Journal ArticleDOI
A MIMO Antenna Structure that Combines Transmit Beamforming and Spatial Multiplexing
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TLDR
In this article, a closed-loop MIMO signal processing scheme that combines transmit beamforming and spatial multiplexing in Rayleigh frequency-flat fading channel environment is proposed.Abstract:
We propose a new closed-loop MIMO (Multiple- Input Multiple-Output) signal processing scheme that combines transmit beamforming and spatial multiplexing in Rayleigh frequency-flat fading channel environment. Diversity gain is achieved by beamforming, and multiplexing gain by spatial multi- plexing. The proposed scheme is particularly useful for downlink communication, where the number of transmit antennas at the base station is greater than the number of receive antennas at the mobile. Beamforming weight vectors are computed at the receiver using the estimated channel matrix and are sent to the transmitter. The computation is based on the mutual information maximization criterion which reduces to a symmetric eigenvalue problem. The BER (Bit Error Rate) performance comparisons with other known schemes are also presented for the cases of the ML (Maximum Likelihood) decoding and the MMSE (Minimum Mean-Squared Error) nulling and ordered-cancellation decod- ing, through extensive Monte-Carlo simulation. The simulation results show that the proposed scheme has lower BER than the other schemes.read more
Citations
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Journal ArticleDOI
The evolution to 4G cellular systems: LTE-Advanced
TL;DR: The main technologies for LTE-Advanced are explained, together with possible improvements, their associated challenges, and some approaches that have been considered to tackle those challenges.
Journal ArticleDOI
Multi-Cell Coordinated Scheduling and MIMO in LTE
TL;DR: An overview of multi-cell coordinated scheduling and multiple-input multiple-output (MIMO) techniques in LTE is provided and potential techniques for further improving the performance of LTE are identified, such as enhanced channel state information feedback and adaptive switching between SU-MIMo and MU-M IMO.
Patent
Adaptive multiple antenna transmission method and apparatus in accordance with antenna transmission power in a wireless communication system
TL;DR: In this paper, an adaptive multiple antenna transmission method and apparatus in accordance with antenna transmission power are disclosed. But, the method of performing multiple antennas transmission from a terminal to a base station according to one embodiment of the present invention may include the steps of determining a reference value for a transmission power of each of a plurality of transmit antennas of the terminal, grouping the plurality of transmissions into a first group of transmit antenna and a second group of transmission antennas in according with the determined reference value, and transmitting a signal to the base station through at least one or more transmit antennas through at
Journal ArticleDOI
Frame Design and Throughput Evaluation for Practical Multiuser MIMO OFDMA Systems
TL;DR: This paper describes the design of a time-division duplexing frame with a variety of pilots for multiuser multiple-input-multiple-output orthogonal frequency-division multiple access (MU-MIMO OFDMA) systems, where the base station and users are equipped with four and two transmitting and receiving antennas, respectively.
Journal ArticleDOI
Spatial-Correlation-Based Antenna Grouping for MIMO Systems
TL;DR: This paper proposes a novel low-complexity antenna-grouping algorithm, which reduces the computational complexity with little degradation of the bit error rate (BER) and derives the BER lower bound of the proposed algorithm in independent and identically distributed channels by using the probability density function of the largest eigenvalue of a Wishart matrix.
References
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Journal ArticleDOI
Capacity of Multi‐antenna Gaussian Channels
TL;DR: In this paper, the authors investigate the use of multiple transmitting and/or receiving antennas for single user communications over the additive Gaussian channel with and without fading, and derive formulas for the capacities and error exponents of such channels, and describe computational procedures to evaluate such formulas.
Journal ArticleDOI
On Limits of Wireless Communications in a Fading Environment when UsingMultiple Antennas
G. J. Foschini,M. J. Gans +1 more
TL;DR: In this article, the authors examined the performance of using multi-element array (MEA) technology to improve the bit-rate of digital wireless communications and showed that with high probability extraordinary capacity is available.
Journal ArticleDOI
Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas
TL;DR: This paper addresses digital communication in a Rayleigh fading environment when the channel characteristic is unknown at the transmitter but is known (tracked) at the receiver with the aim of leveraging the already highly developed 1-D codec technology.