Location-based addressing
A system and method for performing location dependent addressing is provided suitable for use in GSM-R systems. A quadtree is used to store jurisdiction information as a function of location, for example GPS location. When a call is received that contains location information, it is processed by looking up the jurisdiction using the quadtree, and by then establishing a connection to the appropriate destination.
1 . A method comprising:
for a first location dependent information element, storing a hierarchical spatial representation defining a value of the location dependent information element for locations within a geographical coverage area;
for a particular location within the geographical coverage area, looking up the value of the location dependent information element using the hierarchical spatial representation.
2 . The method of claim 1 wherein the hierarchical spatial representation is a quadtree.
3 . The method of claim 2 wherein for a first location dependent information element, storing a quadtree defining a value of the location dependent information element for geographical coverage area comprises:
storing a graphic using the quadtree, the graphic comprising a plurality of polygons each having a respective colour or other graphic display characteristic that is associated with a respective value of the location dependent information element, the quadtree comprising nodes defining the colour or graphic display characteristic of each pixel of the graphic.
4 . The method of claim 3 wherein for a particular location within the geographical coverage area, looking up the value of the location dependent element using the quadtree comprises:
converting the particular location into coordinates of a pixel within the graphic;
determining a colour or graphic display characteristic of the pixel using the quadtree;
mapping the colour or graphic display characteristic to the value of the location dependent information element.
5 . The method of claim 1 wherein each location dependent information element comprises a respective functional entity having geographically defined jurisdictions, and the value comprises connection information for connecting to a particular instance of the functional entity for each geographically defined jurisdiction.
6 . The method of claim 5 wherein each jurisdiction can be disjoint or contiguous.
7 . The method of claim 1 further comprising:
receiving a query comprising information identifying the particular location, the particular location being a location of a sending or receiving party.
8 . The method of claim 7 wherein the first location dependent information element is a location dependent functional entity, the method further comprising:
receiving a call setup request requesting a connection between a calling device and a location dependent functional entity;
looking up connection information of the location dependent functional entity as a function of location of the calling device;
using the connection information, initiating the establishment of a connection between the calling device and an instance of the location dependent functional entity.
9 . The method of claim 1 wherein storing and looking up comprises:
storing a respective quadtree for a plurality of different location dependent information elements one of which is said first location dependent information element;
for a particular location within the geographical coverage area and for a particular location dependent information element, looking up the value of the location dependent element using the quadtree stored for that location dependent information element.
10 . The method of claim 1 wherein information identifying the particular location dependent information element comprises a GSM-R short code.
11 . The method of claim 1 wherein the information identifying the particular location comprises latitude and longitude information.
12 . The method of claim 1 further comprising:
using coarse location information to determine which of a plurality of quadtrees to use.
13 . The method of claim 12 wherein the coarse location information comprises a cell identifier.
14 . The method of claim 1 wherein storing the quadtree comprises storing higher resolution nodes in the quadtree for areas where a higher resolution location-based lookup is to be provided.
15 . The method of claim 1 implemented in a service control point.
16 . A GSM-R system adapted to implement the method of claim 1 .
17 . A system comprising:
a wireless access network serving a coverage area;
a hierarchical spatial representation-based lookup function;
wherein a request for a location dependent communication received from within the coverage area is processed by looking up connection information as a function of a location associated with the request using the hierarchical spatial representation-based lookup function and by initiating or otherwise enabling the communication.
18 . The system of claim 17 wherein the hierarchical spatial representation-based lookup function comprises a quadtree-based lookup function.
19 . The system of claim 18 wherein the hierarchical spatial representation-based lookup function comprises a service control point.
20 . One or more computer readable media having computer executable instructions for executing the method of claim 1.