System and method for identifying hot spots in the D-AMPS wireless system

• US 6,477,367 B1
• Filed: 11/05/1999
• Issued: 11/05/2002
• Est. Priority Date: 11/05/1999
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Kim, Shawn
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/434,083
• Time in Patent Office: 1,096 Days
• Field of Search: 455/423, 455/424, 455/432, 455/434, 455/436, 455/439, 455/443, 455/444, 455/446, 455/449, 455/453, 455/422, 455/445, 455/512, 455/513, 455/67.4, 455/67.1, 370/237, 370/331, 370/332
• US Class Current: 455/423
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

The present invention is a system and method to provide a scientific and quantitative measurement in finding optimal locations for placing new micro or pico cells. Signal strength information of a test transmitter measured by mobile stations is reported to a base station serving a macro cell via call quality messages that the mobile stations are located. A post-processing tool 330 counts the number of call quality messages having a signal strength level measured from the test transmitter above a threshold during a measuring period indicating that a call can be offloaded to the new micro or pico cell. The estimated offloaded traffic volume is then calculated, preferably in Erlangs.

Claims

1. A method for determining high traffic regions of subscribers operating in a macro cell of a cellular communication system, said method comprising the steps of:

transmitting a signal from a test transmitter;

receiving a message containing signal strength information of said signal transmitted from said test transmitter;

setting a signal strength threshold value for the signal strength information to be compared; and

processing said message in accordance with the signal strength threshold value to determine an estimated offloaded traffic volume for said cellular communication system, said processing including;

extracting said signal strength information from said message; and

computing said estimated offloaded traffic volume, said computing including;

counting said call quality messages having said signal strength measurement above a threshold value into a total count, wherein any of said signal strength messages above said threshold value indicates that a given call is capable of being offloaded; and

dividing said total count by a duration of time over which said step of counting is performed.

2. The method according to claim 1, further comprising the step of defining a virtual cell within said cellular communication system.

3. The method according to claim 2, wherein said step of defining further comprises the steps of:

matching a control channel number associated with said virtual cell to a frequency number related to said test transmitter; and

defining said virtual cell as a neighbor cell to said macro cell.

4. The method according to claim 1, wherein said signal transmitted from said test transmitter is a continuous wave or a digital modulated signal.

5. The method according to claim 1, wherein said message is a call quality message.

6. The method according to claim 1, further including the step of:

updating a signal strength table by said signal strength information contained in said message.

7. The method according to claim 1, further comprising altering power of the transmitter based on the estimated offloaded traffic volume.

8. A cellular communication system for determining high traffic regions of subscriber stations operating in a macro cell of said cellular communication system, said cellular communication system comprising:

a test transmitter for transmitting a signal;

a receiver for receiving a message containing signal strength information of said test transmitter, said message being transmitted by said subscriber stations; and

a processor for processing said message in accordance with a signal strength threshold value to determine an estimated offloaded traffic volume from said macro cell, said estimated offloaded traffic volume is computed on said processor by;

counting said call quality messages having said signal strength information above a threshold value into a total count, wherein any of said messages having signal strength information above said threshold value indicates that a given call is capable of being offloaded from said macro cell; and

dividing said total count by a duration of time over which said step of counting is performed.

9. The cellular communication system according to claim 8, further comprising a virtual cell defined in said communication system.

10. The cellular communication system according to claim 9, said virtual cell having a control channel number matching a frequency number related to said test transmitter and said virtual cell further defined as a neighbor cell to said macro cell.

11. The cellular communication system according to claim 9, wherein said virtual cell is defined in a mobile switching center connected to said cellular communication system.

12. The cellular communication system according to claim 8, wherein said signal transmitted from said test transmitter is a continuous wave or a digital modulated signal.

13. The cellular communications system according to claim 8, wherein said message is a call quality message.

14. The cellular communication system according to claim 8, wherein said processor extracts said signal strength information from said message and computes said estimated offloaded traffic volume.

15. The system according to claim 8, further comprising a power adjuster coupled to said test transmitter for altering power of said test transmitter based on the estimated offloaded traffic volume.

16. The cellular communication system according to claim 8, wherein said processor is connected to a base station serving said macro cell.

17. The cellular communication system according to claim 8, further comprising a signal strength table, said signal strength table being updated by said signal strength information contained in said message.

18. A method for determining high traffic regions of subscribers operating in a macro cell of a cellular communications system, said method comprising the steps of:

receiving a definition of a virtual cell for said cellular communication system;

transmitting a signal having a frequency number matching a channel control number associated with said virtual cell;

setting a signal strength threshold value;

receiving at least one message containing signal strength information; and

processing the at least one message in accordance with the signal strength threshold value to determine an estimated offloaded traffic volume of said subscribers, said processing further including;

counting said at least one message having signal strength information above a threshold value to produce a total count, wherein said threshold value indicates that a call is capable of being handed off to a new cell; and

computing said offloaded traffic volume by dividing said total count by a measuring period for said step of counting.

19. The method according to claim 18, further comprising the step of:

receiving said at least one message having signal strength information of said signal.

20. The method according to claim 18, wherein said virtual cell comprises a route and a cell name.

21. The method according to claim 18, further including the step of:

updating a signal strength table by said signal strength information contained in said message.

22. The method according to claim 18, further comprising altering power of said transmitting based on the estimated offloaded traffic volume.

23. A method for determining high traffic regions of subscribers operating in a macro cell of a cellular communication system, said method comprising the steps of:

transmitting a signal from a test transmitter;

receiving a message containing signal strength information of said signal transmitted from said test transmitter; and

processing said message to determine an estimated offloaded traffic volume for said cellular communication system, said processing including;

extracting said signal strength information from said message; and

computing said estimated offloaded traffic volume, said computing including;

counting said call quality messages having said signal strength measurement above a threshold value into a total count, wherein any of said signal strength messages above said threshold value indicates that a given call is capable of being offloaded; and

dividing said total count by a duration of time over which said step of counting is performed.

24. A cellular communication system for determining high traffic regions of subscriber stations operating in a macro cell of said cellular communication system, said cellular communication system comprising:

a test transmitter for transmitting a signal;

a receiver for receiving a message containing signal strength information of said test transmitter, said message being transmitted by said subscriber stations; and

a processor for processing said message to determine an estimated offloaded traffic volume from said macro cell, said processor determining the estimated offload by;

counting said call quality messages having said signal strength information above a threshold value into a total count, wherein any of said messages having signal strength information above said threshold value indicates that a given call is capable of being offloaded from said macro cell; and

dividing said total count by a duration of time over which said step of counting is performed.

25. A method for determining high traffic regions of subscribers operating in a macro cell of a cellular communications system, said method comprising:

receiving a definition of a virtual cell for said cellular communication system;

transmitting a signal having a frequency number matching a channel control number associated with said virtual cell;

receiving at least one message containing signal strength information;

processing the at least one message to determine an estimated offloaded traffic volume of said subscribers, said processing including;

counting said at least one message having signal strength information above a threshold value to produce a total count, wherein said threshold value indicates that a call is capable of being handed off to a new cell; and

computing said offloaded traffic volume by dividing said total count by a measuring period for said step of counting.