01-10-2012, 10:53 AM
Special Issue on Cooperative and Networked Femtocells
1Special Issue on Cooperative.pdf (Size: 38.53 KB / Downloads: 122)
The proliferation of more appealing wireless applications, e.g., mobile TV, Internet
gaming, large file transfers, and the development of more sophisticated user
terminals, e.g., smart phones, notebooks, have dramatically increased user traffic
and network load. In order to meet this traffic growth and provide services to their
end-users, vendors and operators are looking into new communication paradigms.
Among them, the deployment of a large number of small cells increasing coverage,
capacity, energy-efficiency and thus revenues of future cellular networks, seems to
be one of the most promising approaches. Indeed, these small cells, also referred to
as femtocells, have recently gained in momentum in both industry and research
communities, and have been indentified as a key technology for the fourth generation
(4G) mobile networks, such as LTE-Advanced and WiMAX IEEE 802.16m.
Femtocells have already started to be deployed inside homes and enterprises.
Moreover, femtocells are also expected to be deployed outdoors and in large
vehicles such as buses, trains and airplanes. However, since femtocells will be
deployed in a large number and installed by end-users in an unplanned manner, they
generate uncontrolled inter-cell interference to both the existing macrocells and
adjacent femtocells.
Recent advances have shown that cooperation between macrocells and femtocells
and among femtocells themselves may be the key to success. Cooperative
communications, cooperative games and distributed optimization theory can be the
fundamental building blocks for novel designs of future femtocells. These models
should target at achieving an efficient and stable network performance, while taking
decisions at the cell-level involving as little inter-cell communication as possible.
However, inter-cell cooperation, which has to be performed in a decentralized and
distributed manner due to scalability issues, is not easy to achieve due to problems
and threats imposed by the network itself, e.g., limited back-haul capabilities,
dynamics of traffic and radio channel, energy consumption, operational costs, and
difficulties in synchronization.