Method and apparatus for determining if a mobile station is present in an area

• US 6,381,457 B1
• Filed: 04/07/1999
• Issued: 04/30/2002
• Est. Priority Date: 04/09/1998
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Carlsson, Göran, Lundborg, Tomas, Sandegren, Per-Arne
• Primary Examiner(s): LEGREE, TRACY MICHELLE
• Application Number:
  US09/287,840
• Time in Patent Office: 1,119 Days
• Field of Search: 455/435, 455/434, 455/432, 455/553, 455/552, 455/440, 455/439, 455/438, 455/436, 455/442, 455/465, 455/426
• US Class Current: 455/435.2
• CPC Class Codes: H04W 36/142 over the same radio air interface technology
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/16 WPBX [Wireless Private Branch Exchange]

Abstract

A method and arrangement in a radio communication system for determining the presence of a mobile station in a determined area. A first radio channel is allocated for communication of control information and user data information between the mobile station and a first base station. The mobile station transmits identity information repeatedly on the first radio channel. A detecting unit receives at least one occurrence of the transmitted identity information. The mobile station is registered as present in the vicinity of the detecting unit upon receipt of said at least one occurrence of the identity information.

Claims

1. A mobile station presence detection method in a radio communication system, comprising a first base station and a mobile station, the method comprising the steps of:

allocating a first radio channel for communication of control information and user data information between the mobile station and the first base station;

transmitting information identifying the mobile station repeatedly in a portion of the first radio channel used for transmission of the control information;

providing information defining the allocated first channel; and

receiving at least one occurrence of the transmitted identity information at a second base station; and

registering the mobile station as present in a determined area upon receipt of said at least one occurrence of the transmitted identity information at the second base station.

2. A method according to claim 1, wherein:

said information identifying the mobile station is transmitted in a slow associated control channel portion of said first radio channel.

3. A method according to claim 1 wherein said step of receiving at least one occurrence of the transmitted identity further includes the step of:

scanning for radio transmissions belonging to the allocated first radio channel in at least a subset of a radio frequency band used in the radio communication system.

4. A method according to claim 1 wherein said step of receiving at least one occurrence of the transmitted identity further includes the steps of:

providing information defining the allocated first channel; and

tuning a radio receiver according to the provided defining information in order to receive said at least one occurrence of the transmitted identity information.

5. A method according to claim 1 wherein said radio communication system further includes a second base station, and the method further includes the steps of:

determining whether the mobile station is one of a set of at least one mobile stations which preferably should communicate with the second base station instead of with the first base station upon determining the mobile station as present within the coverage area of the second base station; and

handing off the mobile station from said first radio channel to a second radio channel for communication of control information and user data information between the second base station and the mobile station, subsequent to determining the mobile station as being included in said set of mobile stations.

6. A radio communication system, a mobile station and a mobile station presence detector wherein the radio communication system is configured to allocate a first radio channel for communication of control information and user data information between the mobile station and a first base station, the radio communication system comprising:

a mobile station configured to repeatedly transmit identity information identifying the mobile station in a portion of a first radio channel that is further used for transmission of control information; and

a mobile station presence detector located at a second base station comprising;

a receiver configured to receive at least one occurrence of the transmitted identity information; and

a register configured to register the mobile station as present in the vicinity of the mobile station presence detector upon receipt of the identity information by the receiver.

7. A radio communication system according to claim 6 wherein the mobile station is further configured to transmit said identity information in a slow associated control channel portion of said first radio channel.

8. A radio communication system according to claim 6 wherein:

the receiver of the mobile station presence detector is further configured to scan for radio transmissions belonging to the allocated first radio channel in at least a subset of a radio frequency band used in the radio communication system in order to receive said at least one occurrence of the transmitted identity information.

9. A radio communication system according to claim 6 further comprising:

an information unit configured to provide the mobile station presence detector with information defining the allocated first radio channel; and

wherein the receiver is further configured receive the provided defining information.

10. A radio communication system according to claim 6, further comprising:

a second base station, wherein said mobile station presence detector is included within said second base station;

a determination unit configured to determine if the mobile station is one of a set of at least one mobile stations configured to communicate via the second base station instead of the first base station upon said registering of the mobile station as present in the vicinity of the mobile station presence detector; and

a handing off section configured to hand off the mobile station to a second radio channel for communication of control information and user data information between the second base station and the mobile station, subsequent to determining if the mobile station is included in said set of mobile stations.

11. A radio communication system according to claim 10 wherein:

said first base station belongs to a public cellular network, said second base station is a home base station connected to a public wireline network, and that said register and said determination unit are included in said home base station.

12. A radio communication system according to claim 10 wherein said first base station belongs to a public cellular network, said second base station belongs to a wireless office system and said register and said determination unit are included in said wireless office system.