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Random beamforming (RBF) exploits multiuser diversity to increase the sum-rate capacity of MIMO broadcast channels. However, in the presence of spatial correlation between the downlink channels, multiuser diversity can not be exploited and the sum-rate suffers a signal to noise (SNR) hit. In this paper, we explore precoding techniques that minimize this hit. Basically, we derive an optimum and an...
In this paper we investigate the outage probability of multiple-input multiple-output (MIMO) channels, when the probability distribution of the channel gains is not completely known to the transmitter and receiver. The partial knowledge of a true probability distribution of the channel nuH(h) is modelled by a relative entropy constraint H(nuH||muH,nom) les R, R ges 0, where R is the distance from...
This paper presents the modeling and control of a nonlinear coupled three tank system (CTTS). In this work, nonlinear state space dynamics of CTTS are derived. The objective is to control the level and temperature of water in each tank. The control is achieved using classical nonlinear feedback linearization technique. Input and output scaling is done according to the interface with a standard PLC...
In this paper, three new multiple-input multiple-output (MIMO) channel capacity achieving, full and partial diversity, space-time block codes with reduced decoder complexities are proposed for MIMO systems having two, three and four transmit antennas. It is shown that the proposed codes have the same transmission rates as those of spatial multiplexing schemes while, moreover, offer second order transmit...
We investigate the use of space-time block coding (STBC) in multiple-input multiple-output (MIMO) communication systems which employ more than one dual-polarized antennas. The use of dual polarized antennas theoretically double the number of virtual antennas used in the system. On the other hand, the correlation effects and the cross-polar interference (XPI) deteriorates the system performance. In...
Recently, Various blind channel equalization techniques for chaotic communication systems have been developed. However, in most of these studies communication channel is assumed to be single-input single-output (SISO) system. To the best of our knowledge, there is no study about blind equalization of multiple-input multiple-output (MIMO) channel case. In this study, an adaptive blind channel equalization...
In this paper, a simple low complexity iterative receiver for space-time coded (STC) transmission is proposed and the performance over frequency-selective fast and quasistatic fading channels is investigated. Simulation results show that the performance of the proposed structure improves with each iteration. Considering the practically prohibitive complexity of optimal equalizers, the proposed iterative...
In this paper a three-terminal communication scenario where two users exchange information by employing differential binary modulation and network coding via a relay is considered. The transmission is divided into three slots in time where the first and second slots are allocated to the transmission of differential encoded data of the users. After demodulation, the relay broadcasts the bit-wise XOR-ed...
This paper presents some results obtained from a first approach to a point-scatter simulator for multiple-input multiple-output (MIMO) radio channel modeling. Specifically, we present the comparison of capacity obtained using the point-scatter simulator with that obtained with the Kronecker model. Capacity results obtained from measured propagation data are also presented. Ideas to enhance the simulator,...
We consider a general burst block orthogonal space- time coded CPM modulation in MIMO slowly fading Rayleigh channel. The modulated signal has multidimensional constellation waveforms. The optimal receiver must perform a multidimensional matched filtering on its front-end. This operation is highly demanding on the processing computational resources. We derive sub-optimal complexity reducing receiver...
In this paper, new-diversity schemes are formed by applying Rotation and Component Interleaving Diversity (RCID) technique to Multi-Input Multi-Output (MIMO) Ortogonal Frequency Division Multiplexing (OFDM) systems and the optimal rotation angles for these systems are examined for M-ary PSK signal constellations. The examination showed that RCID technique has provided an increase in the diversity...
In LTE TDD there is typically no one-to-one association between UL and DL subframes, and for DL heavy asymmetries with more DL than UL subframes, ACK/NACK reports for multiple DL subframes need to be transmitted in an UL subframe. To improve uplink control channel performance, ACK/NACK bundling, where multiple ACK- NACKs are combined to a single ACK/NACK response for several DL subframes, is supported...
This paper investigates a robust model predictive control approach for a nonlinear aerodynamic test rig, a twin rotor multi-input-multi-output system (TRMS). A highly nonlinear dynamic model of the system has been used to design the robust controller. According to the nonlinear model a polytopic model has been developed considering the nonlinearities and uncertainties of the plant. To this end, a...
IEEE 802.16j multi-hop relay task standard defines two mutually exclusive options: transparent relay systems (T-RS) and non-transparent relay systems (NT-RS). In this work, we compare the two relay systems in term of system capacity under user resource fairness constraint. We jointly study the effect of resource allocation and user association rule for maximizing the system capacity, where the user...
This paper suggests an efficient power allocation scheme for multiple input and multiple output - orthogonal frequency division multiplexing (MIMO-OFDM) systems achieving near-optimum. We deal with power allocation problem with low complexity. It is well known that the conventional waterfilling algorithm runs repetitive calculations and logarithm operations to find out an optimal water level over...
While the conventional codebook is defined only for the initial transmission in the closed-loop MIMO system, this paper proposes a new retransmission structure with a sequence of multiple codebooks, rather than using a single identical codebook for every retransmission. The pre-coding matrices, in each codebook, are sequentially linked so that each one can be used for a sequential hybrid ARQ transmission...
Linear dispersion codes (LDCs) are capable of achieving a good trade-off between link throughput and link robustness in multiple input multiple output (MIMO) broadband wireless access systems. This is thanks to their efficient spreading of data across both time and space domains. This paper proposes a novel LDC design method utilising the unitary matrix theory along with a genetic algorithm (GA)....
A simple, effective, fast codebook index searching algorithm for quantized equal gain transmission (QEGT) in MIMO systems is presented. Rough searching based on the newly defined metric selects a few candidates, then, accurate searching based on the conventional method determines the optimal one. This strategy reduces the overall searching time, while maintaining almost the same link-level performance...
Novel channel models as from COST 273 and IST-WINNER projects are models to evaluate the performance of multi-antenna concepts under link-level and system-level. For consistent performance evaluation the channel models needed to be parameterized by multipath parameters based on measurements. It seems these parameters can be grouped into geometrically co-located paths, so called clusters. The reliability...
We develop a new Gaussian multiple-input multiple-output (MIMO) relay multiple access channel (RMAC) model with two sources and one destination. We determine an inner bound on the capacity of the RMAC under full-duplex decode-and-forward (DF) strategy. A power allocation scheme is proposed to achieve the inner bound. Analytical results and simulation results show that the proposed relay strategy and...
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