Energy-Efficient Small Cell With Spectrum-Power Trading

Wu, Qingqing; Li, Geoffrey Ye; Chen, Wen; Ng, Derrick Wing Kwan

doi:10.1109/jsac.2016.2612061

Cited by 36 publications

(22 citation statements)

References 45 publications

(74 reference statements)

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“…With the fully controllable UAV mobility, the communication distance between the UAV and ground users can be significantly shortened by proper UAV trajectory design and user scheduling. This is analogous and yet in sharp contrast to the existing small-cell technology [19]- [22], where the cell radius is reduced by increasing the number of small-cell BSs deployed, but at the cost of increased infrastructure expenditure. Motivated by this, the UAV trajectory design is rigorously studied in [16] and [23] for a mobile relaying system and point-to-point energy-efficient system, respectively, where sequential convex optimization techniques are applied to solve the non-convex trajectory optimization problems therein.…”

Section: Introductionmentioning

confidence: 99%

Joint Trajectory and Communication Design for Multi-UAV Enabled Wireless Networks

Zeng

Zhang

2018

IEEE Trans. Wireless Commun.

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Unmanned aerial vehicles (UAVs) have attracted significant interest recently in assisting wireless communication due to their high maneuverability, flexible deployment, and low cost. This paper considers a multi-UAV enabled wireless communication system, where multiple UAV-mounted aerial base stations (BSs) are employed to serve a group of users on the ground. To achieve fair performance among users, we maximize the minimum throughput over all ground users in the downlink communication by optimizing the multiuser communication scheduling and association jointly with the UAVs' trajectory and power control. The formulated problem is a mixed integer nonconvex optimization problem that is challenging to solve. As such, we propose an efficient iterative algorithm for solving it by applying the block coordinate descent and successive convex optimization techniques. Specifically, the user scheduling and association, UAV trajectory, and transmit power are alternately optimized in each iteration. In particular, for the non-convex UAV trajectory and transmit power optimization problems, two approximate convex optimization problems are solved, respectively. We further show that the proposed algorithm is guaranteed to converge. To speed up the algorithm convergence and achieve good throughput, a low-complexity and systematic initialization scheme is also proposed for the UAV trajectory design based on the simple circular trajectory and the circle packing scheme. Extensive simulation results are provided to demonstrate the significant throughput gains of the proposed design as compared to other benchmark schemes.

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Section: Introductionmentioning

confidence: 99%

Joint Trajectory and Communication Design for Multi-UAV Enabled Wireless Networks

Zeng

Zhang

2018

IEEE Trans. Wireless Commun.

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“…Although there has been a quantum leap in spectrum efficiency of wireless networks in the last few decades thanks to various technological advances such as ultra-dense network (UDN), massive multiple-input multiple-output (M-MIMO), and millimeter wave (mmWave) communications, the network energy consumption and hardware cost are still critical issues faced in practical implementation [1]. For example, UDNs almost linearly scale the circuit and cooling energy consumption with the number of newly deployed base stations (BSs) [2], while costly radio frequency (RF) chains and complex signal processing techniques are needed for efficient communication at mmWave frequencies. On the other hand, adding an excessively large number of active components such as small-cell BSs/relays in wireless networks also causes a more severe interference issue [3].…”

Section: Introductionmentioning

confidence: 99%

Intelligent Reflecting Surface Enhanced Wireless Network: Joint Active and Passive Beamforming Design

Zhang

2018

2018 IEEE Global Communications Conference (GLOBECOM)

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Intelligent reflecting surface (IRS) is envisioned to have abundant applications in future wireless networks by smartly reconfiguring the signal propagation for performance enhancement. Specifically, an IRS consists of a large number of lowcost passive elements each reflecting the incident signal with a certain phase shift to collaboratively achieve beamforming and suppress interference at one or more designated receivers. In this paper, we study an IRS-enhanced point-to-point multipleinput single-output (MISO) wireless system where one IRS is deployed to assist in the communication from a multi-antenna access point (AP) to a single-antenna user. As a result, the user simultaneously receives the signal sent directly from the AP as well as that reflected by the IRS. We aim to maximize the total received signal power at the user by jointly optimizing the (active) transmit beamforming at the AP and (passive) reflect beamforming by the phase shifters at the IRS. We first propose a centralized algorithm based on the technique of semidefinite relaxation (SDR) by assuming the global channel state information (CSI) available at the IRS. Since the centralized implementation requires excessive channel estimation and signal exchange overheads, we further propose a low-complexity distributed algorithm where the AP and IRS independently adjust the transmit beamforming and the phase shifts in an alternating manner until the convergence is reached. Simulation results show that significant performance gains can be achieved by the proposed algorithms as compared to benchmark schemes. Moreover, it is verified that the IRS is able to drastically enhance the link quality and/or coverage over the conventional setup without the IRS.

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“…From (28), it is easy to find that the received signal after passing S t,r is free of the MCI. In addition, when the r-th receive antenna is out of the overlap, we find that (28) turns into (21), which means that S t,r can be seen as a process of selecting the positionbased channel model.…”

Section: ) MCI Elimination: Inmentioning

confidence: 99%

“…In [17] and [18], two position-based compressed channel estimation methods are developed for HST systems, where the train position information is utilized to improve the estimation performance and combat the ICI. Moveover, many other applications highly depend on accurate channel estimation schemes, such as green communication and wireless power transfer [19]- [21].…”

Section: Introductionmentioning

confidence: 99%

Position-Based Interference Elimination for High-Mobility OFDM Channel Estimation in Multicell Systems

Ren

Chen

Gong

et al. 2017

IEEE Trans. Veh. Technol.

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Orthogonal frequency-division multiplexing (OFDM) and multi-cell architecture are widely adopted in current high speed train (HST) systems for providing high data rate wireless communications. In this paper, a typical multiantenna OFDM HST communication system with multi-cell architecture is considered, where the inter-carrier interference (ICI) caused by high mobility and multi-cell interference (MCI) are both taken into consideration. By exploiting the train position information, a new position-based interference elimination method is proposed to eliminate both the MCI and ICI for a general basis expansion model (BEM). We show that the MCI and ICI can be completely eliminated by the proposed method to get the ICI-free pilots at each receive antenna. In addition, for the considered multi-cell HST system, we develop a low-complexity compressed channel estimation method and consider the optimal pilot pattern design. Both the proposed interference elimination method and the optimal pilot pattern are robust to the train speed and position, as well as the multi-cell multi-antenna system. Simulation results demonstrate the benefits and robustness of the proposed method in the multi-cell HST system.Index Terms-High speed train (HST), compressed sensing (CS), orthogonal frequency-division multiplexing (OFDM), multicell interference (MCI), inter-carrier interference (ICI).

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Energy-Efficient Small Cell With Spectrum-Power Trading

Cited by 36 publications

References 45 publications

Joint Trajectory and Communication Design for Multi-UAV Enabled Wireless Networks

Joint Trajectory and Communication Design for Multi-UAV Enabled Wireless Networks

Intelligent Reflecting Surface Enhanced Wireless Network: Joint Active and Passive Beamforming Design

Position-Based Interference Elimination for High-Mobility OFDM Channel Estimation in Multicell Systems

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