Method and System for Evaluating Radio Coverage

• US 7,522,918 B2
• Filed: 07/06/2006
• Issued: 04/21/2009
• Est. Priority Date: 07/08/2005
• Status: Expired due to Fees

• Current Assignee: CTA Communications, Inc.
• Original Assignee: CTA Communications, Inc.
• Inventors: Wachter, John Robert, Pociluyko, Joseph D., Ballard, Kenneth Alan
• Primary Examiner(s): Bhattacharya; Sam
• Application Number:
  US11/428,855
• Publication Number:
  US 20070010241A1
• Time in Patent Office: 1,020 Days
• Field of Search: 455/456.1, 455/422.1, 455/423, 455/424, 455/456.6, 455/12.1, 455/13.1, 455/13.2, 701/36, 701/200, 701/208, 701/216, 340/425.5, 340/435, 340/436, 342/358, 342/375
• US Class Current: 455/423
• CPC Class Codes: G10L 25/69 for evaluating synthetic or decoded voice signals
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

A system and method for testing radio coverage of a land mobile radio system. The system configuration generally employs a fixed unit, a mobile unit and the two-way radio system (not part of the invention) subject to testing. The test system and method are compatible with any land-mobile radio system (conventional, trunked, using proprietary or standards-based protocols, FDMA or TDMA) operating in any frequency band. One of three methods may be selected to perform testing at any one time: continuous testing, grid testing or receive-only testing. In the continuous and grid modes, both the talk-out and talk-in paths are measured. Test results are recorded in a computer file after being converted to a digital format, and are compared to an original “reference file” via the Perceptual Evaluation of Speech Quality (PESQ) algorithm as defined by ITU-T standard P.862. The PESQ output is then converted to a Delivered Audio Quality (DAQ) score by application of an empirical set of weighting factors to certain of the PESQ parameters.

Claims

1. A method to evaluate the radio coverage of a radio system by employing continuous, two-way testing for an allotted period of time at multiple locations using a system including a mobile location apparatus having a mobile test transceiver, a first GPS system, a programmable attenuator, a first RSSI receiver, a second RSSI receiver, an RSSI antenna system, a mobile control computer connected to a display unit and a first event log maintained by the mobile control computer all situated in a test vehicle and a fixed location apparatus having a stationary control computer, a second GPS system, a stationary test transceiver and a second event log maintained by the stationary control computer comprising:

performing software startup and initialization and GPS synchronization for both the mobile location apparatus using the first GPS system and the fixed location apparatus using the second GPS system;

verifying that the speed of the test vehicle exceeds a pre-selected minimum speed;

storing in the first event log a GPS time, GPS location and speed of the test vehicle when the test vehicle exceeds the pre-selected minimum speed;

adjusting the programmable attenuator based on the location of the test vehicle;

determining and storing noise levels in the first event log;

placing the mobile test transceiver in transmit mode;

if no transmission occurs within a pre-set period of time, returning to verifying;

transmitting a test message having a preamble portion and an audio portion both with known, fixed durations from the mobile location apparatus to the fixed location apparatus through the radio system;

further placing the mobile test transceiver in receive mode;

detecting reception of a preamble portion at the fixed location apparatus;

recording in the second event log the time of detection of a preamble portion;

initiating recording of an audio portion at the fixed location apparatus after expiration of the known duration for a preamble portion;

stopping recording of an audio portion at the fixed location apparatus after expiration of the known duration for an audio portion;

further storing the received recorded audio portion in the second event log as a digital file with a unique identifier together with the time when the received audio portion was received at the fixed location apparatus;

if an election was made not to assign DAQ scores in real time, jumping to pausing;

comparing the received recorded audio portion with a stored reference audio file;

assigning a score for DAQ to the received recorded audio portion;

associating the location tested with the score for DAQ for that location;

yet additionally storing the assigned DAQ score and associated location in the second event log;

pausing for a pre-determined period of time, after the expiration of which, the time is stored by the stationary control computer in the second event log;

yet further placing the stationary test transceiver in transmit mode;

if no transmission occurs within a pre-determined period of time, returning to detecting;

further transmitting a test message having a preamble portion and an audio portion both with known, fixed durations from the fixed location apparatus to the mobile location apparatus through the radio system;

still further placing the stationary test transceiver in receive mode;

monitoring for reception of a preamble portion transmitted by the stationary test transceiver to the mobile test transceiver;

if no preamble is detected within a specified time period, returning to verifying;

yet further storing in the first event log the GPS time, GPS location and test vehicle speed corresponding to when the preamble portion was detected;

collecting and storing RF signal strength levels in the first event log;

further initiating recording of an audio portion at the mobile location apparatus after expiration of the known duration for a preamble portion;

further stopping recording of an audio portion at the mobile location apparatus after expiration of the known duration for an audio portion;

additionally storing the received recorded audio portion in the first event log as a digital file together with a unique identifier;

if an election was made not to assign DAQ scores in real time,

pausing for a pre-determined period of time; and

returning to verifying until the allotted period of time has expired;

further comparing the received recorded audio portion with a stored reference audio file;

assigning a score for DAQ to the received recorded audio portion;

further associating the location tested with the score for DAQ for that location;

still further storing the assigned DAQ score and associated location in the first event log;

indicating on the display unit whether the location tested has passed or failed the test;

further pausing for a pre-defined time delay, and

returning to verifying until the allotted period of time has expired.

2. The method of claim 1 wherein determining and storing further comprises:

connecting the first RSSI receiver and the second RSSI receiver to the antenna system;

tuning the RSSI receivers to preprogrammed frequencies to gather noise data for one second;

storing the noise data in the mobile control computer; and

disconnecting the first RSSI receiver and the second RSSI receiver from the RSSI antenna.

3. The method of claim 1 wherein placing further comprises:

initiating a PTT signal from the mobile test transceiver;

monitoring for a pre-selected time period to detect RF power; and

if RF power is not detected during the pre-selected time period, discontinuing the PTT signal and returning to verifying.

4. The method of claim 3 wherein stopping recording further comprises:

discontinuing the PTT signal from the mobile test transceiver; and

reconnecting the first RSSI receiver and the second RSSI receiver to the RSSI antenna system.

5. The method of claim 1 wherein further stopping recording further comprises disconnecting the first RSSI receiver and the second RSSI receiver from the RSSI antenna system.

6. The method of claim 1 wherein the mobile control computer and the stationary control computer each has stored therein the same lookup table and assigning further comprises:

calculating the average root mean square amplitude of a received recorded audio portion;

if the average root mean square amplitude does not exceed 0.02,

assigning a DAQ of 0.0 to the test location;

designating the location as having failed the test; and

jumping to indicating;

calculating a Combined PESQ score for the received audio portion;

filtering out missing or blank audio from the received recorded message;

converting the PESQ score to a DAQ score by reference to the lookup table stored in the mobile control computer.

7. The method of claim 1 wherein, if the fixed location apparatus includes an optional RSSI receiver connected to an optional RSSI antenna, recording further comprises:

connecting the optional RSSI receiver to the optional RSSI antenna; and

capturing and storing RF signal strength data in the second event log.

8. The method of claim 1 wherein further placing further comprises:

initiating a PTT signal from the stationary test transceiver;

monitoring for a pre-selected time period to detect RF power; and

if RF power is not detected during the pre-selected time period, discontinuing the PTT signal and returning to verifying.

9. The method of claim 1 wherein, if an optional RSSI receiver and an optional RSSI antenna system are included with the fixed location apparatus, the RSSI receiver is disconnected after stopping recording.

10. The method of claim 1 wherein placing the stationary test transceiver in receive mode comprises:

removing the PTT signal from the stationary test transceiver and returning to detecting.

11. The method of claim 1 wherein indicating further comprises either displaying one or more colors or any other visible indicium, such as one or more selected from the group consisting of hatching, shading or inverse display or generating an aural indicium such as one or more selected from the group consisting of one tone, multiple tones or a sequence of tones.

12. A method to evaluate the radio coverage of a radio system by employing two-way testing of a predetermined number of equally sized, rectangular cells in a pre-designated geographic grid each of which is initially labeled as untested, wherein the geographic coordinates of each cell are stored in a first database and each cell is associated with a grid index number, using a system including a mobile location apparatus having a mobile test transceiver, a first GPS system, a programmable attenuator, a first RSSI receiver, a second RSSI receiver, an RSSI antenna system, a mobile control computer connected to a display and a first event log maintained by the mobile control computer all situated in a test vehicle and a fixed location apparatus having a stationary control computer, a second GPS system, a stationary test transceiver and a second event log maintained by the stationary control computer comprising:

performing software startup and initialization and GPS synchronization for both the mobile location apparatus using the first GPS system and the fixed location apparatus using the second GPS system;

verifying that the speed of the test vehicle exceeds a pre-selected minimum speed and that the vehicle has entered an untested cell;

storing in the first event log the GPS time, GPS location, grid index number and speed of the test vehicle based on the first GPS system corresponding to when the test vehicle exceeded the pre-selected minimum speed;

adjusting the programmable attenuator based on location of the test vehicle;

determining and storing noise levels in the first event log;

placing the mobile test transceiver in transmit mode;

if no transmission occurs within a pre-set period of time, returning to verifying;

transmitting a test message having a preamble portion and an audio portion both with known, fixed durations from the mobile location apparatus to the fixed location apparatus through the radio system;

further placing the mobile test transceiver in receive mode;

detecting reception of a preamble portion at the fixed location apparatus;

recording in the second event log the time of detection of a preamble portion;

initiating recording of an audio portion at the fixed location apparatus after expiration of the known duration for a preamble portion;

stopping recording of an audio portion at the fixed location apparatus after expiration of the known duration for an audio portion;

further storing the received recorded audio portion in the second event log as a digital file with a unique identifier together with the time when the received audio portion was received at the fixed location apparatus;

if an election was made not to assign DAQ scores in real time, jumping to pausing;

comparing the received recorded audio portion with a stored reference audio file;

assigning a score for DAQ to the received recorded audio portion;

associating the location tested with the score for DAQ for that location;

yet additionally storing the assigned DAQ score and associated location in the second event log;

pausing for a pre-determined period of time, after the expiration of which, the time is stored by the stationary control computer in the second event log;

yet further placing the stationary test transceiver in transmit mode;

if no transmission occurs within a pre-determined period of time, returning to detecting;

further transmitting a test message having a preamble portion and an audio portion both with known, fixed durations from the fixed location apparatus to the mobile location apparatus through the radio system;

still further placing the stationary test transceiver in receive mode;

monitoring for reception of a preamble portion transmitted by the stationary test transceiver to the mobile test transceiver;

if no preamble is detected within a specified time period, returning to verifying;

yet further storing in the first event log the GPS time, GPS location, grid index number and test vehicle speed corresponding to when the preamble portion was detected;

further adjusting the programmable attenuator based on either the geographic location or the grid index number identifying where the test vehicle is located, as preferred;

collecting and storing RF signal strength levels in the first event log;

further initiating recording of an audio portion at the mobile location apparatus after expiration of the known duration for a preamble portion;

further stopping recording of an audio portion at the mobile location apparatus after expiration of the known duration for an audio portion;

additionally storing the received recorded audio portion in the first event log as a digital file together with a unique identifier;

if an election was made not to assign DAQ scores in real time,

pausing for a pre-determined period of time; and

returning to verifying until the desired number of cells has been tested;

further comparing the received recorded audio portion with a stored reference audio file;

assigning a score for DAQ to the received recorded audio portion;

further associating the location tested with the score for DAQ for that location;

still further storing the assigned DAQ score and associated location in the first event log;

indicating on the display unit whether the cell tested has passed or failed the test by appropriately changing the label associated with that cell;

further pausing for a pre-defined time delay; and

returning to verifying until the desired number of cells has been tested.

13. The method of claim 12 wherein each cell is sized large enough to permit a moving vehicle to collect data while moving therethrough and small enough that the data collected by the moving vehicle is representative of the area contained within the cell.

14. The method of claim 12 wherein the grid containing the cells is rectangularly shaped with top and bottom boundaries parallel to each other along an east-west orientation and side boundaries parallel to each other along a north-south orientation.

15. The method of claim 12 wherein adjusting of the programmable attenuator is based on any unique conditions applicable in each cell as disclosed prior to testing and on whether a portable device hand-held at head level, clipped to a belt or supplied with a public safety speaker/microphone with shoulder-mounted antenna is to be used to perform the test.

16. The method of claim 12 wherein indicating further comprises either displaying

one or more colors or any other visible indicium, such as one or more selected from the group consisting of hatching, shading or inverse display or generating an aural indicium such as one or more selected from the group consisting of one tone, multiple tones or a sequence of tones.

17. The method of claim 12 wherein determining and storing further comprises:

connecting the first RSSI receiver and the second RSSI receiver to the RSSI antenna system;

tuning the RSSI receivers to preprogrammed frequencies to gather noise data for one second;

storing the noise data in the mobile control computer; and

disconnecting the first RSSI receiver and the second RSSI receiver from the RSSI antenna.

18. The method of claim 12 wherein further placing further comprises:

initiating a PTT signal from the mobile test transceiver;

monitoring for a pre-selected time period to detect RF power; and

if RF power is not detected during the pre-selected time period, discontinuing the PTT signal and returning to verifying.

19. The method of claim 18 wherein stopping recording further comprises:

discontinuing the PTT signal from the mobile test transceiver; and

reconnecting the first RSSI receiver and the second RSSI receiver to the RSSI antenna system.

20. The method of claim 12 wherein further stopping recording further comprises disconnecting the first RSSI receiver and the second RSSI receiver from the RSSI antenna system.

21. The method of claim 12 wherein the mobile control computer and the stationary control computer each has stored therein the same lookup table and assigning further comprises:

calculating the average root mean square amplitude of a received recorded audio portion;

if the average root mean square amplitude does not exceed 0.02, assigning a DAQ of 0.0 to the test location;

designating the location as having failed the test; and

jumping to indicating;

calculating a Combined PESQ score for the received audio portion;

filtering out missing or blank audio from the received recorded message;

converting the PESQ score to a DAQ score by reference to the lookup table stored in the mobile control computer.

22. The method of claim 12 wherein, if the fixed location apparatus includes an optional RSSI receiver connected to an optional RSSI antenna, recording further comprises:

connecting the optional RSSI receiver to the optional RSSI antenna; and

capturing and storing RF signal strength data in the second event log.

23. The method of claim 12 wherein further placing further comprises:

initiating a PTT signal from the stationary test transceiver;

monitoring for a pre-selected time period to detect RF power; and

if RF power is not detected during the pre-selected time period, discontinuing the PTT signal and returning to verifying.

24. The method of claim 12 wherein, if an optional RSSI receiver and an optional RSSI antenna system are included with the fixed location apparatus, the RSSI receiver is disconnected after stopping recording.

25. The method of claim 12 wherein placing the stationary test transceiver in receive mode comprises:

removing the PTT signal from the stationary test transceiver and

returning to detecting.

26. The method of claim 12 wherein indicating further comprises either displaying one or more colors or any other visible indicium, such as one or more selected from the group consisting of hatching, shading or inverse display or generating an aural indicium such as one or more selected from the group consisting of one tone, multiple tones or a sequence of tones.

27. A method to evaluate the radio coverage of a radio system through either mobile, receive-only, one-way testing of a pre-determined number of equally sized, rectangular cells in a pre-designated geographic grid each of which is initially labeled as untested, wherein the geographic coordinates of each cell are stored in a first database and each cell is associated with a grid index number, or mobile, receive-only, one-way continuous testing for an allotted period of time at multiple locations as selected by an operator, in both cases using a system including a mobile location apparatus having a mobile test transceiver, a first GPS system, a programmable attenuator, a first RSSI receiver, a second RSSI receiver, an RSSI antenna system, a mobile control computer connected to a display unit and a first event log maintained by the mobile control computer situated in a test vehicle and a fixed location apparatus having a stationary control computer, a second GPS system, a stationary test transceiver and a second event log maintained by the stationary control computer comprising:

performing software startup and initialization and GPS synchronization for both the mobile location apparatus using the first GPS system and the fixed location apparatus using the second GPS system;

connecting first RSSI receiver and second RSSI receiver to the RSSI antenna system;

selecting either grid testing or continuous testing;

placing the mobile test transceiver in receive mode;

monitoring for reception of a preamble portion transmitted by the stationary test transceiver to the mobile test transceiver;

storing the time in the second event log based on the second GPS system;

further placing the stationary test transceiver in transmit mode;

if no transmission occurs within a pre-determined period of time,

taking the stationary test transceiver out of transmit mode;

waiting for a pre-specified period of time; and

returning to further placing;

transmitting a test message having a preamble portion and an audio portion both with known, fixed durations from the fixed location apparatus to the mobile location apparatus through the radio system;

pausing for a pre-determined period of time;

further returning to placing until all cells have been tested, if grid testing was selected, or until a specified period of time has elapsed, if continuous testing was selected;

if grid testing has been selected,

ascertaining the geographic position of the test vehicle and, if the test vehicle has entered a cell previously tested, indicating the cell has been tested by appropriately changing the label associated with that cell and returning to monitoring;

further storing in the first event log the GPS time, GPS location, grid index number, if applicable, and speed of the test vehicle based on the first GPS system corresponding to when the preamble portion was detected;

adjusting the programmable attenuator based on the location of the test vehicle;

gathering and storing RF signal strength data in the first event log;

initiating recording of an audio portion at the mobile location apparatus after expiration of the known duration for a preamble portion;

stopping recording of an audio portion at the mobile location apparatus after expiration of the known duration for an audio portion;

yet further storing the received recorded audio portion in the first event log as a digital file with a unique identifier together with the time when the received audio portion was received at the mobile location apparatus;

if an election was made not to assign DAQ scores in real time,

returning to monitoring until the desired number of cells has been tested or the allotted period of time has expired;

comparing the received recorded audio portion with a stored reference audio file;

assigning a score for DAQ to the received recorded audio portion;

associating the location tested with the score for DAQ for that location;

still further storing the assigned DAQ score and associated location in the first event log;

indicating on the display unit whether the cell or location tested has passed or failed the test by appropriately changing the label and information associated with that cell;

further returning to monitoring until the pre-determined number of cells has been tested or the allotted period of time has expired.

28. The method of claim 27 wherein, if grid testing has been selected, further comprises deciding whether to allow multiple tests within individual cells in the grid and, if so, jumping to storing.

29. The method of claim 27 wherein indicating further comprises either displaying one or more colors or any other visible indicium, such as one or more selected from the group consisting of hatching, shading or inverse display or generating an aural indicium such as one or more selected from the group consisting of one tone, multiple tones or a sequence of tones.

30. The method of claim 27 wherein ascertaining further comprises comparing the location of the test vehicle as determined by the first GPS system with the coordinates for each cell in the grid as stored in the first database.

31. The method of claim 27 wherein further placing further comprises:

initiating a PTT signal from the mobile test transceiver;

monitoring for a pre-selected time period to detect RF power; and

if RF power is not detected during the pre-selected time period, discontinuing the PTT signal and returning to verifying.

32. The method of claim 27 wherein the mobile control computer has stored therein a lookup table and assigning further comprises:

calculating the average root mean square amplitude of a received recorded audio portion;

if the average root mean square amplitude does not exceed 0.02,

assigning a DAQ of 0.0 to the test location;

designating the location as having failed the test; and

jumping to indicating;

calculating a Combined PESQ score for the received audio portion;

filtering out missing or blank audio from the received recorded message;

converting the PESQ score to a DAQ score by reference to the lookup table.