Multiple Input Multiple Output (MIMO) system. The assessment is performed in terms of sum rate capacity. Theoretical analysis as well as computer simulations shows that the spatial correlation downgrades downlink performance of BD. The simulations also reveal that the...
This paper reports investigations into mutual coupling effects on performance of a beamforming transmission scheme of a multiple-input multiple-output (MIMO) system operating under Rician channel conditions. It is shown that the presence of mutual coupling in a transmitting array antenna degrades the radiation pattern. However, it does not adversely affect the system capacity. If the correlated Rayleigh...
This paper reports on the capacity of a MIMO system operating in a multi-access scenario. The investigations take into account co-channel interference as well as spatial correlation and mutual coupling (MC) present in array antennas. A closed-form expression for the upper bound of the mutual information is presented. An optimal signal transmission scheme is proposed to maximize the MIMO capacity....
In this paper, we investigate a switching scheme involving antenna selection and transmit beamforming modes for a multiple input multiple output (MIMO) system operating over a varying Rician channel. It is shown that that beamforming outperforms antenna selection when line of sight (LOS) component dominates the channel. Also transmit beamforming is superior over antenna selection at high values of...
The paper reports on the performances of training-based channel estimation methods in a multiple input multiple output (MIMO) communication system with transmitter equipped with a uniform linear array (ULA) and receiver equipped with either uniform circular array (UCA) or uniform linear array (ULA). In the undertaken investigations, the receiver is assumed to be free from any obstacles while the transmitter...
The paper reports on investigations into the relationship between the channel estimation and the channel effective degree of freedom (EDOF) for a Multiple Input Multiple Output (MIMO) wireless communication system. It is pointed out that both the channel estimation and EDOF, in conjunction with an assumed signal to noise ratio (SNR), affect the MIMO channel capacity. Therefore the two have to be taken...
This paper reports on the performance of the space time block coded MIMO system with spatial redundancy which is accomplished using a larger than required numbers of antennas. The proposed scheme guides the transmitted power onto the RF branches with higher gain coefficients. The carried out theoretical analysis shows that the scheme can achieve higher channel capacity and lower symbol error rate...
In this paper, a whitening-rotation (WR)-based semi-blind channel estimation method for a multiple input multiple output (MIMO) wireless communication system is investigated. The relationship between the estimation accuracy and the channel properties is analyzed. It is shown that the channel estimation minimum square error (MSE) of the investigated semi-blind estimation scheme is dependent on the...
In this paper, the performances of two MIMO channel estimation methods, the scaled least square (SLS) and the minimum mean-square error (MMSE), have been investigated using a two-ring double-bounce channel model representing a signal scattering environment. It has been shown that both SLS and MMSE methods offer a better performance at higher values of the Rician factor K, meaning that the presence...
This paper reports on investigations into the effects of spatial correlation on channel estimation and capacity of a multiple input multiple output (MIMO) system. Minimum mean square error (MMSE) method is applied for channel estimation under a correlated channel scenario. Simulation results for a 4 times 4 MIMO system with the Jakes model describing a channel between a base station and a mobile station...
This paper is concerned with the optimal transmission/power allocation scheme for a MIMO system employing a uniform circular array (UCA) antenna at the transmitter and a uniform linear array (ULA) antenna at the receiver. Investigations include mutual coupling (MC) effects in the UCA. By applying the transmitting mutual impedances, closed-form expressions for the spatial fading correlation (SFC) function...
This paper reports on channel estimation for a multiple input multiple output system, in which the transmitter is equipped with a linear array antenna while the receiver uses a circular array antenna. A model that includes spatial correlated channels and effects of mutual coupling is presented to investigate the performance of a training-based minimum mean-square error MIMO channel estimation method...
The effect of antenna mutual coupling on the channel estimation for MIMO- OFDM system is rigorously studied. Numerical results show that we cannot ignore the influence of antenna mutual coupling on channel estimation. Antenna mutual coupling in general increases channel estimation error but reduces symbol error rate performance.
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