liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Frequency Domain Link Adaptation for OFDM-based Cellular Packet Data
Linköping University, Department of Electrical Engineering.
2006 (English)Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

In order to be competitive with emerging mobile systems and to satisfy the ever growing request for higher data rates, the 3G consortium, 3rd Generation Partnership Project (3GPP), is currently developing concepts for a long term evolution (LTE) of the 3G standard. The LTE-concept at Ericsson is based on Orthogonal Frequency Division Multiplexing (OFDM) as downlink air interface. OFDM enables the use of frequency domain link adaptation to select the most appropriate transmission parameters according to current channel conditions, in order to maximize the throughput and maintain the delay at a desired level. The purpose of this thesis work is to study, implement and evaluate different link adaptation algorithms. The main focus is on modulation adaptation, where the differences in performance between time domain and frequency domain adaptation are investigated. The simulations made in this thesis are made with a simulator developed at Ericsson. Simulations show in general that the cell throughput is enhanced by an average of 3% when using frequency domain modulation adaptation. When using the implemented frequency domain power allocation algorithm, a gain of 23-36% in average is seen in the users 5th percentile throughput. It should be noted that the simulations use a realistic web traffic model, which makes the channel quality estimation (CQE) difficult. The CQE has great impact on the performance of frequency domain adaptation. Throughput improvements are expected when using an improved CQE or interference avoidance schemes. The gains with frequency domain adaptation shown in this thesis work may be too small to motivate the extra signalling overhead required. The complexity of the implemented frequency domain power allocation algorithm is also very high compared to the performance enhancement seen.

Place, publisher, year, edition, pages
Institutionen för systemteknik , 2006. , 95 p.
Keyword [en]
OFDM, 3G LTE, link adaptation, power allocation
National Category
URN: urn:nbn:se:liu:diva-6328ISRN: 3812OAI: diva2:21764
Available from: 2006-04-24 Created: 2006-04-24 Last updated: 2009-10-08Bibliographically approved

Open Access in DiVA

fulltext(971 kB)1787 downloads
File information
File name FULLTEXT01.pdfFile size 971 kBChecksum MD5
Type fulltextMimetype application/pdf

By organisation
Department of Electrical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 1787 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 1629 hits
ReferencesLink to record
Permanent link

Direct link