Multimedia reception in communication networks

• US 7,675,891 B2
• Filed: 09/14/2005
• Issued: 03/09/2010
• Est. Priority Date: 09/23/2004
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Uden, Johan, Lindoff, Bengt, Ewald, Richard
• Primary Examiner(s): Pérez-Gutiérrez; Rafael
• Assistant Examiner(s): Patel; Nimesh
• Application Number:
  US11/226,484
• Publication Number:
  US 20060072509A1
• Time in Patent Office: 1,637 Days
• Field of Search: 370/338, 370/331, 370/328, 455/436, 455/442, 455/453, 455/439, 455/522
• US Class Current: 370/338
• 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 36/302 due to low signal strength
• CPC Class Codes: H04W 72/30 Resource management for broadcast services

Abstract

Functionalities for a user equipment (UE) in a communication system in order to be able to receive broadcast information, such as TV and other multimedia, with good quality are described. In particular, methods and apparatus that schedule system measurement procedures such that the risk of interrupting the broadcast reception is minimized are described.

Claims

1. A method of scheduling received signal measurements in a user equipment (UE) in a communication system, the received signal including broadcast information and being organized in successive frames, comprising the steps of:

evaluating a received signal strength indicator (RSSI) at only time instants outside of a broadcast information reception time, wherein during the broadcast information reception time the UE receives unacknowledged multimedia information, and the evaluating step is performed by the UE based on whether the UE is receiving unacknowledged multimedia information, independent of control by the communication system during a period in which the UE is unknown to the communication system, and during the period during which the UE is receiving unacknowledged multimedia information from the communication system;

based on the evaluated RSSI, carrying out a cell re-selection procedure;

changing a reception frequency to a frequency of a new cell, including checking a list of neighbor cells for the new cell and searching for a physical channel in the new cell at only time instants outside of the broadcast information reception time based on whether the UE is receiving unacknowledged multimedia information;

if the physical channel in the new cell is found, reading a broadcast channel of the new cell and including the new cell in the list of neighbor cells; and

if the physical channel is not found at only time instants outside the broadcast information reception time, interrupting the receiving of unacknowledged multimedia information and searching for the physical channel in the new cell at further time instants not only outside of the broadcast information reception time.

2. The method of claim 1, further comprising the step of determining whether the UE is in a predetermined broadcast information reception mode.

3. The method of claim 1, wherein the interrupting step includes periodically interrupting the broadcast information reception every predetermined number of frames to search for the physical channel.

4. The method of claim 1, wherein the physical channel is at least one of a frequency correction channel and a synchronization channel.

5. The method of claim 1, wherein the interrupting step includes interrupting the broadcast information reception by searching for the physical channel in the new cell at time instants indicated by a broadcast information decoder restart signal.

6. The method of claim 1, wherein a broadcast signal transmitted in the communication system includes at least one idle frame, and the interrupting step includes interrupting the broadcast information reception by searching for the physical channel in the new cell during the at least one idle frame.

7. The method of claim 6, wherein the step of searching for the physical channel in the new cell is carried out at regularly spaced time intervals.

8. The method of claim 6, wherein the spacing of the time intervals is determined by the UE from a received message.

9. The method of claim 6, wherein the spacing of the time intervals is determined by the UE from blindly detected idle frames.

10. A user equipment (UE) for receiving radio signals transmitted in a communication system and scheduling received signal measurements, the received signals including broadcast information and being organized in successive frames, the UE comprising:

a receiver configured to produce a baseband signal from a received radio signal;

a baseband processor configured to determine a received signal strength indicator (RSSI); and

a controller configured to evaluate the RSSI at only time instants outside of a broadcast information reception time and to cause the UE to carry out a cell re-selection procedure based on the evaluated RSSI, wherein during the broadcast information reception time the UE receives unacknowledged multimedia information, and the RSSI is evaluated by the UE based on whether the UE is receiving unacknowledged multimedia information, independent of control by the communication system during a period in which the UE is unknown to the communication system, and during the period during which the UE is receiving unacknowledged multimedia information from the communication system;

wherein the controller is configured to change a reception frequency to a frequency of a new cell, the change including checking a list of neighbor cells for the new cell and searching for a physical channel in the new cell at only time instants outside of the broadcast information reception time based on whether the UE is receiving unacknowledged multimedia information;

if the physical channel in the new cell is found, a broadcast channel of the new cell is read and the new cell is included in the list of neighbor cells; and

if the physical channel is not found at only time instants outside the broadcast information reception time, reception of unacknowledged multimedia information is interrupted to search for the physical channel in the new cell at further time instants not only outside of the broadcast information reception time.

11. The user equipment (UE) of claim 10, wherein the controller is further configured to determine whether the UE is in a predetermined broadcast information reception mode.

12. The user equipment of claim 10, wherein the broadcast information reception is interrupted periodically every predetermined number of frames to search for the physical channel.

13. The user equipment of claim 10, wherein the physical channel is at least one of a frequency correction channel and a synchronization channel.

14. The user equipment of claim 10, wherein the controller includes a decoder for decoding the broadcast information, and broadcast information reception is interrupted to search for the physical channel in the new cell at time instants indicated by a decoder restart signal.

15. The user equipment of claim 10, wherein a broadcast signal transmitted in the communication system includes at least one idle frame, and broadcast information reception is interrupted to search for the physical channel in the new cell during the at least one idle frame.

16. The user equipment of claim 15, wherein at least one of the baseband processor and the controller are configured to detect the idle frames and determine a periodicity of the idle frames.

17. The user equipment of claim 16, wherein the idle frames are detected by estimating received signal energies during known portions of the received radio signal and comparing the estimated received signal energies to at least one of a threshold and other estimated received signal energies.

18. The user equipment of claim 16, wherein the controller includes a decoder configured to decode received broadcast information, and idle frames are detected based on an output of the decoder.

19. The user equipment of claim 10, further comprising an input device configured for activation by a user, wherein the controller determines whether the user equipment is in a predetermined broadcast information reception mode based on a signal generated by or in response to a user input to the input device.

20. A computer-readable medium containing a computer program for scheduling received signal measurements in a user equipment (UE) in a communication system when the UE is in a predetermined broadcast information reception mode, the received signal including broadcast information and being organized in successive frames, the computer program causing the UE to perform the steps of:

evaluating a received signal strength indicator (RSSI) at only time instants outside of a broadcast information reception time, wherein during the broadcast information reception time the UE receives unacknowledged multimedia information, and the evaluating step is performed by the UE based on whether the UE is receiving unacknowledged multimedia information, independent of control by the communication system during a period in which the UE is unknown to the communication system, and during the period during which the UE is receiving unacknowledged multimedia information from the communication system;

based on the evaluated RSSI, carrying out a cell re-selection procedure;

changing a reception frequency to a frequency of a new cell, including checking a list of neighbor cells for the new cell and searching for a physical channel in the new cell at only time instants outside of the broadcast information reception time based on whether the UE is receiving unacknowledged multimedia information;

if the physical channel in the new cell is found, reading a broadcast channel of the new cell and including the new cell in the list of neighbor cells; and

if the physical channel is not found at only time instants outside the broadcast information reception time, interrupting receiving unacknowledged multimedia information and searching for the physical channel in the new cell at further time instants not only outside of the broadcast information reception time.

21. The computer-readable medium of claim 20, wherein the interrupting step includes periodically interrupting broadcast information reception every predetermined number of frames to search for the physical channel.

22. The computer-readable medium of claim 20, wherein the interrupting step includes interrupting the broadcast information reception by searching for the physical channel in the new cell at time instants indicated by a broadcast information decoder restart signal.

23. The computer-readable medium of claim 20, wherein a broadcast signal transmitted in the communication system includes at least one idle frame, and the interrupting step includes interrupting the broadcast information reception by searching for the physical channel in the new cell during the at least one idle frame.

24. The computer-readable medium of claim 23, wherein the interrupting step includes blindly detecting the at least one idle frame.