Saigopal Thota

Computing for rural empowerment: enabled by last-mile telecommunications

Increasing economic and educational exposure, and promotion of global health and wellness can be achieved through the power of sharing knowledge, technology, and resources. ICT can play a key role in disseminating such knowledge across the world. But a digital divide exists between urban and rural/remote areas, which results in economic and social disparities across regions. Developing last-mile telecommunication technologies for rural/remote areas is a crucial aspect in providing computing and ICT services that can integrate millions of stakeholders in rural/remote areas globally into the digital age, particularly with the advent of cloud computing. This article focuses on the different aspects of providing last-mile rural telecommunication access such as interfering factors, technology options, and deployment trends. This article aims to guide service providers, industry practitioners, and local entrepreneurs with a technology-and-deployment-trend analysis to choose, deploy, and operate suitable telecommunication networks depending on the unique features of the rural/remote area. Our goal is to bring attention to accessible and affordable technologies with practical considerations.

Energy-Efficient Virtual Base Station Formation in Optical-Access-Enabled Cloud-RAN

In recent years, the increasing traffic demand in radio access networks (RANs) has led to considerable growth in the number of base stations (BSs), posing a serious scalability issue, including the energy consumption of BSs. Optical-access-enabled Cloud-RAN (CRAN) has been recently proposed as a next-generation access network. In CRAN, the digital unit (DU) of a conventional cell site is separated from the radio unit (RU) and moved to the “cloud” (DU cloud) for centralized signal processing and management. Each DU/RU pair exchanges bandwidth-intensive digitized baseband signals through an optical access network (fronthaul). Time-wavelength division multiplexing (TWDM) passive optical network (PON) is a promising fronthaul solution due to its low energy consumption and high capacity. In this paper, we propose and leverage the concept of a virtual base station (VBS), which is dynamically formed for each cell by assigning virtualized network resources, i.e., a virtualized fronthaul link connecting the DU and RU, and virtualized functional entities performing baseband processing in DU cloud. We formulate and solve the VBS formation (VF) optimization problem using an integer linear program (ILP). We propose novel energy-saving schemes exploiting VF for both the network planning stage and traffic engineering stage. Extensive simulations show that CRAN with our proposed VF schemes achieves significant energy savings compared to traditional RAN and CRAN without VF.

Exploiting wireless connectivity for robustness in WOBAN

This article studies how next-generation optical access networks can exploit the properties of wireless connectivity to provide improved quality of service to users, and reports on a corresponding experimental prototype as well. Optical access networks using the passive optical network architecture are being increasingly deployed worldwide for fiber-to-the-home/business applications. While a PON can support higher data rates, it suffers from its tree architecture since it is vulnerable to a fiber cut on its tree¿s trunk, which will disrupt service to its users. However, by exploiting the properties of wireless connectivity, such as a wireless mesh in the front-end, the network can be made more robust. In case of a network element failure, an alternate path through the wireless-wireline integrated network may be selected, if it exists. Such a network can provide reliable high-capacity connectivity to untethered wireless devices which may be mobile as well. For such wireless-optical broadband access networks, we study a Risk-Aware Routing (RAR) algorithm to make it fault-tolerant and self-healing in case of failures. We also report on results from an experimental prototype developed in our laboratory.

Green Virtual Base Station in optical-access-enabled Cloud-RAN

In recent years, the increasing traffic demand in radio access networks (RAN) has led to considerable growth of the number of base stations (BS), posing a serious scalability issue with respect to the energy consumption of BSs. Optical-access-enabled Cloud RAN (CRAN) has been recently proposed as a next-generation access network, where the digital unit (DU) of a conventional cell site is separated from the radio unit (RU), by an optical access network (fronthaul), and moved to the “cloud” (DU pool) for centralized signal processing and management. Time-Wavelength Division Multiplexing (TWDM) Passive Optical Network (PON) is a promising fronthaul solution due to its low energy consumption and high capacity. In this study, we propose the concept of Virtual Base Station (VBS), which is dynamically formed for each cell by assigning virtualized network resources, including i) a virtualized PON link connecting the DU and RU and ii) virtualized functional entities performing baseband processing in DU pool. We propose a novel energy-saving scheme exploiting VBS formation for CRAN and compare its performance with the optimal results of an Integer Linear Program for VBS formation optimization problem. Numerical evaluation shows that CRAN with VBS formation achieves significant energy savings compared to traditional RAN and CRAN without VBS formation.

Trust-Based Collaboration Service Framework: A Platform for Communication and Content Sharing

This article discusses a novel framework for trust-based multidevice collaboration services. This framework opens up significant scope for applications and collaboration opportunities among heterogeneous devices mimicking human interaction. We present a topology map middleware service and a distributed querying application service that run on top of this framework. We are currently working on addressing the key challenges presented and developing new middleware, application services, and optimization techniques that leverage heterogeneous multidevice collaboration such as colocation detection, determining colocation pattern, and task offloading.

On downstream transmissions in EPON Protocol over Coax (EPoC): An analysis of Coax framing approaches and other relevant considerations

We present different mechanisms for downstream transmissions in the coax segment of Ethernet Passive Optical Network (EPON) Protocol over Coax (EPoC). EPoC is the transparent extension of EPON over a cable operator’s Hybrid Fiber-Coax network. For managing and controlling such a hybrid network, a network operator prefers to have a unified scheduling, management, and quality of service environment that includes both the optical and coax portions of the network. In EPoC, this is achieved by extending the EPON Medium Access Control to run over the coax physical layer, to have a centralized end-to-end network control from the cable head-end to the end users premises. In this paper, we focus on the downstream transmissions in EPoC. We study three different framing approaches for downstream coax frames based on how sub-carriers in an orthogonal frequency division multiplexed symbol are modulated. We discuss the merits and demerits of each approach and then compare them based on their control overheads and the maximum average data transmission rates each of them can achieve. We analyze how different parameters such as modulation profile, symbol duration, number of sub-carriers and length of resource blocks affect the data rates and the performance of downstream transmissions. We present simulation results to examine the implications of these factors on packet-level performance, such as delay. The results indicate that dynamic and hybrid framing approaches tend to perform better than static approaches, when traffic and usage pattern are identical to those in real-world scenarios. Finally, we outline the important engineering and research problems in this area which can be topics of future research.

Application-aware software-defined EPON access network

As bandwidth requirements of users in passive optical networks continue to increase rapidly, especially due to the growth of video-streaming traffic, the need to resolve bandwidth contention among competing users and applications becomes more compelling. To address this problem, we propose application-aware software-defined Ethernet passive optical network (EPON) architecture. It utilizes application-level feedback from the client side (for video users) to the network, through a software-defined network controller, to achieve better client- and service-level differentiation in the downstream direction of an EPON access network. We adopt adaptive video streaming that utilizes feedbacks regarding network congestion for improving Quality of Experience (QoE) of video-streaming clients. Numerical results for video-streaming applications demonstrate that the proposed architecture for downstream resource allocation considerably reduces video stalls, increases video buffer levels, and also reduces video-switching rate, leading to better QoE for users as a result of better client- and service-level differentiation.

On downstream coax framing in EPON protocol over coax (EPoC)

In this short paper, we propose three different framing approaches for downstream transmissions in the coax segment of EPON Protocol over Coax (EPoC), based on how subcarriers in an orthogonal frequency division multiplexed (OFDM) symbol are modulated. We analyze the merits and demerits of each approach, and then compare them based on their control overheads and the maximum average data transmission rates each of them can achieve.

intelliSENSE: Location-based Wi-Fi sensing for energy efficiency in smart mobile devices

Today, we use smart mobile devices to browse content, stream media, etc., in addition to making voice calls. Most smart devices are equipped with IEEE 802.11 (WiFi) interface to connect to the Internet using wireless access points (APs), as WiFi provides cost-effective connectivity to users. Wireless interfaces in smart devices drain high energy while searching for network connectivity and transition into power saving mode (PSM) after connecting to an AP. Hence, we need intelligent and energy-efficient mechanisms to scan and connect to wireless networks. In this work, we propose and investigate the characteristics of intelliSENSE, a location-based WiFi sensing mechanism for energy efficiency in smart mobile devices. We also propose adaptive polling mechanisms to further reduce the energy spent in WiFi sensing.