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Future Cooperative Wireless Networks
The density of nodes in mobile communication networks as well as the
requirement for data throughput has increased steadily in the last decades.
Since the available frequency spectrum is limited and bandwidth is a scarce
resource, future communication systems are expected to utilize it as efficient
as possible. In future systems, increased spectral efficiency (more bits per
second per Hertz of bandwidth) as well as improved link reliability become
even more important. In order to meet the continuously growing demands,
extensive efforts are made to develop new standards for the evolution of
existing third generation (3G) technologies. The next steps in the development
of future cellular networks are the implementation of 3GPP long term
evolution (LTE) technology and its upcoming fourth generation (4G) successor
LTE-Advanced. The aim of next generation technologies is to provide mobile
users with high data rates that meet the requirements for future cellular
networks.
LTE-Advanced offers higher bandwidths as compared to 3G technologies, but the
carrier frequency is expected to be increased (possibly to 2.6 GHz).
Since transmission at higher frequencies may reduce coverage range due to
increased attenuation, concepts to mitigate this effect are required to
fulfill the demands on 4G systems also at the cell edges.
Recent research results show that cooperative schemes can solve many of the
issues faced by future wireless networks. Such cooperative schemes can include
cooperation among several base stations or between mobile user equipment in
order to form distributed multiple-input multiple-output (MIMO) arrays to
achieve higher spectral efficiency and/or data rates. Other schemes make use
of one or several (cooperating) relay stations that increase data rates
over larger distances.
The aim of this project is to develop cooperative methods for
implementation in LTE-Advanced based cellular networks. The schemes are
required to fulfill the demands of 4G systems as defined by the International
Telecommunication Union (ITU), while the costs such as the required
infrastructure (e.g. number of base stations), backhaul traffic, delay, or
financial costs should be minimized.
Such costs might be reduced by sophisticated cooperative schemes.
Recent academic results suggest a huge potential for performance increase in
cooperative communication networks. Relay based concepts and multinode
cooperation are expected to be key enablers for high spectral efficiency,
large coverage, and low latency.
The expected gains should be investigated under realistic conditions. The
concepts developed in this project should be applicable specifically for LTE
and LTE-Advanced networks. In particular, we focus on three different scenarios:
- A: Cooperation between base stations and possibly also between mobile
user stations in micro- and femtocells,
- B: Multinode cooperation with the use of additional nodes acting as
relays in macrocells as well as in micro- and femtocells, and
- C: Relaying concepts in wireless home networks.
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