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Statistical properties of the channel condition number is important in performance analysis and design of communication systems. In this paper we study the condition number distribution of complex non-central correlated Wishart matrices, relevant for spatially correlated Ricean MIMO channels and detection performance in cognitive radio. We present an approximation framework which is utilized to calculate...
In this paper, we consider a large system analysis of regularized channel inversion (RCI) beamforming for MISO broadcast channels (BC) with transmit-side channel correlation. In the analysis, we assume that both the number of users and transmit antennas grow unbounded with a constant ratio. We also assume that the channel correlation model is separable. Under this channel condition, we are particularly...
A construction of Grassmannian packings related to representation theory is applied to build implementation-friendly MIMO precoding codebooks when the number of transmit antennas is a power of a prime. Using the chordal distance as a metric, some of the corresponding packings appear to be optimal by meeting the othoplex bound. Also, by using only some of the codewords, smaller packings satisfying...
The turbo detection of a coded under-determined multiple-input multiple-output (UD-MIMO) system is studied in this paper. A UD-MIMO system with transmit antennas and receive antennas has more unknowns than the observations. However, most existing low complexity detectors, such as the vertical Bell Laboratories Layered Space-Time (V-BLAST) or the block decision feedback equalizer (BDFE),...
In this paper, we present a high-performance hybrid linear precoding scheme for the downlink of multiuser multiple-input multiple-output (MU-MIMO) systems based on the combination of an iterative modified regularized block diagonalization (IMRBD) precoding and minimum mean square error (MMSE) precoding. The proposed hybrid diversity maximization (HDM) scheme aims to maximize the diversity gain by...
We investigate non-coherent multi-input multi-output (MIMO) signal processing which requires no channel state information (CSI) at either the transmitter or the receiver. With non-coherent codes on Grassmann manifold, a receiver employing generalized likelihood ratio test (GLRT) algorithm offers the maximum-likelihood performance even without CSI. However, the conventional GLRT suffers from a severe...
In this work the problem of non-cooperative resource optimization in the uplink of a relay-assisted MIMO MAC system with partial CSI at the transmitter is addressed. Each multiple access user pursues individual rate maximization, whereas the relay designs its amplify-and-forward matrix in order to optimize the system's sum-rate. From a game-theoretic perspective, the resource allocation process is...
We present a new MIMO precoding scheme using the LDL^H channel decomposition. The proposed method is verified to have lower complexity and better bit error rate (BER) performance than that of the conventional singular value decomposition (SVD). SVD is commonly used in decomposing the MIMO channel into parallel eigen-modes. However, the large variation of the singular values often leads to ill-conditioned...
Opportunistic beamforming is a promising technique for downlink channels in cellular systems. When opportunistic beamforming is to support multiple users at a time, beams should be formed to avoid interference and this requires the feedback of channel state information (CSI) from users to a base station (BS). With limited feedback, to minimize the impact of interference, the best beamforming matrix...
An ultra-high data rate Time Reversal (TR) Multiple-Input Multiple-Output (MIMO) Ultra-Wideband (UWB) communication system with space-time pre-equalizer is proposed. When the symbol duration is set to approach the duration of UWB monocycles, the data rate is close to the limit due to the extremely large bandwidth, resulting in the severe intersymbol interference (ISI). The zero-forcing (ZF)criterion...
This paper examines space division duplexing (SDD) in multiple-input multiple-output (MIMO) systems. The antennas each full-duplex node has are partitioned to form two antenna banks - one for transmission, the other for reception. Self-interference is avoided at each full-duplex node by utilizing the nullspace (or the left nullspace) of corresponding self-interference channel for transmission (or...
While the zero-forcing (ZF) transmit beamforming is a widely used technique for realizing multi-input multi-output (MIMO) broadcast transmissions, the ZF receiver combined with multiuser scheduling is an effective alternative that yields improved robustness against CSI mismatch caused by feedback link errors. In this paper we consider the practical scenario that channels are imperfectly estimated...
Inter-cell co-channel interference (CCI) mitigation is investigated in the context of cellular systems relying on dense frequency reuse. A distributed Base Station (BS) cooperation aided soft reception scheme using the Probabilistic Data Association (PDA) algorithm and Soft Combining (SC) is proposed for the uplink of multi-user multi-cell MIMO systems. The realistic hexagonal cellular model relying...
We investigate the capacity bounds for a wireless multicast relay network where two sources simultaneously multicast to two destinations through Gaussian channels with the help of a full-duplex relay node. All the individual channel gains are assumed to be time-invariant and known to every nodes in the network. The transmissions from two sources and from the relay use the same channel resource (i...
In this paper, an efficient closed-loop link adaption scheme consisting of adaptive modulation and coding as well as adaptive precoding is proposed for the 3GPP LTE-A uplink. The uplink envisaged in the LTE-A cellular network will support precoded multi-rank transmission from the users and have base stations with advanced non-linear receivers. Our proposed scheme considers one such advanced receiver,...
We derive a linear transmit precoding scheme based on interference alignment at the transmitters and zero-forcing at the receivers, for the MIMO X channel based on the Generalized Singular Value Decomposition (GSVD) that is able to attain the outer bound on the degrees of freedom (DoF) region [2] for any antenna configuration, except when all terminals have one antenna. Additionally, the proposed...
A low-complexity, effective detection method for multiple-input multiple-output (MIMO) systems based on eigenspace search and linear equalization-based detection schemes is proposed in this paper. Based on the observation that solutions yielded by linear detectors are corrupted by color noise, the proposed method introduces a new constellation search procedure to augment linear detectors. Specifically,...
In this paper, we study the achievable rate of the training-based multi-input multi-output (MIMO) systems over time-varying flat fading channels modeled with the $L$-th order autoregressive, AR($L$), process. Using the Bayesian Cram\'{e}r-Rao lower bound (BCRB) to characterize the mean squared error of channel estimation, the achievable rate of the MIMO systems is investigated from the information-theoretical...
We solve the rate balancing problem in the downlink for a multiuser multiple-input-multiple-output (MIMO) system with multiple linear transmit covariance constraints. In particular, we adopt a linear transceiver structure to maximize the worst-case rate of the user while satisfying multiple linear transmit covariance constraints. The original rate balancing problem in the downlink is more complicated...
This paper considers the joint precoder design problem for multiple-input single-output (MISO) systems with coordinated base stations (BSs). We consider maximization of the total sum rate with per BS antenna power constraint problem. For this problem, we propose a novel linear iterative algorithm. The problem is solved as follows. First, by introducing additional optimization variables and applying...
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