Elizabeth M. Belding

University of California, Santa Barbara | UCSB · Department of Computer Science

While cellular networks connect over 3.7 billion people worldwide, their availability and quality is not uniform across regions. Under-provisioned and overloaded networks, as are common in rural or post-disaster areas, lead to poor network performance and a poor-quality user experience. To address this problem we propose HybridCell: a system that l...

Despite improvements and expansion of cellular coverage in developing regions, a substantial qualitative divide remains. Maps that display the presence or absence of cellular coverage mask critical differences in infrastructure performance and client load. In order to illuminate challenges faced by users of such mobile networks, we collect and anal...

Despite the appearance of uniform availability of mobile services, in many locales granular network analyses reveal the persistence of physical access divides. It stands to reason these divides, similar to those at larger scales, are also reflections of community-level social and economic divides. In this research, we examine community-level physi...

Modern communications systems rely on assumptions of centralized systems and underlying infrastructure that make them vulnerable in computing within limits scenarios. In this paper we offer case studies of issues facing connectivity in three locations in developing regions as a proxy for networks in such scenarios. We explore obstacles presented by...

While cellular networks connect over 3.7 billion people worldwide, their availability and quality is not uniform across regions. Under-provisioned and overloaded networks lead to poor network performance and an aggravated user experience. To address this problem we propose HybridCell: a system that leverages locally-owned small-scale cellular netwo...

Characterization of mobile data traffic performance is difficult given the inherent complexity and opacity of mobile networks, yet it is increasingly important as emerging wireless standards approach wireline-like latencies. Mobile virtual network operators (MVNOs) increase mobile network topology complexity due to additional infrastructure and net...

While online social networks (OSNs) play a critical role in developing social capital [18], many communities are unable to utilize the benefits of OSNs due to lack of Internet accessibility. In this paper, we investigate the feasibility of the Radio Broadcast Data System (RBDS) associated with FM radio stations as a means to deliver social network...

Media uploads and downloads, even those on the order of a few hundred kilobytes, commonly fail when attempted over lossy, low-bandwidth, and high latency connections. These conditions, which are common for networks in rural, resource-poor areas, result in the inability for residents of these areas to fully participate in the modern Internet. We stu...

With broadband penetration rates of less than 10% per capita, Tribal areas in the U.S. represent some of the most underserved communities in terms of Internet access. Although numerous sources have identified this digital divide, there have been no empirical measurements of the performance and usage of services that do exist in these areas. In this...

Abstract The emergence of MIMO antennas and channel bonding in 802.11n wireless networks has resulted in a huge leap in capacity compared with legacy 802.11 systems. This leap, however, adds complexity to optimizing transmission. Not only does the appropriate data rate need to be selected, but also the MIMO transmission technique (e.g., Spatial Div...

Open Charging Kiosk is a solar charging kiosk that provides reliable power to rural residents and income to the kiosk's operator. Open Charging Kiosk empowers kiosk operators by enabling them to build and operate their own equipment, rather than employing them as operators of equipment provided by a franchising company. Open Charging Kiosk provides...

Tribal areas continue to be some of the most under-serviced places in the U.S. with respect to broadband coverage. Despite tribal and FCC interests in addressing this issue, there has never been a network-based characterization on how existing broadband services in these are areas are used. We present one of the first of such characterizations by a...

Cellular phone networks are often paralyzed after a disaster, as damage to fixed infrastructure, loss of power, and increased demand degrade coverage and quality of service. To ensure disaster victims and first responders have access to reliable local and global communication, we propose EmergeNet, a portable, rapidly deployable, small-scale cellul...

The lack of sufficient fixed-line communication infrastructure in African rural areas has resulted in wireless communication being the only cost effective alternative solution for broadband connectivity. However, access to valuable spectrum—specifically sub-1 GHz spectrum—is mostly allocated to broadcasting or mobile telephony. The global digital s...

Due to frequent non-line-of-sight (NLOS) signal reception, geopositioning using Global Navigation Satellite Systems (GNSS), such as GPS, is unreliable in urban environments, with errors on the order of tens of meters. This poses a major problem for mobile services that benefit from accurate urban localization, such as navigation, geofencing, and hy...

Geopositioning using Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), is inaccurate in urban environments due to frequent non-line-of-sight (NLOS) signal reception. This poses a major problem for mobile services that benefit from accurate urban localization, such as navigation, hyperlocal advertising, and geo...

The increased demand for wireless connectivity emphasizes the necessity of efficient wireless communication as resources such as the available spectrum and energy reserves become limiting factors for network proliferation. Recent advancements in software-defined radio enable high flexibility of the physical layer allowing fine grained transmission...

White spaces promise to revolutionize the way wireless connectivity is delivered over wide areas. However, large-scale white space networks face the problem of allocating channels to multiple contending users in the wide white space band. To tackle the issue, we first examine wireless propagation in a long-distance outdoor white space testbed and f...

Cellular networks are often the first telecommunications infrastructure in developing regions. By studying cellular net- work traffic, researchers gain insight into how technologies can be used to access services critical to further development. In this work, we approach a cellular traffic dataset provided by Orange in Cote d'Ivoire with the goal o...

Studies of user behavior in cellular networks have served as a knowledge base for development of critical applications and services catered to specific user needs. In this paper we examine community persistence in egocentric social graphs extracted from cellular network traces in the Cote d'Ivoire provided by Orange. The goal of our study is to inf...

As usage of online social networks and social media continues to experience exponential growth, the amount of data being shared between users is increasing without bound. While this has revolutionized communication for many Internet users, users in rural or developing areas connected behind slow, congested gateways are falling increasingly behind t...

Broadband Internet access has become a critical part of socio-economic prosperity; however, only 6 in 100 inhabitants have access to broadband in developing countries. This limited access is driven predominately by subscriptions in urban areas. In rural developing communities, access is often provided through slow satellite, or other low-bandwidth...

Cellular networks have revolutionized the way people communicate in rural areas. At the same time, deployment of commercial-grade cellular networks in areas with low population density, such as in rural sub-Saharan Africa, is prohibitively expensive relative to the return of investment. As a result, 48\% of the rural population in Africa remains di...

Cellular networks have revolutionized the way people communicate in rural areas. At the same time, deployment of commercial-grade cellular networks in areas with low population density, such as in rural sub-Saharan Africa, is prohibitively expensive relative to the return of investment. As a result, 48% of the rural population in Africa remains dis...

The emergence of MIMO antennas and channel bonding in 802.11n wireless networks has resulted in a huge leap in capacity compared with legacy 802.11 systems. This leap, however, adds complexity to selecting the right transmission rate. Not only does the appropriate data rate need to be selected, but also the MIMO transmission technique (e.g., Spatia...

The IEEE 802.11n standard defines channel bonding that allows wireless devices to operate on 40MHz channels by doubling their bandwidth from standard 20MHz channels. Increasing channel width increases capacity, but it comes at the cost of decreased transmission range and greater susceptibility to interference. However, with the incorporation of Mul...

A fundamental question in multihop wireless network protocol design is how to partition the network's transport capacity among contending flows. A classically "fair” allocation leads to poor throughput performance for all flows because connections that traverse a large number of hops (i.e., long connections) consume a disproportionate share of reso...

The Internet is evolving from a system of connections between humans and machines to a new paradigm of social connection. However, it is still dominated by a hub and spoke architecture with inter-connectivity between users typically requiring connections to a common server on the Internet. This creates a large amount of traffic that must traverse a...

Mobile telephony brings clear economic and social benefits to its users. As handsets have become more affordable, ownership has reached staggering numbers, even in the most remote areas of the world. However, network coverage is often lacking in low population densities and low income rural areas of the developing world, where big telecoms often de...

While broadband Internet connectivity has reached a significant part of the world's population, those living in rural areas of the developing world suffer from poor Internet connectivity over slow long distance links, if they even have connectivity at all. While this has a general negative impact on Internet utilization, our social survey of users...

Information and Communication Technologies for Development (ICTD) is an emerging field that focuses on the design, implementation, deployment, and evaluation of innovative technologies for social and economic development. The ICTD research agenda is driven by a desire to bridge the digital divide and make computing useful to the significant fractio...

Current metrics for evaluating Internet adoption capture the percentage of people with physical access to the Internet and provide a coarse understanding of actual usage. The factors for Internet adoption, however, are related not only to the provision of connectivity but also to individuals' personal experience. We concentrate on rural sub-Saharan...

The IEEE 802.11n standard allows wireless devices to operate on 40MHz-width channels by doubling their channel width fromstandard 20MHz channels, a concept called channel bonding. Increasing channel width should increase bandwidth,but it comes at the cost of decreased transmission range and greater susceptibility to interference. However, with the...

Residential broadband links are characterized by low and variable upload capacity and large latencies, leading to poor video performance. Aggregating multiple backhaul links using 802.11 Access Points has been considered as a solution to increasing the backhaul capacity limit. In this paper, we revisit the problem of backhaul aggregation in the con...

Monitoring and troubleshooting a large wireless mesh network presents several challenges. Diagnosis of problems related to wire- less access in these networks requires a comprehensive set of met- rics and network monitoring data. Collection and offloading of a large amount of data is infeasible in a bandwidth constrained mesh network. Additionally,...

Recent advancements in wireless transmission have enabled networks with a high level of physical layer flexibility. Unfortunately, these new opportunities are not harnessed by modern wireless systems. Due to inefficient resource allocation, systems typically encounter problems such as spectrum scarcity, energy depletion or low quality of service. I...

IEEE 802.11 devices dynamically choose among different modulation schemes and bit-rates for frame transmissions. This rate adaptation, however, is restricted only to unicast frames. Multicast (and broadcast) frames are constrained to use a fixed low bit-rate modulation, resulting in low throughput for multicast streams. Availability of high bandwid...

Accurate measurements of deployed wireless networks are vital for researchers to perform realistic evaluation of proposed systems. Unfortunately, the difficulty of performing detailed measurements limits the consistency in parameters and methodology of current datasets. Using different datasets, multiple research studies can ar-rive at conflicting...

Residential broadband links are characterized by low and variable upload capacity and large latencies, leading to poor video performance. Aggregating multiple backhaul links using 802.11 Access Points has been considered as a solution to increasing the backhaul capacity limit. In this paper, we revisit the problem of backhaul aggregation in the con...

While Internet connectivity has reached a significant part of the world's population, those living in rural areas of the developing world are still largely disconnected. Recent efforts have provided Internet connectivity to a growing number of remote locations, yet Internet traffic demands cause many of these networks to fail to deliver basic quali...

There have been a number of rural wireless network proving Internet access operating since 2005. But little is known about how the Internet is being used on these networks and whether it follows similar trends to Internet usage patterns in developed regions. It is clear that certain commonly accepted content delivery mechanisms such as peer-to-peer...

Wireless mesh networks (WMNs) provide an attractive method to provide Internet connectivity in developing regions. Traditional mesh routing protocols are designed to find high quality/throughput multihop routes in the network. However, these solutions do not consider constraints imposed by the capacity at the gateway, often the bottleneck in such r...

Rate adaptation is a critical component that impacts the performance of IEEE 802.11 wireless networks. In congested networks, traditional rate adaptation algorithms have been shown to choose lower data-rates for packet transmissions, leading to reduced total network throughput and capacity. A primary reason for this behavior is the lack of real-tim...

White space frequencies are highly attractive for long-distance communica-tion due to greater signal propagation. The lack of standards and licensing issues with increased flexibility provided by the cognitive radio allow for sophisticated customized solutions for white spaces. Rural-area networks are seen as the main beneficiaries and white spaces...

Wireless networks have evolved into an important technology for connecting users to the Internet. As the utility of wireless technology grows, wireless networks are being deployed in more widely varying conditions. The monitoring of wireless networks continues to reveal key implementation deficiencies that need to be corrected in order to improve p...

Users are generating and uploading multimedia content to the Internet at an unprecedented rate. Residential broadband networks, however, have low upload capacities and large packet latencies. Wi-Fi networks that are used to access the Internet can suffer from high packet losses and contention latencies. All of these factors can result in poor video...

There have been a number of rural wireless networks provid-ing Internet access over the last decade but little is known about how the Internet is being used, how these networks perform and whether they follow similar trends when com-pared with Internet usage patterns in developed regions. We analyse a set of network traces from the Linknet wireless...

Enterprise wireless local area networks (WLANs) that consist of a high-density of hundreds to thousands of access points (APs) are being deployed rapidly in corporate offices and university campuses. The primary purpose of these deployments is to satisfy user demands for high bandwidth, mobility, and reliability. However, our recent study of two su...

We present a cross-layer modeling and design approach for multigigabit indoor wireless personal area networks (WPANs) utilizing the unlicensed millimeter (mm) wave spectrum in the 60 GHz band. Our approach accounts for the following two characteristics that sharply distinguish mm wave networking from that at lower carrier frequencies. First, mm wav...

Delay Tolerant Network (DTN) routing addresses challenges of providing end-to-end service where end-to-end data forwarding paths may not exist. The performance of current DTN routing protocols is often limited by routing metric “staleness”, i.e., routing information that becomes out-of-date or inaccurate because of long propagation delays. Our prev...

The Internet has revolutionized communication, education, commerce and information access for its users worldwide. Unfortunately, the lack of copper/fiber infrastructure in the rural areas of the developing world has prevented a large majority of the human population from reaping the benefits of the Internet. While the number of mobile subscribers...

Wireless testbeds are typically distributed over large physical areas. There are often many nodes, some of which are difficult to reach on-site or via remote access. As a result, such nodes may be manageable using only in-band management techniques making the task of testbed management challenging. As a remedy, we propose the ATMA framework, a fram...

We propose a representation of wireless workload patterns as large, sparse matrices and provide a method for stochastically generating experimental workloads from a given matrix. The essential property of the algebraic representation is that the summation of vectors naturally yields a faithful description of the aggregate behavior of the correspond...

The availability of Internet services brings many benefits to developing regions, yet Internet deployment levels in these regions remain staggeringly low. In this work we investigate how existing cellular deployments, which have enjoyed more rapid and wider deployment than client Internet infrastructure, could be used to provide very low cost Inter...

We consider the problem of providing ubiquitous yet afford- able Internet connectivity to devices at home, at work, and on the move. In this context, we take advantage of two significant technology trends: the commoditization of WiFi WLAN technology and the rapid growth of cellular data services. We propose an architecture called Cool-Tether that h...

The increasing reliance of users on wireless networks for Internet connectivity has posed two significant challenges for mobile networking research. The first challenge is to provide high quality of service for interactive real-time applications such as VoIP and video conferencing. The second challenge is to reduce the energy consumption of mobile...

Self-powered wireless mesh networks have gained popularity as a cheap alternative for providing Internet access in many rural areas of the developed and, especially, the developing world. The quality of service that these networks deliver is often bounded by such rudi-mentary issues as the unavailability of electrical energy. Depen-dence on renewab...

Because of the near ubiquitous communication available to network nodes beneath a satellites footprint, satellite network technology has enjoyed a recent and substantial increase in interest from academia, government, and commercial sectors. However, the benefit resulting from being beneath the satellite footprint comes at the cost of a substantial...

Multimedia transmission over wireless local area networks (WLANs) is a challenging task due to the varying nature of the wireless channel as well as the inherent difference between multimedia traffic and data traffic. In the MAC layer, a single bit error in the packet can lead to the entire packet being discarded. This results in a higher packet er...

Wireless growth has been limited by the shortage of radio spectrum. While the spectrum assigned to legacy technologies remain unused, new prominent technologies such as Mesh/WiFi networks are forced to crowd into a small unlicensed band, suffering from significant interference and degraded performance. Using economic incentives, dynamic spectrum au...

Traditional rate adaptation solutions for IEEE 802.11 wireless networks perform poorly in congested networks. Measurement studies show that congestion in a wireless network leads to the use of lower transmission data rates and thus reduces overall network throughput and capacity. The lack of techniques to reliably identify and characterize congesti...

A user located in a congested area of a wireless LAN may benefit by moving to a less-crowded area and using a less-loaded access point. This idea has gained attention from researchers in recent literature [A. Balachandran, P. Bahl, G. Voelker, Hot-spot congestion relief in public-area wireless networks, in: IEEE WMCSA, Callicoon, NY, June 2002; M....