Channel estimation and analog beam selection for uplink multiuser hybrid beamforming system

Ko, Young Chai; Kim, Do Young

doi:10.1186/s13638-016-0618-0

Cited by 9 publications

(11 citation statements)

References 16 publications

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“…Considering a multiuser hybrid system, a minimum mean-square error (MMSE) based CE was conducted in [8]. Joint least-squares based CE [9] and analog beam selection was proposed in [10] for the uplink (UL) multiuser hybrid beamforming system. More recently, a new CE approach for the hybrid architecture-based millimeter wave systems was proposed in [11].…”

Section: A State-of-the-artmentioning

confidence: 99%

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Efficacy of Hybrid Energy Beamforming With Phase Shifter Impairments and Channel Estimation Errors

Mishra

Johansson

2019

IEEE Signal Process. Lett.

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The self-archived postprint version of this journal article is available at Linköping University Institutional Repository (DiVA): http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-153499 N.B.: When citing this work, cite the original publication.Abstract-Hybrid energy beamforming (HEB) can reduce the hardware cost, energy consumption, and space constraints associated with massive antenna array transmitter (TX). With a single radio frequency (RF) chain having N digitally controlled phase shifter pairs, one per antenna element, theoretically achieving the same performance as a fully digital beamforming architecture with N RF chains, this letter investigates the practical efficacy of the HEB. First adopting the proposed analog phase shifter impairments model and exploiting the channel reciprocity along with the available statistical information, we present a novel approach to obtain an accurate minimum mean-square error estimate for the wireless channel between TX and energy receiver (RX). Then, tight analytical approximation for the global optimal time allocation between uplink channel estimation and downlink energy transfer operations is derived to maximize the mean net harvested energy at RX. Numerical results, validating the analysis and presenting key design insights, show that with an average improvement of 58% over the benchmark scheme, the optimized HEB can help in practically realizing the fully digital array gains.

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Section: A State-of-the-artmentioning

confidence: 99%

“…where (r1) is obtained on applying no API assumption to covariance definitions [23], and σ 2 w denotes AWGN variance. Using (10), MMSE estimate h A for effective channel h A is:…”

Section: B Mmse Digital Channel Estimatormentioning

confidence: 99%

Efficacy of Hybrid Energy Beamforming With Phase Shifter Impairments and Channel Estimation Errors

Mishra

Johansson

2019

IEEE Signal Process. Lett.

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“…Considering the multiuser hybrid beamforming system, a minimum mean-square error (MMSE) approach was developed in [5] to estimate the effective channel. Joint least-squares (LS) based CE and analog beam selection algorithm was proposed in [10] for an uplink (UL) multiuser hybrid beamforming system. In contrast to these narrow band systems facing flat fading, CE algorithms for a single user multi-carrier hybrid MIMO system was investigated in [6] using both LS and CS approaches.…”

Section: A State-of-the-artmentioning

confidence: 99%

“…Here, p d is the transmit power of S during DL RFET and h A is the LSE for the channel h as defined in (10). However, under API, the analog precoder z A gets practically altered to z A…”

Section: Optimal Precoder Designmentioning

confidence: 99%

Optimal Channel Estimation for Hybrid Energy Beamforming Under Phase Shifter Impairments

Mishra

Johansson

2019

IEEE Trans. Commun.

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Smart multiantenna wireless power transmission can enable perpetual operation of energy harvesting (EH) nodes in the internet-of-things. Moreover, to overcome the increased hardware cost and space constraints associated with having large antenna arrays at the radio frequency (RF) energy source, the hybrid energy beamforming (EBF) architecture with single RF chain can be adopted. Using the recently proposed hybrid EBF architecture modeling the practical analog phase shifter impairments (API), we derive the optimal least-squares estimator for the energy source to EH user channel. Next, the average harvested power at the user is derived while considering the nonlinear RF EH model and a tight analytical approximation for it is also presented by exploring the practical limits on the API. Using these developments, the jointly global optimal transmit power and time allocation for channel estimation (CE) and EBF phases, that maximizes the average energy stored at the EH user is derived in closed form. Numerical results validate the proposed analysis and present nontrivial design insights on the impact of API and CE errors on the achievable EBF performance. It is shown that the optimized hybrid EBF protocol with joint resource allocation yields an average performance improvement of 37% over benchmark fixed allocation scheme.

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“…This puts a bottleneck on the network capacity as well as the simultaneously supported number of users especially if the deployment inter-site distance (ISD) is further decreased. As a response to this problem the introduction of a multi-antenna processing system on the PHY-Layer is of high interest in the recent literature [3], [4], [5], [6], [7], [8].…”

Section: Introductionmentioning

confidence: 99%

Constant modulus hybrid beamforming for multi-user systems in the presence of blockers

Bekkar¹,

Miscopein²,

Bories³

et al. 2018

2018 25th International Conference on Telecommunications (ICT)

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Hybrid beamforming (HBF) solutions, involving both analog and digital stages, are considered as key enablers for next generation of small cell networks wireless communications. They provide interference rejection and spatial multiplexing features for the base stations with fewer radio frequency (RF) chains and analog-to-digital converters (ADCs) compared to the optimal full digital beamforming. However jointly designing the digital beamforming matrix and the analog beamforming matrix with constant modulus entries makes the optimal signal-to-interferenceplus-noise ratio (SINR) solution complex to find. In this paper we propose a simple solution and investigate its SINR loss as a function of angle of arrivals of blockers. The solution consists of setting the analog weights phases equal to those of a full digital beamformer and keeping the modulus of the weights constant, while the complementary digital part is designed with respect to the effective channel matrix. This algorithm is applied over different full digital algorithms, in a medium signal-to-noise ratio (SNR) and high blocker levels. We show that despite that the analog stage introduces losses, the digital stage is still able to compensate them almost to the performance of the optimal full digital beamforming, and so with minor difference between algorithms used in analog stage.

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Channel estimation and analog beam selection for uplink multiuser hybrid beamforming system

Cited by 9 publications

References 16 publications

Efficacy of Hybrid Energy Beamforming With Phase Shifter Impairments and Channel Estimation Errors

Efficacy of Hybrid Energy Beamforming With Phase Shifter Impairments and Channel Estimation Errors

Optimal Channel Estimation for Hybrid Energy Beamforming Under Phase Shifter Impairments

Constant modulus hybrid beamforming for multi-user systems in the presence of blockers

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