Cell reselection method for receiving packet data in a mobile communication system supporting MBMS

• US 20050090278A1
• Filed: 08/23/2004
• Published: 04/28/2005
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Sung-Ho, Van Lieshout, Gert Jan, Jeong, Kyeong-In, Kim, Soeng-Hun, Lee, Kook-Heui
• Granted Patent: US 7,437,178 B2
• Time in Patent Office: Days
• US Class Current: 455/525
• CPC Class Codes: 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
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 72/30 Resource management for broadcast services

Abstract

A method for selecting a cell by a user equipment (UE) to receive a Multimedia Broadcast/Multicast Service (MBMS) service in a mobile communication system which supports the MBMS service with different frequency allocations (FAs) in the same area. In the method, a radio network controller (RNC) transmits information on an MBMS cell to the UE, and the MBMS cell information includes an MBMS offset for guaranteeing priority for cell reselection to the MBMS cell. The UE performs cell reselection using the MBMS cell information and receives the MBMS service from the reselected cell.

Claims

1. A method for selecting a cell by a user equipment (UE) to receive a Multimedia Broadcast/Multicast Service (MBMS) service in a mobile communication system which supports the MBMS service with different frequency allocations (FAs) in the same area, the method comprising the steps of:

transmitting, by a radio network controller (RNC), information on an MBMS cell to the UE, the MBMS cell information including an MBMS offset for controlling priority for cell reselection to the MBMS cell; and

performing, by the UE, cell reselection using the MBMS cell information and receiving the MBMS service from the reselected cell.

2. The method of claim 1, wherein the MBMS cell information further includes frequency information of the MBMS cell.

3. The method of claim 1, wherein the MBMS cell information further includes a cell identifier (ID) for identifying the MBMS cell and a target cell.

4. The method of claim 1, wherein the UE reselects a cell by applying the MBMS offset to an equation predefined for cell reselection.

5. The method of claim 1, wherein the MBMS cell information further includes an MBMS service ID of an MBMS service available in the MBMS cell.

6. The method of claim 1, wherein the RNC transmits the MBMS cell information through a system information block (SIB) separately transmitted for each cell.

7. The method of claim 1, wherein the RNC separately transmits the MBMS cell information through an MBMS-dedicated SIB, for each cell.

8. The method of claim 7, wherein the MBMS-dedicated SIB further includes information indicating whether a serving cell where the UE is located is available for the MBMS service.

9. The method of claim 1, wherein the UE performs cell reselection to a neighbor cell with highest priority using the MBMS offset.

10. A method for reselecting a cell for a Multimedia Broadcast/Multicast Service (MBMS) service in a mobile communication system which supports the MBMS service with different frequency allocations (FAs) in the same area, the method comprising the steps of:

transmitting, by a radio network controller (RNC), a system information block (SIB) to a user equipment (UE), the SIB including identification information indicating whether a neighbor cell is available for the MBMS service; and

performing, by the UE, cell reselection to an MBMS cell using the SIB.

11. The method of claim 10, wherein the identification information includes a cell identifier (ID) of the MBMS cell, frequency information indicating an FA of the MBMS cell, cell information indicating a primary scrambling code for a primary common pilot channel (P-CPICH) of the MBMS cell, and an offset for guaranteeing priority for cell reselection.

12. The method of claim 10, wherein the identification information is separately transmitted to each cell over a broadcasting control channel (BCCH).

13. The method of claim 10, wherein the UE performs cell reselection to the MBMS cell after joining the MBMS service.

14. A method for reselecting a cell for a Multimedia Broadcast/Multicast Service (MBMS) service in a mobile communication system which supports the MBMS service with different frequency allocations (FAs) in the same area, the method comprising the steps of:

periodically transmitting, by a radio network controller (RNC), identification information indicating whether a neighbor cell is available for an MBMS service, to a user equipment (UE) through a control message; and

performing, by the UE, cell reselection to an MBMS cell using the identification information received through the control message.

15. The method of claim 14, wherein the identification information includes a cell identifier (ID) of the MBMS cell, frequency information indicating an FA of the MBMS cell, cell information indicating a primary scrambling code for a primary common pilot channel (P-CPICH) of the MBMS cell, and an offset for controlling priority for cell reselection.

16. The method of claim 14, wherein the identification information is separately transmitted for each MBMS service over an MBMS control channel (MCCH).

17. A method for performing cell reselection to a preferred frequency band by a user equipment (UE) in a mobile communication system which supports a Multimedia Broadcast/Multicast Service (MBMS) service with different frequency allocations (FAs) in the same area, the method comprising the steps of:

receiving, from a radio network controller, a message including an MBMS service identifier (ID), information on a preferred frequency for the MBMS service, and an MBMS offset for controlling cell reselection;

performing inter-frequency measurement using the information included in the message;

and performing cell reselection if a preferred frequency band for an MBMS cell is higher in reception power than a frequency band for a current cell.

18. The method of claim 17, wherein the UE receives a notification message including information transmitted before a start of an MBMS session, performs inter-frequency measurement based on the notification message, and performs cell reselection to the preferred frequency band if the preferred frequency band for an MBMS cell is higher in reception power than the frequency band for the current cell.

19. The method of claim 17, wherein the UE periodically receives a control message including information after a start of an MBMS session, performs inter-frequency measurement based on the control message, and performs cell reselection to the preferred frequency band if the preferred frequency band for an MBMS cell is higher in reception power than the frequency band of the current cell.

20. The method of claim 17, wherein when an MBMS session for the MBMS service is in progress and the UE has selected a new cell, the UE receives a periodically transmitted notification message and performs inter-frequency measurement based on the notification message.

21. The method of claim 20, wherein the UE performs cell reselection if it is determined from the notification message that a frequency band of the reselected cell corresponds to a preferred frequency band.

22. The method of claim 20, wherein the UE stays in the current cell and receives the MBMS service from the current cell, if it is determined from the notification message that a frequency band of the reselected cell does not correspond to a preferred frequency band.

23. A method for providing by a radio network controller (RNC) a Multimedia Broadcast/Multicast Service (MBMS) service to a user equipment (UE) located in a non-MBMS frequency allocation (FA) in a mobile communication system which supports the MBMS service with different FAs in the same geographical area, the method comprising the steps of:

transmitting, by the RNC, a system information block (SIB) including information on an MBMS FA to the UE; and

periodically transmitting a message including information on the MBMS FA to the UE.

24. The method of claim 23, wherein the information on the MBMS FA includes an MBMS service identifier (ID) for the MBMS service, frequency information of the MBMS FA, a cell ID of the FA, and an MBMS offset for controlling cell reselection.

25. A method for receiving a Multimedia Broadcast/Multicast Service (MBMS) service by a user equipment (UE) located in a non-MBMS frequency allocation (FA) in a mobile communication system which supports the MBMS service with different FAs in the same geographical, the method comprising the steps of:

receiving, from a radio network controller (RNC), a system information block (SIB) including information on an MBMS FA;

analyzing the information on the MBMS FA in the SIB; and

performing cell reselection to the MBMS FA based on the analysis result.

26. The method of claim 25, wherein the SIB further includes information on whether an FA where the UE is located is available for the MBMS service.

27. A method for receiving a Multimedia Broadcast/Multicast Service (MBMS) service by a user equipment (UE) located in a non-MBMS frequency allocation (FA) in a mobile communication system which includes at least one non-MBMS cell and supports the MBMS service with different FAs in the same area, the method comprising the steps of:

receiving, by the UE, information on an MBMS cell from a radio network controller (RNC);

requesting, by the UE, a particular MBMS service;

analyzing the received information; and

reselecting a cell available for the particular MBMS service based on the analyzed information.

28. The method of claim 27, wherein the received information includes system information for a particular cell unavailable for the particular MBMS service, and information on a neighbor cell available for the MBMS service.

29. The method of claim 27, wherein the received information includes information indicating whether a cell where the UE is located is available for the MBMS service, frequency information used in a neighbor cell available for the MBMS service, a cell identifier (ID), cell information, and an offset.

30. The method of claim 27, wherein the received information is separately transmitted for each cell through a system information block (SIB).

31. The method of claim 27, wherein the received information is separately transmitted for each MBMS service through a control message periodically transmitted in association with the MBMS service.

32. The method of claim 27, wherein the received information includes both information indicating whether a cell where the UE is located is available for a particular MBMS service and information indicating whether a neighbor cell available for the MBMS service is available for the particular MBMS.

33. The method of claim 28, wherein the UE measures reception power of neighbor cells and selects a neighbor cell available for the requested MBMS service based on the analysis result if there is at least one neighbor cell available for the particular MBMS service.

34. A method for providing a Multimedia Broadcast/Multicast Service (MBMS) service to a user equipment (UE) located in a cell unavailable for the MBMS service by a radio network controller (RNC) including at least one cell unavailable for the MBMS service and other cells providing the MBMS service with different frequencies in the same area in a mobile communication system providing the MBMS service, the method comprising the steps of:

transmitting, by the RNC, a system information block (SIB) for the MBMS service to the UE;

reselecting, by the UE, a cell available for a particular MBMS service upon receiving a request for the particular MBMS service; and

assigning radio resources for providing the particular MBMS service to the UE.

35. The method of claim 34, wherein the SIB includes system information for the cell unavailable for the particular MBMS service and information on a neighbor cell available for the MBMS service.

36. The method of claim 35, wherein information on the neighbor cell includes frequency information used in the neighbor cell, a cell identifier (ID), cell information, and an offset.

37. The method of claim 35, wherein the cell information includes information indicating whether the neighbor cell available for the MBMS service is available for the particular MBMS service.

38. The method of claim 35, wherein the cell information further includes information indicating whether a cell where the UE is located is available for the particular MBMS service.

39. The method of claim 37, wherein the information indicating whether the neighbor cell available for the MBMS service is transmitted through an MBMS enabled cell information field.

40. The method of claim 37, wherein the information indicating whether the neighbor cell available for the MBMS service is transmitted through an MBMS offset field.