A decision-aided channel estimation strategy for the IEEE 802.11p standard

The computational complexity and the power consumption of Channel State Information (CSI) acquisition are important drawbacks in wireless communication systems. Focusing on the special case of the IEEE 802.11p standard for wireless access in vehicular environments, this paper proposes an strategy to reduce the computational complexity associated to the CSI acquisition by including a decision rule to automatically determine the time instants when CSI must be updated. Otherwise, the previous channel estimate is re-utilized. The decision criterion has a very low computational complexity since it consists of calculating the cross-correlation between preambles sent by the transmit antennas which are included in the standard for frame detection as well as for time and frequency synchronization. Since channel estimation takes place only if the decision criterion determines a significant channel variation, it leads to a considerable reduction of computational complexity for channel estimation methods, without penalizing the performance in terms of Bit Error Rate (BER).