Mobile Data Offloading: How Much Can WiFi Deliver?

Vehicular WiFi offloading: Challenges and solutions

“…The performance of WiFi offloading is closely related to the WiFi availability, user mobility, delay tolerance characteristics of user data applications, etc. In [9], a comprehensive experiment is conducted to demonstrate the performance of WiFi offloading. By collecting WiFi connectivity statistics of 97 iphone users, the WiFi availability is first examined: i) the temporal WiFi coverage (the time portion in which a user stays within the WiFi coverage area) is 70% for all day and 63% for the active hours (9:00∼24:00); ii) the spatial WiFi coverage (the ratio of the area which is covered by WiFi over the total area) is about 8.3% for 50 meters WiFi coverage radius and 20.6% for 100 meters WiFi coverage radius; and iii) the connection time to a WiFi AP has an average value of 2 hours (all day) and 52 minutes (active hours), while the average inter-connection time is 40 minutes (all day) and 25 minutes (active hours), and the distributions of both connection and inter-connection times are heavy-tailed.…”

“…In [9], it is shown that a considerable amount of energy can be saved by WiFi offloading. This is because WiFi can provide a higher data rate than 3G networks, which yields a shorter data transmission time and therefore a lower energy consumption.…”

“…The impact of WiFi deployment on the offloading performance is investigated in [9]. The methodology is to gradually eliminate the APs with least user connection times, in order to evaluate the performance at different AP densities.…”

“…By delivering data originally targeted for cellular networks by WiFi, which is referred to as WiFi offloading, the congestion of cellular networks can be alleviated. WiFi offloading has been extensively studied for stationary or slow moving users 2 [9,8,10,11]. It is shown that around 65% of the cellular traffic can be offloaded by merely using the most straightforward way of simply switching the IP connection from the cellular network to WiFi when the WiFi connectivity is available (on-the-spot offloading).…”

“…It is shown that around 65% of the cellular traffic can be offloaded by merely using the most straightforward way of simply switching the IP connection from the cellular network to WiFi when the WiFi connectivity is available (on-the-spot offloading). In addition, significant amount (above 80%) of data can be offloaded by delaying the data application [9] (delayed offloading). For moving vehicle users, one natural question needs to be answered: how much data can be offloaded?…”