Localised FM Digital Audio Broadcasting using WiFi Mesh Networks
preprintposted on 20.12.2020, 12:36 by Ashvin Verma, Somesh Kar, Priyanshi Ahuja
Digital Audio Broadcasting via FM radio transmission on the VHF-II Band remains widely in use despite advancements in other wireless technologies due to its accessibility, particularly in rural areas where CRS help facilitate cultural expression and aid local information delivery. Current CRS are expensive and power-intensive while remaining challenging to scale, especially across hilly environments and uneven terrain.
This paper first examines the need for a low-cost, scalable CRS in 2 regions, namely India and African countries, using recent social science literature and reporting. Then, we evaluate the performance of the proposed community radio mesh system for range, scalability, and transmission quality. The system consists of low-cost and modular FM transmitter units connected to each other via a WiFi MeshNet which is used to transmit digital audio signals from the hub node. Each transmitter unit then broadcasts this digital audio signal in the VHF-II band, supported by standard feature phones and other FM receivers. The transmitter units consist of COTS components running on open-source software.
The transmission quality has been analyzed using objective metrics such as Peak-Signal-to-Noise Ratio and interpreted from PSD spectrograms and the output of Discrete Fourier Transforms. While field trials and further research are necessary, the approach seems promising for rolling out mid-to-large scale community radio mesh systems.