Controlling Energy Consumption of a Wireless Network Node

• US 20120094661A1
• Filed: 02/13/2009
• Published: 04/19/2012
• Est. Priority Date: 02/13/2009
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Hagerman, Bo, Lindoff, Bengt, Parkvall, Stefan, Frenger, Pál
• Granted Patent: US 9,408,161 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04L 65/40 Support for services or applications
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/28 using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 72/0473 the resource being transmission power
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An arrangement for controlling energy consumption of a network node associated with a cell includes a terminal activity monitor (16) configured to detect active terminals served by the cell. A transmission controller (18) is connected to the terminal activity monitor and is configured to restrict transmission downlink in the cell during time periods when there are no active terminals served by the cell. During these time periods transmission is restricted to inermittent transmission of information assisting active terminals not served by the cell in finding the cell.

Claims

1. A method of controlling energy consumption of a wireless network node associated with a cell, including the steps of:

monitoring (S1) the number of active terminals served by the cell;

restricting (S4), during time periods when there are no active terminals served by the cell, transmission downlink in the cell to intermittent transmission of information assisting active terminals not served by the cell in finding the cell.

2. The method of claim 1, including the steps of

detecting (S2) when the number of active terminals served by the cell falls below a predetermined threshold;

handing over (S3) active terminals still served by the cell to at least one other cell;

restricting (S4) transmission downlink when there are no more active terminals served by the cell.

3. The method of claim 1, including the step of restricting transmission downlink when the number of active terminals served by the cell falls below a predetermined threshold.

4. The method of claim 1, 2 or 3, including the steps of

monitoring random access attempts (S13) from terminals not served by the cell during intermittent transmission;

leaving intermittent transmission (S15) and returning to unrestricted continuous transmission if at least one random access attempt has been detected.

5. The method of claim 1, 2 or 3, including the steps of

monitoring handover commands (S14) during intermittent transmission;

leaving intermittent transmission (S15) and returning to unrestricted continuous transmission if at least one handover command has been detected.

6. The method of claim 1, 2, 3, 4 or 5, wherein the coverage area of the cell lies within the coverage area of another cell.

7. The method of claim 6, wherein the cell is a micro cell in a macro cell.

8. The method of claim 6, wherein the base station is a home base station.

9. The method of any of the preceding claims, wherein the intermittent transmission of information includes at least one of:

transmission of reference signals;

transmission of synchronization signals;

transmission of broadcast information.

10. The method of any of the preceding claims, including the step of synchronizing the intermittent transmission of information between several network nodes.

11. An arrangement for controlling energy consumption of a wireless network node associated with a cell, including:

a terminal activity monitor (16) configured to detect active terminals served by the cell;

a transmission controller (18) connected to the terminal activity monitor and configured to restrict, during time periods when there are no active terminals served by the cell, transmission downlink in the cell to intermittent transmission of information assisting active terminals not served by the cell in finding the cell.

12. The arrangement of claim 11, wherein the terminal activity monitor (16) is configured to

detect when the number of active terminals served by the cell falls below a predetermined threshold;

command handover of active terminals still served by the cell to at least one other cell;

restrict transmission downlink when there are no more active terminals served by the cell.

13. The arrangement of claim 11, wherein the terminal activity monitor (16) is configured to restrict transmission downlink when the number of active terminals served by the cell falls below a predetermined threshold.

14. The arrangement of claim 11, 12 or 13, including a random access attempt monitor (22) configured to detect random access attempts from terminals not served by the cell during intermittent transmission and to instruct the transmission controller (18) to leave intermittent transmission and return to unrestricted normal transmission if at least one random access attempt has been detected.

15. The arrangement of claim 11, 12 or 13, including a handover request monitor (24) configured to detect handover commands during intermittent transmission and to instruct the transmission controller (18) to leave intermittent transmission and return to unrestricted normal transmission if at least one handover command has been detected.

16. A base station including an arrangement in accordance with any of the preceding claims 11-15.

17. A method of operating a radio terminal, including the steps of

receiving (S20) signals indicating a time schedule for intermittent transmission of information from a cell;

synchronizing (S21) mobility measurements with the intermittent transmission of information.

18. The method of claim 17, including the step of

synchronizing a discontinuous reception mode of the radio terminal with the intermittent transmission of information to allow mobility measurements.

19. A radio terminal, including a synchronization unit (34) receiving signals indicating a time schedule for intermittent transmission of information from a cell, to synchronize mobility measurements with the intermittent transmission of information.

20. The radio terminal of claim 19, wherein the synchronization unit (34) is configured to synchronize a discontinuous reception mode of the radio terminal with the intermittent transmission of information to allow mobility measurements.

21. A method of operating a radio terminal, including the steps of

performing a first cell search (S30) over a multitude of frequencies;

performing, if the first cell search fails, a second cell search (S32) in which the search duration on each frequency is extended.

22. A radio terminal, including a cell search unit (36) configured to operate in a first mode performing a first cell search over a multitude of frequencies, and a second mode performing a second cell search, in which the search duration on each frequency is extended.

23. The radio terminal of claim 22, wherein the cell search unit (36) is configured to perform the second cell search if the first cell search fails.