Antenna selection technique for fast diversity

摘要

A fast diversity technique using either an EESM or a capacity computation can determine antenna selection in a wireless communication device. A fast Fourier transform (FFT) for the EESM/capacity computation can be performed with consecutive samples of a single symbol period of a short training field (STF) of a packet received by each antenna. The effective signal-to-noise ratio (SNR) for each antenna can be calculated using the results of the EESM or capacity computation. The antenna with the highest effective SNR is selected.

主权项

1. A method of selecting an antenna from a plurality of antennas in a wireless communication device, the method comprising:
detecting a packet using a first antenna and performing a first coarse gain selection for the first antenna, thereby generating a first gain setting; determining one or more calibration parameters for one or more exponential effective SINR (signal to interference plus noise ratio) mapping (EESM) computations; performing a fast Fourier transform (FFT) operation for a first EESM computation of the one or more EESM computations with a first plurality of consecutive samples from a single symbol period of a short training field (STF) of the packet received by the first antenna using the first gain setting; switching to a second antenna; determining whether analog-to-digital conversion (ADC) saturation occurs after switching to the second antenna; and when no ADC saturation occurs after switching to the second antenna:
performing a FFT operation for a second EESM computation of the one or more EESM computations with a second plurality of consecutive samples from the STF received by the second antenna using the first gain setting;calculating an effective signal-to-noise ratio (SNR) for the first and second antennas based on results of the first and second EESM computations; andselecting the antenna from the plurality of antennas, the antenna having a highest effective SNR of the plurality of antennas; and when ADC saturation occurs after switching to the second antenna:
determining a level of ADC saturation, and when the level of ADC saturation exceeds a predetermined threshold, selecting the second antenna without performing a FFT operation for the one or more EESM computations with samples received by the second antenna.