Fractional spaced dual channel estimation based on decimated feedback

A recent development by Xu et al. presented an effective forward channel identification method in duplex wireless mobile communications. By letting the mobile receiver send a fraction of the received data back to the base station, both forward and reverse channel identification can be achieved at the base transmitter. In this work, we extend this bent-pine feedback approach to accommodate fractionally spaced sampling and to utilize known pulse shape for better performance. We demonstrate that the new method requires minor modification on the system structure. Furthermore, with the fractionally spaced channel output, we can use the known information such as the pulse shaping filter and anti-aliasing filter to improve the channel identification and significantly reduce the needed data sample size.