Expert System

• US 20080261587A1
• Filed: 05/02/2006
• Published: 10/23/2008
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lennartson, Benny, Sundberg, Krister
• Granted Patent: US 8,064,901 B2
• Time in Patent Office: Days
• US Class Current: 455/424
• CPC Class Codes: H04B 17/17 Detection of non-compliance or faulty performance, e.g. response deviations H04B17/18 takes precedence
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 7/08 at the receiving station
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition

Abstract

Expert system for evaluating diversity antenna installations. Antenna elements 11a. 11b have the respective coverage areas 32a and 32b. Due to an antenna mismatch the diversity is degraded or even lost for reception from mobile stations 13, 33 especially far from the antenna. By measuring the received signal strength. RXLEV, difference from the mobile stations in the respective branches of the diversity antenna the mismatch could be evaluated and corrected. By dividing the coverage areas into several zones with different distance to the antenna the result is enhanced.

Claims

1. A system for evaluating antenna installations in a mobile radio communication system with more than one antenna element to in radio base stations of the system, wherein the received signal strength at the respective antenna element from a number of transmitting units are measured by means in the base stations, characterized in that the signal strength values from each antenna element of one or several of said base stations are compared in a calculating unit and that a plurality of comparison results are represented as a function of the comparison result and a parameter related to the position of the measured mobile stations relative to the location of the base station.

2. The system of claim 1, wherein the comparison is the difference of signal strength in pairs of antenna elements.

3. The system of claim 1, wherein the comparison is the quotient of signal strength values in pairs of antenna elements.

4. The system of claim 1, wherein the comparison is the average of signal strength values in a number of antenna elements.

5. The system of claim 1, wherein the parameter is the timing advance or the transmission path loss of the mobile stations.

6. The system of claim 1, wherein the parameter is recently made handovers from a neighbouring cell for the measured mobile stations.

7. The system of claim 1, wherein the function of the comparison is displayed on a device in the form of a histogram.

8. The system of claim 1, wherein the evaluation result is presented as a list indicating transceiver groups tested and a fault indicator describing the result of the evaluation.

9. The system of claim 1, wherein the radio base station comprises a transceiver group with several diversity antenna elements covering the same cell area and wherein at least some of the antenna elements are transmit-only antennas and that the evaluation is based on comparison of received dummy receptions from the transmit-only antennas with or without combination with receptions in the other diversity antennas.

10. A method for evaluating antenna installations in a cellular mobile communication system wherein one or several radio base stations of the system, each having more than one antenna element, measures the signal strengths from a number of mobile stations in the cell, characterized in that the received signal strength values are compared with each other and that the number of such comparison results are evaluated as a function of the comparison result and a parameter related to the position of the mobile stations in the cell.