IEEE 802.11be Standards Development
IEEE Standards development with a focus on supporting extremely low-latency services such as Augmented/Virtual Reality
(AR/VR), live-video streaming, and mobile gaming. These services are becoming increasingly popular for supporting critical multi-media applications and next-generation of WiFi and 5G devices need to support very low latency services. My research focuses on developing medium-access protocols and designs for upcoming IEEE 802.11be (WiFi-7) standard, and as such will enable billions of upcoming mobile and IOT devices in supporting these services. Particularly, my research focuses on two features:
(AR/VR), live-video streaming, and mobile gaming. These services are becoming increasingly popular for supporting critical multi-media applications and next-generation of WiFi and 5G devices need to support very low latency services. My research focuses on developing medium-access protocols and designs for upcoming IEEE 802.11be (WiFi-7) standard, and as such will enable billions of upcoming mobile and IOT devices in supporting these services. Particularly, my research focuses on two features:
- Multi-Link Operation to combine WiFi operation in multiple bands to increase capacity and reduce congestion
- Restricted TWT operation to prioritize latency sensitive traffic and provide delay guarantees
mmWave Beam Steering via Light based Mobility Tracking
Design of mmWave beam steering algorithm on mobile devices by tracking AOA of physical LOS path between devices and the AP, which repurposes the collocated indicator LED lights on APs for AOA estimation with o -the-shelf sensors (HotMobile'18, MobiCom'18). We further expand the design to exploit indoor luminaries to estimate both position and orientation of devices, thus solving beam steering problem at both AP and client by tracking both AOA and AOD (MobiHoc'18). Implementation on custom dual-band hardware testbed with VubIQ horn antenna platform and also NI mmWave wideband phased array platform.
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Multi-Stream Beam Steering in mmWave Networks
Design of Diversity Steering with PDP (DSP); a novel system which leverages channel sparsity, GHz-scale sampling rate, and the knowledge of mmWave RF codebook beam patterns to construct a set of candidate beams for multi-stream beam steering. DSP repurposes the mandatory and periodic single-stream beam acquisition sweeps in 60 GHz WLANs to estimate the Power Delay Prfile (PDP) of each beam with zero additional overhead. Coupling PDP estimations with beam pattern knowledge, DSP selects a set of candidate beams that capture diverse or ideally orthogonal paths to obtain maximum stream separability. Implementation on NI mmWave testbed with 2 GHz baseband bandwidth leading to high temporal and spatial resolution. (To appear in ACM MobiCom 2018)
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Mobility Resilience in 60 GHz Networks
Design, implementation and evaluation of MOCA, where we introduce a probing feedback mechanism before data transmissions to identify link impairments, and devise proactive mechanisms to restore broken directional links with minimum overhead. Moreover, we analyze the role of beamwidth in directional networks in terms of overhead, achievable rate, and mobility resilience and propose an algorithm for joint adaptation of data rate and beamwidth, based on nodal and environmental mobility.
Our MobiHoc 2016 paper is available here. |
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MAC Design for Full Duplex
Full Duplex radios double the capacity at the physical layer by simultaneous transmission and reception on the same frequency band. However, we need an efficient MAC protocol to take maximum advantage of this novel capability at physical layer. In this work, we design a novel MAC protocol for full duplex access points communicating with half duplex stations. This protocol explores the possibility of opportunistic full duplex transmissions when there are hidden terminals or when physical link between stations is much weaker than the AP--Station link.
Technical report is available here. |
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Cooperative Communications
Cooperative communications has over the past few years received tremendous research interest. This interest is not unwarranted as it promises, at least in theory, significant gains in terms of increase in throughput, interference minimization, greater power efficiency, and coverage expansion in wireless networks. In this work, we develop a novel compress-forward scheme for cooperative communication systems with feedback-systematic codes. We also implement Amplify Forward, Decode Forward schemes on USRP-1 platform using MATLAB and compare the performance of aforementioned schemes.
Details of the project can be found here. |
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Smart GridsThe Electrical grid and the Internet share the same goal of interconnecting distributed suppliers to geographically dispersed consumers. The existing grid faces several challenges: it is centralized, with wasteful transmission and distribution technologies, carbon-intensive energy sources, limited energy storage, and minimal use of I.C.T. We think the future Electrical Grid will have architecture like the Internet and thus the lessons learnt from Internet’s design and evolution can play a key role towards the Next-Generation Grid (a.k.a Smart Grid).
Our research is focused on the following two problems: |
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i) Electrical Load Prediction in Smart BuildingsDeveloping energy consumption models for smart buildings is important for studying demand response, home energy management, and distribution network simulation. In this work, we use continuous and discrete-time Markov Chains for modeling and predictions of electricity consumption for different periods of a day. To develop these models, we collected two data sets with widely different load profiles over a period of seven months and one year, respectively. The important aspect of our models is parsimony; Markov models do not require inputs like temperature, nature of devices, number of occupants or area of the building. Our results show that Markov-Models capture the inherent uncertainty in load profiles more efficiently than deterministic models like Neural Networks.
Our ICONIP 2012 paper is available here. |
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ii) Communication Technologies for Smart GridsIntroduction of communication technologies in the Power Sector has helped the concept of Power Grid and Energy Sector to make advancements towards practical implementation stage. The power flow was already there long ago but the inclusion of communication technologies has enabled the aspect of bi-directional communication for the Smart Grids. In this work, we investigate various communication technologies (including Zigbee, PLC and WiFi) for communication between Smart Devices and control units. Suitability is studied on basis of the technology’s ability to meet the data-rate and latency requirements of smart devices and factors like support for future growth, ease of deployment, topology support, power consumption, and installation and maintenance costs.
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