Site survey for wireless base station placement
Apparatuses, methods, and systems for surveying a site are disclosed. One method includes transmitting, by a ground unit, wireless signals while a directionally adjustable beam-forming antenna of the ground unit changes a beam direction of the transmission of the wireless signals to N beam directions, wherein the directionally adjustable beam-forming antenna includes a known motion, receiving and measuring, by an elevated unit, a magnitude and phase of the wireless signals transmitted by the ground unit through the N beam directions, determining N complex receive power representations wherein each complex receive power representation includes the measured magnitude and phase of the received wireless signals corresponding with each of the N beam directions, and determining a receive power summation comprising performing a complex summation of the N complex receive power representations.
1. A method of surveying a site, comprising:
transmitting, by a ground unit, wireless signals while a directionally adjustable beam-forming antenna of the ground unit changes a beam direction of the transmission of the wireless signals to N beam directions, wherein the directionally adjustable beam-forming antenna includes a known motion that includes the directionally adjustable beam-forming antenna changing directions at a predetermined rate and each of N beam directions being uniformly separated from each other;
receiving and measuring, by an elevated unit, a magnitude and phase of the wireless signals transmitted by the ground unit through the N beam directions;
determining N complex receive power representations wherein each complex receive power representation includes the measured magnitude and phase of the received wireless signals corresponding with each of the N beam directions; and
determining a receive power summation comprising performing a complex summation of the N complex receive power representations.
2. The method of claim 1 , further comprising designating a location of the ground unit as in-range of a base station at a location of the elevated unit if the determined receive power summation is greater than a predetermined threshold level.
3. The method of claim 1 , wherein the elevated unit includes an omni-directional antenna.
4. The method of claim 1 , wherein the receive power summation is determined at multiple locations of the ground unit.
5. The method of claim 1 , wherein the receive power summation is determined at multiple elevations of the elevated unit or at multiple locations of the elevation platform.
6. The method of claim 1 , wherein the directionally adjustable beam-forming antenna of the ground unit changes a beam direction of the transmission of the wireless signals over a full azimuth sweep of 360 degrees.
7. The method of claim 1 , wherein the directionally adjustable beam-forming antenna of the ground unit changes a beam direction of the transmission of the wireless signals over an elevation sweep of 180 degrees.
8. The method of claim 1 , wherein the directionally adjustable beam-forming antenna of the ground unit comprises a dish antenna.
9. The method of claim 1 , wherein determining the receive power summation further comprises determining a power azimuth spectrum (PAS) for each of the N beam directions, comprising for each one of the N beam directions:
estimating the PAS based on the known motion of the adjustable beam-forming antenna, a known beam-forming pattern of the adjustable beam-forming antenna, and the measured phase and amplitude of the received wireless signals of the one of the N beam directions comprising:
transforming values of the measured phase and amplitude of the received wireless signals of the one of the N beam directions and the known beam-forming pattern into a frequency domain;
performing a power azimuth angular spectrum estimation in the frequency domain; and
transforming the estimated power azimuth angular spectrum back to a time domain.
10. The method of claim 9 , further comprising performing a complex summation of the PAS of the each of the N beam directions.
11. The method of claim 9 , wherein performing the power azimuth angular spectrum estimation in the frequency domain, comprises:
removing frequency domain samples of the known beam-forming pattern having zero values;
removing frequency domain samples of the measured phase and amplitude of the received wireless signals that correspond with the removed frequency domain samples of the known beam-forming pattern;
dividing the frequency domain samples of the measured phase and amplitude of the received wireless signals with the frequency domain samples of the known beam-forming pattern for a frequency bin of each sample after removing the frequency domain samples.
12. The method of claim 9 , wherein estimating the power azimuth angular spectrum of the surveyed site based on the known motion of the adjustable beam-forming antenna, the known beam-forming pattern of the adjustable beam-forming antenna, and the measured phase and amplitude of the received wireless signals comprises:
estimating the power azimuth angular spectrum, comprising:
determining an FFT (fast Fourier transform) of the measured phase and amplitude of the received wireless signals;
determining an FFT of an antenna radiation pattern of the adjustable beam-forming antenna;
frequency domain windowing the FFT of the measured phase and amplitude of the received wireless signals;
frequency domain windowing the FFT of an antenna radiation pattern of the adjustable beam-forming antenna;
frequency domain estimating the frequency domain windowing the FFT of the measured phase and amplitude and the frequency domain windowing the FFT of an antenna radiation pattern; and
determining and IFFT (inverse fast Fourier transform) of the frequency domain estimate.
13. A site survey tool, comprising:
a ground unit operating to transmit wireless signals while a directionally adjustable beam-forming antenna of the ground unit changes a beam direction of the transmission of the wireless signals to N beam directions, wherein the directionally adjustable beam-forming antenna includes a known motion that includes the directionally adjustable beam-forming antenna changing directions at a predetermined rate and each of N beam directions being uniformly separated from each other;
an elevated unit operating to receive and measure a magnitude and phase of the wireless signals transmitted by the ground unit through the N beam directions;
a controller operating to:
determine N complex receive power representations wherein each complex receive power representation includes the measured magnitude and phase of the received wireless signals corresponding with each of the N beam directions;
determine a receive power summation comprising performing a complex summation of the N complex receive power representations.
14. The site survey tool of claim 13 , wherein the controller is further operative to designate a location of the ground unit as in-range of a base station at a location of the elevated unit if the determined receive power summation is greater than a predetermined threshold level.
15. The site survey tool of claim 13 , wherein the receive power summation is determined at multiple locations of the ground unit.
16. The site survey tool of claim 13 , wherein the receive power summation is determined at multiple elevations of the elevated unit or at multiple locations of the elevation platform.
17. The site survey tool of claim 13 , wherein determining the receive power summation further comprises determining a power azimuth spectrum (PAS) for each of the N beam directions, comprising for each one of the N beam directions, the controller operating to:
estimate the PAS based on the known motion of the adjustable beam-forming antenna, a known beam-forming pattern of the adjustable beam-forming antenna, and the measured phase and amplitude of the received wireless signals of the one of the N beam directions comprising:
transform values of the measured phase and amplitude of the received wireless signals of the one of the N beam directions and the known beam-forming pattern into a frequency domain;
perform a power azimuth angular spectrum estimation in the frequency domain; and
transform the estimated power azimuth angular spectrum back to a time domain.
18. The site survey tool of claim 17 , wherein the controller further operates to perform a complex summation of the PAS of the each of the N beam directions.
19. The site survey tool of claim 17 , wherein performing the power azimuth angular spectrum estimation in the frequency domain, comprises the controller operating to:
remove frequency domain samples of the known beam-forming pattern having zero values;
remove frequency domain samples of the measured phase and amplitude of the received wireless signals that correspond with the removed frequency domain samples of the known beam-forming pattern;
divide the frequency domain samples of the measured phase and amplitude of the received wireless signals with the frequency domain samples of the known beam-forming pattern for a frequency bin of each sample after removing the frequency domain samples.
20. The site survey tool of claim 17 , wherein estimating the power azimuth angular spectrum of the surveyed site based on the known motion of the adjustable beam-forming antenna, the known beam-forming pattern of the adjustable beam-forming antenna, and the measured phase and amplitude of the received wireless signals comprises the controller operating to:
estimate the power azimuth angular spectrum, comprising:
determining an FFT (fast Fourier transform) of the measured phase and amplitude of the received wireless signals;
determining an FFT of an antenna radiation pattern of the adjustable beam-forming antenna;
frequency domain windowing the FFT of the measured phase and amplitude of the received wireless signals;
frequency domain windowing the FFT of an antenna radiation pattern of the adjustable beam-forming antenna;
frequency domain estimating the frequency domain windowing the FFT of the measured phase and amplitude and the frequency domain windowing the FFT of an antenna radiation pattern; and
determining and IFFT (inverse fast Fourier transform) of the frequency domain estimate.