Design and experimental evaluation of multi-user beamforming in wireless LANs

Aryafar, Ehsan; Anand, Narendra; Salonidis, Theodoros; Knightly, Edward W.

doi:10.1145/1859995.1860019

Cited by 142 publications

(92 citation statements)

References 14 publications

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“…RELATED WORK There are a few nice experimental work that are closely related to ours. For example, [1] allows a single AP with multiple antennas to send to multiple clients and [11] allows a single AP with multiple antennas to receive data from different clients. [8] and [2] focus on achieving distributed MIMO at the physical layer.…”

Section: Discussionmentioning

confidence: 99%

“…[8] and [2] focus on achieving distributed MIMO at the physical layer. Different from [1] and [11], we take a significant step further by allowing different APs to communicate with different clients at the same time, thereby further increasing multiplexing gain. Different from [8] and [2], we go beyond the PHY-layer design by exploring a range of important MAC layer design issues in distributed MIMO.…”

Section: Discussionmentioning

confidence: 99%

“…For example, using our approach, three 8-antenna APs can support up to 24 concurrent streams instead of limiting to 8 streams as in 802.11ac. Moreover, we go beyond the previous works (e.g., [1], [11], [8], [2]), which all focus on the physical layer, by developing multi-point to multi-point MIMO-aware MAC.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multi-point to multi-point MIMO in wireless LANs

Yun

Qiu

Bhartia

2013

2013 Proceedings IEEE INFOCOM

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Abstract-Distributed multiple-input multiple-output (MIMO) promises a dramatic capacity increase. While significant theoretical work has been done on distributed MIMO at the physical layer, how to translate the physical layer innovation into tangible benefits to real networks remains open. In particular, realizing multi-point to multi-point MIMO involves the following challenges: (i) how to accurately synchronize multiple APs in phase and time in order to successfully deliver precoded signals to the clients, and (ii) how to develop a MAC protocol to effectively support multi-point to multi-point MIMO. In this paper, we develop a practical approach to address the above challenges. We implement multi-point to multi-point MIMO for both uplink and downlink to enable multiple APs to simultaneously communicate with multiple clients. We examine a number of important MAC design issues, such as how to access the medium, perform rate adaptation, support acknowledgments in unicast traffic, deal with losses/collisions, and schedule transmissions. We demonstrate its feasibility and effectiveness through a prototype implementation on USRP and SORA, two of the most well-known software defined radio platforms.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Multi-point to multi-point MIMO in wireless LANs

Yun

Qiu

Bhartia

2013

2013 Proceedings IEEE INFOCOM

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“…The closest to ours is prior work on MIMO systems which enables multiple transmitters to transmit concurrently without interference. This includes schemes like SAM [35], Interference Alignment and Cancellation [21], and beamforming systems [16]. Unlike these schemes, however, TIMO delivers a MIMO system that enables cooperation with multiple different wireless technologies.…”

Section: Related Workmentioning

confidence: 99%

Clearing the RF smog

Gollakota

Adib

Katabi

et al. 2011

Proceedings of the ACM SIGCOMM 2011 Conference

130

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Recent studies show that high-power cross-technology interference is becoming a major problem in today's 802.11 networks. Devices like baby monitors and cordless phones can cause a wireless LAN to lose connectivity. The existing approach for dealing with such high-power interferers makes the 802.11 network switch to a different channel; yet the ISM band is becoming increasingly crowded with diverse technologies, and hence many 802.11 access points may not find an interference-free channel.This paper presents TIMO, a MIMO design that enables 802.11n to communicate in the presence of high-power cross-technology interference. Unlike existing MIMO designs, however, which require all concurrent transmissions to belong to the same technology, TIMO can exploit MIMO capabilities to decode in the presence of a signal from a different technology, hence enabling diverse technologies to share the same frequency band. We implement a prototype of TIMO in GNURadio-USRP2 and show that it enables 802.11n to communicate in the presence of interference from baby monitors, cordless phones, and microwave ovens, transforming scenarios with a complete loss of connectivity to operational networks.

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“…The literature reports a number of SDR test-beds, designed to test network-level protocols. Popular among them are the Wireless Open Access Research Platform (WARP) [10,11] developed at Rice University and the Microsoft Research Software Radio (MS-SORA) [12]. Hydra [13], developed at the University of Texas at Austin, is a SDR testbed comprising radio software by GNU (recursive acronym for "GNU's Not Unix") and universal software radio peripheral (USRP) by Ettus Research™ [14].…”

Section: Introductionmentioning

confidence: 99%

A unified message-passing algorithm for MIMO-SDMA in software-defined radio

Kocian

Badiu

Fleury

et al. 2017

J Wireless Com Network

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This paper presents a novel software radio implementation for joint channel estimation, data decoding, and noise variance estimation in multiple-input multiple-output (MIMO) space division multiple access (SDMA). In contrast to many other iterative solutions, the proposed receiver is derived within the theoretical framework of a unified message-passing algorithm, combining belief propagation (BP) and the mean field approximation (MF) on the corresponding factor graph. The algorithm minimizes the region-based variational free energy in the system under appropriate conditions and, hence, converges to a fixpoint. As a use-case, we consider the high-rate packet-oriented IEEE 802.11n standard. Our receiver is implemented on a software-defined radio platform dubbed MIMONet, composed of a GNU radio software component and a universal software radio peripheral (USRP). The receiver was evaluated in real indoor environments. The results of our study clearly show that, once synchronization issues are properly addressed, the BP-MF receiver provides a substantial performance improvement compared to a conventional receiver also in real-world settings. Such improvement comes at the expense of an increase in running time that can be as high as 87. Therefore, the trade-off between communication performance and receiver complexity should be carefully evaluated in practical settings.

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Design and experimental evaluation of multi-user beamforming in wireless LANs

Cited by 142 publications

References 14 publications

Multi-point to multi-point MIMO in wireless LANs

Multi-point to multi-point MIMO in wireless LANs

Clearing the RF smog

A unified message-passing algorithm for MIMO-SDMA in software-defined radio

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