Test Environmental Research Collection

Permanent URI for this collection

https://hdl.handle.net/1911/118256
This is a test collection created as part of a Fondren Fellows project (2024-2025). This collection is intended to serve as a proof of concept for a permanent collection that showcases environmental research conducted by Rice researchers. All items currently in this collection have been mapped from other collections in R-3.

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Browsing Test Environmental Research Collection by Subject "60 GHz"

Now showing 1 - 3 of 3
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    Enhanced WLAN Performance with New Spectrum at 60 GHz and Visible Light
    (2018-03-01) Naribole, Sharan; Knightly, Edward W.
    To enhance the WLAN operation at sub-6 GHz, research has been directed towards utilizing new spectral bands including millimeter waves (60 GHz) and visible light spectrum. The 7-14 GHz unlicensed band at 60 GHz can enable multi-gigabit rate applications including live HD video streaming, virtual reality, etc. Visible light communication (VLC) is a key emerging energy-efficient communication technology that dual purposes LED-based lighting infrastructure for both illumination and communication. Although both these bands have the potential to enhance WLAN performance, each of them possesses unique physical properties that hinder some existing services readily available in sub-6 GHz bands. First, the strong directionality required at 60 GHz precludes serving all clients in a multicast group with a single transmission and instead is comprised of a sequence of beam-formed transmissions that together cover all multicast group members. I design, implement, and experimentally evaluate scalable directional multicast (SDM) as a technique to address the challenges imposed by directional communication for a scalable multicast service at 60 GHz. Second, the wide coverage and relatively high transmit power realized by the VLC downlink to satisfy the illumination objective is problematic to realize on the uplink. I design, analyze, and implement LiRa, a Light-Radio WLAN that fuses light and radio capabilities in an integrated system design without requiring mobile devices to emit light or infrared. I design an uplink control channel for LiRa that is Wi-Fi compliant, has a controllable impact on airtime taken from legacy Wi-Fi clients, and efficiently scales with increasing VLC user population. Third, contention-based uplink radio access might lead to significant degradation in airtime efficiency and energy efficiency as the time spent “awake” by the radio is dependent on the network traffic conditions. I design and evaluate LiSCAN, a VLC uni-directional control channel that enables virtual full-duplex contention-free operation of uplink radio access. My analysis shows that LiSCAN can provide significant improvements in the radio airtime efficiency, the sessions delivered with pre-defined service quality requirements and energy savings.
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    Geometric Beam Steering via Passive Light Sensing for mmWave WLANs
    (2018-11-30) Haider, Muhammad Kumail; Knightly, Edward W.
    GHz-scale bandwidth in the mmWave spectrum (30 GHz to 300 GHz and beyond) realizes data rates of up to 100 Gb/sec with highly directional links, which can satiate the ever increasing demand for high speed wireless connectivity. However, a key challenge is that end nodes need to continually align their beams to maintain directional links, which incurs significant beam search overhead. This overhead can limit the performance of mmWave networks under nodal or environmental mobility. In this thesis, I present the design, implementation and evaluation of two novel mmWave beam adaptation solutions for achieving out of band steering using passive light sensing with off-the-shelf sensors to completely eliminate the need for in-band training. The key idea is to exploit similar propagation characteristics of higher frequency bands (i.e., light and mmWave bands) to track the dominant component of the mmWave wireless channel solely by using measurements in light band. To this end, I first introduce LiSteer, a system that steers mmWave beams at mobile devices by repurposing indicator LEDs on wireless Access Points (APs) to passively acquire direction estimates. I demonstrate that LiSteer maintains beam alignment at the narrowest beamwidth level even in case of device mobility, without incurring any training overhead at mobile devices. I then present SearchLight, where the key idea is to simultaneously track a mobile device's position and orientation using intensity measurements from lighting infrastructure, and to adapt mmWave beams at both mobile devices and the AP, completely eliminating beam training overhead for mmWave links. My extensive evaluation on a custom dual-band hardware platform comprising highly directional horn antennas as well as practical phased antenna arrays with electronic beam steering shows that both LiSteer and SearchLight achieve direction estimates within 2.5 degrees of ground truth on average. Moreover, both systems track client mobility and achieve up to 3x throughput gains compared to an in-band training strategy, and eliminate milli-second-scale in-band training epochs.
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    Pseudo Lateration: Millimeter-Wave Localization Using a Single Infrastructure Anchor
    (2016-04-22) Chen, Joe; Knightly, Edward W
    While radio-based indoor localization schemes achieve decimeter-scale accuracy, they typically require precise reference measurements or multiple infrastructure nodes with redundant localization anchors. In this paper, we propose Pseudo LATeration (PLAT), an indoor localization protocol that requires only a single infrastructure anchor and does not require prior knowledge of the environment. PLAT leverages the directionality and propagation characteristics of millimeter-wave transmissions to relax the requirement of multiple infrastructure anchors and constructs virtual anchors for multilateration from reflected signal paths. By combining these virtual anchors with time-of-flight measurements for distance estimation, PLAT can localize user devices in indoor environments with only a single infrastructure node. Our evaluation reveals centimeter scale location accuracy for typical office environments. In testbed measurements and simulations, localization errors are below 10 cm for distances up to 1.5 m and beamwidths below 10 degrees. Although accuracy decreases with distance, we show that multiple reflection paths can mitigate this effect.