DocumentCode :
2023988
Title :
Green communications and positioning by integration of adaptive and distributed beam-forming technologies in cognitive radio systems
Author :
Lian, X. ; Nikookar, H. ; Ligthart, L.P.
Author_Institution :
IRCTR, Delft Univ. of Technol., Delft, Netherlands
fYear :
2011
fDate :
Feb. 28 2011-March 3 2011
Firstpage :
1
Lastpage :
6
Abstract :
Cognitive radio (CR) concepts were introduced by J. Mitola in 1999/2000. It is an approach with high potential to allow most-intensive usage of the precious natural source spectrum. CR is capable of sensing the communication environments and of adapting to its environment by adjusting the radio parameters. With beam-forming techniques, CR can direct its main beam towards CR users while creating nulls to licensed users (LU´s) in up-link in order to share the same spectrum with LU´s without disturbing them. Adaptive beam-forming (AB) techniques are used for interference reduction by null broadening (NB) of the beam patterns of a CR base station in down-link operations. In this way by steering those NB angular sectors towards selected regions the LU´s will experience less interference. Distributed Beam-forming (DB) is a new concept to form beams by distributed wireless sensors in order to transmit signals over a long distance with less transmit power. At IRCTR of Delft University cognitive radio concepts receive broad attention in the Radio Advanced Technology and Systems (RATS) program. Several MSc´s and PhD´s participate in this program. In this invited paper the latest IRCTR results on AB and DB are overviewed. Furthermore, our Intelligent-WiMAX (I-WiMAX) initiative is summarized with some focus on adaptive OFDM and on applications for green communications and positioning.
Keywords :
OFDM modulation; adaptive modulation; adaptive signal processing; array signal processing; cognitive radio; interference suppression; wireless sensor networks; CR base station; I-WiMax; IRCTR; NB angular sectors; RATS program; adaptive OFDM; adaptive beamforming technology; cognitive radio systems; distributed beamforming technology; distributed wireless sensors; green communications; intelligent-WiMAX; interference reduction; licensed users; null broadening; radio advanced technology and systems program; Green products; Interference; Niobium; OFDM; Rats; Relays; Wireless communication; OFDM; WiMAX; adaptive/distributed beam-forming; cognitive radio; green communications; license users;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Wireless Communication, Vehicular Technology, Information Theory and Aerospace & Electronic Systems Technology (Wireless VITAE), 2011 2nd International Conference on
Conference_Location :
Chennai
Print_ISBN :
978-1-4577-0786-5
Type :
conf
DOI :
10.1109/WIRELESSVITAE.2011.5940897
Filename :
5940897
Link To Document :
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