Method for transferring intersystem connections

• US 20030031143A1
• Filed: 08/01/2002
• Published: 02/13/2003
• Est. Priority Date: 02/01/2000
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Faerber, Michael
• Granted Patent: US 7,359,355 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0013 Rate matching, e.g. puncturing or repetition of code symbols
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The invention relates to the transfer of intersystem connections, wherein the quality of a transfer to a supplying base station in a first radiocommunication system determined at a given moment by a subscriber station is compared to a threshold value. If the value falls below said threshold, a compressed mode is activated and measurements are carried out by the subscriber station in relation to the transfer qualities to neighbouring base stations in a second radiocommunication network. On the basis of said measurements, the subscriber station selects a base station for the transfer of a connection. If the value falls below the second threshold, information sequences in the organization channels of the selected base stations are detected by the subscriber station.

Claims

1. A method for controlling an intersystem connection transfer from a first radiocommunication system (RS1) having a first transmission method (FDD) to a second radiocommunication system (RS2) having a second transmission method (TDD, GSM), characterized in that a transmission quality (Q) determined by a subscriber station (UE) with respect to transmission characteristics to a supplying base station (NB) of the first radiocommunication system (RS1) is compared with a first threshold value (Th1),

a compressed mode method is activated if the value falls below the first threshold (Th1) , wherein, within at least one transmission gap generated in a time frame of the first transmission method (FDD), the subscriber station (UE) determines transmission characteristics from/to at least one base station (BTS) of the second radiocommunication system (RS2),

the subscriber station (UE) detects information sequences transmitted by the base station (BTS) of the second radiocommunication system (RS2) in a control channel (BCCH) if the value falls below a second threshold (Th2), and

on the basis of the measurements, the subscriber station (UE) selects at least one base station (BTS, NB) suitable for the transfer of a connection.

2. The method as claimed in claim 1, characterized in that a respective receiving level (RSSI) is determined as transmission quality (Q) by the subscriber station (UE).

3. The method as claimed in claim 1 or 2, characterized in that a periodicity for the generation of the transmission gaps is selected depending on a current transmission quality (Q) from/to the supplying base station (NB) of the first radiocommunication system (RS1).

4. The method as claimed in one of the preceding claims, characterized in that the start and/or the periodicity for the generation of the transmission gap is determined by the base station (NB) of the first radiocommunication system (RS1) and signaled to the subscriber station (UE).

5. The method as claimed in one of the preceding claims, characterized in that the compressed mode method is activated for a signal transmission in the uplink and/or in the downlink direction.

6. The method as claimed in one of the preceding claims, characterized in that the measurements of the subscriber station (UE) are signaled together with further characteristic values about transmission characteristics of the radio interface between the base station (NB) of the first radiocommunication system (RS1) and the subscriber station (UE) and/or between a base station (BTS) of the second radiocommunication system (RS2) and the subscriber station (UE) ????? signaled to whom ?????.

7. The method as claimed in one of the preceding claims, characterized in that the first radiocommunication system (RS1) supports an FDD transmission method (FDD), and the second radiocommunication system (RS2) supports a TDD transmission method (TDD) or a GSM transmission method (GSM).

8. A base station system (BSS) of a radiocommunication system (RS1, RS2) for carrying out the method as claimed in one of the preceding claims, characterized in that the radiocommunication system (RS1, RS2) is realized as a mobile communication system or as a wireless subscriber line system.