Performance of Relaying Protocols

No Thumbnail Available
Journal Title
Journal ISSN
Volume Title
Elektroniikan, tietoliikenteen ja automaation tiedekunta | Master's thesis
Date
2009
Department
Major/Subject
Signaalinkäsittelytekniikka
Mcode
S-88
Degree programme
Elektroniikan ja sähkötekniikan tutkinto-ohjelma
Language
en
Pages
125
Series
Abstract
In wireless systems, cooperative diversity and relaying can exploit the benefit of spatial diversity and combat heavy pathloss without requiring multiple antennas at the receivers and transmitters. For practical networks, the use of relays is motivated by the need for simple, inexpensive terminals with limited power and a single antenna. The motivation for this thesis is to study and propose practical relaying protocols that can reduce the power consumption and ameliorate the performance with minimum additional complexity. Based on a dual-hop communication model, we exploit two upper bounds for the end-to-end SNR. These bounds further inspire us to propose new relaying protocols for wireless communication systems. We examine the case of a single user and relay under Rayleigh and Nakagami-m fading conditions. Based on the general upper bound, a new protocol is introduced: Clipped gain. This protocol makes it possible to save the transmit power by stopping the transmission when the quality of the first hop leads to an outage. We consider also user selection and user scheduling for dual-hop communication with multiple users and relays over a Rayleigh fading channel. We introduce new scheduling protocols based on one-bit feedback information. To the best of our knowledge, most of the available literature uses full channel state information to perform user selection and user scheduling. Interestingly, our protocols based on one bit feedback greatly improve the system performance while adding less additional complexity. To carry out rigorous comparison, close-form expressions are derived and analytical results used to assess the outage probability performance.
Description
Supervisor
Wichman, Risto
Thesis advisor
Riihonen, Taneli
Keywords
cooperative diversity, multiple antennas, relay, dual-hop, relaying protocols, user selection, user scheduling, feedback
Other note
Citation