Procedure for setting up an emergency call in a wireless local loop
AssigneeNokia Networks Oy
InventorSimo Penttinen
Life of this patent
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Abstract
Subscriber terminal units (TU) are connected over a wireless link via a base station (BS) to an access node (AN) and further from the access node to a local exchange (LE) via a standard V5.2 interface, in which, when the interface is congested and a subscriber (TU) connected to the access node (AN) is attempting to make an emergency call to a public emergency number, the call control system of the local exchange (LE) cannot at once find a free time slot for the setup of the emergency call. In the procedure, call setup requests for other than emergency calls over the V5.2 interface are disabled during a predetermined period of time t2, and attempts to allocate a time slot in the V5.2 interface for the emergency call are repeated during such predetermined period of time t2.
Claims19
A method for setting up an emergency call in a wireless local loop, in which subscriber terminal units (TU) are connected over a wireless link via a base station (BS) to an access node (AN) and further from the access node to a local exchange (LE) via a standard V5.2 interface, in which, when the interface is congested and a subscriber (TU) connected to the access node (AN) is attempting to make an emergency call to a public emergency number, a call control system of the local exchange (LE) is unable to find a free time slot for the setup of the emergency call within a predetermined period of time t1, wherein:
- a message indicating failure of an attempt to set up an emergency call is given by a V5.2 interface signalling program to a process responsible for the setup of the emergency call;
- via the process responsible for the setup of the emergency call, a message indicating failure of an attempt to set up the emergency call is given to a higher-level process responsible for signalling;
- call setup requests for other than emergency calls over the V5.2 interface are disabled during a predetermined period of time t2;
- and
- attempts to reserve a time slot in the V5.2 interface for the emergency call are repeated during said predetermined period of time t2.
Dependencies are inferred from the claim text.