Method for monitoring the state of interference by a base station of a mobile radio communication system

• US 5,603,093 A
• Filed: 12/13/1995
• Issued: 02/11/1997
• Est. Priority Date: 12/28/1994
• Status: Expired due to Term

• Current Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Inventors: Wakabayashi, Tatsuaki, Yoshimi, Masaaki, Nagata, Kiyohito, Kakinuma, Kazuhiko
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/571,649
• Time in Patent Office: 426 Days
• Field of Search: 455/33.1, 455/33.2, 455/34.1, 455/34.2, 455/50.1, 455/54.1, 455/54.2, 455/56.1, 455/62, 455/63, 455/67.1, 455/67.3, 455/69, 455/70, 455/226.1, 455/226.2 , 455/226.3, 379/59, 379/60
• US Class Current: 455/63.1
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports

Abstract

A mobile station measures the field intensity and bit error rate of a downlink radio wave from a base station at each measurement timing and reports the measured results to the base station. Upon receiving the measured results from each mobile station, the base station compares the measured results with a reference characteristic to determine if they are abnormal or not. The base station acquires the determined results of the measured results for a fixed period of time and statistically processes them to judge the state of interference.

Claims

1. A method for monitoring the state of interference in each zone of a mobile radio communication system wherein a mobile station in each zone performs communication via a base station of said each zone, said method comprising the steps of:

(a) periodically measuring, by said mobile station, the field intensity and quality of a downlink radio wave from said base station;

(b) reporting measured results from said mobile station to said base station;

(c) collecting, by said base station for a predetermined period of time, said measured results reported from said mobile station and statistically processing said collected measured results into data about the state of interference by comparing said measured results with a predetermined reference characteristic to judge whether said measured results are abnormal or not, said reference characteristic being a characteristic predetermined on the basis of a characteristic representing an ideal relationship between field intensity and bit error rate; and

(d) evaluating said data about said state of interference, thereby judging the state of interference between the radio wave from said base station and other radio waves of the same frequency as that of said radio wave from said base station, it being judged whether said measured results are abnormal by comparing said measured results with said bit error rate defined by said reference characteristic, the ratio of the number of measured results judged as abnormal to the number of measured results collected for said predetermined period of time being used as an index indicating said state of interference.

2. The method of claim 1, wherein said downlink radio wave is a downlink control channel.

3. The method of claim 1, wherein said step (b) comprises a step of requesting said mobile station from said base station to send thereto said measured results, and a step of sending said measured results from said mobile station to said base station in response to said request.

4. The method of claim 1, wherein said step (b) comprises a step of voluntarily sending said measured results from said mobile station at regular time intervals.

5. A method for monitoring the state of interference in each zone of a mobile radio communication system wherein a mobile station in each zone performs communication via a base station of said each zone, said method comprising the steps of:

(a) periodically measuring, by said mobile station, the field intensity and quality of a downlink radio wave from said base station;

(b) reporting measured results from said mobile station to said base station;

(c) collecting, by said base station for a predetermined period of time, said measured results reported from said mobile station and statistically processing said collected measured results into data about the state of interference by comparing said measured results with a predetermined reference characteristic to judge whether said measured results are abnormal or not, said reference characteristic being defined by error rate threshold values determined on the basis of an ideal characteristic indicating an ideal relationship between field intensity and bit error rate in respective intensity regions obtained by dividing field intensity; and

(d) evaluating said data about said state of interference, thereby judging the state of interference between the radio wave from said base station and other radio waves of the same frequency as that of said radio wave from said base station, by deciding the intensity region to which said measured results belong, comparing said measured results with said threshold value of said intensity region to determine whether said measured results are abnormal or not, calculating the ratio of the number of measured results determined to be abnormal to the number of measured results belonging to each of said intensity regions during said predetermined period of time, weighting said ratios with predetermined weighting factors, respectively, and summing said weighted ratios to obtain an index indicating said state of interference.