Cellular network having improved method for managing RF channels

• US 6,198,910 B1
• Filed: 04/28/1999
• Issued: 03/06/2001
• Est. Priority Date: 04/28/1999
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Hanley, Donald V.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Jackson, Blane J.
• Application Number:
  US09/301,537
• Time in Patent Office: 678 Days
• Field of Search: 455/67.1, 455/450, 455/436, 455/437, 455/62, 455/522, 455/67.7, 455/452
• US Class Current: 455/67.11
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 28/24 Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/265 taking into account the quality of service QoS
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention is a centralized RF management system that controls RF channels in a cellular network. An RF management system is provided that combines multiple parameters in a way to improve the overall quality of service offered to mobile subscribers, while at the same time greatly simplifying the operator'"'"'s RF engineering activities. The present invention is based on a “Quality Map” or Q-Map of the system. The Q-Map identifies, for a particular mobile at a particular point in time, the estimated quality of service the mobile would receive on each available RF channel in each available mode (i.e. analog, digital) at each available power level. The Q-map is created and updated based on information available from the cellular system, including signal strength measurements, interference, call activity and so on. In addition, each mobile is assigned a quality value (Q-value) that reflects it current quality of service. When a mobile unit'"'"'s Q-value falls below an operator defined threshold (Q-min), the mobile unit'"'"'s current Q-map is searched for the highest channel/mode/power level combination. If that Q-map value is greater than the mobile units current Q-value, then the unit is instructed to take the appropriate action (handoff, change mode, change power level, or a combination of these), resulting in an improved quality of service for the mobile.

Claims

1. A method of managing RF communications between at least one mobile unit and a base station in a mobile telecommunications system, said method comprising the steps of:

setting a threshold minimum level of call quality (Q-min) for said RF communications;

measuring a call quality value (Q-value) of a prescribed call of said RF communications;

comparing said call quality value with said threshold minimum quality value; and

dynamically managing radio frequency channels of said RF communications in said mobile telecommunications network as a function of said call quality value and said minimum level of call quality, wherein dynamically managing radio frequency channels includes generating a quality map (Q-map) of said mobile telecommunications network for each said at least one mobile station during the prescribed call at a particular point in time, the quality map including an estimate of a quality of service said at least one mobile station would receive on each available RF channel in each available mode at each available power level.

2. The method according to claim 1 wherein said step of dynamically managing radio frequency channels further includes adjusting at least one of the following plurality of parameters selected from the group consisting of:

raising a transmission power parameter of said mobile unit;

raising a transmission power parameter of said base station;

changing a frequency parameter of said RF communication; and

changing a mode parameter of said RF communication.

3. The method according to claim 2 wherein said step of dynamically managing radio frequency channels still further includes:

raising said transmission power parameter of said mobile unit;

checking said call quality value against said threshold minimum quality value; and

maintaining said plurality of parameters when said call quality value is greater than said threshold minimum quality value.

4. The method according to claim 2 wherein said step of dynamically managing radio frequency channels still further includes:

raising said transmission power parameter of said base station;

checking said call quality value against said threshold minimum quality value; and

maintaining said plurality of parameters when said call quality value is greater than said threshold minimum quality value.

5. The method according to claim 4 wherein said step of dynamically managing radio frequency channels still further includes:

changing said frequency parameter of said RF communication;

checking said call quality value against said threshold minimum quality value; and

maintaining said plurality of parameters when said call quality value is greater than said threshold minimum quality value.

6. The method according to claim 5 wherein said step of dynamically managing radio frequency channels still further includes:

changing said mode parameter of said RF communication;

checking said call quality value against said threshold minimum quality value; and

maintaining said plurality of parameters when said call quality value is greater than said threshold minimum quality value.

7. The method according to claim 2 wherein said step of dynamically managing radio frequency channels still further includes:

determining a predicted quality value for said RF communication which is generated by sequentially substituting variable parameters for said plurality of parameters; and

changing any one of said plurality of parameters when said predicted quality value is greater than said threshold minimum quality value.

8. A method of managing RF communications between at least one mobile unit and a base station in a mobile telecommunications system, said method comprising the steps of:

setting a threshold minimum quality value for said RF communications;

measuring a call quality value of a prescribed call of said RF communications;

comparing said call quality value with said threshold minimum quality value;

dynamically managing radio frequency channels of said RF communications in said mobile telecommunications network as a function of said call quality value and said threshold minimum level of call quality, wherein dynamically managing radio frequency channels includes generating a quality map (Q-map) of said mobile telecommunications network for each said at least one mobile station during the prescribed call at a particular point in time, the quality map including an estimate of a quality of service said at least one mobile station would receive on each available RF channel in each available mode at each available power level, wherein dynamically managing includes adjusting at least one of a plurality of parameters relating to said RF communication when said call quality value is less than said threshold minimum quality value;

determining a predicted quality value for said RF communication which is generated by sequentially substituting variable parameters for said plurality of parameters; and

changing any one of said plurality of parameters when said predicted quality value is greater than said threshold quality value.

9. The method according to claim 8 wherein adjusting at least one of a plurality of parameters comprises one of the following selected from the group consisting of:

raising a transmission power parameter of said mobile unit;

raising a transmission power parameter of said base station;

changing a frequency parameter of said RF communication; and

changing a mode parameter of said RF communication.

10. A cellular network having an RF management capability comprising:

a mobile switching center;

at least one base station controller operatively coupled to said mobile switching center;

at least one base station operatively coupled to said at least one base station controller;

at least one mobile station operatively coupled to said at least one base station for carrying out a prescribed call; and

a radio frequency manager operatively coupled to said at least one base station and said at least one mobile station for dynamically managing radio frequency channels in said cellular network as a function of a call quality value (Q-value), and more particularly, a minimum level of call quality (Q-min), such that an overall quality of service provided by said cellular network is improved, wherein dynamically managing radio frequency channels by said radio frequency manager includes generating a quality map (Q-map) of said system for each said at least one mobile station during the prescribed call at a particular point in time, the quality map including an estimate of a quality of service said at least one mobile station would receive on each available RF channel in each available mode at each available power level.

11. The network of claim 10, wherein the minimum level of call quality (Q-min) corresponds to a minimum call quality level as determined by an operator of said cellular network.

12. The network of claim 10, wherein available modes include analog and digital modes.

13. The network of claim 10, wherein said RF manager creates and updates the quality map (Q-map) based upon prescribed information available from said system.

14. The network of claim 13, wherein the prescribed information includes at least one of the following selected from the group consisting of signal strength measurements, interference, and call activity.

15. The network of claim 10, wherein said RF manager searches the quality map (Q-map) of a respective mobile station for a highest channel/mode/power level combination for restoring a minimum level of quality upon a determination that the Q-value of a respective said at least one mobile station falls below the minimum acceptable quality level (Q-min).

16. The network of claim 10, wherein said RF manager operates to restore a minimum level of quality upon a determination that the Q-value of a respective said at least one mobile station falls below the minimum acceptable quality level.

17. A cellular network having an RF management capability comprising:

a mobile switching center;

at least one base station controller operatively coupled to said mobile switching center;

at least one base station operatively coupled to said at least one base station controller;

at least one mobile station operatively coupled to said at least one base station for carrying out a prescribed call; and

a radio frequency manager operatively coupled to said at least one base station and said at least one mobile station for dynamically managing radio frequency channels in said cellular network as a function of a call quality value (Q-value), and more particularly, a minimum level of call quality (Q-min), such that an overall quality of service provided by said cellular network is improved, wherein dynamically managing radio frequency channels by said radio frequency manager includes generating a quality map (Q-map) of said system for each said at least one mobile station during the prescribed call at a particular point in time, the quality map including an estimate of a quality of service said at least one mobile station would receive on each available RF channel in each available mode at each available power level wherein each of said at least one mobile stations is assigned a Q-value representative of a current quality of service of a respective said at least one mobile station, further wherein said RF manager operates to adjust prescribed parameters in connection with more than one call by said at least one mobile station upon an occurrence and detection of an interference between two mobile stations.

18. The network of claim 17, further wherein said RF manager operates to restore a minimum level of quality upon a determination that the Q-value of a respective said at least one mobile station falls below the minimum acceptable quality level.

19. A cellular network having an RF management capability comprising:

a mobile switching center;

at least one base station controller operatively coupled to said mobile switching center;

at least one base station operatively coupled to said at least one base station controller;

at least one mobile station operatively coupled to said at least one base station for carrying out a prescribed call; and

a radio frequency manager operatively coupled to said at least one base station and said at least one mobile station for dynamically managing radio frequency channels in said cellular network as a function of a call quality value (Q-value), and more particularly, a minimum level of call quality (Q-min), such that an overall quality of service provided by said cellular network is improved, wherein dynamically managing radio frequency channels by said radio frequency manager includes generating a quality map (Q-map) of said system for said at least one mobile station during the prescribed call at a particular point in time, the quality map including an estimate of a quality of service said at least one mobile station would receive on each available RF channel in each available mode at each available power level, wherein said RF manager creates and updates the quality map (Q-map) based upon prescribed information available from said system, wherein the prescribed information includes at least one of the following selected from the group consisting of signal strength measurements, interference, and call activity, and wherein said RF manager searches the quality map (Q-map) of a respective mobile station for a highest channel/mode/power level combination for restoring a minimum level of quality upon a determination that the Q-value of a respective said at least one mobile station falls below the minimum acceptable quality level (Q-min).