Joint radar-communications (JRC) benefits from multi-functionality of radar and communication operations using same hardware and radio frequency (RF) spectrum resources. Thus, JRC systems possess very high potential t...
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ISBN:
(纸本)9781665491228
Joint radar-communications (JRC) benefits from multi-functionality of radar and communication operations using same hardware and radio frequency (RF) spectrum resources. Thus, JRC systems possess very high potential to be employed into the sixth generation (6G) standards. Besides, intelligent reflecting surfaces have attracted wide attention in communication systems, due to low complexity of implementation. This paper designs a dynamic beamformer for reconfigurable intelligent surfaces (RIS) which maximizes spectral efficiency (SE). We jointly express the mutual information rate for communication and radar entities including a weighting factor which depicts the dominance of one operation over the other. The joint-SE based proposed method optimally selects the RIS subset. Furthermore, when the communication operation takes place the proposed method takes into account the interference occurring from the radar operation and vice-versa. Fractional programming based selection procedure is used for solving the problem of subset selection. Simulation results are presented and compared with different baselines to show effectiveness of the proposed method.
The demands of users are gradually increasing with the passage of time and with the continuous evaluation in wireless communication technology (i.e., from first to fifth-generation (1G to 5G)). To acquire extreme capa...
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ISBN:
(纸本)9781728162645
The demands of users are gradually increasing with the passage of time and with the continuous evaluation in wireless communication technology (i.e., from first to fifth-generation (1G to 5G)). To acquire extreme capacity, extra-high data rates, massive connectivity, extremely low latency and energy consumption, the utilization of a suitable frequency band of the electromagnetic spectrum is inevitable. An appropriate solution is to utilize millimeter-waves (mmWaves) that can offer 200 times more bandwidth than the existing technology to meet the growing demands of applicants. However, these waves have certain degradation problems, which can be solved by deploying multiple-antenna technology owning to short wavelengths offered by mmWave bands. Still, security is one of the major problems associated with the mmWaves and has got a lot of attention from the researchers in recent times. The primary objectives of this study are to first present a secure hybrid precoder design in mmWave massive multiple-input multiple-output (MIMO) communication systems with the aid of artificial noise (AN), and then, compare the results with the most recent method in the literature. Extensive simulation studies confirm that the AN based hybrid precoder provides more secure communication than its counterpart in terms of secrecy rate versus signal-to-noise ratio (SNR).
In this paper, a hybrid precoder and a hybrid combiner are proposed. The analog beamformer of the hybrid precoder aims at the system sum-rate maximization. In contrast, the baseband beamformer of the hybrid precoder a...
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ISBN:
(纸本)9781665467490
In this paper, a hybrid precoder and a hybrid combiner are proposed. The analog beamformer of the hybrid precoder aims at the system sum-rate maximization. In contrast, the baseband beamformer of the hybrid precoder applies a low-dimensional baseband precoder to mitigate the inter-user/symbol interference and runs the proposed power allocation algorithm. The design of the power allocation matrix allocates the available transmit power such that the instantaneous bit error rate (BER) is reduced. On the other hand, the proposed hybrid combiner works cooperatively with the analog beamformer of the hybrid precoder to further increase the sum rate. Extensive simulation results evidence the positive effects of the proposed method in terms of BER and sum-rate performance compared to other processing techniques from the literature.
This paper considers a multiple-input multiple-output (MIMO) joint radar-communication (JRC) transmission with hybrid precoding and low resolution digital to analog converters (DACs). An energy efficient radio frequen...
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ISBN:
(数字)9781538683477
ISBN:
(纸本)9781538683477
This paper considers a multiple-input multiple-output (MIMO) joint radar-communication (JRC) transmission with hybrid precoding and low resolution digital to analog converters (DACs). An energy efficient radio frequency (RF) chain and DAC bit selection approach is presented for a sub-arrayed hybrid MIMO JRC system. We introduce a weighting formulation to represent the combined radar-communications information rate. The presented selection mechanism is incorporated with fractional programming to solve an energy efficiency maximization problem for JRC which selects the optimal number of RF chains and DAC bit resolution. Subsequently, a weighted minimization problem to compute the precoding matrices is formulated, which is solved using an alternating minimization approach. The numerical results show the effectiveness of the proposed method in terms of high energy efficiency whilst maintaining good rate and desirable radar beampattern performance.
Millimeter wave (mmWave) wireless communication systems with hybrid beamforming require reliable estimation of channel state information to perform optimally. Though the combined high-speed analog-to-digital converter...
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ISBN:
(数字)9781665482431
ISBN:
(纸本)9781665482431
Millimeter wave (mmWave) wireless communication systems with hybrid beamforming require reliable estimation of channel state information to perform optimally. Though the combined high-speed analog-to-digital converters (ADCs) and hybrid precoder/combiner architecture of this system ameliorate the problem of high-power consumption, they make channel estimation to become cumbersome. The paper proposed a channel estimation scheme that is based on a conventional subspace pursuit algorithm. The proposed estimator is named Recast Subspace Pursuit (ReSP)-based channel estimator. Besides taking advantage of the inherent sparsity in the mmWave Massive MIMO channel, the ReSP-based estimator also exploits the a-priori knowledge of channel matrix support-set as side information for the estimation procedure. Simulation results confirm that the proposed ReSP-based channel estimator can exhibit improved performance than some traditional and earlier proposed channel estimation schemes.
The paper considers Millimeter Wave Wireless Communication systems based on hybrid precoder-combiner structure with low-bit resolution analog-to-digital converters (ADCs). Though the hybrid precoder-combiner structure...
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ISBN:
(纸本)9781665436991
The paper considers Millimeter Wave Wireless Communication systems based on hybrid precoder-combiner structure with low-bit resolution analog-to-digital converters (ADCs). Though the hybrid precoder-combiner structure and low-bit resolution ADCs address the problem of huge power consumption in the system, channel estimation for the system is cumbersome. In this paper, a new channel estimation scheme based on adjusted Orthogonal Matching Pursuit (OMP) algorithm is proposed. The estimator named "AdOMP-based channel estimator" exploited the side information available at the receiver of the system to enhance the channel estimation procedure. We show through computer simulation that the proposed AdOMP-based channel estimator exhibit better performance, in the wideband wireless channel, in comparison with other three estimators i.) as the number of transmit antennas increases, ii.) as the number of radio frequency (RF) chains increases, and iii.) across the number of frames employed.
Millimeter wave communication and massive MIMO technology are important ingredients for the future generation communication system. In this context, hybrid precoding (HP) is one of the most promising solutions, and it...
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Millimeter wave communication and massive MIMO technology are important ingredients for the future generation communication system. In this context, hybrid precoding (HP) is one of the most promising solutions, and it becomes utterly important in the case of the multi-user scenario. In this paper, authors have analyzed the performance of the lattice reduction aided fully connected structured precoder for millimeter wave massive MIMO under multi-user scenario. This paper deals with Korkine-Zolotareff (KZ) and Lenstra-Lenstra-Lovasz (LLL) algorithms for the lattice reduction (LR). And the presented results show the performance comparison between zero forcing (ZF), minimum mean squared error (MMSE)-based linear precoder with LLL algorithm-based reduction-based ZF (LLR-ZF), LLR-MMSE, KZ-ZF, KZ-MMSE, and Kalman filter-based precoder. Here, the performance of the precoders has been evaluated based on spectral efficiency, energy efficiency diversity order, and bit error rate. This work conveys some important findings: (i) effectiveness of the lattice reduction aided precoder in multi-user scenario;(ii) numerical results pointed out that at low SNR condition, KZ-aided MMSE hybrid precoder provides 4-dB performance than a Kalman filter-based precoder;(iii) KZ-MMSE hybrid precoder outperforms the other precoder.
The introduction of both hybrid precoder-combiner structure and low-bit resolution analog-to -digital converters (ADCs) makes channel estimation in millimeter (mm) Wave Massive MIMO systems to be challenging. In the l...
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The introduction of both hybrid precoder-combiner structure and low-bit resolution analog-to -digital converters (ADCs) makes channel estimation in millimeter (mm) Wave Massive MIMO systems to be challenging. In the literature, several channel estimation schemes presented focus on narrowband channels. However, few works are found to be presented for the case of wideband channels for this system. In this paper, two new channel estimation techniques are proposed with the first scheme based on the Projection-based Orthogonal Matching Pursuit (POMP) algorithm. The second estimation scheme is based on the Predictive Orthogonal Least Squares (POLS) al-gorithm. In all the simulation results, POLS shows the best performance but with the highest computational complexity cost, with POMB exhibiting the next best performance with a lower computational complexity cost. In terms of compromise between performance and computational complexity cost, the proposed POLS-based channel estimator is the best estimator for the wide -band mmWave Massive MIMO systems.
We consider an outage based approach for hybrid beamforming where the channels are modeled as random vectors drawn from an unknown distribution. Our formulation can be applied to both point-to-point transmit beamformi...
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This paper investigates adaptive signal shaping methods for millimeter wave (mmWave) multiple-input multiple-output (MIMO) communications based on the maximizing the minimum Euclidean distance (MMED) criterion. In thi...
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This paper investigates adaptive signal shaping methods for millimeter wave (mmWave) multiple-input multiple-output (MIMO) communications based on the maximizing the minimum Euclidean distance (MMED) criterion. In this work, we utilize the indices of analog precoders to carry information and optimize the symbol vector sets used for each analog precoder activation state. Specifically, we firstly propose a joint optimization based signal shaping (JOSS) approach, in which the symbol vector sets used for all analog precoder activation states are jointly optimized by solving a series of quadratically constrained quadratic programming (QCQP) problems. JOSS exhibits good performance, however, with a high computational complexity. To reduce the computational complexity, we then propose a full precoding based signal shaping (FPSS) method and a diagonal precoding based signal shaping (DPSS) method, where the full or diagonal digital precoders for all analog precoder activation states are optimized by solving two small-scale QCQP problems. Simulation results show that the proposed signal shaping methods can provide considerable performance gain in reliability in comparison with existing mmWave transmission solutions.
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