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作者： Yahia Y. Ahmed Eldemerdash Ahmed Memorial University of Newfoundland

学位级别：博士

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

关键词： Cognitive Radio Space-time block coding multiple-input multiple-output Signal identification

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Novel Unified Analysis of Orthogonal Space-Time Block Codes over Generalized-K and AWGGN MIMO Networks 81

Novel Unified Analysis of Orthogonal Space-Time Block Codes ...

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81st IEEE Vehicular Technology Conference (VTC Spring)

作者： Salahat, Ehab Saleh, Hani Khalifa Univ Sci Technol & Res Abu Dhabi U Arab Emirates

ISBN: (纸本)9781479980888

This paper presents a novel unified performance analysis of Space-Time Block Codes (STBCs) operating in the multiple input multiple output (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.

关键词： Space-Time Block Codes Generalized-K multiple-input multiple-output Additve White Generalized Gaussian Noise Rayleigh-Lognormal ABER

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Multi-User MIMO-OFDM for Indoor Visible Light Communication Systems

Multi-User MIMO-OFDM for Indoor Visible Light Communication ...

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3rd IEEE Global Conference on Signal and Information Processing (GlobalSIP)

作者： Wang, Qi Wang, Zhaocheng Qian, Chen Quan, Jinguo Dai, Linglong Tsinghua Univ Dept Elect Engn Tsinghua Natl Lab Informat Sci & Technol TNList Beijing 100084 Peoples R China Tsinghua Univ Shenzhen Grad Sch Div Informat Sci & Technol Shenzhen 518055 Peoples R China

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.

关键词： Visible light communication multiple-input multiple-output orthogonal frequency-division multiplexing multi-user precoding

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Terrestrial Broadcast Technologies for Next Generation Broadcast Wireless Systems

Terrestrial Broadcast Technologies for Next Generation Broad...

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International Conference on Communication Workshop

作者： Yajun Kou Fang Wang Jinfeng Tian Wenjun Zhang Yunfeng Guan Dazhi He Yijun Shi Shanghai Adv. Res. Inst. Shanghai China

ISBN: (纸本)9781467363068

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).

关键词： NGB-W terrestrial broadcast low-density parity check code bit-interleaved coded modulation multiple-input multiple-output carrier aggregation

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Exploring Coordinated Multipoint Beamforming Strategies for 5G Cellular

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IEEE ACCESS 2014年 2卷 930-946页

作者： Schwarz, Stefan Rupp, Markus Vienna Univ Technol Inst Telecommun A-1040 Vienna Austria

Cellular networks are a central part of today's communication infrastructure. The global roll-out of 4G long-term evolution is underway, ideally enabling ubiquitous broadband Internet access. Mobile network operators, however, are currently facing an exponentially increasing demand for network capacity, necessitating densification of cellular base stations (keywords: small cells and heterogeneous networks) and causing a strongly deteriorated interference environment. Coordination among transmitters and receivers to mitigate and/or exploit interference is hence seen as a main path toward 5G mobile networks. We provide an overview of existing coordinated beamforming strategies for interference mitigation in broadcast and interference channels. To gain insight into their ergodic behavior in terms of signal to interference and noise ratio as well as achievable transmission rate, we focus on a simplified but representative scenario with two transmitters that serve two users. This analysis provides guidelines for selecting the best performing method depending on the particular transmission situation.

关键词： multiple-input multiple-output beamforming multiuser gains coordinated multipoint transmission ergodic transmission rate linear transceivers MMSE receiver

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Three-dimensional Space-Time Shift Keying with Coordinate Combination and Joint Optimisation

Three-dimensional Space-Time Shift Keying with Coordinate Co...

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IEEE/CIC International Conference on Communications in China

作者： Guangtao Zheng Ming Jiang Sun Yat-sen University Guangzhou China

ISBN: (纸本)9781509002443

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.

关键词： Three-dimensional constellation space-time shift keying multiple-input multiple-output coordinate combination joint optimisation multiple input multiple output systems shift keying System performance Three Dimensions CONSTELLATIONS space time frequency shift keying error-resilience Coordinates

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Performance Analysis of Optimal Beamforming in Fixed-Gain AF MIMO Relaying over Asymmetric Fading Channels

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IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第4期62卷 1201-1217页

作者： Jayasinghe, Praneeth Jayasinghe, L. K. Saliya Juntti, Markku Latva-Aho, Matti Univ Oulu Dept Commun Engn SF-90100 Oulu Finland

This paper analyzes the performance of an optimal single stream beamforming scheme for a multiple-input multiple-output (MIMO) relay network with dual-hop fixed-gain amplify-and-forward (AF) relaying. The source-relay and relay-destination channels undergo Rayleigh and Rician fading respectively. Different Rician fading scenarios are considered for relay-destination channel, depending on the rank of the Rician channel matrix. The channel state information is only available at the destination, and the destination computes the optimal transmit and receive beamforming vectors to maximize the instantaneous signal-to-noise ratio (SNR). The optimal transmit beamforming vector is sent back to the transmitter via a dedicated feedback link. We derive new analytical expressions for the cumulative distribution function, probability density function, and moments to statistically characterize the properties of the instantaneous SNR. These statistical properties are used to analyze the system performance in terms of the outage probability, average bit error rate, and the ergodic capacity. The performance analysis investigates the effects of the Rician factor, rank of the line-of-sight component, and number of antennas at the nodes on the system performance. The results reveal that the optimal single stream beamforming system provides better performance than an orthogonal space-time block coded based AF MIMO system.

关键词： Amplify-and-forward relaying bit error rate cumilative distribution function multiple-input multiple-output moments optimal beamforming probability density function Rayleigh fading Rician fading

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Novel Unified Analysis of Orthogonal Space-Time Block Codes over Generalized-K and AWGGN MIMO Networks

Novel Unified Analysis of Orthogonal Space-Time Block Codes ...

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IEEE Vehicular Technology Conference

作者： Ehab Salahat Hani Saleh Khalifa University of Science Technology and Research

ISBN: (纸本)9781479980895

关键词： Space-Time Block Codes Generalized-K multiple-input multiple-output Additive White Generalized Gaussian Noise Rayleigh-Lognormal ABER

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Transmit Designs for the MIMO Broadcast Channel With Statistical CSI

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2014年第17期62卷 4451-4466页

作者： Wu, Yongpeng Jin, Shi Gao, Xiqi McKay, Matthew R. Xiao, Chengshan Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Jiangsu Peoples R China Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Kowloon Hong Kong Peoples R China Missouri Univ Sci & Technol Dept Elect & Comp Engn Rolla MO 65409 USA

We investigate the multiple-input multiple-output broadcast channel with statistical channel state information available at the transmitter. The so-called linear assignment operation is employed, and necessary conditions are derived for the optimal transmit design under general fading conditions. Based on this, we introduce an iterative algorithm to maximize the linear assignment weighted sum-rate by applying a gradient descent method. To reduce complexity, we derive an upper bound of the linear assignment achievable rate of each receiver, from which a simplified closed-form expression for a near-optimal linear assignment matrix is derived. This reveals an interesting construction analogous to that of dirty-paper coding. In light of this, a low-complexity transmission scheme is provided. Numerical examples illustrate the significant performance of the proposed low complexity scheme.

关键词： Broadcast channel multiple-input multiple-output statistical CSI

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Low-Complexity Sorted QR Decomposition for MIMO Systems Based on Pairwise Column Symmetrization

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第3期13卷 1388-1396页

作者： Kim, Tae-Hwan Korea Aerosp Univ Sch Elect Telecommun & Comp Engn Goyang Si 412791 Gyung Gi Do South Korea

QR decomposition (QRD) is a preprocessing technique for detecting symbols in multiple-input and multiple-output (MIMO) systems, but the computational complexity is prohibitively high when the systems incorporate a large number of antennas. This paper presents a low-complexity sorted QRD (SQRD) algorithm for MIMO systems. The proposed algorithm performs SQRD through orthogonalizations based on the modified Gram-Schmidt process, rearranging the column vectors of a real-valued MIMO channel matrix in such a way that the symmetry between the vectors is maintained. By using the symmetry, the computations required for orthogonalizing one of the two adjacent vectors can be eliminated effectively, which significantly reduces the computational complexity. Theoretical analyses show that the proposed algorithm reduces the computational complexity required for SQRD by 50% for any MIMO configurations, when compared to the conventional algorithm. In addition, the memory requirement to store resultant matrices is 50% of that in the conventional one.

关键词： multiple-input multiple-output QR decomposition sphere decoding symbol detection preprocessing Gram-Schmidt process

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