A power control scheme for multiple-input multiple-output systems using spatial multiplexing with a minimum mean square error (MMSE) receiver is proposed under slow fading scenarios. Simulation results show that the p...
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A power control scheme for multiple-input multiple-output systems using spatial multiplexing with a minimum mean square error (MMSE) receiver is proposed under slow fading scenarios. Simulation results show that the proposed scheme provides a significant reduction in bit error rate compared to that of no power control.
Binary continuous phase modulation (CPM) is considered with space-time trellis codes (STTCs) for multiple-input multiple-output systems. Single-h CPM with rectangular, raised cosine and half cycle sinusoid is consider...
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Binary continuous phase modulation (CPM) is considered with space-time trellis codes (STTCs) for multiple-input multiple-output systems. Single-h CPM with rectangular, raised cosine and half cycle sinusoid is considered. The upper bound on the minimum product distance of this signalling scheme is determined over a quasi-static Rayleigh fading channel, Based on the rank and determinant criterion, best STTC/CPM combinations are identified for two transmit and an arbitrary number of receive antennas.
multiple-inputmultiple-output (MIMO) antennas can be combined with orthogonal frequency division multiplexing (OFDM) to achieve diversity. gain and/or to increase system spectral efficiency through spatial multiplexi...
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multiple-inputmultiple-output (MIMO) antennas can be combined with orthogonal frequency division multiplexing (OFDM) to achieve diversity. gain and/or to increase system spectral efficiency through spatial multiplexing. In this letter, we derive the probability density function (pdf) expressions of the condition number (i.e., the maximum-to-minimum-singular-value ratio, MMSVR) of the channel state information (CSI) matrix. We show that this ratio is directly related to the noise enhancement in open-loop MIMO systems and provides a significant insight on the overall system capacity. The pdf of this ratio could be used to predict the relative performances of various MIMO configurations without complex system-level simulations. The pdf can also be used to compute the probability of whether certain channels will fail in the high-throughput mode. Extensive simulations are performed to validate the accuracy of the closed-form pdf of the MMSVR derived in this letter.
We present a network framework for evaluating the theoretical performance limits of wireless data communication. We address the problem of providing the best possible service to new users joining the system without af...
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We present a network framework for evaluating the theoretical performance limits of wireless data communication. We address the problem of providing the best possible service to new users joining the system without affecting existing users. Since, interference-wise, new users are required to be invisible to existing users, the network is dubbed PhantomNet. The novelty is the generality obtained in this context. Namely, we can deal with multiple users, multiple antennas, and multiple cells on both the uplink and the downlink. The solution for the uplink is effectively the same as for a single cell system since all the base stations (BSs) simply amount to one composite BS with centralized processing. The optimum strategy, following directly from known results, is successive decoding (SD), where the new user is decoded before the existing users so that the new users' signal can be subtracted out to meet its invisibility requirement. Only the BS needs to modify its decoding scheme in the handling of new users, since existing users continue to transmit their data exactly as they did before the new arrivals. The downlink, even with the BSs operating as one composite BS, is more problematic. With multiple antennas at each BS site, the optimal coding scheme and the capacity region for this channel are unsolved problems. SD and dirty paper (DP) are two schemes previously reported to achieve capacity in special cases. For PhantomNet, we show that DP coding at the BS is equal to or better than SD. The new user is encoded before the existing users so that the interference caused by his signal to existing users is known to the transmitter. Thus the BS modifies its encoding scheme to accommodate new users so that existing users continue to operate as before: they achieve the same rates as before and they decode their signal in precisely the same way as before. The solutions for the uplink and the downlink are particularly interesting in the way they exhibit a remarkable simplicit
In this paper, we optimize delay diversity (DD) for the case when computationally efficient decision-feedback equalization (DFE) is used at the receiver. We consider the general case of transmission over a cor-related...
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ISBN:
(纸本)0780385233
In this paper, we optimize delay diversity (DD) for the case when computationally efficient decision-feedback equalization (DFE) is used at the receiver. We consider the general case of transmission over a cor-related multiple-inputmultiple-output (MIMO) frequency-selective fading channel. The proposed optimization requires the knowledge of the statistical properties of the wireless channel at the transmitter, but channel state information is only required at the receiver side. Based on an approximation of the pairwise error probability for DFE, we derive a stochastic gradient algorithm that allows us to optimize the DD transmit filters. Simulation results for the GSM/EDGE system show significant performance gains of the proposed optimized DD scheme over the DD schemes reported in [I] and [2], respectively, if DFE is used at the receiver.
A novel closed-loop MIMO architecture is proposed, in which channel state information is fully utilised to maximise channel capacity. Simulation results show that compared with V-BLAST, it can achieve much better perf...
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A novel closed-loop MIMO architecture is proposed, in which channel state information is fully utilised to maximise channel capacity. Simulation results show that compared with V-BLAST, it can achieve much better performance while maintaining the same high spectral efficiency. Nearly 5 dB gain can be provided by this new architecture over V-BLAST.
Downlink multiple-input, multiple-output (MIMO) systems assuming a large number of base station antennas, a small number of mobile station antennas, and rich-scattering, quasi-stationary, and flat-fading channel envir...
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Downlink multiple-input, multiple-output (MIMO) systems assuming a large number of base station antennas, a small number of mobile station antennas, and rich-scattering, quasi-stationary, and flat-fading channel environments are considered. A MIMO space-division multiple access (SDMA) technique is proposed which enables concurrent transmission of multiple data streams to each multiple mobile station. The proposed method can achieve much higher downlink channel capacity than conventional MIMO techniques.
Computational electromagnetics is used to characterise the effect of realistic propagation on the capacity of multiple-input, multiple-output (MIMO) communication systems. Mutual information results for a MIMO system ...
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Computational electromagnetics is used to characterise the effect of realistic propagation on the capacity of multiple-input, multiple-output (MIMO) communication systems. Mutual information results for a MIMO system operating at 1.8 GHz in an urban micro-cellular environment are presented.
This paper describes the digital control of a vibratory pile driver in which the vibration is generated via two tandem pairs of electrically driven, geared, contra-rotating eccentrics. Experimental results are include...
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This paper describes the digital control of a vibratory pile driver in which the vibration is generated via two tandem pairs of electrically driven, geared, contra-rotating eccentrics. Experimental results are included to show the controller-induced system dynamics for a variety of load conditions, and to highlight the fact that, if the relative phase of the eccentric pairs is not controlled, the natural tendency at high excitation frequency is for the pile driver to operate with a low vibration amplitude. An analytical technique for identifying the system parameters is presented, and analytical performance predictions are compared with experimental results. Analysis of the power flow in the system shows that, although significant power transfer occurs between the two electrical drives, the net power dissipation during pile driving is relatively low.
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