FALLBACK BETWEEN RADIO ACCESS TECHNOLOGIES

• US 20120015650A1
• Filed: 06/17/2011
• Published: 01/19/2012
• Est. Priority Date: 06/17/2010
• Status: Active Grant

• Current Assignee: Vodafone IP Licensing Limited (Vodafone Group PLC)
• Original Assignee: Vodafone IP Licensing Limited (Vodafone Group PLC)
• Inventors: Pudney, Christopher, Neal, Adrian
• Granted Patent: US 8,611,897 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04W 36/0022 for transferring data sessions between adjacent core network technologies
• CPC Class Codes: H04W 36/00224 between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 8/08 Mobility data transfer

Abstract

A method for assigning a location area to a mobile device for use in circuit switched fallback from a first radio access network to a second radio access network. Two counters are implemented at the eNode B—a first counter to count the numbers of times a mobile reports a given last-used location area code and a second counter for counting the numbers of certain unique combinations of location area code and further identifying data. Whenever the eNode B receives a signal incorporating a location area code, checking the respective first counter for that code and conditionally incrementing the first counter such that if the first counter is below a predefined threshold the first counter is incremented. If the first counter is equal to the threshold, obtaining further identifying data in addition to the location area code and incrementing the corresponding second counter.

Claims

1. A method for assigning a location area to a mobile device in fallback from a first radio access network to a second radio access network, the first radio access network including at least a base station node, the method comprises:

whenever the base station node receives signals incorporating a location area code and further identifying data corresponding to the second radio access network, providing a respective first counter for each unique location area identified in said signals, said location area having a corresponding location area code;

for each received signal, checking the respective first counter for the location area code and conditionally incrementing the first counter such that if the first counter is below a predefined threshold the counter is incremented;

if the first counter is equal to the threshold, incrementing a second counter for corresponding unique combination of location area code and further identifying data; and

reporting, at predetermined intervals, the counts from second counters to the first radio access network.

2. A method as claimed in claim 1, wherein the first radio access network is an LTE network and the second radio access network is a GERAN.

3. A method as claimed in claim 1, wherein the first radio access network is an LTE network and the second radio access network is a UTRAN.

4. A method as claimed in claim 1, wherein the first radio access network is an LTE network and the second radio access network is a GERAN.

5. A method as claimed in claim 1, further comprising:

checking whether the second counter exists for the signal as identified by the combination of LAC and further identifying data; and

if the second counter does not exist, providing a second counter for the signal.

6. A method as claimed in claim 1, wherein the reporting step includes reporting a subset of the second counters to the first radio access network, said subset representing the second counters having the highest counts over the preceding reporting period.

7. A base station node arranged to implement the method of claim 1.

8. A method for assigning a location area to a mobile device in fallback from a first radio access network to a second radio access network, the first radio access network including at least a base station node, the method comprises:

providing a respective first counter for each location area corresponding to the second radio access network, said location area having a corresponding code (LAC);

whenever the base station node receives a signal incorporating a location area code, checking the respective first counter for that code and conditionally incrementing the first counter such that if the first counter is below a predefined threshold the counter is incremented;

if the first counter is equal to the threshold, examining the signal, the signal including the LAC and further identifying data, checking whether a second counter exists for the signal as identified by the combination of LAC and further identifying data;

if the second counter does not exist, providing a second counter for the signal and otherwise incrementing the second counter; and

reporting, at predetermined intervals, a subset of the second counters to the first radio access network, said subset representing the second counters having the highest counts over the preceding reporting period.