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Optimizing client association in 60 GHz wireless access networks,” arXiv:1301.2723, 2013, available: http://arxiv.org/abs/1301.2723
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Demystifying 60GHz Outdoor Picocells
"... Mobile network traffic is set to explode in our near future, driven by the growth of bandwidth-hungry media applications. Current capacity solutions, including buying spectrum, WiFi offloading, and LTE picocells, are unlikely to supply the orders-of-magnitude bandwidth increase we need. In this pape ..."
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Mobile network traffic is set to explode in our near future, driven by the growth of bandwidth-hungry media applications. Current capacity solutions, including buying spectrum, WiFi offloading, and LTE picocells, are unlikely to supply the orders-of-magnitude bandwidth increase we need. In this paper, we explore a dramati-cally different alternative in the form of 60GHz mmwave picocells with highly directional links. While industry is investigating other mmwave bands (e.g. 28GHz to avoid oxygen absorption), we pre-fer the unlicensed 60GHz band with highly directional, short-range links (∼100m). 60GHz links truly reap the spatial reuse benefits of small cells while delivering high per-user data rates and leverag-ing efforts on indoor 60GHz PHY technology and standards. Using extensive measurements on off-the-shelf 60GHz radios and system-level simulations, we explore the feasibility of 60GHz picocells by characterizing range, attenuation due to reflections, sensitivity to movement and blockage, and interference in typical urban environ-ments. Our results dispel some common myths, and show that there are no fundamental physical barriers to high-capacity 60GHz out-door picocells. We conclude by identifying open challenges and associated research opportunities.
60 GHz Indoor Networking through Flexible Beams: A Link-Level Profiling
"... 60 GHz technology holds tremendous potential to upgrade wireless link throughput to Gbps level. To overcome in-herent vulnerability to attenuation, 60 GHz radios commu-nicate by forming highly-directional electronically-steerable beams. Standards like IEEE 802.11ad have tailored MAC/PHY protocols to ..."
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60 GHz technology holds tremendous potential to upgrade wireless link throughput to Gbps level. To overcome in-herent vulnerability to attenuation, 60 GHz radios commu-nicate by forming highly-directional electronically-steerable beams. Standards like IEEE 802.11ad have tailored MAC/PHY protocols to such flexible-beam 60 GHz networks. However, lack of a reconfigurable platform has thwarted a realistic proof-of-concept evaluation. In this paper, we conduct an in-depth measurement of indoor 60 GHz networks using a first-of-its-kind software-radio platform. Our measurement focuses on the link-level behavior with three major perspec-tives: (i) coverage and bit-rate of a single link, and im-plications for 60 GHz MIMO; (ii) impact of beam-steering on network performance, particularly under human block-age and device mobility; (iii) spatial reuse between flexible beams. Our study dispels some common myths, and reveals key challenges in maintaining robust flexible-beam connec-tion. We propose new principles that can tackle such chal-lenges based on unique properties of 60 GHz channel and cognitive capability of 60 GHz links.
DFT based spatial multiplexing and maximum ratio transmission for mm-wave large MIMO
"... Abstract-By using large point-to-point multiple input multiple output (MIMO), spatial multiplexing of a large number of data streams in wireless communications using millimeter-waves (mmwaves) can be achieved. However, according to the antenna spacing and transmitter-receiver distance, the MIMO cha ..."
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Abstract-By using large point-to-point multiple input multiple output (MIMO), spatial multiplexing of a large number of data streams in wireless communications using millimeter-waves (mmwaves) can be achieved. However, according to the antenna spacing and transmitter-receiver distance, the MIMO channel is likely to be ill-conditioned. In such conditions, highly complex schemes such as the singular value decomposition (SVD) are necessary. In this paper, we propose a new low complexity system called discrete Fourier transform based spatial multiplexing (DFT-SM) with maximum ratio transmission (DFT-SM-MRT). When the DFT-SM scheme alone is used, the data streams are either mapped onto different angles of departures in the case of aligned linear arrays, or mapped onto different orbital angular momentums in the case of aligned circular arrays. Maximum ratio transmission pre-equalizes the channel and compensates for arrays misalignments. Simulation results show that, although the DFT-SM-MRT scheme has a much lower complexity than the SVD scheme, it still achieves large spectral efficiencies and is robust to misalignment and reflection.
Energy-Efficiency and Spectrum-Efficiency Tradeoff in Coordinated Small-Cell Networks
"... Abstract—Small-cell networks play an important role in next generation mobile networks. Multiple antennas can be employed at the small-cell base stations (SBS) to further improve the spectrum-efficiency. However, the increased number of antenna elements induces more energy consumption, i.e., there e ..."
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Abstract—Small-cell networks play an important role in next generation mobile networks. Multiple antennas can be employed at the small-cell base stations (SBS) to further improve the spectrum-efficiency. However, the increased number of antenna elements induces more energy consumption, i.e., there exists a tradeoff between the energy-efficiency and the spectrum-efficiency. In this paper, the network performance is analyzed which takes the coordinated scheduling into account. The co-ordination relationship among neighboring SBSs is modeled by a coordination graph. The coordinated scheduling is achieved by finding the maximum independent set of the graph. By deriving the average size of the maximum independent set, the network throughput is obtained. Simulation results validate the derivation. Then, the tradeoff between the energy-efficiency and the spectrum-efficiency is analyzed. It is found that the single-antenna SBSs are not energy-efficiency as the density of SBSs increases. Index Terms—Energy efficiency, spectrum efficiency, small cell, inter-cell coordination, random graph I.
Shine: A Step Towards Distributed Multi-Hop Visible Light Communication
"... Abstract—Visible light communication (VLC), a novel tech-nology that enables standard Light-Emitting-Diodes (LEDs) to transmit data, is gaining significant attention. In the near future, this technology could enable devices containing LEDs –such as car lights, city lights, screens and home appliance ..."
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Abstract—Visible light communication (VLC), a novel tech-nology that enables standard Light-Emitting-Diodes (LEDs) to transmit data, is gaining significant attention. In the near future, this technology could enable devices containing LEDs –such as car lights, city lights, screens and home appliances – to form their own networks. VLC, however, is currently limited to point-to-point communication. To unleash VLC’s full potential, we need to provide it with more sophisticated networking capabilities. In this paper, we present the design and implementation of a novel platform aimed at distributed multi-hop visible light communication. Compared to the state-of-the-art, our platform provides similar data rates and coverage, but adds two unique characteristics: (i) 360 ◦ coverage, which is necessary to investigate an important property of LED communication: directionality, and (ii) a flexible design, which allows our platform to be connected to many experimental boards such as Arduino, Beaglebone, Raspberry Pi and sensor nodes. To quantify the communication capabilities of our board, we evaluate three key components: link quality, neighbor discovery and packet forwarding. Overall, we hope that our work will lower the entry barrier for members of the pervasive and networking communities to investigate and exploit future LED-based networks. I.
Interference Statistics in Random mmWave Ad Hoc Networks 3
, 2015
"... Why millimeter wave wireless networks? u Huge amount of spectrum possibly available in mmWave bands u Technology advances make mmWave possible for cheap consumer devices u Applicable for WLAN, cellular, device-to-device, and ad hoc networks ..."
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Why millimeter wave wireless networks? u Huge amount of spectrum possibly available in mmWave bands u Technology advances make mmWave possible for cheap consumer devices u Applicable for WLAN, cellular, device-to-device, and ad hoc networks
Auction-based Resource Allocation in MillimeterWave Wireless Access Networks
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1Tractable Model for Rate in Self-Backhauled Millimeter Wave Cellular Networks
"... Abstract—Millimeter wave (mmW) cellular systems will re-quire high gain directional antennas and dense base station (BS) deployments to overcome high near field path loss and poor diffraction. As a desirable side effect, high gain antennas provide interference isolation, providing an opportunity to ..."
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Abstract—Millimeter wave (mmW) cellular systems will re-quire high gain directional antennas and dense base station (BS) deployments to overcome high near field path loss and poor diffraction. As a desirable side effect, high gain antennas provide interference isolation, providing an opportunity to in-corporate self-backhauling–BSs backhauling among themselves in a mesh architecture without significant loss in throughput–to enable the requisite large BS densities. The use of directional antennas and resource sharing between access and backhaul links leads to coverage and rate trends that differ significantly from conventional microwave (µW) cellular systems. In this paper, we propose a general and tractable mmW cellular model capturing these key trends and characterize the associated rate distribution. The developed model and analysis is validated using actual building locations from dense urban settings and empirically-derived path loss models. The analysis shows that in sharp contrast to the interference limited nature of µW cellular networks, the spectral efficiency of mmW networks (besides total rate) also increases with BS density particularly at the cell edge. Increasing the system bandwidth, although boosting median and peak rates, does not significantly influence the cell edge rate. With self-backhauling, different combinations of the wired backhaul fraction (i.e. the faction of BSs with a wired connection) and BS density are shown to guarantee the same median rate (QoS). I.
Distributed Association Control and Relaying in MillimeterWave Wireless Access Networks
"... Abstract—In millimeterWave wireless networks the rapidly varying wireless channels demand fast and dynamic resource allocation mechanisms. This challenge is hereby addressed by a distributed approach that optimally solves the fundamental resource allocation problem of joint client association and re ..."
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Abstract—In millimeterWave wireless networks the rapidly varying wireless channels demand fast and dynamic resource allocation mechanisms. This challenge is hereby addressed by a distributed approach that optimally solves the fundamental resource allocation problem of joint client association and relay-ing. The problem is posed as a multi-assignment optimization, for which a novel solution method is established by a series of transformations that lead to a tractable minimum cost flow prob-lem. The method allows to design distributed auction solution algorithms where the clients and relays act asynchronously. The computational complexity of the new algorithms is much better than centralized general-purpose solvers. It is shown that the algorithms always converge to a solution that maximizes the total network throughput within a desired bound. Both theoretical and numerical results evince numerous useful properties in compar-ison to standard approaches and the potential applications to forthcoming millimeterWave wireless access networks. I.
