Mobile radio channels' Estimation for SC-FDMA systems by means of adequate Noise and Inter-carrier Interference filtering in a transformed domain
Abstract
This paper proposes a new channel estimation technique for mobile radio multipath channels in the context of SCFDMA1[ 1],[2],[3],[4] system. SC-FDMA is currently adopted for mobile radio uplink communications in 3G LTE2 because of its low PAPR3. In this system, 1/7 SC-FDMA time symbols are dedicated to perform the channel estimation. This is sufficient when the channel can be considered as constant over the 7 symbol periods. But it is clear that transmission channel can change rapidly over time, typically when the user (UE) moves with an important enough velocity, thus introducing Doppler effect and therefore Inter-Carrier Interference (ICI). Our proposition deals with this situation, and consists in filtering the channel noise and ICI perturbation through a new transformed domain. This approach is based on the variation rate of the channel's frequency response and the nature of the noise and ICI component in the Transformed domain. The performances obtained are very convincing since we have up to 3 dB gain compared to the simple interpolation solution encountered in the literature.