Geocasting in cellular ad hoc augmented networks

Delivering information to every user on a pre-specified geographic area via the Internet can be accomplished by geocasting in single-hop cellular networks. Geocasting is the mechanism to multicast messages to the network nodes whose physical locations lie within a given geographic area, termed the target area. In this paper, we propose the use of cellular ad hoc augmented network (CAHAN) architecture to improve total transmitted power expended for geocast services in cellular networks. CAHAN, in which ad hoc relaying technology is applied, is an evolutionary approach to conventional single-hop cellular networks. CAHAN regulates the number of hops between the base station and the mobile terminals (MTs) given a delay constraint. Notice that when the ad hoc communication range of each MT is zero, CAHAN simplifies to a conventional cellular network. We describe the CAHAN architecture, geocast session setup, geocast routing strategy, and power consumption models. The proposed architecture also implements a simple minimum-power path search scheme that can further reduce the total geocast energy in CAHAN. The advantages of CAHAN are demonstrated by comparing the geocasting performance of CAHAN with pure cellular networks in terms of total transmitted energy. We show that by using CAHAN for geocasting, saving in total transmitted energy can be achieved as compared to the case of pure cellular networks. When the size of geocast target area is large, CAHAN can save larger transmitted energy. Finally, we show that the dense target area in CAHAN would save more transmitted energy in general.