This application claims the benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 2005-94611 filed Oct. 7, 2005, in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to a mobile communication system. More particularly, the present invention relates to a method and apparatus for communications using an Internet Protocol (IP) address in a User Equipment (UE).
2. Description of the Related Art
The traditional Internet which provides connectivity to fixed hosts in a wired network has evolved to support UEs roaming from one network to another in a wired-wireless network interworking environment. A protocol developed to support the mobility of such UEs over the Internet is IP. Mobile IP enables a UE to continue on-going communications with a Correspondent Node (CN) even after the UE changes its point of access to an Internet link. In Mobile IP, however, the UE has to support a mobile IP stack and a network has to support new entities such as a Home Agent (HA) and a Foreign Agent (FA).
A mobile communication network is typically configured to include a Node B wirelessly connectable to the UE and a GateWay (G/W) for connecting the Node B to an IP network. The G/W functions to connect the UE connected to the Node B over a wireless network to the IP network inside or outside the wireless network. The coverage area of the G/W is called a subnet. The G/W allocates an IP address to a UE within the subnet, and manages and maintains the mobility of the UE. The Node B provides radio resources to the UE so that the UE can connect to the IP network via the G/W. The IP network is defined as a network for providing an IP service to the UE, like the Internet.
Referring to
The old RAI is the ID of an old routing area before the movement of the UE 100, and the new RAI is the ID of the new routing area acquired from the broadcast information. A P-TMSI is a unique ID identifying the UE 100 within a routing area and thus the old P-TMSI identifies the UE 100 within the old routing area.
After the G/W 102 receives the RAU request message, security functions are performed between the UE 100 and the G/W 102, when needed in step 106. Then the G/W 102 allocates a new P-TMSI to the UE 100 and notifies the UE 100 of the new P-TMSI by an RAU accept message in step 108. The UE 100 replies with an RAU complete message in step 110, thus completing the routing area update.
The development of communication technology and a variety of demands from users and service provides have driven the use of a plurality of G/Ws in communication networks. The G/Ws manage the IP addresses of UEs within their subnets and a UE moving between subnets is allocated a new IP address.
According to the above-described conventional technology, when the UE moves to the service area of a new G/W, it cannot reuse an old IP address used in the subnet of an old G/W. In a system with a plurality of G/Ws, the change of the G/W managing the UE leads to the change of the IP address, thus causing service interruptions. Therefore, it is impossible to provide a seamless service to the UE.
Accordingly, there is a need for an improved method and apparatus for controlling communications of a user equipment using internet protocol.
Exemplary embodiments of the present invention address at least the above problems and/or disadvantages and provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method and apparatus for allocating a new IP address to a UE or allowing the UE to reuse an old IP address according to the radio resource and service status of the UE.
According to one exemplary aspect of the present invention, in a method of communicating using an IP address in a UE in a mobile communication system, when the UE moves from an old subnet managed by an old gateway to a new subnet managed by a new gateway, it determines whether there are its allocated radio resources. In the absence of the allocated radio resources, the UE determines whether an IP-based application service is in progress. If the IP-based application service is in progress, the UE determines to reuse an old IP address in the new subnet. The old IP address is an IP address used in the old subnet. If the IP-based application service is not in progress, the UE determines to use a new IP address in the new subnet. Then the UE sends to the new gateway an RAU request message including an indication indicating whether the old IP address or the new IP address will be used in the new subnet.
According to another exemplary aspect of the present invention, in a method of supporting communications of a UE using an IP address in a new gateway in a mobile communication system, the new gateway receives an RAU request message from the UE, when the UE in an idle state moves from an old subnet managed by an old gateway to a new subnet managed by the new gateway. The new gateway determines whether the UE will reuse an old IP address in the new subnet, referring to an indication included in the RAU request message. The old IP address is an IP address used in the old subnet. If the indication indicates that the old IP address will be reused, the new gateway registers the old IP address in a routing table for the UE so that the old IP address can be used in the new subnet. If the indication indicates that the old IP address will not be reused, the new gateway acquires a new IP address and stores the new IP address for the UE. Here, the indication is decided according to whether the UE has allocated radio resources and an IP-based application service is in progress for the UE, when the UE moves to the new subnet.
According to a third exemplary aspect of the present invention, in a method of supporting communications of a UE using an IP address in an old gateway in a mobile communication system, the old gateway receives a gateway context request message from a new gateway, when the UE in an idle state moves from an old subnet managed by the old gateway to a new subnet managed by the new gateway. The old gateway determines whether the UE will reuse an old IP address in the new subnet, the old IP address being an IP address used in the old subnet, referring to an indication included in the gateway context request message. The old gateway registers a new RAI being an ID of a new RA to which the UE moves, and a new P-TMSI allocated to the UE by the new gateway in a routing table for the UE. Here, the indication is decided according to whether the UE has allocated radio resources and an IP-based application service is in progress for the UE, when the UE moves to the new subnet.
According to a fourth exemplary aspect of the present invention, in an apparatus for communicating using an IP address in a UE in a mobile communication system, a controller determines whether an IP-based application service is in progress for the UE, when the UE in an idle state moves from an old subnet managed by an old gateway to a new subnet managed by a new gateway, determines to reuse an old IP address in the new subnet, the old IP address being an IP address used in the old subnet, if the IP-based application service is in progress, determines to use a new IP address in the new subnet, if the IP-based application service is not in progress, and generates an indication indicating whether the old IP address or the new IP address will be used in the new subnet. A transmitter sends an RAU request message including the indication to the new gateway.
According to a fifth exemplary aspect of the present invention, in a mobile communication system, a plurality of gateways are connected to an IP network. A UE capable of communicating using radio resources and supporting an IP-based application service determines whether an IP-based application service is in progress for the UE, when the UE in an idle state moves from an old subnet managed by an old gateway to a new subnet managed by a new gateway. If the IP-based application service is in progress, the UE determines to reuse an old IP address in the new subnet. The old IP address is an IP address used in the old subnet. If the IP-based application service is not in progress, the UE determines to use a new IP address in the new subnet. Then the UE sends to the new gateway an RAU request message including an indication indicating whether the old IP address or the new IP address will be used in the new subnet.
According to a sixth exemplary aspect of the present invention, in a method of communicating using an IP address in a UE in a mobile communication system, the UE moves from an old subnet managed by an old gateway to a new subnet managed by a new gateway. It sends a request message including an old IP address used in the old subnet to the new gateway in order to request reuse of the old IP address in the new subnet. The UE receives from the new gateway a response message indicating the old IP address can be used in the new subnet.
According to a seventh exemplary aspect of the present invention, in a method of supporting communications of a UE using an IP address in a new gateway in a mobile communication system, the new gateway receives from the UE a request message with an old IP address used in an old subnet, requesting reuse of the old IP address in a new subnet, when the UE moves from the old subnet managed by an old gateway to the new subnet managed by the new gateway. The new gateway registers the old IP address in a routing table for the UE so that the old IP address can be used in the new subnet, and sends to the UE a response message indicating that the old IP address can be used in the new subnet.
According to an eighth exemplary aspect of the present invention, in a mobile communication system, a plurality of gateways are connected to an IP network. When a UE capable of communicating using radio resources and supporting an IP-based application service moves from an old subnet managed by an old gateway to a new subnet managed by a new gateway, it sends a request message including an old IP address used in the old subnet to the new gateway in order to request reuse of the old IP address in the new subnet, and receives from the new gateway a response message indicating the old IP address can be used in the new subnet.
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:
Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features, and structures.
The matters defined in the description such as a detailed construction and elements are provided to assist in a comprehensive understanding of the embodiments of the invention and are merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. Exemplary embodiments of the present invention will be described herein below with reference to the accompanying drawings.
Exemplary embodiments of the present invention are intended to provide a technique for allocating a new IP address to a UE or allowing the UE to reuse an old IP address by identifying the state of the UE defined according to radio resource allocation and service provisioning to the UE, when a UE enters into a new subnet. If the UE reuses the old IP address in the new subnet, it sends the old IP address directly to a new G/W managing the new subnet so that the new G/W can manage the old IP address.
While exemplary embodiments of the present invention will be described in detail in the context of nodes and messages used in a particular system, it is clearly understood to those skilled in the art that a UE's IP address management according to exemplary embodiments of the present invention can be carried out in any other mobile communication system with a similar technological background and channel structure with a slight modification which is within the scope of the present invention.
Referring to
Initially, a UE 200 communicates with Node B 1 in subnet 1 under management of the O-G/W 222. During the communications, the UE 200 is connected to Node B 2 belonging to a new G/W (N-G/W) 224 by inter-RA movement 202 (movement A). The UE 200 (in other words 204) accesses a third Node B 214 (Node B 3) by inter-subnet movement 206 (movement B). The N-G/W 224 manages a second subnet 220 (subnet 2) and a third Node B 214 (Node B 3) and a fourth Node B 216 (Node B 4) are located in subnet 2. Node B 3 and Node B 4 are within a third RA (RA 3) and thus have the same RAI, RAI 3.
As described above, the RA change may cause the change of the subnet or not. The movement 202 is made from RA 1 to RA 2. Despite the movement 202, the UE 204 maintains its IP address unchanged because it is still in the same subnet 218. On the other hand, the movement 206 is made from RA 2 to RA 3, and the UE 204 (in other words 208) is in subnet 2 after the movement 206. With the inter-subnet movement 206, the UE 208 is allocated a new IP address by the N-G/W 224.
As a result, an on-going service for the UE 208 is interrupted. Accordingly, there exists a need for deciding as to whether an IP-based application service is in progress for the UE 208.
A plurality of LE modes are defined depending on whether radio resources are in use or not for the UE. When the LE is allocated radio resources and a call is in progress, it is in a CONNECTED state. If the radio resources are not used, the LE is in an IDLE state. For example, the LE conducts a voice call with the other party or receives data streams continuously from a streaming server in the CONNECTED state. According to the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard, an LTE Active state and an LTE IDLE state are equivalent to the CONNECTED state and the IDLE state, respectively.
It may occur that the UE is receiving a particular service without occupying radio resources. For example, a File Transfer Protocol (FTP) service or a HyperText Transfer Protocol (HTTP) service is bursty rather than continuous. In this case, the UE is neither fully in the CONNECTED state nor in the IDLE state. The state where a call is connected (in other words a service application is in progress) but no file transmission using radio resources takes place is defined as an IP_PRESERVE mode, and the rest IDLE state is defined as an IP_RESET mode.
In other words, the UE in the IDLE state can be in the IP_PRESERVE mode or the IP_RESET mode depending on whether the LE is receiving an application service. The IP_PRESERVE mode is an IDLE+ state in which no data transmission is carried out using radio resources with an application service in progress. When the UE is in this IP_PRESERVE mode, not the Node B but the G/W manages a context required for the communications of the LE (hereinafter, referred to as a LE context). The IP_RESET mode is an IDLE-state where the UE is not receiving the application service, in other words the call is not connected. If the UE is in the IP_RESET mode, the UE context is maintained in neither the Node B nor the G/W. In case of inter-subnet movement, the UE is allocated a new IP address or reuses an old IP address according to its state.
Referring to
In the absence of the allocated radio resources, the UE determines whether an IP-based application service is in progress, considering that it is in the IDLE state in step 308. If the service is in progress, the UE determines to reuse an old IP address used in an old subnet in the new subnet considering that it is in the IP_PRESERVE mode in step 310. On the contrary, if the service is not on-going, the UE determines to be allocated a new IP address in the new subnet, considering that it is in the IP_RESET mode in step 312.
In step 314, the UE sends an indication indicating reuse of the old IP address or allocation of the new IP address to the N-G/W of the new subnet. Then the UE communicates using the old IP address or the new IP address in the new subnet. The indication may be included in an RAU request message that the UE sends to the N-GW in the IDLE state in order to notify the entry into the new subnet.
That is, the UE adds the indication indicating whether its IP address will be maintained or changed to the RAU request message delivered to notify the N-G/W of the entry into the new subnet. The new G/W determines from the indication set in the received RAU request message whether to operate in the IP_PRESERVE mode or the IP_RESET mode.
The indication includes at least one of a 1-bit con-indicator, indicating whether the IP address is maintained or changed, and the old IP address. If the con-indicator is “1”, this implies that the UE's IP address will be changed. If the con-indicator is “0”, this implies that the UE's IP address will be kept unchanged. While it is described herein that the con-indicator is 1 bit, it can be one or more bits depending on system implementation. The con-indicator is determined at the application level of the UE, that is, at a layer above an IP level. When the UE is receiving an application/service (for example TCP/IP service) requiring no IP change for its seamless provisioning, it sets the con-indicator to “0”. In another case, the UE sends the old IP address in the RAU request message. The N-G/W uses the old IP address for the UE in the new subnet when the received RAU request message includes the old IP address of the UE.
Referring to
The IP_PRESERVE mode operation is that the N-G/W registers the old IP address of the UE in a routing table in order to reuse the old IP address for communications of the UE in the new subnet. The N-G/W may acquire the old IP address from the UE or query the O-G/W for the old IP address.
The IP_RESET mode operation is that the N-G/W uses a new IP address for the UE's communications in the new subnet. The new IP address is allocated to the UE by the N-G/W or generated from the UE itself.
If a con-indicator is used as the indication and it is set to 0, the N-G/W operates in the IP_PRESERVE mode in step 404. If the con-indicator is 1, the N-G/W operates in the IP_RESET mode in step 406.
If the old IP address is used as the indication and included in the RAU request message, the N-G/W operates in the IP_PRESERVE mode in step 404. In the absence of the old IP address, the N-G/W operates in the IP_RESET mode in step 406.
After receiving the RAU request message from the UE, the N-G/W notifies the O-G/W whether it will operate in the IP_PRESERVE mode or in the IP_RESET mode. The O-G/W decides as to whether to operate in the IP_PRESERVE mode or in the IP_RESET mode according to the information received from the N-G/W.
Referring to
Referring to
Upon receipt of the RAU request message, the N-G/W 608 sends to an O-G/W 606 a Gateway Context Request message to acquire a UE context from the O-G/W 606 in step 614. The Gateway Context Request message contains the old RAI, the old P-TMSI, and the con-indicator. The old P-TMSI is used to detect the context of the UE 600 among UE contexts stored in the O-G/W, and the con-indicator is set to 1 as received from the UE 600. It can be further contemplated as another exemplary embodiment that if the change of the IP address is requested by excluding the old IP address from the RAU request message, the N-G/W 608 generates a con-indicator to be included in the Gateway Context Request message.
In step 616, the O-G/W 606 sends the UE context for the UE 600 to the N-G/W 608 by a Gateway Context Response message. The N-G/W 608 stores the UE context included in the received Gateway Context Response message. Thereafter, unless otherwise specified by the network, the O-G/W 606 does not need to maintain UE information including the old IP address of the UE 600. The UE context contains authorization information and Quality of Service (QoS) information. It may further include other information. In step 618, a security-related operation can be performed between the UE 600 and the N-G/W 608 and between the N-G/W 608 and a Home Subscriber Server (HSS) 610. The HSS 610 stores and manages subscription information and location information of the UE 600. The O-G/W 606, the N-G/W 608 and the HSS 610 update the location information of the UE 600 and the N-G/W 608 stores subscriber data of the UE 600 received from the HSS 610 in step 620. In this way, when the HSS 610 recognizes the movement of the UE 600 to the N-G/W 608, it can command deletion of the UE information of the UE 600 to the O-G/N 606.
The following operation after step 620 can be embodied in at least two ways. One exemplary method, shown in step 636, is that the UE 600 itself generates an IP address. Specifically, the N-G/W 608 allocates a new P-TMSI to the UE 600 in step 622. The new P-TMSI together with the address prefix of the N-G/W 608 is sent to the UE 600 by an RAU accept message. The UE 600 generates a new IP address for use in the new subnet, referring to the address prefix of the new N-G/W 608 in step 624 and notifies the N-G/W 608 of the new IP address by an RAU complete message in step 626.
Another exemplary operation, shown in step 638, is that the N-G/W 608 generates a new IP address and allocates it to the UE 600. Specifically, the N-G/W 608 generates and stores the new IP address for the UE 600 to use in the new subnet in step 628 and sends the new IP address together with a new P-TMSI to the UE 600 by an RAU accept message in step 630. In step 632, the UE 600 replies with an RAU complete message.
After the IP address allocation by the operation 636 or 638, the N-G/W 608 stores the new IP address in a routing table for the UE 600 so that the UE 600 can use the new IP address for communications in the subnet of the N-G/W 608.
After acquiring the new IP address, the UE 600 sends an IP Multimedia Subsystem (IMS) registration message including the new IP address to a server for managing packet communications over an IP network, for example, an IMS server in step 634. Thus, the UE 600 is able to send packet data by paging.
The IMS server, which is defined in the 3GPP, functions to provide an IP service to subscribers. The IMS registration message is used to register the UE 600 to the IMS server.
Referring to
Upon receipt of the RAU request message, the N-G/W 708 updates a routing table for the UE 700 by registering the old IP address, the old RAI, and the old P-TMSI in the routing table in step 714. Thus, the old IP address can be used in the new subnet of the N-G/W 708. After the routing table update, the N-G/W 708 sends to an O-G/W 706 a Gateway Context Request message to acquire a UE context from the O-G/W 706 in step 716. The Gateway Context Request message contains the old RAI, the new RAI, the old P-TMSI, a new P-TMSI, and the con-indicator. It can be further contemplated as another exemplary embodiment that if the reuse of the IP address is requested by including the old IP address in the RAU request message, the old IP address is included in the Gateway Context Request message, instead of the con-indicator.
In step 718, the O-G/W 706 updates its routing table for the UE 700 by registering information about the N-G/W 706, the new P-TMSI, and the new RAI based on the Gateway Context Request message. Then the O-G/W 706 replies with a Gateway Context Response message including the UE context in step 720. Since the routing table already has the old IP address of the UE 700, the old IP address of the UE 700 is managed by both the O-G/W 706 and the N-G/W 708 in effect. In step 722, a security-related operation can be performed between the UE 700 and the N-G/W 708 and between the N-G/W 708 and an HSS 710. The O-G/W 706, the N-G/W 708 and the HSS 710 update the location information of the UE 700 and the N-G/W 708 stores subscriber data of the UE 700 received from the HSS 710 in step 724.
After the registration of the old IP address of the UE 700 for use in the new subnet, the N-G/W 708 sends an RAU accept message including the new P-TMSI to the UE 700 in step 726. In step 728, the UE 700 replies with an RAU complete message. Thus, the UE 700 is able to send packet data by paging.
When the UE moves to the new subnet in the above procedures, incoming packets for the UE in the IP_PRESERVE mode are delivered to the O-G/W because their destination address is set to the subnet address of the O-G/W: Hereinbelow, an exemplary method of sending the packets to the UE which has moved to the new subnet through paging will be described. The path of the incoming packets to the UE after the inter-subnet movement depends on whether a data tunnel is established between the O-G/W and a new Node B (
Referring to
In step 814, the N-G/W 808 broadcasts the paging request message to Node Bs within its subnet and the Node Bs page the UE 800 according to the paging request message. The new Node B 804 covering the UE 800 receives a paging response message from the UE 800.
The new Node B 804 sends the paging response message to the N-G/W 808 in step 816 and the N-G/W 808 sends the paging response message with information about the new Node B 804 to the O-G/W 806 in step 818. The O-G/W 806 establishes a data tunnel with the new Node B 804 based on the information about the new Node B 804 in step 820 and forwards the packets to the UE 800 via the data tunnel in step 822. In this way, packets from the IP network are delivered to the UE 800 using the old IP address.
Referring to
The N-G/W 908 broadcasts a paging request message for the received packets to Node Bs within its subnet and the Node Bs page the UE 900 according to the paging request message in step 916. The new Node B 904 covering the UE 900 receives a paging response message from the UE 900.
The new Node B 904 sends the paging response message to the N-G/W 908 in step 918. In step 920, the N-G/W 908 establishes a data tunnel with the new Node B 904. Then, the N-G/W 908 forwards the packets to the LE 900 via the data tunnel between the N-G/W 908 and the new Node B 904 in step 922.
Referring to
In the presence of allocated radio resources for the UE, the controller 1002 queries the application controller whether the UE is using an IP-based application service. If the IP-based application service is in progress, the controller 1002 determines that the LE is in the IP_PRESERVE mode and otherwise, the controller 1002 determines that the LE is in the IP_RESET mode. The controller 1002 generates an RAU request message according to the mode of the LE, including at least one of a con-indicator and the old IP address of the UE as an indication indicating whether the old IP address will be reused or changed in the new subnet. The RAU request message is sent to the N-G/W through the transceiver 1004. Then the controller 1002 completes an RAU by exchanging messages illustrated in
In accordance with exemplary embodiments of the present invention as described above, since it is determined whether to change or reuse the IP address of a UE according to the state of the UE, a seamless service can be provided to the UE even when the UE moves to another subnet.
While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
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2005-94611 | Oct 2005 | KR | national |