UMTS call handling methods and apparatus

A media gateway apparatus configured to support media flow of a universal mobile telecommunications service (UMTS) call between a local call instance and a remote call instance, comprising:

• a negative-acknowledgement timer active for a first predetermined duration commencing substantially simultaneously with initial transmission of an initialization message;
• a no-acknowledgement timer active for a second predetermined duration commencing substantially simultaneously with the initial transmission of the initialization message, wherein the second predetermined duration is substantially greater than the first predetermined duration;
• and
• means for re-transmitting the initialization message until the earliest of:
• receipt of positive-acknowledgement from the remote call instance;
• expiration of the negative-acknowledgement timer if negative-acknowledgement is received from the remote call instance;
• and
• expiration of the no-acknowledgement timer if neither positive-acknowledgement nor negative-acknowledgement is received from the remote call instance.

A method of operation for a universal mobile telecommunications service (UMTS) protocol state machine having a Null state, an Initialization state, and a Data Transfer Ready state, comprising:

• transitioning from the Null state to the Initialization state to initialize a call between a local UMTS call instance and a remote UMTS call instance;
• transitioning from the Initialization state to the Data Transfer Ready state when the UMTS call is initialized;
• and
• switching a local UMTS call instance between modules of a local media gateway without transitioning to the Initialization state.

A switching apparatus configured to switch a local instance of a universal mobile telecommunications service (UMTS) call, comprising:

• a first wireless service module configured to support at least one local call instance via UMTS protocol;
• and
• a second wireless service module configured to support at least one local call instance via UMTS protocol;
• wherein:
• the first wireless service module is configured to generate a Local-Init-Only message in response to receiving switchover instruction;
• the first wireless service module is configured to transmit the Local-Init-Only message to the second wireless service module;
• and
• the second wireless service module is configured to adjust an associated state machine in response to receipt of the Local-Init-Only message, the second wireless service module thereby entering an active state, suppressing UMTS INIT messaging transmission to a remote terminal of the UMTS call, and taking control from the first wireless service module of active wireless service and protocol messaging according to UMTS protocol.

A switching apparatus state machine for switching a local instance of a universal mobile telecommunications service (UMTS) call terminating at a remote call instance, comprising:

• means for transitioning the local instance from a Null state to a Data Transfer Ready state, including:
• transitioning the local instance from the Null state to an Initialization state and then transitioning the local instance from the Initialization state to the Data Transfer Ready state;
• and
• transitioning the local instance from the Null state to the Data Transfer Ready state without transitioning the local instance through the Initialization state.