The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Multi-user MIMO systems have the potential to combine the high capacity achievable with MIMO processing with the benefits of space-division multiple access. Although recent theoretical results show that the sum capacity grows linearly with the minimum of the number of antennas and users, the sum rate of channel inversion does not due to the large spread in the singular values of the channel matrix...
In this paper, we introduce a full-duplex relay (FDR) based on block diagonalization (BD) and analyze the corresponding sum rate in a multiantenna multiuser relay system. The poposed precoding scheme can suppress the self-interference as well as to support multiple users at the same time slot. Simulation results show that the proposed FDR scheme enhances significantly the sum rate performance compared...
Block diagonalization (BD) and coordinated beamforming (CBF) are two major signal processing schemes to achieve the sum rate close to the sum capacity of a multiuser multiple-input multiple-output (MU-MIMO) downlink. However, they do not achieve the full spatial multiplexing gain except under a special antenna configuration. In this paper, therefore, we propose a new linear precoding algorithm for...
The average channel capacity for 3GPP LTE downlink multiuser Multiple Input Multiple Output (MIMO) systems is analyzed in this paper. A packet scheduler is used to exploit the available multiuser diversity in all the three physical domains (i.e., space, time and frequency). A mathematical model is established to derive the channel capacity of multiuser MIMO systems with the frequency domain packet...
In this paper, we propose a novel interference alignment (IA) scheme via convex optimization based on minimum mean square error criterion subject to individual transmit power constraints for the MIMO interference channel system. We show that transceiver under such criterion can be realized through an efficient iterative algorithm. The convergence of the proposed algorithm is discussed. Simulation...
We propose an enhanced linear minimum mean square error (LMMSE) turbo equalization scheme for multiple-input multiple-output (MIMO) communication systems. The turbo equalizer employs soft interference cancellation (SIC), where tentative soft decisions of the interfering symbols are subtracted from the received samples before the LMMSE filtering. The enhanced LMMSE turbo equalization with SIC introduces...
In this paper, we present the sum-rate analysis of multiuser multiple-input multiple-output (MIMO) downlink systems with incremental beamforming (IB). We develop the analytical expressions of the ergodic sum-rate for the dual-transmit-antenna scenario. Based on the analytical results, we compare the performance of the proposed IB scheme with popular random beamforming techniques, such as random unitary...
The ergodic capacity is a key performance parameter of a multiple-input-multiple-output (MIMO) fading channel. We would like to determine the optimal number of transmit antennas to be used for a given signal-to-noise ratio (SNR) and a given total number of antennas in the system. Thus, we obtain here three simple and tight bounds on the ergodic capacity of the MIMO Rayleigh fading channel, which show...
In this paper, joint transmitter receiver filter optimization for channel equalization is investigated for a multiuser multiple input multiple output frequency selective slowly varying channel. Minimum mean square error criterion is used in the equalization under a total transmit power constraint. Because of the simplicity of the optimization of multiple access channel, channel duality is used for...
We propose a new framework for MIMO decoding based on a recently developed technique for reliably conveying linear equations over wireless channels. Each transmit antenna sends an independent data stream using the same linear code. As a result, any integer combination of the codewords is itself a codeword. Each receive antenna observes a random complex-valued combination of the codewords according...
This article proposes a hardware triply selective Rayleigh fading channel emulator which is implemented by incorporating spatial and inter-tap correlation matrices into uncorrelated frequency-flat Rayleigh fading waveforms with a Kronecker product method. The Kronecker product of square roots of three correlation matrices are computed in real time via serial, parallel, or mixed serial-parallel computational...
The polarimetric characteristics of the signal back scattered from a building wall are studied in this paper with the aid of MIMO measurements and Ray Tracing simulation. A very simple environment with a single rural building amid an open area is considered to reduce complexity and better isolate the different kinds of back-scattered contributions: specular reflection, diffractions, diffuse scattering...
This paper proposes a novel three-dimensional (3D) regular-shaped geometry-based stochastic model (RS-GBSM) for non-isotropic multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) Ricean fading channels. The proposed model, combining a two-sphere model and an elliptic-cylinder model, is the first 3D RS-GBSM that has the ability to investigate the impact of the vehicular traffic density (VTD)...
Geometric mean decomposition (GMD) has been proposed as an elegant tool for MIMO transceiver architecture design. Under the ideal assumptions, MIMO-GMD schemes can realize multiple spatial sub-channels with identical gains. The main goal of this paper is to provide analytical distribution functions for sub-channels gains and capacities of MIMO-GMD schemes. In particular, we have derived closed-form...
We describe a channel sounding system designed for small outdoor cell (~400 meter radius) wireless channel characterization. We report on a program of path loss measurements using a 2×2 MIMO configuration and data reduction in the frequency range of 5.7-5.75 GHz. The results are based on over 10,000 independent complex frequency responses collected in residential neighborhoods in northern New Jersey...
A joint channel impulse response (CIR) and noise-variance estimation scheme is proposed for multi-user Multiple-Input-Multiple-Output (MIMO) Orthogonal Frequency-Division Multiplexing/Space Division Multiple Access (OFDM/SDMA) systems, which is based on the Expectation Maximization (EM) algorithm. Multiple users communicating over time-invariant and/or time-variant channels are considered in this...
In this paper, the variational expectation-maximization (VEM) algorithm is used to provide channel estimates in a space-time decoder. The proposed estimator works for many types of space-time codes (STC), including full-rate full-diversity (FRFD) codes, Bell Laboratories layered space-time architecture (BLAST) and orthogonal STC's. The principle idea is to treat the channel coefficients as the unknown...
This paper presents a multiple-access MIMO wireless transceiver combining space- and frequency-domain spreadings with a frequency-domain block-coding strategy. Spreading across space (transmit antennas) and frequency (subcarriers) adds resilience against deep channel fades while providing space and frequency diversities, and block-coding enables multiple-access transmission. The merits of the proposed...
In this contribution, we propose a Distributed Concatenated Irregular Convolutional Coded Unity Rate Coded and Space Time Trellis Coded (DC-IrCC-URC-STTC) scheme for cooperative communications employing multiple single-antenna relays. Each coding arrangement is designed for efficient decoding convergence by employing non-binary Extrinsic Information Transfer (EXIT) charts. The source node transmits...
The performance of a multi-hop amplify-and-forward relay network is analyzed. The source and destination terminals are equipped with multiple-antennas and the relays with single-antennas. The cumulative distribution function and the moment generating function of two tight upper bounds of the end-to-end signal-to-noise ratio are derived. The lower bounds for the outage probability and the average symbol...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.