Handy Antenna Service

Handy Antenna Service (ハンディアンテナサービス) is a cellphone service found in Academy City that allows each individual cellphone to act in the place of a cellphone tower.

Principles
The service had cell phones of everyone who is part of the network in the city act as a relay antenna. Even if there were no cell phone towers around, a person could connect via persons (or more appropriately, cellphones) who were part of it, relaying the signal until is able to eventually connect to a person who was near a cellphone tower. Basically, it connected using a route that went through several people in something like a net, ensuring that the connection would not be easily dropped, until the signal reached the person near the cellphone tower. The technology was apparently helped paid for by university to have it tested, as such, the service fees were supposed to be cheap.

However, not much has been done to ensure the sound quality when the method was used. Moreover, the minor system only works if its users all walk around with their cell phones constantly on to act as relay antennae. According to Kamijou Touma, he has heard that the service drains the battery power quickly, and that only a few people are signed up for it.

The technology was later used to have airships become part of an emergency air communications network through the use of the few antennae installed on them. The airships could be sent out when normal towers were brought down in a disaster.

Academy City Invasion Arc
Misaka Mikoto uses this as an excuse to coerce Touma into signing a couple pair contract for cellphones in order for her to attain Gekota goods. After some hesitation from Touma and an interruption from Shirai Kuroko, she is successful in her endeavors and managed to obtain her desired Gekota cellphone straps.

The service may have been helpful during Vento of the Front's invasion of Academy City, which likely crippled communication services.