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Record 50-Gb/s wireless signal transmission over 4 m is experimentally demonstrated using a 2×2 MIMO Radio-over-Fiber system at 60 GHz. MIMO spatial multiplexing and 16-QAM OFDM modulation were used to achieve a high combined spectral efficiency of up-to 8 b/s/Hz.
A space-time/space-time-frequency-coding-based 2 × 2 multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) power line communication system that employs a maximum ratio combining receiver, also called a rake receiver, not only improves the bit error rate performance (relative to existing schemes) but is also insensitive to crosstalk.
In this paper we consider two alternate packet structures for estimating the multi-input multi-output (MIMO) powerline channel and their impact on achievable application throughputs. In the first packet structure, an orthogonal pair of OFDM symbols is used to estimate the channel. When compared to single-input single-output (SISO) transmissions that use one OFDM symbol to estimate the channel, there...
This paper outlines the use of symbol repetition technique together with space time block code orthogonally frequency division multiplexing (STBC-OFDM) scheme for power line communication (PLC) when the receiver has complete knowledge about the channel state information. Due to redundancy in the proposed technique, a low-complex FFT can be implemented. Also, the way as the symbol diversity is explored,...
This survey examines the bandwidth efficiency of wireless signals, beginning with a review of the Shannon capacity and of the important differences between signal to noise ratio (snr) and individual bit energy to noise density (IBEND = Eb/N0). Recognizing that communication systems are successful only if they are profitable, value propositions that have been realized along the evolution of adopted...
This paper investigates the implementation scenario of Space Division Multiple Access(SDMA) which is a notable application of Multiple Input Multiple Output(MIMO) system. SDMA is one of the most promising techniques aiming at solving the capacity problem of wireless communication systems and achieving higher spectral efficiency, depending on multiplexing signals based on their spatial signature. This...
The MIMO system convincingly promises a better bit rate in comparison with a SISO system. The system gets even efficient when OFDM is implemented with MIMO to obtain better data rates even in hostile channel environment. Research establishes OFDM as a potential candidate for use in MIMO systems for the reasons like inherent FFT, waveform adaptation, advanced antenna techniques, multiple access, interoperability,...
In highly spatially correlated channels the diversity gain achieved by space-frequency (SF) coding is significantly low. Nevertheless, when full or partial channel state information is available at the transmitter, improved performance can be obtained by combining transmit beamforming with SF coding. In this paper we propose two novel transmit beamforming techniques based on the minimum pair-wise...
In this paper we analyze the performance of advanced OFDM packet scheduling techniques based on 3GPP UTRAN Long Term Evolution (LTE) framework for high velocity scenarios. Based on our previous investigations in system performance analysis, we demonstrate that packet scheduler being part of the whole radio resource management (RRM) process has a major impact on it. On the other hand high user velocities...
A number of peak-to-average power ratio (PAPR) reduction techniques have been proposed for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems; however, most of them involve very high computational complexity and are not applicable to MIMO-OFDM systems with space frequency block coding (SFBC). In this paper, we propose a low-complexity PAPR reduction scheme...
This paper presents results from a novel OFDMA multi-cell mobile broadband system level simulator. The tool is used to statistically characterize uplink and downlink inter-cell interference. Without suitable interference management, multi-billion dollar networks can collapse under the strain of heavy traffic loads. Fully loaded interference studies cannot be performed on the network until it has been...
Turbo equalization schemes based on minimum mean square error (MMSE) criteria available in the literature for multiple-input multiple-output (MIMO) systems are computationally expensive, as they require a relatively large matrix inversion. In this paper, we propose a low complexity turbo equalization (TE) scheme with successive interference cancellation for orthogonal frequency division multiplexing...
MIMO, OFDMA and cooperative relaying are the key technologies in future wireless communication systems. However, under the usage of these technologies, resource allocation becomes a more crucial and challenging task. In multi-user MIMO-OFDMA relay-enhanced cellular networks, we formulate the optimal instantaneous resource allocation problem including user group selection, path selection, power allocation,...
The MIMO system convincingly promises a better bit rate in comparison with a SISO system. The system gets even efficient when OFDM is amalgamated with MIMO to obtain better data rates even in hostile channel environment. Research establishes OFDM as a potential candidate for use in MIMO systems for the reasons like inherent FFT, waveform adaptation, advanced antenna techniques, multiple access, interoperability,...
Although maximum a posteriori probability (MAP) channel estimator has an optimal performance for MIMO-OFDM systems, its high complexity could be in the order of O(K3), where K is the number of subcarriers. So, in this paper, we introduce an H-infinity estimator which has good performance, but with much less complexity. Next, lots of matrices inversions and multiplications are reduced by the iterative...
Turbo equalization schemes based on minimum mean square error (MMSE) criteria available in the literature for multiple-input multiple-output (MIMO) systems are computationally expensive as they require a relatively large matrix inversion. In this paper, we propose a low complexity turbo-equalization scheme with successive interference cancellation for the equalization of rapidly time varying multi-path...
It is well-known that for single-input and single-output (SISO) narrow-band transmission on frequency-flat fading channels, uncoded communication with only receiver channel state information (Rx-CSI) leads to extremely poor reliability performance whereas transmitter CSI (Tx-CSI) allows us approach the reliability of an additive white Gaussian noise (AWGN) channel via power control. In this paper,...
SDMA (Space-Division Multiple Access) is a MIMO (Multiple-Input and Multiple-Output) based wireless communication network architecture which has the potential to significantly increase the spectral efficiency and system performance. So far several multiuser detection (MUD) schemes like Zero Forcing (ZF), Minimum Mean Square Error estimation (MMSE), ordered successive interference cancellation (OSIC)...
The performance of orthogonal frequency division multiplexing/code-division multiple-access (OFDM/CDMA) system is featured by the resistance to frequency selective fading and the support of multiple user access. However, OFDM/CDMA system suffers from multiple-access interference (MAI) and doubly selective fading in highly mobile channel. Based on basis expansion model (BEM), this paper proposes a...
The following topics are dealt with: communication and information theory; authentication and identification; antennas; networks performance analysis; speaker verification and recognition; MIMO; optical communications; next generation networks; Indian languages processing; OFDM; image and audio processing applications; ad hoc and sensor networks; microwaves; speech processing; image processing; channel...
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