Method and apparatus for deriving a channel impulse response estimate for a wireless channel

• Main Authors: KASTURI NITIN, SETHURAMAN VIGNESH, MERGEN GOKHAN, SUBRAHMANYA PARVATHANATHAN
• Format: Patent
• Language: English
• Published: 17.05.2007
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

Techniques for deriving a channel impulse response estimate (CIRE) having improved quality are described. A first CIRE with multiple channel taps is obtained based on (1) an initial CIRE derived from a received pilot or (2) a filtered CIRE derived from the initial CIRE. In one aspect, the channel taps in the first CIRE are scaled with multiple scaling factors to obtain a second CIRE. For point-wise LMMSE scaling, the energy of each channel tap is estimated. The noise energy for the channel taps is also estimated, e.g., based on energies of channel taps on one or both edges of the first CIRE. Each channel tap is scaled based on a scaling factor determined by the energy of that channel tap and the noise energy. Each channel tap with energy below a threshold may be set to zero. In another aspect, the second CIRE is obtained by zeroing out selected ones of the channel taps in the first CIRE.