Browsing by Author "Gameiro, A."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- An iterative pilot-data aided estimator for OFDM-based relay-assisted systemsPublication . Neves, D.; Ribeiro, Carlos; Silva, A.; Gameiro, A.We propose and assess a pilot-data aided channel estimation scheme for realistic relay-assisted scenarios designed for the downlink SFBC OFDM-based systems. We consider that both the base station and the relay node are equipped with an antenna array whereas the user terminal is a single antenna device. The relay protocol considered is equalise-and-forward. The channel estimation method iteratively uses the information carried by the pilots and data to improve the estimate of the equivalent channels for the path Base Station - Relay Node - User Terminal. The MMSE criterion is used in the design of the estimator for both the pilot-based and data-aided iterations. The results show the benefits of cooperation in terms of MSE and also show that the proposed scheme allows, with a single data iteration, a reduction of the number of pilots when compared with non-data-aided schemes.
- A Pilot-Data Based Channel Estimation Method for OFDM Relay-Assisted SystemsPublication . Neves, D.; Ribeiro, C.; Silva, A.; Gameiro, A.In this work we propose and evaluate a pilot and data-based channel estimation scheme for SFBC OFDM-based cooperative scenario. We consider that both the base station and the relay node are equipped with double antenna arrays whereas the user terminal is a single antenna device. The relay protocol considered is equalise-andforward. In this paper we propose a channel estimation method that iteratively uses the information carried by the pilots and data to improve the estimate of the equivalent channels for the path Base Station – Relay Node – User Terminal. The MMSE criterion is used in the design of the estimator for both the pilot-based and data-aided iterations. The proposed method is evaluated in terms of the channel estimation MSE and the results show that the proposed scheme allows, with a single data iteration, a reduction of the number of pilots by a factor of approximately two when compared with non-data-aided schemes.
- A Time Domain Channel Estimation Scheme for Equalize-and-Forward Relay-Assisted SystemsPublication . Neves, D.; Ribeiro, C.; Silva, A.; Gameiro, A.In this paper we propose a scheme with a dedicated relay node for an OFDM-based system. We consider an antenna array at the base station and a single antenna at both the user terminal and the relay node. The relay-assisted protocol considered is equalize-and-forward. The proposed scheme requires the computation of parameters which depend on unknown variables at the destination and we show that under some assumptions the scheme is suitable to provide all those requirements. Also, we show that since the pilots at the relay node are properly designed the TD-MMSE estimator can still provide the required channel estimate. The system performance is evaluated by considering a typical pedestrian scenario based on WiMAX specification. The results show that the degradation in the estimator performance is negligible.