Method and apparatus for cell reselection within a communications system

• US 20050059399A1
• Filed: 08/29/2002
• Published: 03/17/2005
• Est. Priority Date: 08/29/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Raval, Tushar, Vasudevan, Damodaran, Seeley, Kris A.
• Granted Patent: US 6,990,342 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection

Abstract

Transferring communication within a communication system occurs as follows: during communication with a serving base station, in order to shorten the duration before downlink data can be initiated to a remote unit that has performed cell reselection, an automatic downlink procedure is executed. The auto downlink procedure transfers remote unit related information to a scheduler for appropriate allocation of air interface resources for a remote unit that recently has undergone a cell reselection procedure. When the remote unit reestablishes itself in a target cell, the source packet control unit determines that the cell reselection was successful and selectively transfers radio access capability information to the target packet control unit. The target packet control unit immediately is able to transfer downlink data arriving from the serving GPRS support node to the remote unit without first establishing a downlink temporary block flow, thereby significantly reducing the time required for cell reselection.

Claims

1. A method for transferring communication within a communications network, the method comprising the steps of:

identifying a target cell to which to transfer communication from a remote unit, wherein the remote unit is in communication with a source cell;

initiating a cell reselection request to the target cell for requesting transferring of remote unit communication from the source cell to the target cell;

transmitting the identity of the remote station to the target cell; and

transferring remote station capability information to the target cell subsequent to the cell reselection request being initiated and prior to a first uplink data block containing the remote unit'"'"'s identification information.

2. The method of claim 1, wherein the transferring step is executed prior to the remote device receiving downlink data from the network.

3. The method of claim 1, wherein the transferring step is executed subsequent to an uplink immediate assignment message being transmitted by the target cell.

4. The method of claim 2, wherein the transferring step is executed prior to establishing a downlink temporary block flow for enabling immediate downlink data flow from the network.

5. The method of claim 1, wherein the transferring step is executed subsequent to completion of cell reselection.

6. The method of claim 1, wherein the transferring step is executed prior to completion of cell reselection.

7. The method of claim 6, wherein cell reselection is initiated by a communication network.

8. The method of claim 5, wherein cell reselection is initiated by the remote unit.

9. An apparatus for controlling cell reselection in a communication system, comprising:

a target control unit associated with a target cell for controlling communicating between a target base station and an RU;

a source control unit associated with a source cell for controlling communicating between a source base station and an RU, wherein the RU abandons communication with the source cell and establishes communication with the target cell during cell reselection, the source control unit configured to transfer RU operating information to the target control unit subsequent to the cell reselection operation; and

an SGSN for transferring downlink data to the target control unit for enabling the target control unit to transfer the received downlink data to the RU without prior establishment of a downlink temporary block flow.

10. The apparatus of claim 9, wherein the communication system is a General Packet Radio Service (GPRS) system overlaid with a Global System for Mobile Communications (GSM) system.

11. The apparatus of claim 9, wherein the source and target control units comprise packet control units for directing data traffic in the communication system.

12. A method for transferring communication within a communications system, the method comprising the steps of:

initiating a cell reselection request to a source cell for requesting transferring of communication between a RU and the source cell to the remote unit and a target cell;

transmitting the identity of the RU to the target cell for completing the cell reselection operation; and

transferring RU capability information to the target cell subsequent to the cell reselection request being initiated and prior to uplink data being transmitted to an SGSN.

13. The method of claim 12, further comprising the step of transferring downlink data arriving from the SGSN without first establishing a downlink temporary block flow.