Process and device for managing intercellular transfers of radio communications in a cellular radio communication system by measuring virtual speeds of cellular devices

• US 6,253,084 B1
• Filed: 12/31/1998
• Issued: 06/26/2001
• Est. Priority Date: 06/07/1996
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Monot, Jean-Jacques
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US09/147,358
• Time in Patent Office: 908 Days
• Field of Search: 455/440, 455/441, 455/444, 455/449, 455/456, 455/457, 342/450, 342/457, 342/461
• US Class Current: 455/441
• CPC Class Codes: G01S 3/30 derived directly from separate directional systems
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells

Abstract

A process for managing intercellular transfers of communication in a cellular radio communication system. A specified number of microcells inside umbrella cells each respectively possess a base station for allowing the routing of the communications. Radio direction finding is used to pinpoint at least two successive virtual positions of the mobile stations in communication in relation to the base station of the umbrella cell in order to deduce therefrom a speed of movement of each mobile station in the time interval which separates the pinpointing of their positions. The speeds of movement which are obtained are compared to the specified speed values so as to entrust the management of the communication from a mobile station to the base station of the umbrella cell in which it lies when its speed is greater than the specified speed value, or to the base station of the microcells when it is not greater than the specified speed value.

Claims

1. Process for managing an intercellular transfer of communications from a mobile station in a cellular radio communication system including a specific number of microcells inside umbrella cells, wherein each of said microcells and each of said umbrella cells includes a base station for allowing a routing of said communications, comprising the steps of:

counting a number of handovers H_o of said mobile station between said microcells during a specified observation interval T_o when said mobile station is under control of the base station of a microcell;

calculating a rate of transfer H_o/T_o for performing said intercellular transfer of communications to an umbrella station when said rate of transfer is greater than a specified threshold value when said mobile station is under a control of said base station of said microcell;

maintaining said intercellular transfer of communications to said base station of said microcell when said rate of transfer is below said specified threshold value when said mobile station is under control of said base station of said microcell; and

performing direction finding to measure a virtual speed of movement of said mobile station in relation to said base station of said umbrella cell in such a way as to perform said intercellular transfer of communications to said base station of said microcell when said virtual speed of movement measured by said direction finding is below a specified speed value when said mobile station is under control of said umbrella cell.

2. Process according to claim 1, wherein said mobile station communicates with said base station in accordance with GSM cellular radio communication network interfaces and protocols.

3. Process according to claim 1, further comprising the steps of:

performing said direction finding to pinpoint at least two successive virtual positions of said mobile station in relation to said base station of said umbrella cell so as to deduce therefrom said virtual speed of movement of said mobile station in a time interval which separates a pinpointing of said at least two successive virtual positions of said mobile station;

comparing said virtual speed of movement with said specified speed value so as to manage said communications of said mobile station at said base station of said umbrella cell in which said mobile station lies when said virtual speed of movement of said mobile station is greater than said specified speed value; and

comparing said virtual speed of movement with said specified speed value so as to transfer management of said communications of said mobile station from said base station of said umbrella cell in which said mobile station lies to said base station of said microcell when said virtual speed of movement of said mobile station is less than or equal to said specified speed value.

4. Process according to claim 3, further comprising the step of pinpointing said at least two successive positions of said mobile station in terms of azimuth and distance.

5. Process according to claim 4, wherein azimuthal pinpointing is performed with aid of a multichannel radio direction finder by determining an angle of arrival of electromagnetic waves transmitting electromagnetic signals from said mobile station.

6. Process according to claim 5, further comprising the step of synchronizing said multichannel radio direction finder to said base station of said umbrella cell so as to allow angular locating of said mobile station with a best signal-to-noise ratio.

7. Process according to claim 6, further comprising the step of determining a distance separating said mobile station from said base station of said umbrella cell by measuring, in said base station, a time of propagation of radio waves between said mobile station and said base station.

8. Process according to claim 6, wherein said mobile station communicates with said base station in accordance with GSM cellular radio communication network interfaces and protocols.

9. Process according to claim 5, further comprising the step of determining a distance separating said mobile station from said base station of said umbrella cell by measuring, in said base station, a time of propagation of radio waves between said mobile station and said base station.

10. Process according to claim 5, wherein said mobile station communicates with said base station in accordance with GSM cellular radio communication network interfaces and protocols.

11. Process according to claim 4, further comprising the step of determining a distance separating said mobile station from said base station of said umbrella cell by measuring, in said base station, a time of propagation of radio waves between said mobile station and said base station.

12. Process according to claim 4, wherein said mobile station communicates with said base station in accordance with GSM cellular radio communication network interfaces and protocols.

13. Process according to claim 3, further comprising the step of determining a distance separating said mobile station from said base station of said umbrella cell by measuring, in said base station, a time of propagation of radio waves between said mobile station and said base station.

14. Process according to claim 13, wherein said mobile station communicates with said base station in accordance with GSM cellular radio communication network interfaces and protocols.

15. Process according to claim 3, wherein said mobile station communicates with said base station in accordance with GSM cellular radio communication network interfaces and protocols.