Method and server for determining associations between pools of core network nodes and base stations

Patent metadata

Field	Value
Publication number	US-9088870-B2
Application number	US-201114240823-A
Country	US
Kind code	B2
Filing date	Oct 25, 2011
Priority date	Aug 31, 2011
Publication date	Jul 21, 2015
Grant date	Jul 21, 2015

Abstract

The present invention relates to positioning in a communication network. In Long Term Evolution, LTE networks the positioning server E-SLMC needs routing information in order to communicate with individual base stations, eNodeBs. For LTE networks configured with one Mobility Management Entity, MME or one pool of MMEs, the routing information can be obtained by interrogating the MME or an arbitrary MME in the MME pool. However, if the network is configured with several MME pools serving different sets of eNodeBs, the E-SLMC has now knowledge of which MME or MME pool that is serving a certain eNodeB. The invention includes a method and a position server ( 111 ) configured to quickly determine which MME pool ( 120,130 ) is serving a certain eNodeB ( 141 - 153 ) so that the relevant routing information necessary for the positioning server ( 111 ) to communicate with the eNodeBs ( 141 - 153 ) is obtained.

First claim

The invention claimed is:

1. A method, in a positioning server in a communication network, for determining associations between a plurality of pools of core network nodes and base stations served by the pools, the method comprising:
selecting a base station;
calculating a probability index (Pj) for each pool based on a location of the selected base station and estimated locations of the pools;
determining the pool that is serving the selected base station by interrogating, in descending order, a core network node in at least one pool starting with a pool having the highest probability index, until a serving pool has been identified;
receiving, from the interrogated core network node, associations between the corresponding identified serving pool and the selected base station;
storing the received associations;
repeating the selecting, calculating, determining, receiving, and storing for each remaining base station.

2. The method of claim 1 , further comprising recalculating the estimated pool location of the identified serving pool based on locations of the base stations so far identified as served by the identified serving pool.

3. The method of claim 2 , wherein the recalculating comprises setting the estimated pool location to an average of locations of the base stations so far identified as served by the identified serving pool.

4. The method of claim 2 :
wherein the estimated pool location is defined as a geometrical shape having a border;
wherein the recalculating the estimated pool location comprises amending the border of the geometrical shape to include, within the border, the locations of the base stations so far identified as served by the pool;
wherein the probability index is calculated according to the equation:
Pj=inside(Sj, G_enb), where inside(Sj, G_enb) is a mathematical operation indicating if the location of the selected base station is within the border or not.

5. The method of claim 1 , wherein the probability index is calculated according to the equation Pj=1/max(1, dist(Gj, G_enb)), where dist(Gj, G_enb) is a geographical distance between the estimated pool location and the location of the selected base station.

6. The method of claim 1 , wherein the probability index is calculated according to the equation Pj=1/max(1, Dj), where (Dj) is a geographical distance between the location of the selected base station and a location of a base station that is both already identified to be served by the pool and closest to the selected base station.

7. The method of claim 1 :
wherein the estimated pool location is defined as a geometrical shape having a border where locations of base stations so far identified as served by the pool are within the border;
wherein the probability index has a binary value calculated according to the equation:
Pj=inside(Sj, G_enb), where inside(Sj, G_enb) is a mathematical operation indicating if the location (G_enb) of the selected base station is within the border or not.

8. The method of claim 1 , further comprising determining and storing routing information from the core network node to enable the positioning server to communicate with the selected base station via the core network node.

9. The method of claim 1 , further comprising, prior to the storing the received associations:
for all remaining base stations belonging to the same tracking area (TA) as the selected base station, determining associations between the identified serving pool and the remaining base stations belonging to the same TA by interrogating the core network node;
receiving, from the core network node, associations between the identified serving pool and the remaining base stations belonging to the same TA as the selected base station.

10. The method of claim 1 , wherein the positioning server is an Evolved Serving Mobile Location Center (E-SMLC).

11. The method of claim 1 , wherein:
the core network node is a Mobility Management Entity (MME);
the base station is a Long Term Evolution evolved Node B (eNodeB).

12. A positioning server in a communication network for determining associations between a plurality of pools of core network nodes and base stations served by the pools, the positioning server comprising:
at least one communication interface configured to be connected to at least one core network node;
a storing device for storing the associations;
a processing circuit connected to the communication interface and to the storing device and configured to:
select a base station;
calculate a probability index (Pj) for each pool based on a location of the selected base station and estimated locations of the pools;
determine a pool that is serving the selected base station by interrogating, in descending order, a core network node in at least one pool starting with a pool having the highest probability index, until a serving pool has been identified;
receive, from the interrogated core network node, associations between the corresponding identified serving pool and the selected base station;
store the received associations;
repeat the selecting, calculating, determining, receiving, and storing for each remaining base station.

13. The positioning server of claim 12 , wherein the processing circuit is configured to recalculate the estimated pool location of the identified serving pool based on locations of the base stations so far identified as served by the pool.

14. The positioning server of claim 13 , wherein the processing circuit is configured to recalculate the estimated pool location as an average of locations of the base stations so far identified as served by the identified serving pool.

15. The positioning server of claim 13 :
wherein the estimated pool location is defined as a geometrical shape having a border;
wherein the processing circuit is configured to:
recalculate the estimated pool location by amending the border to include within the border the locations of the base stations so far identified as served by the identified serving pool;
calculate the probability index according to the equation:
Pj=inside(Sj, G_enb), where inside(Sj, G_enb) is a mathematical operation indicating if the location of the selected base station is within the border or not.

16. The positioning server of claim 12 , wherein the processing circuit is configured to calculate the probability index according to the equation Pj=1/max(1, dist(Gj, G_enb)), where dist(Gj, G_enb) is a geographical distance between the estimated pool location and the location of the selected base station.

17. The positioning server of claim 12 , wherein the processing circuit is configured to calculate the probability index according to the equation Pj=1/max(1, Dj), where (Dj) is a geographical distance between the location of the selected base station and a location of a base station that is both already identified to be served by the pool and closest to the selected base station.

18. The positioning server of claim 12 :
wherein the estimated pool location is defined as a geometrical shape having a border;
wherein the processing circuit is configured to calculate the probability index according to the equation: Pj=inside(Sj, G_enb), where inside(Sj, G_enb) is a mathematical operation indicating if the location (G_enb) of the selected base station is within the border or not.

19. The positioning server of claim 12 , wherein the processing circuit is configured to determine routing information from the core network node and to cause the routing information to be stored in the storing device.

Assignees

• Busin Åke
• Zhang Yang
• Ericsson Telefon Ab L M

Inventors

• Busin Åke
• Zhang Yang

Classifications

• H04W4/023 Primary

  using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds · CPC title

• H04W64/00

  Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management · CPC title

• G01S5/0242

  Determining the position of transmitters to be subsequently used in positioning (G01S5/0289 takes precedence) · CPC title