Optimal Energy-Efficient Transmit Beamforming for Multi-User MISO Downlink

Tervo, Oskari; Tran, Le-Nam; Juntti, Markku

doi:10.1109/tsp.2015.2453134

Cited by 144 publications

(191 citation statements)

References 39 publications

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“…We can see that compared to the conventional design, where the efficiency is assumed to be fixed [9], PA consumption of each antenna scales with ||ŵi||2 instead of ||ŵi|| 2 2 . This suggests that for small transmit powers, the total power consumption is larger than in the conventional design, since the PA efficiency is poor.…”

Section: Energy Efficiency Maximizationmentioning

confidence: 97%

“…Bearing this in mind, recent research has been focusing on the energy-efficient transmission [2][3][4][5][6][7][8][9]. Employing more antennas requires extra circuitry, having a significant impact on the complexity and the processing power consumption.…”

Section: Introductionmentioning

confidence: 99%

“…This is different and more practical system compared to the conventional joint beamforming and antenna selection problem considered in [9] where each antenna is individually connected with an RF chain (using a switch). In addition, here we consider non-linear PA efficiency whereas the linear case has been assumed in the prior works.…”

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confidence: 99%

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Energy-efficient joint transmit beamforming and subarray selection with non-linear power amplifier efficiency

Tervo

Tran

Juntti

2016

2016 IEEE Global Conference on Signal and Information Processing (GlobalSIP)

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Another important fact arising from the use of large numbers of antennas is the limited numbers of RF chains, i.e., the latter may be smaller than the former. This means that the beamforming gain and the number of parallel streams becomes limited. However, huge numbers of antenna elements can be installed in the transmitter in particular at higher center frequencies, like mm-waves [11]. The same has also been proposed for more conventional microwave frequencies below 10 GHz [11]. One option to benefit from the large number of antenna elements with a smaller number of transceiver processing chains to achieve array gain is to divide the antennas into subarrays each of which is connected to an RF chain. In general, the number of RF chains may be smaller than that of subarrays. This kind of system model is called hybrid beamforming [12] which becomes very relevant in mm-wave systems. In addition to enable hybrid beamforming, the model results in smaller power variations between antennas, which means that the non-linear effects of the power amplifiers become less significant. Such antenna grouping could be used even in the case with conventional antenna selection problem, where we could group the antennas and select the sub-groups just to simplify the antenna selection problem.In this paper, we consider the energy efficiency with joint beamforming and subarray selection (JBSAS) and non-linear efficiency of PA in multiuser multiple-input single-output (MISO) system. This is different and more practical system compared to the conventional joint beamforming and antenna selection problem considered in [9] where each antenna is individually connected with an RF chain (using a switch). In addition, here we consider non-linear PA efficiency whereas the linear case has been assumed in the prior works. To tackle the resulting challenging mixed-Boolean non-convex optimization problem, we rely on continuous relaxation and successive convex approximation framework where a convex problem is solved in each iteration. Numerical results demonstrate the achieved energy efficiency gains of the subarray selection and shows that non-linear PA efficiency has a significant impact on the optimization. We also observe that on contrast to using linear PA efficiency model, the nonlinear PA efficiency model yields the fact that it is better to stay silent rather than transmit with very low transmit power.Notations: X T is transpose of X; |x| represents the absolute value of x and x 2 is 2-norm of x; Im(X) means the imaginary part of X. PROBLEM FORMULATION System ModelWe consider a single-cell MISO downlink channel, where a base station with N antenna elements transmits data to K single-antenna ABSTRACTWe study the problem of energy efficiency maximization (EEmax) with joint beamforming and subarray selection, by taking into account the non-linear power amplifier (PA) efficiency in a multi-user multiple-input single-output system. The subarray selection problem is formulated using the concept of perspective formulation with additional penalty t...

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Section: Energy Efficiency Maximizationmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Energy-efficient joint transmit beamforming and subarray selection with non-linear power amplifier efficiency

Tervo

Tran

Juntti

2016

2016 IEEE Global Conference on Signal and Information Processing (GlobalSIP)

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“…In our work [38], we use a novel group sparsity of weighted 1 -norm corresponding to switching-off SBSs and associated users for joint linear precoder design in EE maximization problem. The Dinkelbachtype algorithms [13] of fractional programming is used as the main approach for obtaining computational solutions of EE maximization [17,52,55]. From the considered HetNet scenario in [39], we propose a novel computational algorithm for maximizing EE via a convex quadratic program at each iteration under threeobjective (EE, QoS and BS service loading) optimization.…”

Section: Energy Efficiency In Small Cell With User Associationmentioning

confidence: 99%

Resource Allocation for Energy Efficiency in 5G Wireless Networks

Nguyen¹

2018

EAI Endorsed Transactions on Industrial Networks and Intelligen

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Resource allocation is one important mission in wireless communication systems. In 5G wireless networks, it is essential that the new systems be more dynamic and wiser to simultaneously satisfy various network demands, by using new wireless technologies and approaches. To this end, resource allocation is faced with many significant challenges such as interference alignment, security attacks, or green communication. On the other hand, as one serious problem in 5G networks, the issue of energy is affected directly by the allocated resources in the system, i.e., bandwidth allocation, power control, association allocation, and deployment strategies. Consequently, together with the enhancement of spectral efficiency performance, an emerging trend of 5G wireless networks is to approach green communication via energy efficiency (EE) (bits/Hz/Joule), whose most significant challenge is due to its belonging to the fractional programming in the optimization field, i.e., nonconvex programming. This leaves many difficult tasks for improving network EE performance. In this paper, we will tackle the critical EE in 5G wireless networks.

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“…Designing an energy efficient BS is particularly difficult, because the amount of signal transmissions is drastically increases day by day. Large-scale antenna systems (LSASs) that use a large number of transmitter (TX) antennas and serve a limited number of users, have a high possibility to increase the EE of the BS, and this has already been shown in several parts of the existing literature [6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Energy Efficiency Gain of Cellular Base Stations with Large-Scale Antenna Systems for Green Information and Communication Technology

Lee

2017

Sustainability

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Due to the ever-increasing data demand of end users, the number of information and communication technology (ICT)-related devices and equipment continues to increase. This induces large amounts of heat emissions, which can cause serious environmental pollution. In recent times, signal transmission systems such as cellular base stations (BSs) have been constructed everywhere and these emit a large carbon footprint. Large-scale antenna systems (LSASs) that use a large amount of transmission antennas to serve a limited number of users can increase energy efficiency (EE) of BSs based on the beamforming effect, and thus can be a promising candidate to reduce the carbon footprint of the ICT field. In this paper, we discuss the necessary schemes to realize LSASs and show the expected EE gain of the LSAS with enough practicality. There are many obstacles to realize the high EE LSAS, and even though several studies have shown separate schemes to increase the EE and/or throughput (TP) of LSASs, few have shown combinations of schemes, and presented how much EE gain can be achieved by the schemes in the overall system. Based on the analysis in this paper, we believe more detailed work for the realization of high energy efficient BSs with LSASs is possible because this paper shows the necessary schemes and the maximum achievable energy efficiency gain as a reference. Extensive analysis and simulation results show that with proper implementation of the power amplifier/RF module and a robust channel estimation scheme, LSASs with 600 transmitter (TX) antennas can achieve 99.4 times more EE gain compared to the current systems, thereby resulting in significant reduction of carbon footprints.

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Optimal Energy-Efficient Transmit Beamforming for Multi-User MISO Downlink

Cited by 144 publications

References 39 publications

Energy-efficient joint transmit beamforming and subarray selection with non-linear power amplifier efficiency

Energy-efficient joint transmit beamforming and subarray selection with non-linear power amplifier efficiency

Resource Allocation for Energy Efficiency in 5G Wireless Networks

Energy Efficiency Gain of Cellular Base Stations with Large-Scale Antenna Systems for Green Information and Communication Technology

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