Nonlinearities in wireless communication channels foil the performance of the communication systems either at the transmitter or receiver end. This paper explains the concept of the transmitter-side nonlinearities tha...
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ISBN:
(纸本)9781479912971
Nonlinearities in wireless communication channels foil the performance of the communication systems either at the transmitter or receiver end. This paper explains the concept of the transmitter-side nonlinearities that are induced by the High Power Amplifiers (HPA), the final stage at the transmitter side of the communication system. HPA nonlinearities create in-band and out-of-band distortions in wireless communication systems. The in-band distortion results in the degradation of overall performance of Bit Error Rate (BER) and the capacity of the mobile operations. On the other hand, out-of-band distortion creates the spectral broadening effects that degrade the performance of other operators usually operate in the near bands. This paper presents a novel method for the mitigation of HPA nonlinearities by joint predistorter and constellation rotation in multiple-input multiple-output (MIMO) wireless communication systems. The results reveal that the joint nonlinearity compensation technique in MIMO communications system enhances the overall error rate performance of the system. Furthermore to exploit the benefits of proposed technique;Symbol Error Rate (SER) curves for the MIMO multiplexing and Alamouti Space Time Block Codes (STBC) are presented with improvements in their signal to noise ratio.
A novel scheme of the Frequency-Modulated Continuous-Wave Synthetic Aperture Radar (FMCW SAR) with multiple orthogonal transmitted waveforms is introduced in this paper. Based on the Interleaved Orthogonal Frequency D...
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ISBN:
(纸本)9781479921867
A novel scheme of the Frequency-Modulated Continuous-Wave Synthetic Aperture Radar (FMCW SAR) with multiple orthogonal transmitted waveforms is introduced in this paper. Based on the Interleaved Orthogonal Frequency Division multiplex (I-OFDM) principle, the transmit waveform successfully combines the advantages of the linear frequency modulated waveform and the OFDM waveform. This maintains FMCW SAR system smart and miniature, with lower cross correlation and higher coherence. Instead of band pass filter for traditional frequency division waveform, the division of the novel waveform is performed efficiently by the demodulation using discrete Fourier transform. At last, to verify the novel scheme, a simulation of imaging of one point is performed with two transmit waveform.
In this paper, we propose a joint transmission and reception with phase control for beamforming in a multi-cell environment. For generated transmit weight vectors of multiple base stations (BSs), a mobile station (MS)...
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ISBN:
(纸本)9781479975754
In this paper, we propose a joint transmission and reception with phase control for beamforming in a multi-cell environment. For generated transmit weight vectors of multiple base stations (BSs), a mobile station (MS) calculates phases to maximize an achievable rate with low rate feedback. By using the phases, the multiple transmit weight vectors are coordinated to improve the signal to noise ratio (SNR). In order to find optimal phases, we present a phase control method for the effective channel via geometrical approach.
In this paper, we analyze the performance of two sub-optimal antenna selection strategies for single relay based selective decode-and-forward (DF) cooperative multiple-input multiple-output (MIMO) systems. We assume t...
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ISBN:
(纸本)9781479923618
In this paper, we analyze the performance of two sub-optimal antenna selection strategies for single relay based selective decode-and-forward (DF) cooperative multiple-input multiple-output (MIMO) systems. We assume that the source-relay, relay-destination, and the source-destination channels follow the Rayleigh fading. We derive the closed-form expressions and the upper bounds of the symbol error rate (SER) for selective DF cooperative MIMO systems employing M-ary phase shift keying in both the antenna selection strategies. From the derived SER upper bounds, we extract the diversity orders of the system in both the selection strategies. The optimal power allocation for the source and relay is derived in both the selection strategies, which minimize the SER of DF cooperative MIMO system.
Space-time block codes (STBCs) from orthogonal designs have attracted considerable attention due to their fast maximum-likelihood (ML) decoding and full diversity. A full rate (R=1) is achieved for 3 and 4 antennas us...
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ISBN:
(纸本)9781479938209
Space-time block codes (STBCs) from orthogonal designs have attracted considerable attention due to their fast maximum-likelihood (ML) decoding and full diversity. A full rate (R=1) is achieved for 3 and 4 antennas using "triple QPSK" for complex (STBCs). This paper proposes a family of new space-time block codes (STBC) for 6 transmit antennas that achieves full rate. This paper also proposes a modified QPSK constellation scheme that can achieve the full rate for both 6 and 8 transmit antennas.
For differential space-time block coding (DSTBC), this paper proposes a simple decision-feedback block differential detection (DFBDD) scheme with small computational complexity, in order to improve tracking capability...
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ISBN:
(纸本)9781479944828
For differential space-time block coding (DSTBC), this paper proposes a simple decision-feedback block differential detection (DFBDD) scheme with small computational complexity, in order to improve tracking capability on fast time-varying fading channels. Decisions can be derived directly without computation of metrics in the proposed DFBDD. It can also employ higher-order channel prediction, which needs neither complex trellis search algorithms nor complex channel prediction recursive algorithms. Finally, computer simulation results confirm that the proposed DFBDD with higher-order channel prediction has higher tracking capability at low computational complexity than the conventional block differential detection without channel prediction.
In this paper, the problem of power allocation for a multiple-input multiple-output two-way system is investigated in underlay Cognitive Radio (CR) set-up. In the CR underlay mode, secondary users are allowed to explo...
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ISBN:
(纸本)9781479920037
In this paper, the problem of power allocation for a multiple-input multiple-output two-way system is investigated in underlay Cognitive Radio (CR) set-up. In the CR underlay mode, secondary users are allowed to exploit the spectrum allocated to primary users in an opportunistic manner by respecting a tolerated temperature limit. The secondary networks employ an amplify-and-forward two-way relaying technique in order to maximize the sum rate under power budget and interference constraints. In this context, we formulate an optimization problem that is solved in two steps. First, we derive a closed-form expression of the optimal power allocated to terminals. Then, we employ a strong optimization tool based on particle swarm optimization algorithm to find the power allocated to secondary relays. Simulation results demonstrate the efficiency of the proposed solution and analyze the impact of some system parameters on the achieved performance.
The problem of adaptively equalizing doubly dispersive MIMO channels for FBMC/OQAM systems is studied in this paper. The challenges in this type of multicarrier systems include their intrinsic self-interference and th...
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ISBN:
(纸本)9781479958634
The problem of adaptively equalizing doubly dispersive MIMO channels for FBMC/OQAM systems is studied in this paper. The challenges in this type of multicarrier systems include their intrinsic self-interference and the need to cope with time-and frequency-selective subchannels in realistic propagation conditions. An efficient and numerically stable algorithm is adopted, relying on a decision feedback structure that implements BLAST ordering for the input signals recovery. The ability of this algorithm to address the above challenges has been demonstrated. The focus of this paper is on reducing the needs of this equalizer in training information. A channel estimate-based (re-)initialization scheme is developed and shown to be quite effective in lowering the training overhead, at an affordable additional cost in complexity. For the sake of comparison, the MIMO-OFDM problem is also studied. Simulation results for practical scenarios demonstrate the effectiveness of the proposed approach.
multiple-input multiple-output (MIMO) technology provides a means of boosting network capacity without requiring additional spectrum. It has received widespread attention over the past decade from both industry and ac...
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ISBN:
(纸本)9781450326209
multiple-input multiple-output (MIMO) technology provides a means of boosting network capacity without requiring additional spectrum. It has received widespread attention over the past decade from both industry and academic researchers,no w forming a key component of nearly all emerging wireless standards. Despite the huge promise and considerable attention,a rigorous algorithm-theoretic framework for maximizing network capacity in multihop wireless MIMO networks is missing in the state of the art. The existing algorithms and protocols for maximizing network capacity in multihop wireless MIMO networks are purely heuristic without any provable performance guarantees. In this paper we conduct a comprehensive algorithm study for maximizing network capacity in multihop wireless MIMO networks with receiver-side interference suppression,including the full characterization of NP-hardness and APX-hardness, the polynomial time approximation schemes,and the practical approximation algorithms with provable performance guarantees.
A single-carrier multiple-input multiple-output (MIMO) system with frequency-selective channels suffers from the inter-symbol interference (ISI) and the co-channel interference (CCI). To eliminate both type of interfe...
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A single-carrier multiple-input multiple-output (MIMO) system with frequency-selective channels suffers from the inter-symbol interference (ISI) and the co-channel interference (CCI). To eliminate both type of interference, we propose in this letter a hybrid two-stage decision-feedback equalizer (HTS-DFE), which performs the frequency-domain equalization (FIDE) in the first stage and the layered serial interference-cancellation (SIC) in the second stage. Since the decision-feedback (DF) or noise-prediction (NP) architecture can be employed in FIDE or SIC, the proposed equalizer actually can have four variations that achieve the same mean square error (MSE) under the assumption of perfect feedback. Further, we combine HTS-DFE with the decoded decision-feedback (131317) scheme to mitigate the error-propagation encountered in the practice. Simulation results confirm that the proposed HTS-DFE can outperform the existing equalizers significantly.
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