Name
Abstract | ||
|---|---|---|
While the cellular revolution has made voice connectivity ubiquitous in the developing world, data services are largely absent or are prohibitively expensive. In this paper, we present Hermes1, a point-to-point data connectivity solution that works by modulating data onto acoustic signals that are sent over a cellular voice call. The main challenge is that most voice codecs greatly distort signals that are not voice-like; furthermore, the backhaul can be highly heterogeneous and of low quality, thereby introducing unpredictable distortions. Hermes modulates data over the extremely narrow-band approximately 3kHz bandwidth) acoustic carrier, while being severely constrained by the requirement that the resulting sound signals are voice-like, as far as the voice codecs are concerned. Hermes uses a robust data transcoding and modulation scheme to detect and correct errors in the face of bit flips, insertions and deletions; it also adapts the modulation parameters to the observed bit error rate on the actual voice channel. Through real-world experiments, we show that Hermes achieves approximately 1.2 kbps goodput which when compared to SMS, improves throughput by a factor of 5× and reduces the cost-per-byte by over a factor of 50x |
Year | DOI | Venue |
|---|---|---|
2010 | 10.1145/1859995.1860010 | MobiCom |
Keywords | Field | DocType |
robust data,data service,actual voice channel,acoustic carrier,voice codecs,voice connectivity,point-to-point data,data transmission,modulating data,cellular voice call,unknown voice channel,hermes modulates data,point to point,bit error rate,codec,developing world,performance,measurement,modulation | Transcoding,Data transmission,Computer science,Communication channel,Computer network,Real-time computing,Bandwidth (signal processing),Goodput,Throughput,Codec,Bit error rate | Conference |
Citations | PageRank | References |
21 | 1.26 | 8 |
Authors | ||
7 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Aditya Dhananjay | 1 | 138 | 10.45 |
| Ashlesh Sharma | 2 | 72 | 5.74 |
| Michael Paik | 3 | 63 | 6.89 |
| Jay Chen | 4 | 191 | 15.47 |
| Trishank Karthik Kuppusamy | 5 | 31 | 4.03 |
| Jinyang Li | 6 | 3186 | 385.60 |
| Lakshminarayanan Subramanian | 7 | 1540 | 163.14 |