Method of spatial location of a mobile station in a cell of a communication network and corresponding base station, mobile station and signaling packet

• US 6,269,247 B1
• Filed: 11/23/1998
• Issued: 07/31/2001
• Est. Priority Date: 11/27/1997
• Status: Expired due to Fees

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Chiodini, Alain
• Primary Examiner(s): Woo, Stella
• Assistant Examiner(s): Taylor, Barry W.
• Application Number:
  US09/198,055
• Time in Patent Office: 981 Days
• Field of Search: 455/447, 455/466, 455/446, 455/449, 455/561, 455/560, 455/562, 455/456, 343/909, 343/841
• US Class Current: 455/456.2
• CPC Class Codes: H01Q 15/0006 Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices H01Q15/12, H01Q15/22, H01Q15/24 take precedence
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

In a method for spatially locating a mobile station in a cell of a mobile radio network, the cell being of the type controlled by a base station with an omnidirectional antenna and divided into a plurality of angular sectors centered on the base station, a separate location signal element is allocated to each angular sector. The mobile station sends a signaling packet carrying all the location signal elements. For each angular sector the base station modifies the signaling packet sent by the mobile station before it is received by the omnidirectional antenna, the modification being specific to the angular sector. The base station determines the modification that has been made from the signaling packet received by the omnidirectional antenna and deduces from it the angular sector in which the mobile station is located. A corresponding base station with an omnidirectional antenna, mobile station and signaling packet are also disclosed.

Claims

1. A method for spatially locating a mobile station in a cell of a mobile radio network, said cell being of the type controlled by a base station with an omnidirectional antenna, said cell being divided into a plurality of angular sectors centered on said base station, said method comprising:

allocating a separate location signal element to each angular sector;

said mobile station sending a signaling packet carrying all location signal elements for said cell;

for each angular sector, modifying the signaling packet sent by the mobile station before it is received by said omnidirectional antenna, said modifying being specific to said each angular sector;

determining, from the modified signaling packet received by said omnidirectional antenna, the modification made; and

deducing, from said modification made, the angular sector in which said mobile station is located.

2. A spatial location method as claimed in claim 1, wherein each allocated location signal element corresponds to a different predetermined frequency range or frequency, and wherein said modifying specific to each angular section includes filtering said signaling packet in accordance with the predetermined frequency range or frequency assigned to the angular sector.

3. A spatial location method as claimed in claim 1 wherein said signaling packet transmitted by said mobile station is a reference signal the instantaneous frequency of which changes continuously over a given time period so as to include in succession all frequency values allocated to said angular sectors.

4. A spatial location method as claimed in claim 3 wherein said reference signal is also used to synchronize said base station and said mobile station.

5. A spatial location method as claimed in claim 1 wherein said location signal elements belong to the group comprising frequencies, frequency ranges, specific combinations of at least two frequencies, and temporal sequences of specific frequencies.

6. A spatial location method as claimed in claim 1 wherein said mobile station transmits said signaling packet when setting up a call with said base station.

7. A spatial location method as claimed in claim 1 wherein said mobile station transmits said signaling packet periodically.

8. A spatial location method as claimed in claim 1 wherein said mobile station transmits said signaling packet when setting up a call with said base station and periodically thereafter.

9. A base station having an omnidirectional antenna and controlling a cell of a mobile radio network, said cell being subdivided into a plurality of angular sectors centered on said base station and to each of which a separate location signal element is assigned, a mobile station transmitting a signaling packet carrying all of said location signal elements, said base station comprising:

for each angular sector, means for modifying the signaling packet transmitted by said mobile station before it is received by said omnidirectional antenna, said modification being specific to said angular sector; and

means for determining from the signaling packet received by said omnidirectional antenna the specific modification made by said modifier means and for deducing therefrom the angular sector in which said mobile station is located.

10. A base station as claimed in claim 9 wherein, for each angular sector, said modifying means comprise separate filter means responsive to a respective predetermined frequency range or frequency assigned to the corresponding angular sector.

11. A base station according to claim 10 wherein said filter means each comprise a grid forming one side of a Faraday cage surrounding said omnidirectional antenna, the Faraday cage having the same number of sides as there are angular sectors, the mesh of each said grid assuring high-pass filtering according to the respective predetermined frequency range or frequency assigned to said corresponding angular sector.

12. A base station as claimed in claim 9 wherein said means for determining the specific modification made comprise:

the same number of correlation means as there are angular sectors, said correlation means each supplying information indicating the presence or the absence of one of said location signal elements in said received signaling packet; and

means for deciding the angular sector in which said mobile station is located in accordance with presence or absence information provided by said correlation means.