Cooperative Relaying in Wireless Networks

Acronym: RELAY
Start: 01.2008
End:   12.2010


Abstract
The basic problem of networked systems is to deliver information from one network node to another network node in a reliable and resource-efficient manner. This problem is well solved for quasi-static networks (e.g., phone network, Internet) and for networks in which only the end-device is mobile (e.g., cellular networks). In self-organizing networks in which each node can be mobile, however, various research challenges appear.

Important aspects:

• energy efficiency
  
  
• robustness to mobility and failure of nodes
  
  
• wireless routing

In particular if certain Quality of Service (QoS) demands must be fulfilled for multimedia applications.

Mobile networks of the next generation
Devices in current mobile networks communicate through installed base stations and a fixed net-infrastructure. For mobile networks of the next generation the principle of ad hoc communication will gain importance. Thus, devices can communicate with each other, resulting in a wireless, self-organizing network which does not rely on infrastructure. For this new way of communication, also called "relaying", there is a broad spectrum of applications.

Applications
It can be used for inter-car-communication to prevent accidents and for the linkage of autonomous robots or wireless sensors - all fields of technology where huge growth is predicted. But also in conventional, cellular mobile radio researchers expect tremendous improvements of the system through relay-methods.

Cooperative relaying
The concept of cooperative relaying promises gains in robustness and energy- efficiency in wireless networks. The goal of this project is to design and assess concepts, algorithms, and protocols for cooperative relaying in the context of self-organizing wireless networked systems.

Working areas
The working areas include:

• design of protocols for relay selection
  
  
• analysis of the network capacity
  
  
• design of cooperative channel and network coding
  
  
• physical layer aspects, such as cooperative modulation and channel estimation.

Future perspectives
Despite the progress in certain aspects of relay systems during the past years, several research and development issues remain or have just emerged. In fact, much more work is needed to obtain a clear and broader understanding of the critical design issues and performance results of such systems. Furthermore, the actual deployment of these technologies into real systems that serve a particular application field is still in the fledgling stages.