Performance comparison of 3G and metro-scale wifi for vehicular network access

We perform a head-to-head comparison of the performance characteristics of a 3G network operated by a nation-wide provider and a metro-scale wifi network operated by a commercial ISP, from the perspective of vehicular network access. Our experience shows that over a wide geographic region and under vehicular mobility, these networks exhibit very different throughput and coverage characteristics. Wifi has frequent disconnections even in a commercially operated, metro-scale deployment; but when connected, indeed delivers high throughouts even in a mobile scenario. The 3G network offers similar or lower throughputs in general, but provides excellent coverage and less throughput variability. The two network characteristics are often complementary. It is conceivable that these properties can be judiciously exploited for a hybrid network design where 3G data can be offloaded to wifi for better performance and to reduce 3G network congestion and to lower costs.