Patent ID: 8098749

Claim:
A channel frequency response (CFR) estimation method for a multi-band orthogonal frequency division multiplexing (OFDM)-based ultra-wideband (UWB) system to achieve a CFR estimation, ĥ r =[ĥ r (0),ĥ r (1), . . . , ĥ r (N−1)] T , on an rth sub-band, N indicating the number of subcarriers employed by one OFDM symbol, the superscript T denoting transpose, comprising: receiving an OFDM-UWB frame in an OFDM-UWB receiver of the multi-band OFDM-based UWB system; obtaining, by the OFDM-UWB receiver, a first CFR estimation ĥ r (1) =[ĥ r (1) (0),ĥ r (1) (1), . . . , ĥ r (1) (N−1)] T by performing least square estimation using a channel estimation sequence in the received OFDM-UWB frame; obtaining a second CFR estimation ĥ r (2) =[ĥ r (2) (0),ĥ r (2) (1), . . . , ĥ r (2) (N−1)] T by applying frequency-domain smoothing to the first CFR estimation ĥ r (1) using a first smoothing factor; obtaining, from the received OFDM-UWB frame, a frame header containing a plurality of OFDM symbols, each OFDM symbol being transmitted with frequency-domain spreading, and being divided into N transmitted signals for modulating corresponding subcarriers; for each OFDM symbol, detecting signs of the N transmitted signals using two frequency-domain spread signals corresponding to each of the N transmitted signals and the second CFR estimation ĥ r (2) ; obtaining a third CFR estimation ĥ r (3) =[ĥ r (3) (0),ĥ r (3) (1), . . . , ĥ r (3) (N−1)] T using the detected signs and a finite-alphabet feature of the N transmitted signals for each OFDM symbol; obtaining a fourth CFR estimation ĥ r (4) =[ĥ r (4) (0), ĥ r (4) (1), . . . , ĥ r (4) (N−1)] T by applying frequency-domain smoothing to the third CFR estimation ĥ r (3) with a second smoothing factor; and obtaining the CFR estimation ĥ r by averaging the second and fourth CFR estimations ĥ r (2) and ĥ r (4) .