# US 8,571,054 B2 · Terminal distribution control for point-to-multipoint service in wireless communication system

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- Number: US 8,571,054 B2
- Document ID: US8571054B2
- Status: Granted
- Kind: B2
- Application number: 12/496,554
- Filed: 2009-07-01
- Published: 2009-10-22
- Granted: 2013-10-29
- Earliest claimed: 2004-08-19
- Assignees: LG Electronics Inc.
- Applicants: Young Dae Lee; Sung-Duck Chun
- Inventors: Young Dae Lee; Sung-Duck Chun
- Web page: https://patentgrep.com/patent/US8571054B2

## CPC

- H04W 72/30: Resource management for broadcast services
- H04W 36/0007: {for multicast or broadcast services, e.g. MBMS (multicast or broadcast application services H04W4/06; resource management for broadcast services H04W72/30; connection management for selective distribution or broadcast H04W76/40)}
- H04W 36/0058: {Transmission of hand-off measurement information, e.g. measurement reports}
- H04W 36/0055: {Transmission or use of information for re-establishing the radio link}
- H04W 36/249: {according to timing information}
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A method for controlling a user equipment (UE) capable of receiving a point-to-multipoint service in a wireless communication system comprises receiving a point-to-multipoint service and performing a cell reselection in response to completion of the receiving of the point-to-multipoint service. The cell reselection is performed among multiple frequencies. The cell reselection may be performed in response to signaling from the network. The cell reselection may be performed regardless of whether cell reselection criteria are satisfied. The cell reselection criteria may comprise at least one of a cell reselection reference value between frequencies and a cell reselection reference value within a frequency. The cell reselection criteria may be embodied in frequency layer dispersion (FLD) information. Alternatively, the cell reselection criteria may be embodied in frequency layer convergence (FLC) information.

## Claims

### Claim 1

A method for controlling a user equipment (UE) configured to receive a point-to-multipoint service in a wireless communication system, the method performed by the UE and comprising:
receiving the point-to-multipoint service;
completing the reception of the point-to-multipoint service by releasing a point-to-multipoint radio bearer; and
performing a cell reselection based on control information received from a base station after the completion of the reception of the point-to-multipoint service,
wherein the control information includes a first parameter associated with measurement between frequencies and a second parameter associated with measurement within a frequency,
wherein performing the cell reselection comprises:
selecting a frequency randomly from among a plurality of frequencies using the control information; and
selecting a suitable cell within the selected frequency,
wherein the point-to-multipoint service is received based on a frequency indicated by the control information,
wherein the cell reselection is performed when the UE decides to no longer receive the point-to-multipoint service,
wherein the cell reselection is performed among multiple frequencies without measuring all candidate frequencies,
wherein the control information further includes frequency layer convergence (FLC) information,
wherein the FLC information indicates at least one preferred frequency,
wherein the FLC information includes an offset to be applied to the at least one preferred frequency, and
wherein the offset is added to a quality measurement value of a cell positioned at the preferred frequency for comparing the cell with another cell during the cell reselection.

### Claim 2

A user equipment (UE) for receiving a point-to-multipoint service in a wireless communication system, the UE comprising:
means for receiving the point-to-multipoint service;
means for completing the reception of the point-to-multipoint service by releasing a point-to-multipoint radio bearer; and
means for performing a cell reselection based on control information received from a base station after the completion of the reception of the point-to-multipoint service,
wherein the control information includes a first parameter associated with measurement between frequencies and a second parameter associated with measurement within a frequency,
wherein the means for performing the cell reselection performs the cell reselection by:
selecting a frequency randomly from among a plurality of frequencies using the control information; and
selecting a suitable cell within the selected frequency,
wherein the point-to-multipoint service is received based on a frequency indicated by the control information,
wherein the cell reselection is performed when the UE decides to no longer receive the point-to-multipoint service,
wherein the cell reselection is performed among multiple frequencies without measuring all candidate frequencies,
wherein the control information further includes frequency layer convergence (FLC) information,
wherein the FLC information indicates at least one preferred frequency,
wherein the FLC information includes an offset to be applied to the at least one preferred frequency, and
wherein the offset is added to a quality measurement value of a cell positioned at the preferred frequency for comparing the cell with another cell during the cell reselection.

### Claim 3 (depends on 1)

The method of claim 1, wherein the cell reselection is performed if a variable related to previous frequency information for the point-to-multipoint service is not empty.

### Claim 4 (depends on 2)

The UE of claim 2, wherein the cell reselection is performed if a variable related to previous frequency information for the point-to-multipoint service is not empty.