Semester projet / Master thesis

Summer semester 2007

Adaptive Bit Loading and Power Loading for Cellular Two Way Relaying Systems

Relaying technology has recently become a hot research area in wirelees communication community. It has been shown to be promising in extending the coverage and combating shadowing effects. However, current relays cannot transmit and receive signals using the same time and frequency channel (half-duplex constraints). Thus traditional relaying schemes suffer from the loss in spectral efficiency. Recently, a spectral efficient relaying scheme called two-way relaying [1] has been proposed. This scheme achieves bidirectional transmission between the source and the destination in two time slots instead of four by combining the uplink and downlink transmission together, which avoids the spectral efficiency loss.

In the two way relaying scheme, the relay can obtain the channel knowledge from the source and destination in the first time slot transmission. Thus the relay can adapt the transmission power and the modulation constellation according to the channel knowledge in the second time slot. In this project, adaptive bit loading and power loading schemes [2] are to be investigated for the two way relaying scheme. We shall focus on scenarios in a cellular network. You will compare different bit or power loading schemes, and figure out the pros and cons of those schemes. Simulation results with be compared to traditional relaying systems.

This work will be done in corporation with DoCoMo Euro-Labs.


[1] B. Rankov and A. Wittneben, Spectral efficient protocols for half-duplex fading relay channels, IEEE J. Select. Areas Commun., 2007.
[2] C. Mutti, Link adaptation schemes for wireless multicarrier transmission systems. Ph.D thesis, 2005.

Type Semester projet / Master thesis
Subject area MIMO communication systems, link adaptation
Type of work 50% Theory, 50% Software (Matlab)
Supervisor Dr. Jian Zhao, Dr. Marc Kuhn
Professor Prof. Dr. Armin Wittneben