This paper evaluates the performance of space shift keying (SSK) free-space optical communication (FSO) over moderate and strong turbulent channels. It has been shown previously that repetition codes (RCs) using inten...
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ISBN:
(纸本)9781628414776
This paper evaluates the performance of space shift keying (SSK) free-space optical communication (FSO) over moderate and strong turbulent channels. It has been shown previously that repetition codes (RCs) using intensity modulation with direct detection techniques are superior to SSK system for a spectral efficiency of 1 bit/s/Hz. It is shown in this study that SSK outperforms RCs using M-ary pulse amplitude modulation for spectral efficiencies of 3 bits/s/Hz or larger. Analytical expressions for the bit error rate for the SSK system under study are derived and extensive simulation results corroborate the correctness of the conducted analysis.
The IEEE 802.11n standard utilizes multiple-input multiple-output (MIMO) technology in order to improve the throughput as well as the transmission range of the communication link. In this paper, the range performance ...
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ISBN:
(纸本)9781479978007
The IEEE 802.11n standard utilizes multiple-input multiple-output (MIMO) technology in order to improve the throughput as well as the transmission range of the communication link. In this paper, the range performance evaluation of IEEE 802.11n standard compliant devices based on different configuration parameters, such as modulation and coding schemes, antenna numbers, and various available MIMO operational modes, is presented. The range improvement provided by IEEE 802.11n MIMO modes over the single-input single-output (SISO) system configuration is highlighted. The improved range reduces the number of required Wi-Fi devices in an area for a given reliability factor, such as the packet error rate (PER). Conversely, the reliability of a link can be improved for a given transmission range. Availability of such performance benchmark figures under different channel conditions allow the commissioning engineer to optimally design the network before the actual deployment. As a result, the overall installation/maintenance cost can be significantly reduced. The obtained results are applicable to both the traditional star as well as mesh topology networks.
The next generation broadcast wireless (NGB-W) system is aimed to provide high-speed, ubiquitous, and secure tri-play services to massive users. In this paper, a new terrestrial broadcast solution for the NGB-W system...
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ISBN:
(纸本)9781467363051
The next generation broadcast wireless (NGB-W) system is aimed to provide high-speed, ubiquitous, and secure tri-play services to massive users. In this paper, a new terrestrial broadcast solution for the NGB-W system is proposed. The system and the key techniques of the proposed solution are introduced. The performance of the proposed solution is evaluated by simulations. It is shown that the performance of the proposed solution is better than that of the second generation terrestrial broadcast systems of Digital Video Broadcasting (DVB).
In this paper, the concept of three-dimensional (3-D) space-time shift keying (STSK) is introduced, which incorporates 3-D constellations into conventional STSK systems. The new 3-D STSK techniques enjoy better error ...
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ISBN:
(纸本)9781509002436
In this paper, the concept of three-dimensional (3-D) space-time shift keying (STSK) is introduced, which incorporates 3-D constellations into conventional STSK systems. The new 3-D STSK techniques enjoy better error resilience than their two-dimensional (2-D) counterparts. Firstly, based on different sampling rates, two three-dimensional (3-D) STSK schemes referred to as R2 3-D STSK and R3 3-D STSK, respectively, are proposed. Both schemes show improved effective spectral efficiency (ESE) than 2-D STSK at relatively low signal-to-noise ratios (SNRs). Further, the optimal combinations of the constellation coordinates for R2 3-D STSK are derived by maximising the minimal determinant of the so-called difference matrices, yielding a better system performance. In addition, a joint optimisation mechanism utilising the simplified conjugate gradient (SCG) algorithm is devised for 3-D STSK, aiming for further enhancing the achievable system performance. Finally, extensive simulation results are provided to demonstrate the benefits of the proposed schemes, exhibiting the design tradeoffs concerning date rate, link robustness and computational complexity.
Spectrum scarcity is an obstacle to deploy emerging high speed wireless services that require more frequency spectrum. Cognitive radio (CR) appears as a promising solution for the spectral congestion by allowing spect...
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Spectrum scarcity is an obstacle to deploy emerging high speed wireless services that require more frequency spectrum. Cognitive radio (CR) appears as a promising solution for the spectral congestion by allowing spectrum sharing between primary and secondary users in which optimum utilization of the available spectrum is achieved. Efficient coex- istence between different users requires full knowledge of the activities in the spectrum of interest. Spectrum awareness is the terminology used to describe the techniques that detect the presence of signals in certain frequency bands, as well as identify the main pa- rameters of such signals, e. g., modulation scheme. These two tasks are commonly referred by the terms spectrum sensing and signal identification, respectively. Blind signal identification was initially used by military applications, such as radio surveillance and electronic warfare, and has recently been extended to civilian applica- tions. This problem becomes more challenging in multiple-input multiple-output (MIMO) scenarios due to the diverse transmission schemes that can be employed, e. g., spatial multi- plexing (SM) and space-time block codes (STBCs). A large number of studies have been carried out for developing blind signal identification algorithms in single-input single- output (SISO) scenarios, including identification of the modulation format and recogni- tion of single-carrier (SC) versus multicarrier transmissions. However, the problem of signal identification for MIMO systems remains at an incipient stage. In this dissertation, we develop novel algorithms to blindly identify the MIMO transmission scheme of the received signal. More specifically, in Chapters 2 and 3, we address the problem of identifying STBCs for the SC transmission. Unlike most of the work done to date, we show that STBC iden- tification can be performed using a single receive antenna. Four algorithms are proposed in Chapter 2 to identify SM and Alamouti STBC. Then, the idea
This paper presents a novel unified performance analysis of Space-Time Block Codes (STBCs) operating in the multipleinputmultipleoutput (MIMO) network. Specifically, we derive a novel unified expression for the ave...
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ISBN:
(纸本)9781479980888
This paper presents a novel unified performance analysis of Space-Time Block Codes (STBCs) operating in the multipleinputmultipleoutput (MIMO) network. Specifically, we derive a novel unified expression for the average bit error rate for all coherent modulation schemes assuming independent and identically distributed generalized-K fading channels, which accounts for both multipath fading and shadowing, and modeled via the Nakagami-m distribution and the gamma distributions, respectively. The noise model in the network is assumed to be an Additive White Generalized Gaussian Noise (AWGGN), which encompasses the Laplacian and the Gaussian noise environments as special cases. The derived expression obviates the need to recalculate the diversity of various receivers for many fading and noise models in a piecemeal fashion. Published results from the literature as well as numerical integration methods corroborate the accuracy of the unified expression.
In this paper, we investigate an indoor multi-user visible light communication system employing multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM). For each subcarrier in OFDM, the...
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ISBN:
(纸本)9781479975914
In this paper, we investigate an indoor multi-user visible light communication system employing multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM). For each subcarrier in OFDM, the corresponding precoding matrix is calculated in the frequency domain to eliminate multi-user interference. The distances of the multiple transmitter-receiver links are different, which results in various temporal delays and phase differences in the frequency domain. Phase information is firstly considered, whereby complex instead of real channel matrices are used for precoding, which reduces the channel correlation and achieves better performance. Moreover, two DC bias and scaling factor calculation schemes are proposed, and their performances are compared with zero forcing and minimum mean-squared error (MMSE) precoding techniques.
A compact dual-band multiple-input multiple-output (MIMO) antenna is presented for wireless local area networks (2.45/5.8 GHz) applications in mobile handsets. The proposed MIMO antenna consists of two planar inverted...
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A compact dual-band multiple-input multiple-output (MIMO) antenna is presented for wireless local area networks (2.45/5.8 GHz) applications in mobile handsets. The proposed MIMO antenna consists of two planar inverted-F antennas loaded with inverted J-shaped slot and inverted L-shaped slot. The defected ground structure of fork shaped slot is proposed between antenna elements to achieve high port-to-port isolation (<-20 dB). The distribution of specific absorption rate (SAR) over 1-g and 10-g tissues in human head are also studied for two different positions of the antenna at 2.45/5.8 GHz frequencies through SAR to PEAK location spacing ratio (SPLSR) according to Federal Communication Commission standard. The values of SPLSR are observed over 1-g of tissues between 0.107 and 0.246 W/kg/cm and 0.304-0.122 W/kg/cm and over 10-g of tissues between 0.242 and 0.124 W/kg/cm and 0.154 and 0.045 W/kg/cm at 2.45 GHz and 5.8 GHz, respectively. The S-parameters, surface current distribution, diversity parameters, and radiation patterns are presented. The fabricated prototype are measured and obtained good agreement with simulated results. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:906-912, 2015
This article is intended to suggest a mobile-embedded antenna with tunable capacitance and the validity of the proposed solution was proved through design, fabrication, and measurement. The aforementioned antenna is a...
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This article is intended to suggest a mobile-embedded antenna with tunable capacitance and the validity of the proposed solution was proved through design, fabrication, and measurement. The aforementioned antenna is applicable to long term evolution (LTE), including band 5, band 8, band 13, and band 17 that are in use today. The 4G mobile services' antennas need to ensure the extension of bandwidth in order to include LTE bands as well as other different services. Low-band characteristics, however, are difficult to achieve mainly because of lack of space for antennas in terminals. The problem may be solved by using a SP4T switch of RFMD, which is to generate the operation frequency of low-band tunable. The optimized parameters were able to fabrication and measure antennas. Hence, antennas come to meet with operation frequency and performance for low bands;also, the performance of the fabricated antenna that has been measured with the optimized parameters has been compared and analyze. (C) 2015 Wiley Periodicals, Inc.
Results from an experiment that applied one class of multiple-input multiple-output (MIMO) waveform techniques to over-the-horizon radar (OTHR) are reported. The experiment objective was to demonstrate that adaptive t...
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Results from an experiment that applied one class of multiple-input multiple-output (MIMO) waveform techniques to over-the-horizon radar (OTHR) are reported. The experiment objective was to demonstrate that adaptive transmitter beamforming could be used in an appropriately design radar to reject spatially discrete Doppler-spread clutter. In the particular MIMO radar architecture that the authors call non-causal transmit beamforming, conventional or adaptive transmitter beamforming occurs following waveform transmission, propagation, scatter from targets and clutter sources, return propagation and finally signal reception. In the case reported herein spatially discrete clutter was successfully rejected to the noise floor of the radar return with rejection in excess of 35 dB achieved using common adaptive algorithms and straightforward training data selection. As part of the rejection algorithm the transmitted waveform direction-of-departure (DOD) from the transmitter array to the target was estimated and used as the preserved steer direction in the adaptive beamformer. The DOD estimates agree well with the geometrically determined true values. The demonstration of non-causal transmit beamforming suggests that it will be possible to create multiple simultaneous adaptive range-dependent transmitter beams with an appropriately designed OTHR. This has several applications including for the mitigation of Doppler-spread clutter.
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