SONIC: Cost-Effective Web Access for Developing Countries

TL;DR

SONIC addresses the offline Internet divide by delivering Web content and LLM-based interactions over a low-cost FM broadcast channel with SMS uplink. The system encodes webpages as WebP images and transmits them via OFDM-based audio at approximately 10 kbps, while enabling interactive AI queries through SMS; a real-world Cameroon deployment demonstrates stable downlink performance (10 kbps) and meaningful user engagement despite infrastructure challenges. This work validates a practical framework for repurposing existing broadcast infrastructure to provide affordable, scalable access to information and AI services in developing regions. Overall, SONIC combines end-to-end system design, OS-level FM integration, and real-world evaluation to show how data-over-FM can complement traditional connectivity in resource-constrained settings.

Abstract

Over 2.6 billion people remain without access to the Internet in 2025. This phenomenon is especially pronounced in developing regions, where cost and infrastructure limitations are major barriers to connectivity. In response, we design SONIC, a low-cost, scalable data delivery system that builds on existing infrastructures: FM radio for downlink broadcasting, and SMS for personalized uplink. SONIC is motivated by the widespread availability of FM radio and SMS infrastructure in developing regions, along with embedded FM radio tuners in affordable mobile phones. SONIC offers several innovations to effectively transmit Web content over sound over FM radio, in a reliable and compressed form. For example, we transmit pre-rendered webpages and leverage pixel interpolation to recover errors at the receiver. We further modify Android to offer a simpler deployment pipeline, supporting a wide range of devices. We deployed SONIC at an FM radio station in Cameroon for six weeks with 30 participants. Our results demonstrate a sustained downlink throughput of 10 kbps, less than 20% loss for a majority of transmissions with signal strength above -90 dbM, and a strong user engagement across both Web browsing and ChatGPT interactions.

Figures (20)

• Figure 1: Network performance of MTN, the best available mobile network provider at our deployment site in Cameroon.
• Figure 2: Barriers to Web access from speed and cost. The main plot shows CDF of how SONIC users agree with avoiding websites due to slow internet. The inset shows the % of users indicating that their browsing is restricted by data costs.
• Figure 3: Mobile phones supporting FM receivers for the top four Android brands grouped by release year (2017-2024).
• Figure 4: CDF of prices for android phones equipped with an FM radio receiver. Green dotted lines indicate the monthly Gross National Income (GNI) per capita for selected low- and middle-income countries.
• Figure 5: SONIC workflow.