An efficient method for enhancing TDD over the air reciprocity calibration

Shi, Jing; Luo, Qinglin; You, Mingli

doi:10.1109/wcnc.2011.5779154

Cited by 65 publications

(39 citation statements)

References 4 publications

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“…Channel reciprocity means that the uplink and downlink share the same frequency band in TDD systems and that the receive weight created by the uplink channel can be utilized for the transmit weight [30]. In order to realize IBF, a calibration technique for the transmitters and receivers is essential [22][23][24].…”

Section: Ibfmentioning

confidence: 99%

“…However, it is necessary to calibrate the amplitude and phase errors between the branches of the array, because of individual differences in the radio frequency (RF) devices of the receivers and transmitters [18,19]. Thus, various automatic calibration methods for adaptive BS antennas that are well suited to TDD communication systems have been proposed in previous studies [20,21].We note that some of these methods allow the transmitter and receiver calibration values to be obtained automatically [20][21][22][23][24]. In recent research, the calibration method for massive antennas utilizing the channel reciprocity in a TDD system is proposed [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

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Effectiveness of Implicit Beamforming with Large Number of Antennas Using Calibration Technique in Multi-User MIMO System

et al. 2017

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This paper examines the effectiveness of implicit beamforming (IBF), which enables transmission without channel state information (CSI) feedback in multi-user multiple-input multiple-output (MU-MIMO) systems with a large number of antennas. First, we explain why CSI feedback from terminal stations to the base station produces a very large overhead. A calibration technique is then introduced, which compensates for the difference between the complex amplitudes of the transmitters and receivers to facilitate CSI-feedback-free beamforming; this technique is called IBF. The efficacy of this calibration technique is demonstrated by measuring the amplitude and phase errors obtained using a 16-element array testbed and by performing a channel capacity evaluation. Finally, the throughput under IEEE802.11ac-based massive MIMO transmission, both with and without CSI feedback, is obtained in terms of the medium access control efficiency.

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Section: Ibfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effectiveness of Implicit Beamforming with Large Number of Antennas Using Calibration Technique in Multi-User MIMO System

et al. 2017

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“…However, in order to achieve full channel reciprocity, one must compensate for random phase and amplitude differences in the transceiver radio frequency (RF) chains [12]. In general, this can be established by either internal self-calibration [13] or external calibration mechanisms [33]. A recent non-commercial testbed developed using off-the-shelf hardware has shown that this is generally possible, even for very large antenna arrays [32].…”

Section: Channel Reciprocitymentioning

confidence: 99%

Making smart use of excess antennas: Massive MIMO, small cells, and TDD

Hoydis¹,

Hosseini²,

Brink³

et al. 2013

Bell Labs Tech. J.

180

130

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“…Channel reciprocity means that the uplink and downlink share the same frequency band in time division duplex (TDD) systems, and the receive weight created by the uplink channel can be utilized for the transmit weight [85]. A calibration technique is essential among the transmitters and receivers for realizing implicit beamforming [86]- [91]. Figure 12 shows the frame format of MU-MIMO without CSI feedback.…”

Section: Implicit Beamformingmentioning

confidence: 99%

Survey of Transmission Methods and Efficiency Using MIMO Technologies for Wireless LAN Systems

Hiraguri

Nishimori

2015

IEICE Trans. Commun.

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SUMMARY Multiple-input multiple-output (MIMO) transmission is attracting interest for increasing the transmission rates of wireless systems. This paper surveys MIMO transmission technology from the viewpoints of transmission methods, access control schemes, and total transmission efficiency. We consider wireless local area networks (WLAN) systems that use MIMO technology; moreover, we focus on multiuser MIMO (MU-MIMO) technology, which will be introduced in next-generation WLAN systems such as IEEE802.11ac. This paper explains the differences in the detailed access control procedures for MIMO and MU-MIMO transmission, including channel state information (CSI) acquisition. Furthermore, the issues related to CSI feedback and solutions are also discussed. Related works on the medium access control (MAC) protocol in MIMO/MU-MIMO transmission are introduced. In addition, the throughput performance using MIMO/MU-MIMO transmission is evaluated considering an IEEE802.11ac-based WLAN system. From the numerical evaluation, it is shown that the overhead due to CSI feedback from the user terminals to the base station causes a decrease in the throughput. We verified that implicit beamforming, which eliminates CSI feedback, is effective for solving this issue. , and commercial products based on these standards will appear in the near future. Moreover, the standardization of next-generation wireless LAN (WLAN) aims to achieve further high performance and high efficiency by using MU-MIMO transmission technology, and a task group for that standard called IEEE802.11ax [22] [32]. However, the transmission rate achieved by SU-MIMO/MU-MIMO transmission is not currently adequately utilized because the overhead of the access control protocol in the medium access control (MAC) layer decreases the transmission efficiency, even though the physical transmission rate has been increased in the PHY layer by the adoption of SU-MIMO/MU-MIMO technology. Therefore, the MAC-service access point (MAC-SAP) throughput including the protocol in the MAC layer decreases greatly creases in multilevel modulation and the number of subcarriers in WLAN systems. The decrease in the transmission efficiency is a significant issue because the ratio of the overhead of the MAC protocol is larger for MU-MIMO transmission. Although there are above issues, the frequency utilization and channel capacity have been evaluated in only PHY-layer.Further, the throughput and delay characteristics in relation to the access control scheme have been evaluated in the MAC layer. Therefore, these studies have been individually evaluated. No adequate evaluation of the throughput and transmission efficiency considering both the PHY and MAC layers has not been published.This paper surveys conventional SU-MIMO/MU-MIMO transmission technology from the viewpoints of both wireless communication systems and transmission efficiency, and the most popular WLAN systems that use SU-MIMO/MU-MIMO technology are chiefly discussed. Moreover, we survey the MU-MIMO technology used in next-generatio...

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An efficient method for enhancing TDD over the air reciprocity calibration

Cited by 65 publications

References 4 publications

Effectiveness of Implicit Beamforming with Large Number of Antennas Using Calibration Technique in Multi-User MIMO System

Effectiveness of Implicit Beamforming with Large Number of Antennas Using Calibration Technique in Multi-User MIMO System

Making smart use of excess antennas: Massive MIMO, small cells, and TDD

Survey of Transmission Methods and Efficiency Using MIMO Technologies for Wireless LAN Systems

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