WiLDNet

From CATER

Networking solutions in developing regions is either poor or expensive. Current networking technologies are geared towards developed countries with high user density.

WiFi-based Long Distance Networks (WiLDNet) are emerging as a potential low-cost alternative to traditional connectivity solutions for rural regions. Traditionally mesh networks which use omni-directional antennas are used to cater short ranges such as 1-2 kms, but WiLD networks use high gain directional antennas with line of sight (LOS) over long distances (around 10-100 kms).

WiFi-based Long Distance (WiLD) networks with links as long as 50–100 km have the potential to provide connectivity at substantially lower costs than traditional approaches. However, real-world deployments of such networks yield very poor end-to-end performance due to two reasons. First, the current 802.11 MAC protocol has fundamental shortcomings when used over long-distances. Second, WiLD networks can exhibit high and variable loss characteristics, thereby severely limiting end-to-end throughput.

WiLDNet is a system that overcomes these two problems and provides enhanced end-to-end performance in WiLD networks. To address the protocol shortcomings, WiLDNet makes several essential changes to the 802.11 MAC protocol, but continues to rely on standard WiFi network cards. To better handle losses and improve link utilization, WiLDNet uses an adaptive loss-recovery mechanism using FEC and bulk acknowledgements. Based on a real-world deployment, WiLDNet provides a 2–5 fold improvement in TCP/UDP throughput (along with significantly reduced loss-rates) in comparison to the best throughput achievable by conventional 802.11 MAC. WiLDNet can also be configured to adapt to a range of end-toend performance requirements (bandwidth, delay, loss, jitter)

WiLD network is currently deployed in many countries such as India, Ghana, Guinea Bissau and Philippines.

For a more detailed description, look at the Wireless section at TIER

People

Eric Brewer
Lakshminarayanan Subramanian
Rabin Patra
Sergiu Nedevschi
Sonesh Surana
Anmol Sheth

Publications

• Beyond Pilots: Keeping Rural Wireless Networks Alive. Sonesh Surana, Rabin Patra, Sergiu Nedevschi, Manuel Ramos, Lakshminarayanan Subramanian, Yahel Ben-David, Eric Brewer. To appear in ACM USENIX NSDI, 2008.
• WiLDNet: Design and Implementation of High Performance WiFi Based Long Distance Networks. Rabin Patra, Sergiu Nedevschi, Sonesh Surana, Anmol Sheth, Lakshminarayanan Subramanian, Eric Brewer. USENIX NSDI, April 2007. PDF
• Packet Loss Characterization in WiFi-based Long Distance Networks. Anmol Sheth, Sergiu Nedevschi, Rabin Patra, Sonesh Surana, Lakshminarayanan Subramanian, Eric Brewer. IEEE INFOCOM, May 2007. PDF
• Rethinking Wireless in the Developing World. Lakshminarayanan Subramanian, Sonesh Surana, Rabin Patra, Sergiu Nedevschi, Melissa Ho, Eric Brewer and Anmol Sheth. Hot Topics in Networks (HotNets-V), November 2006. PDF