Information Access under Poor Connectivity


  • Lakshminarayanan Subramanian

Consider three different worlds of poor network connectivity:

  • Scenario 1: A user in Africa uses a cheap mobile device with voice and SMS as the only data connectivity channel (140 bytes per message and each SMS costs money).
  • Scenario 2: A university in India has good connectivity which is shared simultaneously by 400 users. (Per user share = 2 Kbps)
  • Scenario 3: A school in Kenya has a computer but no Internet.

In this talk, I will describe a range of techniques we have developed to enhance information access in these three scenarios of poor connectivity. In Scenario 1, we have built an entire SMS-based protocol stack for mobile applications being used in India, Mexico and Ghana as well as a live SMS search engine in Kenya. We are also rolling out a data-over-GSM voice stack to support data connectivity over cellular voice.

In Scenario 2, I will describe why some of the fundamentals of network protocols break down in these regimes and why we need a completely new Web architecture for these types of networks. We have deployed early versions of our system in a few schools and universities in India, Kenya.

In Scenario 3, I will describe how we can use vertical search engines to deliver a vertical slice of the Web in a hard-disk and provide an offline searchable and browse-able Internet. This system has been used in schools in India and Kenya as an educational tool for students and teachers.

This is joint work with several others with Jay Chen being a primary leader for many of these projects.

Lakshminarayanan Subramanian is an Assistant Professor in the Courant Institute of Mathematical Sciences at NYU.

His research interests are in the areas of networks, distributed systems and computing for development. He co-leads the Networks and Wide-Area Systems(NeWS) group (which investigates software solutions for distributed systems, wireline and wireless networking, operating system, security and privacy, technologies and applications for the developing world) and the CATER Lab at NYU ( which focuses on developing and deploying low-cost, innovative technology solutions to some of the problems in developing regions in terms of communication, healthcare and microfinance).

Recently, he has co-established a new Center for Technology and Economic Development (CTED) at NYU Abu Dhabi which brings together students from several disciplines (CS, economics, healthcare, education, policy). He is the recipient of several awards including the  NSF CAREER Award (2009), IBM Faculty Award (2009, 2010) and C.V. Ramamoorthy Award. He has been at the forefront of several technological innovations for development that have been used in several countries around the world.