Method for detecting RF link imbalances in a wireless communications network

• US 20090003272A1
• Filed: 06/29/2007
• Published: 01/01/2009
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Payne, Steven John, Irving, Stuart John
• Granted Patent: US 7,916,667 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A method for determining an RF link imbalance between an Uplink Path and a Downlink Path of an RF Link formed between a User Equipment (UE) and a Node in a wireless network is provided. The method includes determining the UE receive power levels and the UE transmit power levels for the RF Links at the UE side of the radio interface and identifying one or more RF Links having AvgSum_Tx+Rx values deviating from the AvgSum_Tx+Rx values of other RF Links, as one or more RF Links having an RF Link imbalance.

Claims

1. A method for determining an RF Link Imbalance between an Uplink Path (UL_Path) and a Downlink Path (UL_Path) of an RF Link between a User Equipment and a NodeB in a 3 G UMTS wireless network comprising:

determining the DL_Path_Loss from the UE side of the RF Link as CPICH_Tx_Power−

CPICH_Rx_Power;

determining the UL_Path_Loss from the UE side of the RF Link as UE_Tx_Power−

NodeB_Expected_Rx_Power; and

determining RF Link Imbalance as UL_Path_Loss−

DL_Path_Loss.

2. The method defined in claim 1 wherein the step of determining the DL_Path_Loss further comprises obtaining CPICH_Tx_Power from signaling to the UE.

3. The method defined in claim 1 wherein the step of determining the UL_Path_Loss comprises estimating the NodeB_Expected_Rx_Power using the expected Noise Floor of the NodeB, the Receive Sensitivity of the NodeB on the Network side of the RF Link, the Processing Gain of a voice call, and the approximate target Signal to Interference ratio at the NodeB.

4. The method defined in claim 3 wherein the step of estimating the NodeB_Expected_Rx_Power includes the summation of the values of the expected Noise Floor of the NodeB, the Processing Gain for a test call and the typical target Signal to Interference ratio

5. A method of determining an RF link imbalance between an

Uplink Path (UL_Path) and a Downlink Path (UL_Path) of an RF Link between a User Equipment (UE) and a NodeB in a 3 G UMTS wireless network comprising:

establishing RF Links at different locations within the network, each RF link including an UL_Path and a DL_Path between a UE and one or more Nodes in a wireless network;

determining the UE receive power levels (UE_Rx) and the UE transmit power levels (UE_Tx) for the RF Links;

determining the sums (Sum_Rx+Tx) of UE_Rx and UE_Tx for the RF Links;

collecting sets of one or more Sum_Rx+Tx, each set corresponding to a different RF Link;

determining the averages (AvgSum_Rx+Tx) of the Sum_Rx+Tx values for each set;

identifying one or more RF Links having AvgSum_Tx+Rx values deviating from the AvgSum_Tx+Rx values of other RF Links, as one or more RF Links having an RF Link imbalance.

6. The method defined in claim 5 wherein the identifying step further comprises:

creating a high threshold value and a low threshold value; and

identifying one or more RF Links having AvgSum_Tx+Rx values exceeding the high threshold value or falling below the low threshold value.

7. The method defined in claim 6 wherein the high threshold value and the low threshold value are formed using the standard deviation of the AvgSum_Tx+Rx values.

8. The method defined in claim 5 wherein the identifying step further comprises:

displaying the AvgSum_Tx+Rx values as plotted values; and

marking the high threshold and low threshold on the plot for identifying one or more RF Links having AvgSum_Tx+Rx values exceeding the high threshold value or falling below the low threshold value.

9. The method defined in claim 5 wherein the AvgSum_Tx+Rx values each correspond to a different Scrambling Code.

10. The method defined in claim 5 wherein the RF Links each correspond to a different sector of a NodeB.

11. The method defined in claim 5 wherein the establishing step further comprises filtering data for measurements corresponding to single RF links existing in an Active Set.

12. The method defined in claim 5 wherein the one or more Nodes are one or more NodeBs in a 3 G UMTS wireless network.

13. The method defined in claim 5 wherein the step of determining the UE_Rx and UE_Tx includes determining the UE_Rx and UE_Tx at the UE side of the RF Links.

14. The method defined in claim 5 wherein the RF Links established in the step of establishing RF Links at different locations within the network do not include RF Links in Handover.

15. The method defined in claim 5 further comprising collecting UE_Rx power level values and UE_Tx power level values from one or more UEs at one or more network nodes via an RF Call Trace command and the identifying step being performed by the network.

16. The method defined in claim 15 wherein a Radio Network Controller collects the UE_Rx power level values and UE_Tx power level values and detects the one or more RF Link Imbalances in the identifying step.

17. A method of determining one or more Nodes having an RF link imbalance between an Uplink Path (UL_Path) and a Downlink Path (UL_Path) of an RF Link between the one or more Nodes and User Equipment (UE) in a wireless communications network comprising:

establishing RF Links at different locations within the network, each RF link including an UL_Path and a DL_Path between a UE and a Node in a wireless network;

determining the Averages of the Sums (AvgSum_Tx+Rx) of the UE receive power levels (UE_Rx) and the UE transmit power levels (UE_Tx) for a plurality of RF Links corresponding to a Scrambling Code;

determining a plurality of AvgSum_Tx+Rx each corresponding a different one of a plurality of Scrambling Codes in the network;

determining a window having a high threshold value and a low threshold value;

identifying one or more AvgSum_Tx+Rx having values falling outside the window; and

identifying one or more Nodes corresponding to the one or more AvgSum_Tx+Rx having values falling outside the window as the one or more Nodes having an RF Link imbalance.