System and method for point to multipoint radio survey
First Claim
1. A method for simultaneously performing a radio frequency evaluation survey of multiple base station site candidates, the method comprising:
- i) a plurality of stationary receiver units, wherein at least one stationary receiver unit being located at each base station candidate site;
ii) a mobile test transmit unit located in a test vehicle;
iii) transmitting one or more radio test signals from said mobile test unit;
iv) recording a time stamp for each location along the drive route 900 of said test vehicle, the power of said transmitted radio signals, and geographical coordinates of each location;
v) receiving said radio test signals at each of said stationary test receivers, measuring the signal strength of said radio test signals, and recording said signal strength of these measurements along with a time stamp for each measurement;
vi) correlating said recorded signal strength measurements with the location of the mobile test unit for each recorded corresponding time stamp;
vii) calculating the path loss between the location of each base station candidate site, and each location along the drive route 900 visited by said test vehicle during the test survey as the ratio of transmitted and received test signals for the timestamp corresponding to said location;
whereby said path loss information for said base station candidate sites is obtained with a single drive of said test vehicle throughout the desired test area.
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Abstract
A methodology and system for performing radio network coverage surveys of multiple site candidates concurrently using one reserved channel based on reverse path signal strength measurements of a signal from a test mobile station transmitter (100) to a plurality of prospective base station receiver sites (200, 200′, . . . ) over a geographical area is presented. The instantaneous position, time-stamp and power of the Transmitter (101) is recorded and stored as it moves along a test route(s). Stationary Test Receiver(s) (201) tuned to the selected channel at each prospective site location (200, 200′, . . . ) save received instantaneous signal strength and, it'"'"'s time-stamp so they can matched up to the position of the Test Transmitter (101) and used to ascertain received signal strength at each site. Results can be useful for ascertaining optimum site locations, antenna configurations, propagation model tuning, frequency planning, pilot planning and extraction of signal correlation statistics.
14 Citations
23 Claims
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1. A method for simultaneously performing a radio frequency evaluation survey of multiple base station site candidates, the method comprising:
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i) a plurality of stationary receiver units, wherein at least one stationary receiver unit being located at each base station candidate site; ii) a mobile test transmit unit located in a test vehicle; iii) transmitting one or more radio test signals from said mobile test unit; iv) recording a time stamp for each location along the drive route 900 of said test vehicle, the power of said transmitted radio signals, and geographical coordinates of each location; v) receiving said radio test signals at each of said stationary test receivers, measuring the signal strength of said radio test signals, and recording said signal strength of these measurements along with a time stamp for each measurement; vi) correlating said recorded signal strength measurements with the location of the mobile test unit for each recorded corresponding time stamp; vii) calculating the path loss between the location of each base station candidate site, and each location along the drive route 900 visited by said test vehicle during the test survey as the ratio of transmitted and received test signals for the timestamp corresponding to said location; whereby said path loss information for said base station candidate sites is obtained with a single drive of said test vehicle throughout the desired test area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
wherein said test receiver, receives said radio test signals, measures the signal strength received at said receive antennas, generates an accurate time stamp corresponding to each received signal measurement, and records said measurements and the corresponding time stamp for future download and analysis.
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3. A stationary test receiver of claim 2 wherein said receiver control and alarm function block is comprised of a single board microcomputer with all associated processors, firmware and, software stored in appropriate on board memory elements.
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4. A stationary test receiver of claim 2 wherein said receiver timing system is comprised of a global positioning receiver with its accompanying external antenna.
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5. A method of claim 1 wherein a mobile test transmitter comprising:
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i) a transmitter control and alarm function block that performs all control and alarming functions of said mobile test transmitter, wherein said alarm function block is connected via internal electronic data communications buses to all other blocks of said mobile test transmitter; ii) a radio frequency transmitter unit comprising; (a) a radio frequency transmitter that generates said radio test signals; (b) a plurality of transmit antennas connected to output of said radio frequency transmitter to transmit said radio test signals; (c) a synthesizer unit to synthesize waveforms of said test signals, and set the transmit frequency of said radio frequency transmitter, wherein the selection of said radio frequency and waveforms is determined by commands from said transmitter control and alarm function block iii) a transmitter positioning and timing system to track accurately the exact geographical location and the exact time said mobile test transmitter is at that geographical location, iv) a transmitter storage means to store the exact geographical location and the exact time said mobile test transmitter is at that exact geographical location as it moves about the geographical area of the radio coverage survey, wherein the transmitter storage means may also store other pertinent data including alarms, transmitter frequency and power level; v) a transmitter user interface wherein an operator provides configuration and control commands to said test transmitter, and stored test locations and their corresponding time stamps, and any other data stored in said transmitter storage means, are downloaded to external devices; vi) a wireless modem and its external antenna wherein the modem may be used to wirelessly connect said mobile test transmitter unit to external locations; vii) a power supply unit to supply regulated power from the mobile test vehicle to said mobile test transmitter at the power levels required for all its various constituent parts; wherein said mobile test transmitter, generates and transmits said radio test signals, accurately tracks the exact geographic location of said mobile test transmitter as it moves about the geographical area of the radio coverage survey, generates an accurate time stamp corresponding to each exact geographic location, and records said locations and the corresponding time stamp for future download and correlation with receive measurements from said stationary receiver units.
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6. A mobile test transmitter of claim 5 wherein said transmitter control and alarm function block is comprised of a single board microcomputer with all associated processors, firmware and, software stored in appropriate on board memory elements.
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7. A mobile test transmitter of claim 5 wherein said transmitter positioning and timing system is comprised of a global positioning receiver with its accompanying external antenna.
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8. A mobile test transmitter of claim 5 wherein said transmitter positioning and timing system is comprised of a dead-reckoning system.
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9. A mobile test transmitter of claim 7 wherein said transmitter positioning and timing system is comprised of a dead-reckoning system to provide a backup system in case the global positioning receiver loses satellite coverage.
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10. A method of claim 1 further comprising a control and alarming mainframe connected to each of said stationary test receiver units via wireless or wired connection, and also connected to said mobile test transmit unit via wireless connection.
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11. A control and alarming mainframe of claim 10 wherein said control and alarming mainframe collects operational data, alarms, faults and other information from said stationary test receiver units, and relays this information to said mobile test transmit unit.
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12. A control and alarming mainframe of claim 10 wherein said control and alarming mainframe receives control and configuration commands from said mobile test transmit unit, intended for one or more of said stationary test receiver units, and said control and alarming mainframe relays commands to said stationary test receiver units.
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13. A control and alarming mainframe of claim 12 wherein said control and alarming mainframe receives responses for and acknowledgements to said control and configuration commands, from responding stationary test receiver units, and relays said responses and acknowledgements to said mobile test transmit unit.
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14. A control and alarming mainframe of claim 10 wherein said control and alarming mainframe collects operational data, alarms, faults and other information from said stationary test receiver units, and said mobile test unit, and relays this information to an external user or control system for further action.
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15. A control and alarming mainframe of claim 10 wherein said control and alarming mainframe receives control and configuration commands from external user or control system, intended for one or more of said stationary test receiver units, or for one or more of said mobile transmit units, and said control and alarming mainframe relays these commands to said stationary test receiver units and said mobile transmit units.
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16. A control and alarming mainframe of claim 15 wherein said control and alarming mainframe receives responses for and acknowledgements to said control and configuration commands, from responding stationary test receiver units, or responding mobile transmit units, and relays said responses and acknowledgements to said external user or control system.
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17. A control and alarming mainframe of claim 10 comprising of a readily available commercial personal computer, modem and, all related firmware, software and, algorithms.
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18. A method of post-processing samples of measured radio test signals collected per the method of claim 1, the method comprising:
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i) correlating a time stamp associated with each digitized sample of said test signals received by a fixed test receiver unit, to the corresponding time stamp collected by said mobile transmit unit; ii) associated said time stamp collected by said mobile transmit unit with an exact geographical location of said test vehicle; iii) calculating the path loss and phase difference between said base station candidate, corresponding to said fixed test receiver unit, and said exact geographical location of said test vehicle; iv) whereby said path loss is calculated as the ratio of transmitted and received test signals for the timestamp corresponding to said location; b) whereby said phase difference is calculated as the difference in phase of transmitted and received test signals for the timestamp corresponding to said location.
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19. The method of claim 18 wherein said calculation of path loss and phase difference is employed to characterize multiple input multiple output channel between said base station candidate location and test vehicle location, wherein the method of claim 18 is repeatedly applied to each pair of transmit and receiver antennas, individually.
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20. The method of claim 18 wherein filtering is applied to the collected signal strength data samples, prior to or following the calculation of the corresponding path loss or phase difference values.
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21. The method of claim 20 wherein said filtering is applied to signal strength data samples spaced evenly in time, to achieve temporal averaging of the path loss values.
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22. The method of claim 20 wherein said filtering is applied to signal strength data samples spaced evenly in distance, to achieve spatial averaging of the path loss values.
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23. The method of claim 18 wherein the correlation is calculated between two different path loss values obtained for two of the said based station candidate locations, or two receiver antenna locations at the same based station candidate locations, or two receiver antennas at different based station candidate locations.
Specification