User equipment and system architecture for voice over long term evolution via generic access

This application claims the benefit of U.S. Provisional Application 61/048,943, entitled “Circuit Switched (CS) Domain Services Over the Evolved Packet System (EPS) Using Generic Access”, filed Apr. 29, 2008; U.S. Provisional Application 61/104,690, entitled “Circuit Switched (CS) Domain Services Over the Evolved Packet System (EPS) Using Generic Access”, filed Oct. 10, 2008; U.S. Provisional Application 61/152,965, entitled “Voice Over LTE Via Generic Access; Stage 2 Specification; Phase 1”, filed Feb. 16, 2009; U.S. Provisional Application 61/153,052, entitled “Voice Over LTE Via Generic Access; Stage 2; Phase 1”, filed Feb. 17, 2009; U.S. Provisional Application 61/160,278, entitled “TLS-Based Security for Voice over LTE via Generic Access (VoLGA)”, filed Mar. 13, 2009; and U.S. Provisional Application 61/171,738, entitled “Macro Cell Re-mapping at Call setup for Voice over LTE via Generic Access (VoLGA)”, filed Apr. 22, 2009. The contents of the above mentioned provisional applications, namely Application 61/048,943, Application 61/104,690, Application 61/152,965, Application 61/153,052, Application 61/160,278, and Application 61/171,738 are hereby incorporated by reference.

The invention relates to telecommunication. More particularly, this invention relates to a method of supporting voice over LTE using generic access network technology.

Licensed wireless systems provide mobile wireless communications to individuals using wireless transceivers. Licensed wireless systems refer to public cellular telephone systems and/or Personal Communication Services (PCS) telephone systems. Wireless transceivers include cellular telephones, PCS telephones, wireless-enabled personal digital assistants, wireless modems, and the like.

Increasing demand for high data speeds and lower packet latency has required the mobile service operators to upgrade the existing Universal Mobile Telecommunication System (UMTS) cellular technology. Long Term Evolution (LTE) is one such upgrade which provides improved spectral efficiency, lower costs, and improved service.

The decision was made in the third generation partnership (3GPP) standards to not continue to define and support circuit switched (CS) services in LTE (i.e., to not support the use of the existing CS call control protocol and procedures for voice calls). Instead, the expectation was that operators would transition to the use of IP Multimedia Subsystem (IMS)-based voice service in tandem with their addition of LTE (i.e., “4G”) air interface and network technology.

In order to make the best use of the existing resources, access from the legacy core network infrastructure and services should be possible to provide CS services (e.g., voice and short message service “SMS”). This will allow avoiding a major switch in the voice call control paradigm as well as retaining the currently provided functionalities. Therefore, there is a need in the art to reuse parts of an existing technology, such as Generic Access Network (GAN), to provide CS services over the LTE networks.

This specification discloses service description for “Voice”over long term evolution (LTE) via Generic Access (VoLGA). VoLGA supports two modes of operation: VoLGA A-mode and VoLGA Iu-mode. VoLGA A-mode supports an extension of GSM CS services that is achieved by tunneling Non Access Stratum (NAS) protocols between the UE and the Core Network over evolved packet system (EPS) bearers and the A interface to the MSC. VoLGA Iu-mode supports an extension of UMTS CS services that is achieved by tunneling Non Access Stratum (NAS) protocols between the UE and the Core Network over EPS bearers and the Iu-cs interface to the MSC.

In some embodiments, the architecture is comprised of a user equipment (UE), an access point (often an evolved UMTS terrestrial radio access network (E-UTRAN) cell) coupled to the UE, a mobility management entity (MME) coupled to the access point, a gateway entity coupled to the MME and the access point, a network controller capable of accessing VoLGA services (often a VoLGA Access Network Controller, or VANC) coupled to the MME and gateway entity, a policy and charging rules function (PCRF) coupled to the network controller and the gateway entity, and a Circuit Switched (CS) domain core network (CN) coupled to the network controller. In some embodiments several UEs are coupled to the access point. In some embodiments there are several access points coupled to the MME.

Some embodiments define a control plane architecture protocol stack. In some embodiments, there is a first set of protocol layers used with Internet Protocol (IP) for dividing data for transmission and reassembling data once it is received. A second set of protocol layers manages resources between the UE and the network controller. Some embodiments disclose a third set of protocol layers for establishing a secure communication path between the UE and the network controller.

Some embodiments define a user plane architecture protocol stack. In some embodiments, there is a first set of protocol layers used with Internet Protocol (IP) for dividing data for transmission and reassembling data once it is received. A second set of layers manages the transmission of multimedia data. Finally, some embodiments show a third set of protocol layers for sending and receiving user data.

Some embodiments of the present invention provide a method for UE registration for VoLGA services. The method sends a register request message from the UE to the VANC to register the UE with the VANC. The register request message includes location information that identifies an EPS cell upon which the UE has camped. The method receives a register response message at the UE from the VANC. The register response message indicates whether the UE is permitted to access services of the VANC.

Some embodiments disclose a UE architecture for the VoLGA control plane. In some embodiments, the architecture includes an access mode switch that allows switching between E-UTRAN RRC, UTRAN RRC, and Generic Access (GA) Layer 3 protocols. Some embodiments disclose a UE architecture for the VoLGA user plane. In some embodiments the architecture includes an access mode switch to switch between UTRAN RLC/MAC and RTP modes.

Some embodiments provide a communication system that includes (1) an evolved packet system (EPS) that includes an evolved packet core (EPC) and several evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRANs) for communicatively coupling a user equipment (UE) to the EPC, where the EPC is not capable of providing circuit switched (CS) services for the UE and (2) a Voice over long term evolution (LTE) via Generic Access (VOLGA) network controller (VANC) communicatively coupling the UE through the EPS to a legacy circuit switched (CS) core network, where the legacy CS core network is capable of providing CS services to the UE.

Some embodiments provide a user equipment (UE) for providing circuit switched (CS) services in an evolved packet system (EPS). The UE includes (1) several EPS protocol layers for communicatively coupling the UE with an evolved packet core (EPC) of the EPS through an evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRAN), (2) several generic access (GA) protocol layers over said EPS protocol layers, (3) several UTRAN protocol layers communicatively coupling the GA protocol layers and the EPS protocol layers through a plurality of interfaces, (4) and an access mode switch for switching several circuit switched (CS) protocol layers between the GA protocol layers and the UTRAN protocol layers.

Some embodiments provide a method of macro cell remapping at a Voice over LTE via Generic Access (VOLGA) access network controller (VANC). The method receives a service request message from a user equipment (UE). The service request message includes macro cell information that includes an identity of a current camping cell; and mapping the macro cell information provided by the UE into a corresponding service area identifier (SAI).

Some embodiments provide a method for updating registration information of a user equipment (UE) in a communication system that includes several evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRANs) that communicatively couple the UE to a Voice over long term evolution (LTE) via Generic Access (VOLGA) network controller (VANC). The method receives a message at the UE from the VANC. The message includes a list of E-UTRAN tracking areas (TAs) served by the VANC, each tracking area identified by a tracking area identifier (TAI). The method stores the list of E-UTRAN tracking areas at the UE. The method sends a register update message that includes a TAI of a particular E-UTRAN tracking area from the UE to the VANC when the UE moves into the particular E-UTRAN tracking area and the particular E-UTRAN TAI is not in the list of E-UTRAN tracking areas (TAs) served by the VANC.

Some embodiments provide a computer readable medium of a Voice over long term evolution (LTE) via Generic Access (VOLGA) network controller (VANC) in a communication system that includes several evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRANs) that are communicatively couple a User Equipment (UE) to the VANC. The computer readable storage medium stores a computer program. The computer program is executable by at least one processor. The computer program includes a set of instructions for sending a message to the UE from the VANC. The message includes a list of E-UTRAN tracking areas (TAs) served by the VANC, each tracking area identified by a tracking area identifier (TAI). The computer program also includes a set of instructions for receiving a register update message that includes a TAI of a particular E-UTRAN tracking area from the UE, when the UE moves into the particular E-UTRAN tracking area and the particular E-UTRAN TAI is not in the list of E-UTRAN tracking areas (TAs) served by the VANC.