Method, network nodes, and computer program products for load based adaptive CRS power adjustment

• US 9,854,532 B2
• Filed: 12/09/2014
• Issued: 12/26/2017
• Est. Priority Date: 12/05/2014
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Sun, Ying, Zhao, Wei
• Primary Examiner(s): Rutkowski, Jeffrey M
• Assistant Examiner(s): WOOD, JONATHAN
• Application Number:
  US14/564,721
• Publication Number:
  US 20160165546A1
• Time in Patent Office: 1,113 Days
• Field of Search: None
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/18 TPC being performed according to specific parameters
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range

Abstract

A method performed in a network node. The method includes the network node receiving a report regarding a traffic load of at least one network cell of a plurality of network cells. The method further includes the network node determining whether the traffic load of the at least one network cell is greater than an average traffic load of the plurality of network cells. The method further includes the network node adjusting a power of a reference signal based on said determining. The method also includes the network node transmitting the adjusted reference signal in the at least one network cell.

Claims

1. A method performed in a network node, the method comprising:

the network node determining a first traffic load for a first network cell of a plurality of network cells, said plurality of network cells comprising a second network cell and a third network cell;

for each of the plurality of network cells, the network node determining a traffic load value, thereby determining a plurality of traffic load values;

the network node determining the average of said plurality of traffic load values, thereby determining an average traffic load of the plurality of network cells;

the network node determining whether the first traffic load of the first network cell is greater than the determined average traffic load of the plurality of network cells;

the network node adjusting a power of a reference signal based on said determining; and

the network node transmitting the adjusted reference signal in the first network cell, wherein

adjusting the power of the reference signal based on said determining comprises;

determining a network performance parameter for the first network cell;

determining whether the network performance parameter meets a network performance criteria;

determining whether a current power of the reference signal is above a predetermined minimum power threshold by at least a power signal decrement; and

decreasing the power of the reference signal by an amount equal to the power signal decrement as a result of determining that;

     1) the first traffic load of the first network cell is greater than the determined average traffic load of the plurality of network cells,

     2) the network performance parameter for the cell meets the network performance criteria, and

     3) the current power level of the reference signal is above the predetermined minimum power level by at least the power signal decrement.

2. The method of claim 1, further comprising,

in response to determining that the first traffic load of the first network cell is less than or equal to the average traffic load of the plurality of network cells, the network node determining a power signal increment;

and

in response to determining that the power of the reference signal plus the determined power signal increment is less than a maximum power threshold, the network node adjusting the power of the reference signal by incrementing the power of the reference signal in accordance with the determined power signal increment.

3. The method of claim 1, wherein

determining the network performance parameter for the first network cell comprises:

1) for each user equipment (UE) being served by the network cell, determining whether a quality of service (QoS) requirement for the UE is not being met;

     2) determining the total number of UEs served by the network cell for which the QoS requirement is not being met; and

     3) determining the percentage of the UEs being served by the first network cell for which the QoS requirement is not being met, and

determining whether the network performance parameter meets the network performance criteria comprises determining whether the determined percentage of the UEs exceeds a performance threshold.

4. The method of claim 1, wherein

determining the network performance parameter for the first network cell comprises:

1) for each user equipment (UE) being served by the network cell, determining the UE'"'"'s packet loss rate;

     2) for each determined packet loss rate, determining whether the packet loss rate exceeds a packet loss threshold;

     3) determining the total number of UEs served by the network cell that have a determined packet loss rate that exceeds the packet loss threshold; and

     4) determining the percentage of the UEs being served by the first network cell that have a determined packet loss rate that exceeds the packet loss threshold, and

determining whether the network performance parameter meets the network performance criteria comprises determining whether the determined percentage of the UEs exceeds a performance threshold.

5. The method of claim 1, wherein the network node is a base station and the reference signal is a cell specific reference signal.

6. The method of claim 1,

wherein the network node transmits the adjusted reference signal in a radio frame including a plurality of slots,

wherein the transmitted adjusted reference signal is assigned to a first slot from the plurality of slots;

wherein a non-reference signal is assigned to a second slot from the plurality of slots, and

wherein the network node does not adjust the power of the non-reference signal assigned to the second slot.

7. A network node, the network node comprising:

a processor; and

a non-transitory computer readable medium coupled to the processor, said computer readable medium containing instructions executable by the processor, whereby the network node is operative to;

determine a first traffic load of a first network cell of a plurality of network cells comprising a second network cell and a third network cell,

determine, for each of the plurality of network cells, a traffic load value, thereby determining a plurality of traffic load values,

determine the average of said plurality of traffic load values, thereby determining an average traffic load of the plurality of network cells,

determine whether the first traffic load of the first network cell is greater than the average traffic load of the plurality of network cells,

adjust a power of a reference signal based on said determination, and

transmit the adjusted reference signal in the first network cell, wherein

the network node is configured to adjust the power of the reference signal based on said determining by performing a process comprising;

determining a network performance parameter for the first network cell;

determining whether the network performance parameter meets a network performance criteria;

determining whether a current power of the reference signal is above a predetermined minimum power threshold by at least a power signal decrement; and

decreasing the power of the reference signal by an amount equal to the power signal decrement as a result of determining that;

     1) the first traffic load of the first network cell is greater than the determined average traffic load of the plurality of network cells,

     2) the network performance parameter for the cell meets the network performance criteria, and

     3) the current power level of the reference signal is above the predetermined minimum power level by at least the power signal decrement.

8. The network node of claim 7, whereby the network node is further operative to:

in response to determining that the first traffic load of the first network cell is less than or equal to the average traffic load of the plurality of network cells, determine a power signal increment, and

in response to determining that the power of the reference signal plus the determined power signal increment is less than a maximum power threshold, adjust the power of the reference signal by incrementing the power of the reference signal in accordance with the determined power signal increment.

9. The network node of claim 7, wherein

the network node is configured to determine the network performance parameter for the first network cell by performing a process comprising:

1) for each user equipment (UE) being served by the network cell, determining whether a quality of service (QoS) requirement for the UE is not being met;

     2) determining the total number of UEs served by the network cell for which the QoS requirement is not being met; and

     3) determining the percentage of the UEs being served by the first network cell for which the QoS requirement is not being met, and

the network node is configured to determine whether the network performance parameter meets the network performance criteria by performing a process comprising determining whether the determined percentage of the UEs exceeds a performance threshold.

10. The network node of claim 9, wherein

the network node is configured to determine the network performance parameter for the first network cell by performing a process comprising:

1) for each user equipment (UE) being served by the network cell, determining the UE'"'"'s packet loss rate;

     2) for each determined packet loss rate, determining whether the packet loss rate exceeds a packet loss threshold;

     3) determining the total number of UEs served by the network cell that have a determined packet loss rate that exceeds the packet loss threshold; and

     4) determining the percentage of the UEs being served by the first network cell that have a determined packet loss rate that exceeds the packet loss threshold, and

the network node is configured to determine whether the network performance parameter meets the network performance criteria by performing a process comprising determining whether the determined percentage of the UEs exceeds a performance threshold.

11. The network node of claim 7, wherein the network node is a base station and the reference signal is a cell specific reference signal.

12. A computer product comprising a non-transitory computer readable medium storing computer instructions, which when executed by a network node cause the network node to:

determine a first traffic load of a first network cell of a plurality of network cells comprising a second network cell and a third network cell;

determine, for each of the plurality of network cells, a traffic load value, thereby determining a plurality of traffic load values,

determine the average of said plurality of traffic load values, thereby determining an average traffic load of the plurality of network cells,

determine whether the first traffic load of the first network cell is greater than the average traffic load of the plurality of network cells;

adjust a power of a reference signal based on said determining; and

transmit the adjusted reference signal in the first network cell, wherein

the computer instructions further configure the network node such that the network node adjusts the power of the reference signal based on said determining by performing a process comprising;

determining a network performance parameter for the first network cell;

determining whether the network performance parameter meets a network performance criteria;

determining whether a current power of the reference signal is above a predetermined minimum power threshold by at least a power signal decrement; and

decreasing the power of the reference signal by an amount equal to the power signal decrement as a result of determining that;

     1) the first traffic load of the first network cell is greater than the determined average traffic load of the plurality of network cells,

     2) the network performance parameter for the cell meets the network performance criteria, and

     3) the current power level of the reference signal is above the predetermined minimum power level by at least the power signal decrement.

13. A method performed in a network node for adjusting a power offset for a cell specific reference signal (CRS) for use in a cell of a wireless network, the method comprising:

the network node transmitting the CRS in the cell at a first power level;

the network node determining the load of the cell;

the network node determining whether the load of the cell exceeds a load threshold;

the network node determining a network performance parameter for the cell;

the network node determining whether the determined network performance parameter meets a network performance criteria;

the network node determining whether the first power level is above a predetermined minimum power level by at least a power signal decrement; and

the network node transmitting the CRS in the cell at a power level equal to the first power level minus the power signal decrement as a result of determining that;

     1) the load of the cell exceeds the load threshold,

     2) the network performance parameter for the cell meets the network performance criteria, and

     3) the first power level is above the predetermined minimum power level by at least the power signal decrement.

14. The method of claim 13, wherein

determining the network performance parameter for the cell comprises:

1) for each user equipment (UE) being served by the cell, determining the UE'"'"'s packet loss rate;

     2) for each determined packet loss rate, determining whether the packet loss rate exceeds a packet loss threshold;

     3) determining the total number of UEs served by the network cell that have a determined packet loss rate that exceeds the packet loss threshold; and

     4) determining the percentage of the UEs being served by the first network cell that have a determined packet loss rate that exceeds the packet loss threshold, and

determining whether the network performance parameter meets the network performance criteria comprises determining whether the determined percentage of the UEs being served by the first network cell that have a determined packet loss rate that exceeds the packet loss threshold exceeds a performance threshold.

15. The method of claim 13, wherein

determining the network performance parameter for the cell comprises:

1) for each user equipment (UE) being served by the cell, determining whether a quality of service (QoS) requirement for the UE is not being met;

     2) determining the total number of UEs served by the cell for which the QoS requirement is not being met; and

     3) determining the percentage of the UEs being served by the cell for which the QoS requirement is not being met, and

determining whether the network performance parameter meets the network performance criteria comprises determining whether the determined percentage of the UEs exceeds the packet loss threshold exceeds a performance threshold.

16. The method of claim 15, wherein

the method further comprises determining the load threshold, wherein determining the load threshold comprises:

1) for each of the plurality of cells, the network node determining a traffic load value, thereby determining a plurality of traffic load values; and

     2) the network node determining the average of said plurality of traffic load values, thereby determining an average traffic load of the plurality of cells, and

the step of determining whether the load of the cell exceeds a load threshold comprises determining whether the load of the cell exceeds the determined average traffic load of the plurality of cells.