Detecting the number of transmit antennas in wireless communication systems
US7539260B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2005 |
| Grant date | May 26, 2009 |
| Priority date | — |
| Expiry date | Jan 31, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W88/06
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
To detect the number of transmit antennas, a fast Fourier transform operation is performed on the received samples of the transmitted long training symbols of a preamble. Next, each of the Fourier transformed results is multiplied with the reference frequency-domain representation of the long training symbol so as to remove the effect of the symbols and to maintain the channel information. Next, inverse Fourier transform or least squares operations is performed on the multiplied values to compute channel impulse response. The number of shifted impulse response in the channel impulse response represents the detected number of transmit antennas. Packets containing preambles of the present invention may be received by extended devices as well as by legacy receivers that are not configured to receive and interpret these preambles. The training symbols may be cyclically-shifted and transmitted on different transmit antennas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.