Closed-loop downlink transmit power assignments in a small cell radio access network

Patent metadata

Field	Value
Publication number	US-10863445-B2
Application number	US-202016848610-A
Country	US
Kind code	B2
Filing date	Apr 14, 2020
Priority date	Feb 15, 2016
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A method for assigning downlink transmit power levels to radio nodes (RNs) in a small cell radio access network (RAN) includes assigning initial power levels to the RNs. For each cell, first events are counted indicating that UEs receiving a signal from their serving cells with a signal strength below a specified value have entered a coverage hole. For each cell, second events are counted indicating that UEs have re-established a previous connection on one of the cells. For each pair of cells, a coverage hole is identified between them if the number of first events for one cell exceeds a threshold and, a number of second events or re-establishment of a previous connection on the other cell exceeds another threshold. For each identified coverage hole, the downlink transmit power level is increased of at least one RN in the pair of cells between which the coverage hole is identified.

First claim

We claim:

1. A method of operating a radio access network (RAN), comprising:
(a) assigning initial power levels to at least one of a plurality of radio nodes (RNs) distributed over multiple floors of the RAN, each RN having at least one antenna and being connected to an access controller configured to aggregate voice and data traffic;
(b) receiving transfer requests from a macro network each requesting a hand-in of a UE from the macro network to one of the cells, at least one of the transfer requests including UE history information for the UE being handed-in;
(c) for any pair of cells in the RAN, inferring that a coverage hole exists between the pair of cells if the UE history information received by one of the cells in the pair for a given UE indicates that the given UE was connected to the other cell in the pair prior to the transfer of the given UE to the macro cell; and
(d) counting a number of received transfer requests from which existence of a coverage hole is inferred between each pair of cells in the RAN and, if the number for a particular pair exceeds a threshold value, adjusting upward the downlink transmit power of at least one of the RNs associated with the cells in the pair,
wherein the threshold values are based on a fraction of a number of handovers that occur between the pairs of cells.

2. The method of claim 1 , further comprising resetting the number of received transfer requests being counted and repeating steps (b)-(d) after expiration of a specified period of time.

3. The method of claim 2 , wherein the services node coordinate steps (b)-(d).

4. The method of claim 3 , wherein the RNs are coupled to the access controller over a local area network (LAN).

5. The method of claim 1 , wherein the RNs are coupled to the access controller over a LAN.

6. A method of assigning downlink transmit power levels to a plurality of RNs in a RAN, comprising:
(a) assigning initial power levels to at least one of the RNs in the RAN, wherein the RNs are distributed over multiple floors of the RAN, each RN having at least one antenna and being connected to an access controller configured to aggregate voice and data traffic;
(b) receiving transfer requests from a macro network each requesting a hand-in of a UE from the macro network to one of the cells, each of the transfer requests including UE history information for the UE being handed-in;
(c) for any pair of cells in the RAN, inferring that a coverage hole exists between the pair of cells if the UE history information received by one of the cells in the pair for a given UE indicates that the given UE was connected to the other cell in the pair prior to the transfer of the given UE to the macro cell; and
(d) counting a number of received transfer requests from which existence of a coverage hole is inferred between each pair of cells in the RAN and, if the number for a particular pair exceeds a threshold value, adjusting the downlink transmit power of at least one of the RNs associated with the cells in the pair,
wherein the threshold values are based on a preconfigured fraction of a total number of handovers that occur between the pairs of cells.

7. The method of claim 6 , wherein the transfer requests conform to the S1 application protocol (S1AP).

8. The method of claim 7 , further comprising resetting the number of received transfer requests being counted and repeating steps (b)-(d).

9. The method of claim 8 , wherein the RNs are coupled to the access controller over a LAN.

10. The method of claim 9 , wherein the access controller coordinates steps (b)-(d).

11. The method of claim 6 , wherein the RNs are coupled to the access controller over a LAN.

12. The method of claim 6 , wherein the access controller coordinates steps (b)-(d).

13. A method of operating a RAN, comprising:
assigning initial power levels to a plurality of RNs in a deployed RAN wherein the RNs are distributed over multiple floors of the RAN, each RN having at least one antenna and being connected to an access controller configured to aggregate voice and data traffic;
for at least one cell associated with the plurality of RNs, counting a number of first events indicating that UEs receiving a signal from their serving cells with a signal strength below a specified value have entered a coverage hole;
for at least one cell associated with the plurality of RNs, counting a number of second events indicating that UEs have re-established a previous connection on one of the cells;
for each pair of cells i and j in the RAN, identifying a coverage hole between a cell i and a cell j in the RAN if a number of first events counted for cell i exceeds a threshold level and a number of second events counted for re-establishment of a previous connection on cell j from a disconnect on cell i exceeds another threshold level; and
for at least one of the identified coverage holes, increasing the downlink transmit power level of at least one of the RNs associated with the pair of cells between which the coverage hole has been identified, wherein
counting the number of first events includes receiving messages from the UEs indicating that the UEs receiving a signal from their serving cells with a signal strength below the specified value have entered a coverage hole.

14. The method of claim 13 , wherein counting the number of second events includes receiving messages from the UEs indicating that the UEs have re-established a previous connection on one of the cells.

15. The method of claim 14 , wherein the threshold levels are based on a preconfigured fraction of a total number of handovers that occur between the cells i and j.

16. The method of claim 15 , wherein the RAN includes an access controller operatively coupled to the RNs.

17. The method of claim 16 , wherein the RNs are coupled to the access controller over a LAN.

18. The method of claim 13 , wherein the RNs are coupled to the access controller over a LAN.

19. The method of claim 13 , wherein the threshold levels are based on a preconfigured fraction of a total number of handovers that occur between the cells i and j.

Assignees

• Corning Optical Communications LLC

Inventors

• Nama Hithesh
• Shen Cong
• Worters Peter J
• Zhang Lili

Classifications

• H04W52/50

  at the moment of starting communication in a multiple access environment · CPC title

• H04W52/346

  distributing total power among users or channels · CPC title

• H04W52/143 Primary

  Downlink power control · CPC title

• H04W52/245

  taking into account received signal strength · CPC title

• H04W52/343

  taking into account loading or congestion level · CPC title