Towards Systems Beyond 3G Based on Adaptive OFDMA Transmission
Artikel i vetenskaplig tidskrift, 2007

High data rates, high spectral efficiency, flexibility, and low delays over the air interface will be important features in next-generation wireless systems. The overall challenge will be packet scheduling and adaptive radio transmission for multiple users, via multiple antennas and over frequency-selective wideband channels. This problem needs to be structured to obtain feasible solutions. The basic simplifying assumptions used here are clustering of antennas into cells, orthogonal transmission by use of cyclic-prefix orthogonal frequency-division multiplexing (OFDM) and a time-scale separation view of the total link adaptation, scheduling and intercell coordination problem. Based on these assumptions, we survey techniques that adapt the transmission to the temporal, frequency, and spatial channel properties. We provide a systematic overview of the design problems, such as the dimensioning of the allocated time-frequency resources, the influence of duplexing schemes, adaptation control issues for downlinks and uplinks, timing issues, and their relation to the required performance of channel predictors. Specific design choices are illustrated by recent research within the Swedish Wireless IP program and the EU IST-WINNER project. The presented results indicate that high-performance adaptive OFDM transmission systems are indeed feasible, also for challenging scenarios that involve vehicular velocities, high carrier frequencies, and high bandwidths.

orthogonal frequency-division multiplexing (OFDM)

broadband radio transmission

link adaptation

channel prediction

spatial division multiple access (SDMA)

orthogonal frequency-division multiple access (OFDMA)

wireless broadband

channel-aware scheduling

channel estimation

timedivision multiple access (TDMA)


Mikael Sternad

Uppsala universitet

Tommy Svensson

Chalmers, Signaler och system, Kommunikation, Antenner och Optiska Nätverk

Tony Ottosson Gadd

Chalmers, Signaler och system, Kommunikation, Antenner och Optiska Nätverk

Anders Ahlen

Uppsala universitet

Arne Svensson

Chalmers, Signaler och system, Kommunikation, Antenner och Optiska Nätverk

Anna Brunström

Karlstads universitet

Proceedings of the IEEE

0018-9219 (ISSN) 15582256 (eISSN)

Vol. 95 12 2432 - 2455 4389761


Informations- och kommunikationsteknik


Elektroteknik och elektronik



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