MADF: a novel approach to add an ad-hoc overlay on a fixed cellular infrastructure

In a cellular system, if there are too many data users in a cell, which we refer to as a hot cell, data may suffer large delay, and system´s quality of service (QoS) may degrade. A dynamic channel-allocation scheme assigns more channels to those hot cells under centralized control (CC). In mobile-assisted data forwarding (MADF), we add an ad-hoc overlay to the fixed cellular infrastructure and special channels-called forwarding channels-are used to connect users in a hot and its surrounding cold cells without going through the hot cell´s base station. The forwarding-channel management in MADF is done by the mobile units themselves to relieve the load on the CC. We find that, using MADF, under a certain delay requirement, the system performance can be greatly improved