Title :
Compensating for CQI aging by channel prediction: The LTE downlink
Author :
Akl, R.A. ; Valentin, Stefan ; Wunder, Gerhard ; Stanczak, Slawomir
Author_Institution :
Fraunhofer Inst. for Telecommun., Heinrich Hertz Inst., Berlin, Germany
Abstract :
In the downlink of Long Term Evolution (LTE) systems, feedback and processing delays cause a mismatch between the current channel state and the Channel Quality Information (CQI) at the base station. This CQI aging leads to inaccurate channel adaptation and can, thus, highly degrade the cell capacity. To compensate for this performance loss, we study several CQI predictors under realistic delay and channel assumptions. Our results on cell throughput show that linear prediction with Stochastic Approximation provides at least the performance gains of the computationally more complex covariance-based linear predictors and Kalman filters. This surprising result points to Stochastic Approximation as a powerful and practical technique to increase downlink performance with limited channel knowledge.
Keywords :
Kalman filters; Long Term Evolution; approximation theory; channel allocation; covariance analysis; delays; feedback; stochastic processes; telecommunication network reliability; CQI aging; CQI predictors; Kalman filters; LTE downlink; LTE systems; base station; cell capacity; cell throughput; channel adaptation; channel assumptions; channel prediction; channel quality information; covariance-based linear predictors; current channel state; downlink performance; feedback; limited channel knowledge; linear prediction; long term evolution systems; performance gains; performance loss; processing delays; realistic delay; stochastic approximation;
Conference_Titel :
Global Communications Conference (GLOBECOM), 2012 IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
978-1-4673-0920-2
Electronic_ISBN :
1930-529X
DOI :
10.1109/GLOCOM.2012.6503882