| 摘要 |
<p>In a multiple-input, multiple-output (MIMO) system, a wireless node's receive chain demodulation function is enhanced to include phase tracking. VHT Long Training Fields (LTFs) embedded in a frame preamble are used for phase tracking. Single stream pilot tones are added during transmission of VHT-LTFs. A receiver estimates the channel using the pilot tones in a first set of LTFs. A second set of LTFs are used to estimate the phase of the pilot tones using the estimated channel. The phase estimation is continuously applied to other received data tones throughout the VHT-LTFs of data symbols. Phase errors due to PLL mismatches and phase noise are reduced at reception, leading to better signal to noise ratio for different levels of drift and frequency offset. Further, MIMO channel estimation is more accurate, improving the overall wireless network when the accurate MIMO channel estimation data participates in calibration and handshake between wireless nodes.</p> |
