HK1085321A - Early determination of network support for mobile ip - Google Patents

Description

Early determination of network support for mobile IP

Technical Field

The present invention relates generally to the field of wireless communications, and more particularly to a system and method for early determination of network support for mobile ip (mobileip).

Background

Recent developments in wireless communications and the proliferation of internet usage have greatly increased the demand for mobile computing. Code Division Multiple Access (CDMA) technology plays an important role in meeting the demand.

CDMA IS a digital Radio Frequency (RF) technology defined in the telecommunications industry association/electronics industry association interim STANDARD-95, generally referred to as "IS-95" and entitled "mobile STATION-BASE STATION COMPATIBILITY for mobile STATION cellular-MODE wide SPREAD SPECTRUM", published 7 months 1993, and IS considered an example of a system to which various embodiments of the present invention are applied.

CDMA communication devices assign a unique code to communication signals and spread the signals over a common spread-spectrum (spread-spectrum) bandwidth. As long as the communication device has the correct coding, it can successfully detect and select its signal from other signals transmitted simultaneously over the bandwidth.

The increased reliability of mobile communications has created a need for remote wireless computing in which a computing device, such as a laptop or palmtop computer, is remotely coupled to a computer network (e.g., the internet) via a mobile telephone. Although IS-95 does not explicitly define the protocols for the remote wireless computing, there are a number of standards that describe the protocols and/or algorithms for the interfaces and applications. The Internet Protocol (IP) standard has been introduced in many wireless communication devices. The standard is a network layer PROTOCOL that provides for the packing of data for transmission, and is Request form No.791(RFC 791) entitled "INTERNET PROTOCOL PROGRAM PROTOCOL specialization", published 9/1981. The addressing and routing information is included in a packet header. The header includes an address identifying the transmitting and receiving device. These addresses are used by routers in the network to select a path to deliver each packet to the final destination of the desired destination address.

Another known protocol in wireless communications is the point-to-point protocol (PPP), which is used to control access of wireless communications to a computer network, such as the internet. The PPP PROTOCOL is described in Request For Comment 1661(RFC 1661) entitled "THEPOINT-TO-POINT PROTOCOL (PPP)" published in month 7 of 1994. The PPP protocol specifies standards for transporting data for point-to-point links, which include techniques for encapsulating multi-protocol data, a Link Control Protocol (LCP) to establish and configure data links, and a Network Control Protocol (NCP) to establish and configure network layer protocols.

Another standard, known as IETF RFC 2002, provides a communications standard, but does not address the wireless aspects of mobile computing, which is entitled "IP MOBILITY support IPv4," commonly referred to as "mobile IP.

Telecommunications standards have been introduced for wireless network communications by employing third generation (3G) standards for CDMA communications. The telecommunications STANDARD known as IS-835 and the telecommunications STANDARD known as IS-835A require specific communication protocols for use with 3G CDMA equipment, with IS-835 titled "CDMA 2000 WIRELESS NETWORK STANDARD", published in 6/2000 and IS-835A published in 5/2001. These standards are referred to herein as "IS-835".

There is an increasing demand for packetized data services in wireless communication systems. Since conventional wireless communication systems are designed for voice communications, the expansion to support data services presents many challenges. In particular, the configuration of IP for mobile devices (i.e., mobile IP) has a unique set of requirements and goals. Mobile IP is a standard specifically used for IPv 4. Other methods for configuring IP over a wireless network may exist. Mobile IP configuration in a wireless communication system creates unique requirements and problems that are different from the problems faced in configuring IP in a non-mobile environment.

One problem with mobile IP is the total cost of connection time and air resources. Mobile IP registration occurs after a packet network connection has been established. In wireless networks, over-the-air resources and connection time are expensive resources for providers and consumers. There are problems in mobile IP configuration in terms of management and resource saving.

Therefore, there is a need for an efficient method for managing the resources in a wireless communication system implementing mobile IP. In particular, there is a need for a method of early termination or disconnection of a mobile device from a wireless network when the wireless network does not support mobile IP. Additionally, there is a need for a method of detecting that the network does not support mobile IP during or before initiating communication.

Drawings

FIG. 1 is a block diagram of a communication network implementing Mobile IP to enable communication with mobile nodes;

fig. 2 is a diagram of a spread spectrum communication system supporting multiple users;

FIG. 3 is a block diagram of a communication system supporting IP data transport;

FIG. 4 is a functional block diagram of a wireless connection of a computing device to a computer network;

FIG. 5 illustrates a logical link between a computing device and a Mobile IP network using a wireless system similar to that of FIG. 4;

FIG. 6 illustrates a flow chart for early determination of network support for Mobile IP;

FIG. 7 illustrates a signal flow associated with an origination message from a mobile node in a wireless communication system topology;

fig. 8 illustrates signal flow associated with registering a mobile node in a wireless communication system topology via a home (home) agent;

FIG. 9 illustrates signal flows associated with negotiating a wireless communication link using the system of FIG. 5;

FIG. 10 illustrates a flow chart for early determination of network support for Mobile IP; and

fig. 11 illustrates a block diagram of certain components in an embodiment of a subscriber unit.

Detailed Description

In a wireless communication system, a method for early determination of network support for mobile IP is disclosed. Early determination refers to a determination made before or during the start of communication. The determination identifies a network status as to whether the network supports mobile IP. Currently, after a packet network connection is established, mobile IP registration is performed. The general method first establishes an air link between the mobile device and the wireless network for packet data service, then negotiates a packet data connection through PPP 3, and finally performs mobile IP registration. In wireless networks, over-the-air resources and connection time are expensive resources for providers and consumers. Thus, if step 3 is not available, it is wasteful to use the resources during steps 1 and 2. The embodiments and methods described herein allow for early detection of network compatibility, i.e., whether the network supports mobile IP, thereby providing a more efficient registration mechanism. In other words, the method allows for a determination of mobile IP compatibility prior to packet network connection.

In one embodiment, a mobile node is connected to a wireless network. Then, a check is made for a disconnect condition, which is an early indication of network support for mobile IP. If the disconnect condition is found, the mobile node disconnects from the wireless network. If the disconnect condition is not found, the mobile node maintains a connection to the wireless network.

The disconnect condition may be an indication that IS-835 network for mobile IP IS not supported. There are many different disconnect conditions that can be used. For example, one disconnect condition is: before or during the start, the protocol revision supported by the wireless network is less than PREV6 (discussed below). Another disconnect condition is: during LCP negotiation, the wireless network needs authentication.

Other disconnect conditions are: during IP control protocol (IPCP) negotiation, the wireless network sends a Configure-Not-Acknowledge including an IP address option. Another disconnect condition is: a no agent advertisement (advertisement) message is received by the mobile node in response to a proxy solicitation (solicitation) message during mobile IP registration and before a registration request message is sent.

The early indication may be an indicator prior to sending a registration request message during mobile IP registration. Additionally, the early indication may be an indicator before or during the start. The early indication may also be an indicator during LCP negotiation or during IPCP negotiation.

The present application also discloses a mobile station for a wireless communication system, wherein the mobile station determines network support for mobile IP. The mobile station includes an antenna for receiving wireless signals, a receiver in electronic communication with the antenna, and a transmitter in electronic communication with the antenna. The mobile station also includes a processor for executing instructions and a memory for storing the instructions. (this application) discloses guidance for implementing a method for early determination of network support for mobile IP. The mobile node is connected to a wireless network. Then, a check is performed for a disconnect condition, wherein the disconnect condition is an early indication of network support for mobile IP. If a disconnect condition is found, the mobile node disconnects from the wireless network. If the disconnect condition is not found, the mobile node maintains a connection to the wireless network.

A wireless communication system including embodiments of the mobile station is also disclosed. In addition to a mobile station, a wireless communication system includes an IP network and a proxy in electronic communication with the IP network.

The functions and methods disclosed herein may be embodied in a computer readable medium. The media stores data including instructions for implementing the methods and functions described herein.

"exemplary" is used exclusively herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although the various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The following discussion presents embodiments by first presenting a network that implements mobile IP to communicate data to and receive data from a mobile node. Next, a spread spectrum wireless communication system is discussed. Next, a mobile IP network implemented in the wireless communication system is displayed. A functional and logical block diagram of a wireless link of a computing device having a computer network is shown. Finally, a method for early determination of network support for mobile IP is illustrated and described.

Note that one embodiment is provided throughout the discussion as an example, however, other embodiments may incorporate aspects without departing from the scope of the invention. In particular, the present invention is applicable to data processing systems, wireless communication systems, mobile IP networks, and any other system in which it is desirable to efficiently use and manage resources.

The present embodiment employs a spread spectrum wireless communication system. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), or some other modulation technique. CDMA systems provide certain advantages over other types of systems, including increased system capacity.

The System may be designed to support one or more standards, such as "TIA/EIA/IS-95-B Mobile Station-Base Station compatibility Standard" for DuaI-Mode Wireless Spread Spectrum Cellular System "referred to herein as the IS-95 standard, for example, by the name" 3^rdThe standard provided by the alliance of Generation Partnership Project ", referred to herein as 3GPP, is embodied in a series of documents, including documents 3GTS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214, 3G TS 25.302, referred to herein as the W-CDMA standard, for example, by the name" 3G TS Project^rdThe standard provided by the alliance of Generation PartnershipProject 2 ", herein referred to as 3GPP2, and for example, TR-45.5, herein referred to as the cdma2000 standard, formally named IS-2000MC。

Each standard specifically defines the processing of data for transmission from a base station to a mobile station, and vice versa. By way of example, one embodiment is described in detail in the following discussion that contemplates a spread spectrum communication system consistent with the protocols of the CDMA2000 standard. Other embodiments may incorporate additional criteria.

The following definitions are used throughout the following discussion and are specific to mobile IP communications.

Local network: a network over which the mobile node appears to be reachable to the rest of the internet based on the IP address (i.e., home address) assigned to the mobile node.

The local proxy: a node on a home network effective to make a mobile node reachable at a home address of the mobile node even when the mobile node is not attached to the home network.

Local address: is assigned an IP address of the mobile node that causes the mobile node to be logically attached to the home network.

Care-of (Care-of) address: an IP address at the mobile node's current point of attachment to the internet through which IP traffic for the mobile node may be forwarded when the mobile node is not attached to the home network.

Communication (coresponsent) node: a node that transmits or receives packets to a mobile node; the corresponding node may be another mobile node or a non-mobile internet node.

Foreign (foreign) agent: a mobile (mobility) agent on the foreign network may assist the mobile node in receiving datagrams distributed to care-of addresses.

The foreign network: such a network to which the mobile node is connected when the mobile node is not connected to its home network, and on which the care-of address is reachable from the rest of the internet.

Redirection: a message intended to cause a change in routing conditions of the receiving node.

Registering: a process by which the mobile node notifies the home agent of its current care-of address.

The mobile node: nodes that change connection points to the internet as part of normal use.

A mobile agent: a node (typically a router) that provides support services to a mobile node. The mobility agent may be a home agent or a foreign agent.

Fig. 1 is a block diagram of a communication network 100 that implements mobile IP to enable communication with a mobile node 102. The home agent 104, the correspondent node 106, and the foreign agent 108 may all communicate with one another over an IP network 110. The mobile node 102 has an assigned home address that identifies the mobile node 102 on the foreign network 112 through the home agent 104.

The mobile node 102 may change its location from one network or subnetwork to another. In fig. 1, the mobile node 102 is illustrated in a foreign network 112. The mobile node 102 may obtain an IP address and use its IP address to communicate with other nodes, including the correspondent node 106, over the IP network 110. The mobile node 102 obtains an IP address from the home agent 104. The IP address from the home agent 104 may be referred to as a home address. The home address is a long-term IP address on the home network 114. When the mobile node 102 visits the foreign network 112, a care-of address may be associated with the mobile node 102 to reflect the mobile node's current point of attachment to the IP network 110. When sending data, the mobile node 102 typically uses its home address as the source address for IP datagrams.

The home agent 104 is located in the home network 114 of the mobile node 102 and maintains current location information for each of its mobile nodes 102. The home agent 104 stores information needed to forward data to the mobile node 102 belonging to the home network 114. The information may be stored in a mobile binding. The mobility binding may include a plurality of records including the home address, the associated care-of address, and the age of the association.

The home network 114 has a network prefix that matches the network prefix of the home address of the mobile node 102. The IP routing mechanism operates to pass IP data sent to the home address of the mobile node 102 to the home network 114 of the mobile node 102. The local network 114 may be a virtual network.

The foreign agent 108 is an agent in another network 112 (not the home network 114) in which the mobile node 102 is currently located. The foreign agent 108 cooperates with the home agent 104 to send data to the mobile node 102 when the mobile node 102 is outside of its home network.

One skilled in the art will appreciate that one or more intermediate nodes (not shown) may be located in the communication path between the home agent 104 and the foreign agent 108. The intermediate nodes (not shown) may be on the IP network 110 and are typically routers. Thus, when data is sent between the home agent 104 and the foreign agent 108, it passes through and is routed by one or more intermediate nodes (not shown).

The network 100 of fig. 1 may be implemented as a different type of network. Those skilled in the art will recognize various types of networks that may benefit from the inventive principles herein. One possible network in which mobile IP and embodiments disclosed herein may be implemented is illustrated in fig. 2 and 3.

Fig. 2 serves as an example of a communication system 200 that supports multiple users and is capable of implementing at least some aspects of the embodiments discussed herein. Any of a variety of algorithms and methods may be used to schedule transmissions in system 200. System 200 provides communication for a plurality of cells 202A-202G, each of which is served by a respective base station 204A-204G. In one embodiment, some of the base stations 204 have multiple receive antennas, while others have only one receive antenna. Similarly, some of the base stations 204 have multiple transmit antennas, while others have only a single transmit antenna. There is no limitation on the combination of the transmit and receive antennas. Thus, it is possible for a base station 204 to have multiple transmit antennas and a single receive antenna, or to have multiple receive antennas and a single transmit antenna, or to have a single transmit and receive antenna, or multiple transmit and receive antennas.

Terminals 206 within the coverage area may be fixed (i.e., stationary) or mobile. The mobile terminal 206 may be the mobile node 102 in fig. 1. As shown in fig. 2, the various terminals 206 are dispersed throughout the system. Each terminal 206 communicates with at least one base station 204 and possibly multiple base stations 204 on the downlink and uplink at any given moment, e.g., depending on whether soft handoff is employed or whether the terminal is designed and operated to receive multiple transmissions (simultaneously or subsequently) from multiple base stations. Soft HANDOFFs IN CDMA communication SYSTEMs are known IN the art and are described IN detail IN U.S. Pat. No. 5,101,501, entitled "METHOD AND SYSTEM FOR PROVIDING A SOFT HANDOFF IN A CDMACELLULAR TELEPHONE SYSTEM", assigned to the assignee of the present invention.

The downlink refers to transmission from the base station 204 to the terminal 206, and the uplink refers to transmission from the terminal 206 to the base station 204. In one embodiment, some of the terminals 206 have multiple receive antennas, while others have only one receive antenna. In fig. 2, base station 204A transmits data on the downlink to terminals 206A and 206J, base station 204B transmits data to terminals 206B and 206J, base station 204C transmits data to terminal 206C, and so on.

In one embodiment, the components of FIG. 1 may be used and implemented in a wireless communication system, as shown in FIG. 3. IP packets or IP data may be communicated between the corresponding node 306, the home agent 304, and the Mobile Node (MN)302 via an IP network 310. In the depicted embodiment 300, the Packet Data Serving Node (PDSN) also serves as a foreign agent (PDSN/FA) 312. As shown, multiple PDSNs/FAs 312 may be connected to the IP network 310. The IP network 310 may be the internet, an intranet, a private IP network, etc. Data is transmitted as IP data packets ("IP packets") over the IP network 310. Many different kinds of data may be transmitted between the correspondent node 306 and the mobile node 302. For example, audio data, video data, text data, electronic files, etc. may be transmitted between the corresponding node 306 and the Mobile Node (MN) 302.

The PDSN/FA 312 receives and processes the IP data for transmission to one or more Base Stations (BS) 308. As shown, each PDSN/FA 312 is in electronic communication with one or more BSs 308. Once the BS308 receives the data, the BS308 then sends the data to one or more MNs 302. MN 302 corresponds to mobile terminal 206 of figure 2. Each BS308 may serve one or more MNs 302. The BS308 typically serves a plurality of MNs 302.

For purposes of this disclosure, the functionality provided by the BS308 and/or the functionality provided by the entities or components of the BS308 will be generally referred to as the BS 308. Those skilled in the art will appreciate that in various instances the use of the BS may refer to functionality provided by a particular entity. For example, at the IP level, the PCF (packet control function) is an entity (included in the BS) between the PDSN and the MN. For the sake of explanation, the more general term BS will be used.

The above information describes a particular embodiment of the system 100 as applied and used in the wireless communication system 200 shown in fig. 2. However, those skilled in the art will appreciate that the inventive principles herein may be applied in other environments where mobile IP may be employed.

Fig. 4 is a functional block diagram illustrating a wireless computer network connection for a Mobile Station (MS) 402. MS 402 is one of mobile nodes 302 discussed above. In fig. 4, Terminal Equipment (TE)404 may be a laptop, palmtop, or other computing device. The TE 404 is coupled to a wireless communication device, such as a wireless telephone (MT) 406. The TE 404 is passed through, for example, R_mThe connections of the interface specified by the standard communicate with the MT 406. The R is_mThe interface may be implemented by various techniques. For example, the R_mThe interface may be implemented by conventional interfaces such as RS-232, RS-422, IEEE4888, IEEE1394, Bluetooth * technology, etc. Note that the Bluetooth * is BLUETOOTH SIG, INC. CORPORATION BASSIGNMENT DELAWARE 1301K STREET, NW, SUITE 600 EASTTOR C/O SONNENSCHEN NATH&Rosenthawashington d.c. 20005. Some of the conventional interface techniques described are known in the art and need not be described here. The disclosed embodiments are not limited by the R_mThe particular form of interface. Note that other types of interfaces may also be implemented. In addition, various components and functions of the MS 402 may be incorporated in one device or one chip. For example, a single device may include the computing portion and the radio frequency portion. Alternatively, the various modules and functions described may be combined with each other or provided as separate components.

The TE 404 and MT 406 may be conveniently collectively referred to as a Mobile Station (MS) 402. The MT 406 includes a transmitter 408 and a receiver 410 that operate in a known manner to allow voice or data communication with a remote location.

The wireless communication system of fig. 4 also includes a Base Station (BS)412, which may also include a Mobile Switching Center (MSC). The BS 412 communicates with the MS 402 over a wireless interface, as specified by the standard, such as U_mAn interface. The U is_mDetails of the operation of the interfaceAre known to the skilled person and need not be described in more detail here. The BS 412 is coupled to a computer network 414 via an interface, as specified by the standard, such as the L interface. The operational details of the L-interface are also specified by industry standards and need not be described in greater detail herein.

To establish a communication link between the TE 404 and the network 414, communication data packets are passed through the R_mAnd U_mThe interface is switched and a PPP session is established. The various protocols and standards described above provide a framework for implementing wireless computer network connections. The actual implementation of the hardware and software within the framework is left to the discretion of the designer. While the various standards described above provide for the mobile IP registration, overlapping standards often result in inefficiencies in the registration process. Thus, it can be appreciated that an optimized registration process is highly desirable for mobile computing applications. The disclosed embodiments provide this and other advantages as will be apparent from the detailed description and drawings.

Embodiments herein indicate a more efficient registration mechanism for mobile IP registration. As discussed above with respect to fig. 4, the goal is to register a mobile terminal device (e.g., the TE 404) over a computer network (e.g., the network 414), such as the internet.

As noted above, there are many different standards for managing wireless IP communications. These standards may be implemented in many different ways to provide some flexibility to the designer. Fig. 4 illustrates a simplified general wireless network supporting the communication process.

In the functional block diagram of fig. 5, the communication process between the TE 404 and the network 414 is illustrated at the IP communication layer. As previously discussed, the TE 502 passes through the R_mAn interface communicates with the MT 504. Then, the MT 504 passes through the U_mthe/A interface communicates with a Foreign Agent (FA) 506. The "A interface" illustrated in FIG. 5 is commonSimilarly, refers to the A8, A9, A10, and A11 INTERFACES in, FOR example, an IS-835 NETWORK, which includes the BS/MSC to PDSN connection, which IS illustrated in TIA/EIA-2001-A, entitled "INTEROPERABILITY SPECIFICATIONS (IOS) FOR CDMA2000 ACCESS NETWORK INTERFACES", which was published in 8 months 2001 and which IS incorporated herein by reference. Note that the "a interface" is not standardized. Other interfaces (e.g., A1 through A11) are defined in IS-835, but do refer to interfaces that include the BS/MSC and are not relevant to an understanding of the present system. Those skilled in the art will appreciate that the a interface refers to one or more interfaces defined in IS-835. Consistent with some communication standards, the MT 504 may communicate with a peer (peer), such as the Packet Data Serving Node (PDSN) described in IS-835, which in one embodiment IS associated with the FA 506.

It should be noted that the BS 412 is not illustrated in fig. 5, as it essentially acts as a transparent relay mechanism at the network level. The BS 412 typically does not assume a role in the IP layer level communication. The FA506 serves as a roaming connection point between the TE 502 and the network 510. The FA506 may also change if the MT 504 performs a handoff (i.e., a handoff to a different BS). Thus, as the MT 504 moves, it communicates with the local FA 506.

The FA506 communicates with a Home Agent (HA) 508. The FA506 and HA508 are both illustrated processes for mobile IP communications. The HA508 acts as a data dispatcher (broker) for the communication link between the FA506 and the network 510. The HA508 is a fixed point and HAs a designated IP address used by the network 510. The HA508 remains fixed during the entire IP session between the TE 502 and the network 510 even when the MT 504 is handed off to a different BS.

As previously described, mobile IP registration is performed after the packet network connection is established. In wireless networks, air resources and connection time are expensive resources for both the provider and the consumer. The disclosed system and method allow for early detection of networks that will not support mobile IP, thereby providing a more efficient registration mechanism. One common method for registration is: (1) establishing an air link between the mobile device and the wireless network for packet data services, (2) negotiating a packet data connection over PPP, and (3) performing mobile IP registration. During the course of the normal method, there are several indicators on the IS-835 network that indicate that the network will not support mobile IP, allowing the mobile node to drop its connection attempt.

Fig. 6 IS a flow diagram illustrating a general method 600 for early determination of IS-835 network support for mobile IP. The mobile node is provided 602 in a coverage area. The mobile node then connects 604 to the wireless network. To perform an early determination for a network that will not support mobile IP, the mobile node then attempts 606 to detect an early disconnect condition. An early disconnect condition is any condition that may be detected by a mobile node that allows the mobile node to determine whether the wireless network supports mobile IP. The mobile node then determines 608 whether any of the disconnect conditions are satisfied. If one of the disconnect conditions is met, the mobile node disconnects 610 from the wireless network. If either disconnect condition is not met, the mobile node remains 612 connected to the wireless network and continues operation.

Off condition

There are many different disconnect conditions that can be used. For example, the following disconnect conditions may be used: (1) before or during start-up; protocol revision supported by the network is less than PREV6, (2) during LCP negotiation; if the network requires authentication (CHAP or PAP), (3) during IPCP negotiation; if the network sends a Configure-Not-Acknowledge (C-NAK) including the IP address option, and (4) during mobile IP registration, before a registration request is sent, if no agent advertisement message is received in response to an agent solicitation message. The following description and figures will be used to discuss each of these possible disconnect conditions.

Example situation

Fig. 7 illustrates a flow diagram of one possible disconnect condition for early determination of network support for mobile IP. To obtain packet data service, the mobile node 302 performs registration over the serving wireless network and then over the packet network. The mobile node 302 sends a start Message (Origination Message) to the BS308 at time t1, the Message including the packet data service option. At time t2, the BS308 acknowledges the receipt of the start message to the MS 302 by a base station acknowledgement (BS AckOrder). The start message results in: allocating the transport channel, establishing the A10 connection, establishing the Link layer (PPP), and for the case where Mobile IP is used by the terminal, performing Mobile IP registration over the serving packet network, as indicated by time t 3. Other details and messages are known to those skilled in the art and are defined by various CDMA and mobile IP specifications, which are not shown in fig. 7. One disconnect condition for early determination of network support for mobile IP is: before or during the start, the mobile station 302 or the mobile node 102 discovers that the protocol revision supported by the network is less than PREV (protocol revision) 6. In CDMA, the PREV6 IS used as per IS-2000 and earlier standards to indicate the level of protocol support in the BS. When the mobile node 302 detects the disconnect condition, it stops the connection to the wireless network, releases air resources and minimizes the connection time. This corresponds to the disconnection condition (1) given above.

Fig. 8 illustrates a flow chart of another possible disconnect condition for early determination of network support for mobile IP. Fig. 8 shows the Foreign Agent (FA)108 advertising after being caused to advertise by the Mobile Node (MN) 102. The horizontal axis represents the topology of the system, i.e. the base element. The vertical axis represents the time line.

At time t1, the mobile node 102 may solicit an agent advertisement message by sending a solicitation message. At time t2, the Foreign Agent (FA)108 sends an agent advertisement message. The Mobile Node (MN)102 receives the agent advertisement and determines whether the mobile node 102 is on its home network 114 or a foreign network 112. In the example shown in fig. 8, the mobile node 102 determines that it is on a foreign network 112. In addition, the mobile node 102 may obtain a care-of address from the agent advertisement message. The care-of address is typically the IP address of the foreign agent 108. The mobile node 102 may then register the new care-of address with its Home Agent (HA) 104. At time t3, the mobile node 102 may register the new care-of address with its home agent 104 by sending a registration request message to the foreign agent 108. Other processing may be performed by the foreign agent 108 at this time, including but not limited to: MS authentication, relay protection, dynamic home agent address resolution, etc. The foreign agent 108 then forwards the registration request message to the home agent 104 at time t 4.

At time t5, the Home Agent (HA)104 replies by sending a registration reply message to the Foreign Agent (FA)108, which forwards the message to the Mobile Node (MN)102 at time t 6. The registration reply message indicates to the mobile node 102 whether the home agent 104 accepts the registration. If the home agent accepts the registration, the home agent 104 provides the corresponding IP address to the mobile node 102 and sends the IP address to the mobile node 102 in the registration reply message.

The disconnect condition for early determination of network support for mobile IP illustrated in fig. 8 is: no agent advertisement message is received as a response to the solicitation message during mobile IP registration. This is determined before the registration request message is sent, as shown in fig. 8. This corresponds to the disconnect condition (4) given above.

The Internet Control Message Protocol (ICMP) defined in RFC 792, which is incorporated herein by reference, may be used in sending messages in connection with the embodiments disclosed herein. Additionally, ICMP router discovery, as defined in RFC 1256, which is incorporated herein by reference, may be used in the discovery of agents, whether the agent is a home agent 104 or a foreign agent 108.

Other disconnect conditions will be discussed with respect to the embodiment shown in fig. 4. Recall that fig. 4 is a functional block diagram illustrating a wireless computer network connection for a Mobile Station (MS) 402. The MS 402 is one of the mobile nodes discussed herein.

The system illustrated in fig. 4 illustrates the entities involved in mobile IP registration. Fig. 9 illustrates the flow of messages back and forth between the various components of the system. The terminal device (e.g., TE 404 of fig. 4) is indicated on the left side of fig. 9, while the network (e.g., network 414 of fig. 4) is indicated on the right side of fig. 9. Between the terminal device and the network is the mobile terminal (e.g., MT 406 in fig. 4), which is indicated by an indication MT. Also illustrated in FIG. 9 are the PDSN/FA 312 and the HA 304. Those skilled in the art will be aware of the communication flow between the MT 406 and the network 510 through the BS 308. However, some portions of the processing illustrated in FIG. 9 are described at the network layer rather than the physical link layer. Thus, for convenience, FIG. 9 illustrates a U passing through the U_mInterface communications between the MT 406 and the PDSN/FA 312.

In fig. 9, the process indicated by the reference numeral 1 is the PPP session establishment and the mobile IP registration process that occurs between the MT 406 and the PDSN/FA 312. The procedures include Link Control Protocol (LCP) negotiation and IP control protocol (IPCP) negotiation. Those skilled in the art will appreciate that there are many messages that can flow back and forth between the MT 406 and the FA312 for the LCP negotiation and the IPCP negotiation. Used in the wireless communicationA transmitter within the communication device sends messages from the MT 406 and a receiver within the wireless communication device receives negotiation messages. For clarity, only the chosen messages that are germane to mobile IP registration are illustrated in fig. 9. In the process, PPP session is in the U_mAn interface is established. The MT 406 is in U_mMobile IP registration is performed on the interface and an IP address is assigned.

In the subsequent procedure indicated by reference numeral 2 in fig. 9, PPP session negotiation of the TE 404, i.e., IP connection establishment, takes place in the course of communication with the MT 406. During this process, a second PPP session occurs at R_mAnd (4) an interface. Those skilled in the art will appreciate that there are many messages to be transmitted back and forth between the TE 404 and the MT 406 for the LCP negotiation and the IPCP negotiation. For the sake of brevity, the single message is not illustrated in fig. 9.

The MT 406 provides the previously assigned IP address to the TE 404. The protocol options between the different PPP sessions may be different. The subsequent mobile IP negotiation is transparent. Subsequent IP traffic occurs between the TE 404 and the network 510 through the MT 504 and the BS 412, as indicated in fig. 4. The process illustrated in fig. 9 is adapted to the various communication standards and ultimately results in the appropriate IP address assignment.

Other disconnect conditions may be found in the LCP negotiation shown in fig. 9 and in the IPCP negotiation. One additional disconnect condition is: during LCP negotiation, if the network requires authentication (CHAP or PAP), the mobile node may determine that IS-835 network support for mobile IP IS not available and disconnect from the wireless network. This corresponds to the disconnection condition (2) given above. One authentication Protocol is the Challenge Handshake Authentication Protocol (CHAP). Another Authentication Protocol is the Password Authentication Protocol (PAP). The PDSN 312 may support both authentication mechanisms (CHAP and PAP) described above. The disconnect condition may be satisfied only if the PDSN requires CHAP or PAP.

The network may indicate that CHAP is required by: i) transmitting a plurality of LCPConfigure-requests including said Authentication Protocol (AP) option indicating CHAP authentication or ii) aborting said PPP negotiation upon receiving an LCPConfigure-Request indicating an AP option for CHAP from said mobile station. The network may indicate that PAP is required by: i) sending a plurality of LCP Configure-requests including the Authentication Protocol (AP) option indicating PAP authentication, or ii) aborting the PPP negotiation when an LCP Configure-Request is received indicating the AP option of PAP from the mobile station.

In LCP, the Authentication Protocol (AP) option including the AP value indicating the method of authentication (i.e., CHAP, PAP, etc.) may be negotiated. Therefore, to propose CHAP or PAP, the PDSN sends an LCP Configure-Request (C-REQ), which includes the AP option, whose value is equal to CHAP or PAP. By sending an LCPConfigure-Reject (C-REJ) including the rejected AP option and an option value (CHAP or PAP), the mobile node may indicate to the PDSN that it is not performing authentication. Otherwise, the mobile node may indicate to the PDSN that it does Not wish to perform authentication by sending an LCP Configure-Not-Acknowledge (C-NAK) including the rejected AP option and an option value (CHAP or PAP). In this case, the PDSN may again present the disputed option in a later C-REQ. There may be a variety of sequences of LCP messages exchanged at this time, the meaning of which is known to those skilled in the art, according to the PPP specification. The final result of the LCP negotiation is represented by an option included in the conclusion Configure-Acknowledgement (C-ACK) message sent by the MS to the PDSN. Assuming that the MN indicates by LCP C-REJ mechanism that CHAP and/or PAP are not supported, the mobile node may make an early determination that the network does not support mobile IP.

Another disconnect condition may be found in the IPCP negotiation shown in fig. 9. If the IP address option of IPCP IS negotiated during IPCP, the mobile node may determine that IS-835 network support for mobile IP IS not available and disconnect from the wireless network. This corresponds to the disconnection condition (3) given above.

Fig. 10 IS a flow chart illustrating a method for early determination of IS-835 network support for mobile IP. The mobile node connects 1002 to a wireless network. To make an early determination of a network that does not support mobile IP, the mobile node attempts to detect an early disconnect condition. As discussed above, there are many different disconnect conditions that can be used. The mobile node may determine 1004 before or during the start whether the protocol revision supported by the network is less than PREV6 (referred to as disconnect condition a in fig. 10). If disconnect condition A is satisfied, the mobile node disconnects 1006 from the wireless network. If the disconnect condition is not met, the mobile node remains connected to the wireless network and continues operation, and also determines whether there are any other disconnect conditions.

The mobile device may then determine 1008 during LCP negotiation whether the network requires authentication (CHAP or PAP) (referred to as disconnect condition B in fig. 10). If disconnect condition B is satisfied, the mobile node disconnects 1006 from the wireless network. If the disconnect condition is not met, the mobile node remains connected to the wireless network and continues operation, and also determines whether there are any other disconnect conditions.

The next disconnect condition may be checked when the mobile device determines 1010 during IPCP whether the network sends a Configure-Not-Acknowledge (C-NAK) including the IP address option, (referred to as disconnect condition C in fig. 10). If disconnect condition C is satisfied, the mobile node disconnects 1006 from the wireless network. If the disconnect condition is not met, the mobile node remains connected to the wireless network and continues operation, and also determines whether there are any other disconnect conditions.

Then, during mobile IP registration and before the registration request is sent, the mobile device may determine 1012 whether no agent advertisement message is received as a response to the agent solicitation message, (referred to as disconnect condition D in fig. 10). If disconnect condition D is satisfied, the mobile node disconnects 1006 from the wireless network. If the disconnect condition is not satisfied, the mobile node remains connected to the wireless network and continues operation. If none of the disconnect conditions are met, the mobile device may assume IS-835 network support for mobile IP (unless or until it finds otherwise).

An embodiment of a mobile node 102, 302 is shown in a subscriber unit system 1100, which is illustrated in the functional block diagram of fig. 11. The system 1100 includes a Central Processing Unit (CPU)1102 that controls the operation of the system 1100. The CPU 1102 may also be referred to as a processor 1102. Memory 1102, which may include Read Only Memory (ROM) and Random Access Memory (RAM), provides instructions and data to the CPU 1102. The portion of the memory 1104 may also include non-volatile random access memory (NVRAM).

The system 1100 is typically embodied in a wireless communication device, such as a cellular telephone, and the system 1100 further includes a housing 1106 that includes a transmitter 1108 and a receiver 1110 to allow transmission and reception of data, such as audio voice communications, between the system 1100 and a remote location, such as a cell site controller or base station 308. The transmitter 1108 and receiver 1110 may be incorporated in a transceiver 1112. An antenna 1114 is attached to the housing 1106 and is electrically coupled to the transceiver 1112. The operation of the transmitter 1108, receiver 1110, and antenna 1114 is known in the art and need not be described herein. Additionally, the transmitter 1108, receiver 1110, and antenna 1114 correspond to the transmitter 408, receiver 410, and antenna illustrated in fig. 4.

The system 1110 also includes a signal detector 1116 for detecting and quantifying the level of signals received by the transceiver 1112. The signal detector 1116 detects such signals as total power, pilot power per Pseudorandom Noise (PN) chips, power spectral density, and other signals, as is known in the art. Various indicators and values are calculated by the signal detector 1116 for use in the system 1110, as described in further detail below.

A set of timers 1118 works in conjunction with a pilot strength processor 1120, a pilot received power processor 1122, and a total received power processor 1124. By measuring the levels of the received signals and processing these signals, the system 1100 can determine the quality of the communication channel between the wireless communication device and its base station 308.

The pilot strength processor 1120 receives a pilot strength indication (Ec/Io) from the signal detector 1116. The signal detector 1116 divides the ratio of pilot energies (ratio) of each PN chip (Ec) by the total power spectral density (Io) received at the receiver 1112. The ratio of pilot energy to total received energy is referred to as "pilot strength" as is known in the art. As is also known in the art, the pilot strength depends on the load conditions of the active cell as well as neighboring cells and is thus an indication of the traffic load in a particular cell.

The total received power processor 1124 uses a variable R_xThe variable is detected and quantified at the signal detector 1116. The total received power (R)_x) Is a measure of the total power received at the transceiver 1112. Which includes thermal noise, interference from other callers, and a pilot signal sent to the particular transceiver 1112. A sum of all of the received energy is stored to indicate the total received power.

The pilot received power processor 1122 receives a Received Signal Strength Indication (RSSI) from the signal detector 1116. The RSSI indicates the pilot received power and, in one embodiment, the RSSI is calculated by adding the total received power to the (Ec/Io) as is known in the art. The RSSI is independent of system load and a change in the RSSI indicates a change in forward link path loss. These path loss changes are important in determining when to switch services, as will be described in more detail below.

The state changer 1126 of the system 1100 controls the state of the wireless communication device based on the current state and other signals received by the transceiver 1112 and detected by the signal detector 1116. The wireless communication device is capable of operating in any of a plurality of states.

The system 1110 also includes a system determiner 1128 for controlling the wireless communication device and determining to which service provider system the wireless communication device should be transferred when it determines that the current service provider system is not appropriate.

The various components of the system 1100 are coupled together by a bus system 1130, which may include a power bus, a control signal bus, and a status signal bus in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in FIG. 11 as the bus system 1130. Those skilled in the art will appreciate that the system 1100 illustrated in FIG. 11 is a functional block diagram rather than a listing of specific components. For example, although the pilot strength processor 1120, pilot received power processor 1122, and the total received power processor 1124 are illustrated as three separate blocks in the system 1100, they may in fact be embodied in one physical component, such as a Digital Signal Processor (DSP). It can also be located as program code in the memory 1104 and operated on by the CPU 1102. The same considerations apply to the other components listed in the system 1100 of fig. 11.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with the following means: a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may be in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An embodiment of a storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In addition, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may be located at a user terminal. In addition, the processor and the storage medium may reside as discrete components in a user terminal.

The methods disclosed herein comprise one or more steps or actions for achieving the above described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the invention. In other words, unless a specific order of steps or actions is required for proper operation of the described embodiments, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (20)

1. A method for configuring a mobile node for communicating in a wireless communication system, the method comprising:

connecting to a wireless network;

verifying a disconnect condition, wherein the disconnect condition is an early indication of network support for mobile IP, wherein the step of verifying comprises determining that the wireless network requires authentication;

disconnecting from the wireless network if the disconnect condition is satisfied; and

maintaining connection to the wireless network if the disconnect condition is not satisfied.

2. The method of claim 1, wherein the disconnect condition comprises a plurality of disconnect conditions, and wherein verifying the disconnect condition comprises: verifying satisfaction of any of the plurality of disconnect conditions.

3. The method of claim 1, further comprising: a request for Challenge Handshake Authentication Protocol (CHAP) authentication is detected.

4. The method of claim 1, further comprising: a request for cryptographic authentication protocol (PAP) authentication is detected.

5. The method of claim 2, further comprising: detecting receipt of a Configure-Not-Acknowledge sent by the wireless network during IPCP negotiation including an IP address option that satisfies the disconnect condition.

6. The method of claim 2, wherein verifying the disconnect condition further comprises: determining whether a protocol version supported by the wireless network is compatible with a predetermined protocol version supporting mobile IP.

7. The method of claim 2, further comprising:

sending a proxy solicitation message during mobile IP registration;

detecting that an agent advertisement message is not received during a predetermined period of time after sending the agent solicitation message, wherein detecting that no reception satisfies a disconnect condition.

8. A mobile station for use in a wireless communication system, wherein the mobile station determines network support for mobile IP, the mobile station comprising:

an antenna for receiving a wireless signal;

a receiver in electronic communication with the antenna;

a transmitter in electronic communication with the antenna;

a processor for executing instructions;

a memory for storing the instructions, wherein the instructions perform a method comprising:

connecting to a wireless network;

verifying a disconnect condition, wherein the disconnect condition is an early indication of network support for mobile IP, wherein the step of verifying comprises determining whether the wireless network requires authentication;

disconnecting from the wireless network if the disconnect condition is satisfied; and

if the disconnect condition is not satisfied, continuing to connect to the wireless network.

9. The mobile station of claim 8, wherein the disconnect condition comprises a plurality of disconnect conditions.

10. The mobile station of claim 8, wherein verifying the disconnect condition further comprises: determining whether a protocol version supported by the wireless network is compatible with a predetermined protocol version supporting mobile IP.

11. The mobile station of claim 8, wherein the authentication is CHAP.

12. The mobile station of claim 8, wherein the authentication is PAP.

13. The mobile station of claim 8, wherein verifying the disconnect condition further comprises: detecting receipt of a Configure-Not-Acknowledge sent by the wireless network during IPCP negotiation including an IP address option that satisfies the disconnect condition.

14. The mobile station of claim 8, wherein the instructions further perform:

sending a proxy solicitation message during mobile IP registration;

detecting that an agent advertisement message is not received during a predetermined period of time after sending the agent solicitation message, wherein detecting that no reception satisfies a disconnect condition.

15. A mobile node adapted to communicate in an Internet Protocol (IP) enabled network, the mobile node comprising:

a processor for executing instructions; and

memory for storing the instructions, wherein the instructions check for a disconnect condition, wherein the disconnect condition is evaluated prior to packet network connection, wherein the disconnect condition identifies network non-support for mobile IP, wherein the disconnect condition includes a determination of authentication requirements for the wireless network, and wherein the instructions disconnect from the wireless network if the disconnect condition is found.

16. The computer readable medium of claim 15, wherein the authentication is CHAP.

17. The computer readable medium of claim 15, wherein the verification is PAP.

18. The computer readable medium of claim 15, the method further comprising: detecting receipt of a Configure-Not-Acknowledge sent by the wireless network during IPCP negotiation including an IP address option that satisfies the disconnect condition.

19. The computer readable medium of claim 15, the method further comprising:

sending a proxy solicitation message during mobile IP registration;

detecting that an agent advertisement message is not received during a predetermined period of time after sending the agent solicitation message, wherein detecting that no reception satisfies a disconnect condition.

20. A mobile station for use in a wireless communication system, wherein the mobile station determines network support for mobile IP, the mobile station comprising:

means for connecting to a wireless network;

means for verifying a disconnect condition, wherein the disconnect condition is an early indication of network support for mobile IP, the means comprising means for determining whether there is a requirement for authentication of the wireless network;

means for disconnecting from the wireless network if the disconnect condition is satisfied; and

means for continuing to be connected to the wireless network if the disconnect condition is not satisfied.