System and method for determining the severity of interference in different areas of a cellular radio network and coordinating radio resource management features in response
An interference analysis tool for identifying an interference problem area in a cellular radio network in which at least a first User Equipment (UE 1 ) and a second UE (UE 2 ) operate. The tool receives signal quality measurements and determines uplink or downlink interference severity. For UE 2 uplink interference, the tool determines a first uplink Signal-to-Interference-and-Noise-Ratio (SINR) experienced by UE 2 , wherein the first SINR includes uplink interference from UE 1 . The tool also determines a second uplink SINR level (SINR 0 ) experienced by UE 2 , wherein SINR 0 does not include the uplink interference from UE 1 . The tool calculates a difference (ΔSINR) between SINR and SINR 0 for UE 2 , and identifies the area where UE 1 is operating as an interference-causing area when the ΔSINR for UE 2 is greater than a threshold value. The tool may present interference severity levels to an operator, and may initiate Radio Resource Management (RRM) procedures to mitigate interference problems in the network.
1. A method in a cellular radio network in which at least a first User Equipment (UE 1 ) and a second User Equipment (UE 2 ) are operating, wherein UE 1 is in a first cell (Cell 1 ) served by a first base station and UE 2 is in a second cell (Cell 2 ) served by a second base station, wherein the method determines a level of severity of interference to UE 2 originating in Cell 1 , wherein the interference to UE 2 originating in Cell 1 is uplink interference caused by uplink transmissions from UE 1 , the method comprising the steps of:
determining by an interference analysis tool, a first signal quality level experienced by UE 2 , wherein the first signal quality level includes the interference originating in Cell 1 , wherein determining the first signal quality level includes determining a first uplink Signal-to-Interference-and-Noise-Ratio level (SINR) experienced by UE 2 , wherein the first uplink SINR level includes uplink interference from UE 1 ;
determining by the interference analysis tool, a second signal quality level experienced by UE 2 , wherein the second signal quality level does not include the interference originating in Cell 1 , wherein determining the second signal quality level includes determining a second uplink SINR level (SINR 0 ) experienced by UE 2 , wherein the second uplink SINR level (SINR 0 ) does not include the uplink interference from UE 1 ; and
calculating by the interference analysis tool, a difference (Δ-measure) between the first and second signal quality levels for UE 2 , wherein the Δ-measure is a difference (ΔSINR) between the first and second uplink SINR levels for UE 2 indicating the level of severity of interference to UE 2 originating in Cell 1 ;
wherein the step of determining the first uplink SINR level experienced by UE 2 includes calculating the first uplink SINR level such that:
SINR
=
P
2
g
22
P
1
g
12
+
I
0
where:
P 2 is an allocated transmission power for UE 2 ;
g 22 is an estimated path gain from UE 2 to the second base station;
P 1 is an allocated transmission power for UE 1 ;
g 12 is an estimated path gain from UE 1 to the second base station; and
I 0 is background noise and other interference.
2. The method as recited in claim 1 , further comprising identifying an area of Cell 2 where UE 2 is operating as an interference-problem area when the Δ-measure of UE 2 is greater than a threshold value.
3. The method as recited in claim 1 , further comprising identifying an area of Cell 1 where UE 1 is operating as an interference-causing area when the Δ-measure of UE 2 is greater than a threshold value.
4. The method as recited in claim 1 , further comprising performing Radio Resource Management (RRM) procedures to reduce a risk of interference problems for UE 2 caused by UE 1 when the Δ-measure of UE 2 is greater than a threshold value.
5. The method as recited in claim 4 , wherein the step of performing RRM procedures includes reducing an allocated transmission power for UE 1 (P 1 ).
6. The method as recited in claim 1 , wherein the interference analysis tool is implemented or located in a centralized unit in the cellular radio network.
7. The method as recited in claim 1 , wherein the step of determining the second uplink SINR level (SINR 0 ) experienced by UE 2 includes calculating the second uplink SINR level (SINR 0 ) such that:
SINR
0
=
P
2
g
22
I
0
where:
P 2 is the allocated transmission power for UE 2 ;
g 22 is the estimated path gain from UE 2 to the second base station; and
I o is background noise and other interference.
8. The method as recited in claim 7 , wherein the step of calculating the difference (ΔSINR) between the first and second uplink SINR levels for UE 2 includes calculating the ΔSINR such that:
Δ
SINR
12
=
10
log
(
SINR
0
)
-
10
log
(
SINR
)
=
10
log
(
1
+
P
1
g
12
I
0
)
.
9. The method as recited in claim 8 , wherein the interference analysis tool is implemented in the second base station, and the method further comprises the steps of:
receiving by the second base station from the first base station, information for dynamically estimating ΔSINR by the interference analysis tool, wherein the information includes either the interfering power P 1 g 12 of UE 1 as calculated by the first base station, or P 1 and g 12 separately so that the second base station can calculate P 1 g 12 ; and
dynamically estimating ΔSINR by the interference analysis tool in the second base station.
10. The method as recited in claim 1 , wherein the interference analysis tool is implemented or located in a centralized unit in the cellular radio network, and the method further comprises the steps of:
determining by the interference analysis tool, whether the Δ-measure for UE 2 exceeds a predefined threshold; and
sending an indication from the interference analysis tool to base stations in the cellular radio network indicating that the Δ-measure for UE 2 exceeds the predefined threshold.
11. A method in a cellular radio network in which at least a first User Equipment (UE 1 ) and a second User Equipment (UE 2 ) are operating, wherein UE 1 is in a first cell (Cell 1 ) served by a first base station and UE 2 is in a second cell (Cell 2 ) served by a second base station, wherein the method determines a level of severity of interference to UE 2 originating in Cell 1 , wherein the interference to UE 2 originating in Cell 1 is uplink interference caused by uplink transmissions from UE 1 , the method comprising the steps of:
determining by an interference analysis tool, a first signal quality level experienced by UE 2 , wherein the first signal quality level includes the interference originating in Cell 1 , wherein determining the first signal quality level includes determining a first uplink Signal-to-Interference-and-Noise-Ratio level (SINR) experienced by UE 2 , wherein the first uplink SINR level includes uplink interference from UE 1 ;
determining by the interference analysis tool, a second signal quality level experienced by UE 2 , wherein the second signal quality level does not include the interference originating in Cell 1 , wherein determining the second signal quality level includes determining a second uplink SINR level (SINR 0 ) experienced by UE 2 , wherein the second uplink SINR level (SINR 0 ) does not include the uplink interference from UE 1 ;
calculating by the interference analysis tool, a difference (Δ-measure) between the first and second signal quality levels for UE 2 , wherein the Δ-measure is a difference (ΔSINR) between the first and second uplink SINR levels for UE 2 indicating the level of severity of interference to UE 2 originating in Cell 1 ;
receiving by the interference analysis tool, signal quality measurements from a plurality of UEs operating throughout the cellular radio network, each of the signal quality measurements identifying a location and a corresponding serving cell;
calculating by the interference analysis tool, a ΔSINR value for each of the plurality of UEs; and
plotting the ΔSINR values on a network cell map shaded to show the value of ΔSINR at different locations throughout the network.
12. A method in a cellular radio network in which at least a first User Equipment (UE 1 ) and a second User Equipment (UE 2 ) are operating, wherein UE 1 is in a first cell (Cell 1 ) served by a first base station and UE 2 is in a second cell (Cell 2 ) served by a second base station, wherein the method determines a level of severity of interference to UE 2 originating in Cell 1 , wherein the interference to UE 2 originating in Cell 1 is downlink interference caused by downlink transmissions from the first base station, the method comprising the steps of:
determining by an interference analysis tool, a first signal quality level experienced by UE 2 , wherein the first signal quality level includes the interference originating in Cell 1 , wherein determining the first signal quality level includes determining a first downlink Signal-to-Interference-and-Noise-Ratio level (SINR) experienced by UE 2 , wherein the first downlink SINR level includes downlink interference from the first base station;
determining by the interference analysis tool, a second signal quality level experienced by UE 2 , wherein the second signal quality level does not include the interference originating in Cell 1 , wherein determining the second signal quality level includes determining a second downlink SINR level (SINR 0 ) experienced by UE 2 , wherein the second downlink SINR level (SINR 0 ) does not include the downlink interference from the first base station; and
calculating by the interference analysis tool, a difference (Δ-measure) between the first and second signal quality levels for UE 2 , wherein the Δ-measure is a difference (ΔSINR) between the first and second downlink SINR levels for UE 2 indicating the level of severity of interference to UE 2 originating in Cell 1 ;
wherein the step of determining the first downlink SINR level experienced by UE 2 includes calculating the first downlink SINR level such that:
SINR
=
P
2
g
22
P
1
g
21
+
I
0
where:
P 2 is an allocated transmission power for the second base station;
g 22 is an estimated path gain from the second base station to UE 2 ;
P 1 is an allocated transmission power for the first base station;
g 21 is an estimated path gain from the first base station to UE 2 ; and
I 0 is background noise and other interference.
13. The method as recited in claim 12 , wherein the step of determining the second downlink SINR level (SINR 0 ) experienced by UE 2 includes calculating the second downlink SINR level (SINR 0 ) such that:
SINR
0
=
P
2
g
22
I
0
where:
P 2 is the allocated transmission power for the second base station;
g 22 is the estimated path gain from the second base station to UE 2 ; and
I 0 is background noise and other interference.
14. The method as recited in claim 13 , wherein the step of calculating the difference (ΔSINR) between the first and second downlink SINR levels for UE 2 includes calculating the ΔSINR such that:
Δ
SINR
=
10
log
(
SINR
0
)
-
10
log
(
SINR
)
=
10
log
(
1
+
P
1
g
21
I
0
)
.
15. The method as recited in claim 14 , wherein the interference analysis tool is implemented in the second base station, and the method further comprises the steps of:
receiving by the second base station from the first base station, the allocated transmission power for the first base station (P 1 ); and
dynamically estimating ΔSINR by the interference analysis tool in the second base station.
16. An interference analysis tool for determining a level of severity of interference to a second User Equipment (UE 2 ) in a cellular radio network, wherein a first User Equipment (UE 1 ) is operating in a first cell (Cell 1 ) served by a first base station, and UE 2 is operating in a second cell (Cell 2 ) served by a second base station, and the interference to UE 2 originates in Cell 1 , wherein the interference to UE 2 originating in Cell 1 is uplink interference caused by uplink transmissions from UE 1 , the interference analysis tool comprising:
a processor; and
a non-transitory memory connected to the processor for storing computer program instructions, wherein when the processor executes the computer program instructions, the processor causes the interference analysis tool to:
determine a first Signal-to-Interference-and-Noise-Ratio level (SINR) experienced by UE 2 , wherein the first SINR level is a first uplink SINR level that includes the uplink interference from UE 1 ;
determine a second SINR level (SINR 0 ) experienced by UE 2 , wherein the second SINR level (SINR 0 ) is a second uplink SINR level that does not include the uplink interference from UE 1 ; and
calculate a difference (ΔSINR) between the first and second SINR levels for UE 2 , wherein the ΔSINR indicates the level of severity of interference to UE 2 originating in Cell 1 ;
wherein the interference analysis tool is configured to determine the first uplink SINR level experienced by UE 2 such that:
SINR
=
P
2
g
22
P
1
g
12
+
I
0
where:
P 2 is an allocated transmission power for UE 2 ;
g 22 is an estimated path gain from UE 2 to the second base station;
P 1 is an allocated transmission power for UE 1 ;
g 12 is an estimated path gain from UE 1 to the second base station; and
I 0 is background noise and other interference.
17. The interference analysis tool as recited in claim 16 , wherein the interference analysis tool is configured to identify an area of Cell 2 where UE 2 is operating as an interference-problem area when the ΔSINR of UE 2 is greater than a threshold value.
18. The interference analysis tool as recited in claim 16 , wherein the interference analysis tool is configured to identify an area of Cell 1 where UE 1 is operating as an interference-causing area when the ΔSINR of UE 2 is greater than a threshold value.
19. The interference analysis tool as recited in claim 18 , wherein the interference analysis tool is configured to initiate Radio Resource Management (RRM) procedures to reduce the risk of interference problems for UE 2 caused by UE 1 when the ΔSINR of UE 2 is greater than a threshold value.
20. The interference analysis tool as recited in claim 16 , wherein the interference analysis tool is configured to determine the second uplink SINR level (SINR 0 ) experienced by UE 2 such that:
SINR
0
=
P
2
g
22
I
0
where:
P 2 is the allocated transmission power for UE 2 ;
g 22 is the estimated path gain from UE 2 to the second base station; and
I 0 is background noise and other interference.
21. The interference analysis tool as recited in claim 20 , wherein the interference analysis tool is configured to determine the difference (ΔSINR) between the first and second uplink SINR levels for UE 2 such that:
Δ
SINR
12
=
10
log
(
SINR
0
)
-
10
log
(
SINR
)
=
10
log
(
1
+
P
1
g
12
I
0
)
.
22. The interference analysis tool as recited in claim 16 , wherein the interference analysis tool is implemented or located in a centralized unit in the cellular radio network.
23. The interference analysis tool as recited in claim 16 , wherein the interference analysis tool is implemented in the second base station, and the interference analysis tool is further configured to:
receive from the first base station, an allocated transmission power for UE 1 (P 1 ) and a background noise and interference level in Cell 1 (I 1 ); and
dynamically estimate ΔSINR using P 1 and I 1 .
24. An interference analysis tool for determining a level of severity of interference to a second User Equipment (UE 2 ) in a cellular radio network, wherein a first User Equipment (UE 1 ) is operating in a first cell (Cell 1 ) served by a first base station, and UE 2 is operating in a second cell (Cell 2 ) served by a second base station, and the interference to UE 2 originates in Cell 1 , wherein the interference to UE 2 originating in Cell 1 is downlink interference caused by downlink transmissions from the first base station, the interference analysis tool comprising:
a processor; and
a non-transitory memory connected to the processor for storing computer program instructions, wherein when the processor executes the computer program instructions, the processor causes the interference analysis tool to:
determine a first Signal-to-Interference-and-Noise-Ratio level (SINR) experienced by UE 2 , wherein the first SINR level is a first downlink SINR level that includes the downlink interference from the first base station;
determine a second SINR level (SINR 0 ) experienced by UE 2 , wherein the second SINR level (SINR 0 ) is a second downlink SINR level that does not include the downlink interference from the first base station; and
calculate a difference (ΔSINR) between the first and second SINR levels for UE 2 , wherein the ΔSINR indicates the level of severity of interference to UE 2 originating in Cell 1 ;
wherein the interference analysis tool is configured to determine the first downlink SINR level experienced by UE 2 such that:
SINR
=
P
2
g
22
P
1
g
21
+
I
0
where:
P 2 is an allocated transmission power for the second base station;
g 22 is an estimated path gain from the second base station to UE 2 ;
P 1 is an allocated transmission power for the first base station;
g 12 is an estimated path gain from the second base station to UE 1 ; and
I 0 is background noise and other interference.
25. The interference analysis tool as recited in claim 24 , wherein the interference analysis tool is configured to determine the second downlink SINR 0 level experienced by UE 2 such that:
SINR
0
=
P
2
g
22
I
0
where:
P 2 is the allocated transmission power for the second base station;
g 22 is the estimated path gain from the second base station to UE 2 ; and
I 0 is background noise and other interference.
26. The interference analysis tool as recited in claim 25 , wherein the interference analysis tool is configured to calculate the difference (ΔSINR) between the first and second downlink SINR levels for UE 2 such that:
Δ
SINR
=
10
log
(
SINR
0
)
-
10
log
(
SINR
)
=
10
log
(
1
+
P
1
g
21
I
0
)
.
27. The interference analysis tool as recited in claim 26 , wherein the interference analysis tool is implemented in the second base station, and the interference analysis tool is further configured to:
receive from the first base station, the allocated transmission power for the first base station (P 1 ) and the background noise and interference level in Cell 1 (I 1 ); and
dynamically estimate ΔSINR using P 1 and I 1 .
28. The interference analysis tool as recited in claim 16 , wherein the interference analysis tool is implemented or located in a centralized unit in the cellular radio network, and the method further comprises the steps of:
determining by the interference analysis tool, whether the ΔSINR for UE 2 exceeds a predefined threshold; and
sending an indication from the interference analysis tool to base stations in the cellular radio network indicating that the ΔSINR for UE 2 exceeds the predefined threshold.