Patent ID: 7839914
Filing Date: 2010-11-23
Classification: H04B,H04L

Abstract:
1. A method for channel estimation regarding multi-path characteristics of electromagnetic wave between a sender and a receiver by using a narrowband chirp-shift-keying signal or a narrowband multiple center-frequency-chirp signal, the narrowband chirp-shift-keying signal having narrowband chirp signals repeated along an axis of time, the narrowband multiple center-frequency-chirp signal being a sum of chirp signals having various center frequencies, the method comprising the steps of: (a) multiplying a received composite signal by the narrowband chirp-shift-keying signal or the narrowband multiple center-frequency-chirp signal generated by the receiver and outputting a sum of individual frequency components resulting from difference in distances of multiple paths for up-chirp signal portions and down-chirp signal portions of a chirp-shift-keying signal, respectively, the received composite signal being formed by superimposing and adding the narrowband chirp-shift-keying signals or the narrowband multiple center-frequency-chirp signals sent at a transmission antenna of the sender and received at a reception antenna of the receiver via a multi-path channel; (b) multiplying outputs of the up-chirp signal portion and the down-chirp signal portions of the sum of individual frequency components to thereby produce a tolerance frequency output; (c) compensating for a frequency tolerance of the sum of individual frequency components by using the tolerance frequency output to thereby generate a frequency compensation output; (d) compensating for discontinuity of chirp-shift-keying signals resulting from use of the narrowband chirp-shift-keying signals or the narrowband multiple center-frequency-chirp signals regarding the frequency compensation output to thereby generate a discontinuity compensation output; (e) decomposing the discontinuity compensation output into individual multi-path signals by using a frequency analysis method; and (f) extracting an attenuation component and a time delay component caused by the multi-path channel from the individual multi-path signals by using a size of frequency components of each frequency.