HK1050798B - Method and apparatus for requesting point-to-point protocol (ppp) instances from a packet data services network - Google Patents

Description

Method and apparatus for requesting point-to-point (PPP) protocol instances from a packet data service network

Background

I. Field of the invention

The present invention generally pertains to the field of communications, and more particularly to requesting point-to-point protocol (PPP) instances from a packet data service network.

II. background

Wireless communication and internet applications continue to grow in popularity, with the rise in the market for products and services that combine the two. As a result, various methods and systems have been developed for providing wireless internet services that allow wireless telephone or wireless terminal users to access email, web pages, and other network resources. Since information on the internet is organized into discrete "data packets," these services are commonly referred to as "packet data services.

Among the various types of wireless communication systems that are used to provide wireless packet data services are Code Division Multiple Access (CDMA) systems. The use of CDMA modulation techniques is one of several communication techniques that facilitate the presence of a large number of system users. Framing and transmission of Internet Protocol (IP) data over CDMA wireless networks IS well known in the industry and IS described in TIA/EIA/IS-707-a entitled "data traffic selection for spread spectrum systems," hereinafter referred to as IS-707.

Other multiple-access communication system techniques, such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), and AM modulation methods, such as Amplitude Companded Single Sideband (ACSSB) modulation, are well known in the art. These technologies have been standardized to facilitate the intercommunication between devices manufactured by different companies. CDMA communication systems have been standardized by the american telecommunications industry association, TIA/EIA/IS-95-B entitled "mobile station base station compatibility standard for dual mode wideband spread spectrum cellular systems," hereinafter referred to as IS-95.

The international telecommunications union has recently requested proposals for methods of providing high-rate data services and high-quality voice services over wireless communication channels. The first of these proposals was made by the telecommunications industry association, entitled "cdma 2000 ITU-R RTT candidate proposal," hereinafter referred to as cdma 2000. The second of these proposals is proposed by the European Telecommunications Standards Institute (ETSI) under the heading "ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT candidate proposal", also known as "wideband CDMA", and referred to hereinafter as W-CDMA. A third proposal is proposed by u.s.tg 8/1 entitled "UWC-136 candidate proposal", hereinafter EDGE. The contents of these proposals are publicly reported and are well known in the art.

To facilitate the use of mobile packet data services of the internet, several standards have been developed by the Internet Engineering Task Force (IETF). Mobile IP is a standard designed to allow a device having an IP address to exchange data with the internet when it physically moves throughout a network (or network group). Mobile IP is described in detail in IETF request for comments (RFC) entitled "IP mobility support," which is incorporated by reference.

Several other IETF standards propose techniques that reference the above nomenclature. The Point-to-Point protocol (PPP) is well known in the industry and is described in IETF RFC 1661, entitled "Point-to-Point protocol (PPP)" and published in July 1994. PPP includes a Link Control Protocol (LCP) and several Network Control Protocols (NCP) for establishing and configuring different network layer protocols over the PPP link. One such NCP is the internet protocol control system (IPCP) known in the art, described in IETF RFC 1332 entitled "PPP Internet Protocol Control Protocol (IPCP)" published in june 1992, hereinafter referred to as IPCP. An extension of LCP known in the art is described in IETF RFC 1570 entitled "PPP LCP extension", published in January 1994, hereinafter LCP.

A mobile station, such as a cellular or PCS phone with an internet connection, typically sends data packets over the network by establishing a PPP link (or PPP instance, or PPP session) with a Packet Data Service Node (PDSN). The mobile station sends packets across an RF interface, such as a CDMA interface, to the base station or packet control function. The base station or packet control function establishes a PPP instance with the PDSN. More such PPP instances may be established contemporaneously (e.g., if both the phone and the laptop require a connection). According to a particular PPP instance, data packets are sent from the PDSN to the Home Agent (HA) over the IP network. Packets sent to the mobile station are sent from the HA to the PDSN through the IP network, from the PDSN to the base station or packet control function through the PPP instance, and from the base station or packet control function to the mobile station through the RF interface.

When a mobile station leaves the vicinity of one PDSN and enters the vicinity of another PDSN, the mobile station sends a source message. If the mobile station is in a data call, the origination message requests a re-association or establishment of the associated PPP instance. Otherwise, the source message informs the new PDSN of the new location of the mobile station. However, any packets sent to the mobile station will be directed to the old PDSN because the mobile station has not established a PPP instance with the new PDSN. And packets destined for the mobile station will be lost. Therefore, there is a need for a method to inform the PDSN of the number and identity of PPP instances established for a newly arriving mobile station.

Summary of the invention

The present invention relates to a method of informing a PDSN to establish the number and identity of a PPP instance for a newly arrived mobile station. Accordingly, in one aspect of the invention, a method is provided for notifying a packet data service network of dormant network connections associated with a mobile station when the mobile station moves from a first infrastructure element of the packet data service network to a second infrastructure element of the packet data service network. The method advantageously comprises the step of sending a message from the mobile station, the message including the number of dormant network connections associated with the mobile station and a list of identifiers associated with the dormant network connections.

In another aspect of the invention, a mobile station is provided that is configured to notify a packet data service network of a dormant network connection associated with the mobile station when it moves from a first infrastructure element of the packet data service network to a second infrastructure element of the packet data service network. The mobile station advantageously includes an antenna, a processor coupled to the antenna, and a processor readable medium accessible to the processor and containing a set of instructions executable by the processor for modulating and transmitting a message from the mobile station, the message containing a number of dormant network connections associated with the mobile station and a list of identifiers associated with the dormant network connections.

In another aspect of the invention, a mobile station is provided that is configured to notify a packet data service network of a dormant network connection associated with the mobile station when it moves from a first infrastructure element of the packet data service network to a second infrastructure element of the packet data service network. The mobile station advantageously includes a device configured to send a message from the mobile station, the message containing the number of dormant network connections associated with the mobile station and a list of identifiers associated with the dormant network connections.

In another aspect of the invention, a mobile station is provided that is configured to notify a packet data service network of a dormant network connection associated with the mobile station when it moves from a first infrastructure element of the packet data service network to a second infrastructure element of the packet data service network. The mobile station advantageously includes a means for sending a message from the mobile station, the message containing the number of dormant network connections associated with the mobile station and a list of identifiers associated with the dormant network connections.

Brief description of the drawings

Fig. 1 is a block diagram of a wireless communication system configured to perform packet data networking.

Fig. 2 is a block diagram of a Packet Data Service Node (PDSN).

Fig. 3A is a block diagram of two PDSNs coupled to a Radio Access Network (RAN) when a Mobile Station (MS) moves near the second PDSN but a new PPP instance has not yet been established, and fig. 3B is a block diagram of two PDSNs coupled to the RAN when the MS moves near the second PDSN and a new PPP instance has been established.

Fig. 4 is a flow chart of method steps performed by the mobile station to inform the PDSN of the number and identity of PPP instances that are required to be established.

Detailed description of the preferred embodiments

In one embodiment, a wireless communication system 100 that performs packet data networking includes the elements shown in fig. 1. Mobile station_[n1](MS)102 is advantageously capable of performing one or more wireless packet data protocols. In one embodiment, MS 102 is a wireless telephone running an IP-based web browser application. In one embodiment, MS 102 is not connected to any external device, such as a laptop computer. In another embodiment, MS 102 IS a wireless telephone connected to an external device, wherein a protocol option IS used, equivalent to network layer R described in IS-707_mAn interface protocol option. In another embodiment, MS 102 IS a wireless telephone connected to an external device, wherein a protocol option IS used, equivalent to Relay layer R described in IS-707 above_mAn interface protocol option.

In one particular embodiment, MS 102 communicates with Internet Protocol (IP) network 104 via wireless communication with Radio Access Network (RAN) 106. MS 102 generates IP packets for IP network 104 and compresses the IP packets into frames destined for Packet Data Serving Node (PDSN) 108. In one embodiment, the IP packets are compressed using a Point-to-Point protocol (PPP), and the resultant PPP byte stream is transmitted over a Code Division Multiple Access (CDMA) network using a Radio Link Protocol (RLP).

MS 102 modulates and conveys frames via an antenna 110 to send the frames to RAN 106. These frames are received by RAN 106 through antenna 112. The RAN 106 sends the received frames to the PDSN 108 where the IP packets are extracted from the received frames. After the PDSN 108 extracts the IP packets from the data stream, the PDSN 108 sends the IP packets to the IP network 104. In turn, PDSN 108 can send the compressed frames to MS 102 through RAN 106.

In one embodiment, the PDSN 108 is coupled to a Remote Authentication Dial In User Service (RADIUS) server used to authenticate the MS 102. The PDSN 108 is also connected to a Home Agent (HA) that supports the mobile IP protocol. HA 116 advantageously comprises an entity capable of authenticating MS 102 and allowing MS 102 to use an IP address when using mobile IP. Those skilled in the art will appreciate that RADIUS server 114 may be replaced with a DLAMETER server or any other authentication, authorization, accounting (AAA) server.

In one embodiment, the MS 102 generates IP packets and the PDSN 108 interfaces with the IP network 104. Those skilled in the art will recognize that alternate embodiments may use formats and protocols other than IP. In addition, PDSN 108 may be coupled to networks that may use protocols other than IP.

In one embodiment, RAN 106 and MS 102 communicate with each other using wireless spread spectrum techniques. In one particular embodiment, data is transmitted wirelessly using CDMA multiple access techniques, as described in U.S. patent nos. 5,103,459 and 4,901,307, which are assigned to the assignee of the present invention and incorporated herein by reference. Those skilled in the art will appreciate that the methods and techniques described herein may be used in conjunction with several alternative modulation techniques, including TDMA, CDMA2000, W-CDMA, and EDGE.

In one embodiment, the MS 102 is capable of performing RLP, PPP, Challenge Handshake Authentication Protocol (CHAP), and Mobile IP. In a particular embodiment, RAN 106 communicates with MS 102 using RLP. In an embodiment, PDSN 108 supports PPP functions including Link Control Protocol (LCP), CHAP, and PPP Internet Protocol Control Protocol (IPCP). In an embodiment, PDSN 108, RADIUS server 114, and HA 116 are physically located in different physical devices. In another embodiment, one or more of these entities may be located in the same physical device.

In one embodiment, as shown in fig. 2, the PDSN 200 includes a control processor 202, a network packet switch 204, an IP network interface 206, and a RAN interface 208. The IP network interface 206 is coupled to the network packet switch 204. The network packet switch 204 is coupled to the control processor 202 and the RAN interface 208. RAN interface 208 receives data packets (not shown) from the RAN. RAN interface 208 receives data packets on the physical interface. In an embodiment where the physical interface is T3, the standard data telecommunications interface has a 45Mbps transmission rate. The physical T3 interface can be replaced by a T1 interface, an ethernet interface, or any other physical interface for data networking.

The RAN interface 208 sends the received packet to the network packet switch 204. In a typical embodiment, the coupling between the network packet switch 204 and the RAN interface 208 comprises a memory bus coupling. The coupling between the RAN interface 208 and the network packet switch 204 may be ethernet or any other various communication links known in the art. The RAN interface 208 is also advantageously capable of receiving packets from the network packet switch 204 over the same connection and transmitting the packets to the RAN.

Network packet switch 204 is preferably a configurable switch capable of transferring packets between various interfaces. In one embodiment, the network packet switch 204 is configured such that all packets received from the RAN interface 208 and the IP network interface 206 are sent to the control processor 202. In another embodiment, network packet switch 204 is configured such that a subset of received frames from RAN interface 208 are communicated to IP network interface 206 and a remaining subset of received frames from RAN interface 208 are communicated to control processor 202. In one embodiment, the network packet switch 204 sends the packet to the control processor 202 over a shared memory bus connection. The coupling between the RAN interface 208 and the network packet switch 204 may be ethernet or any other various communication links known in the art. When the network packet switch 204 is coupled to the RAN interface 208 and the IP network interface 206, those skilled in the art will recognize that the network packet switch 204 can be coupled to a greater or lesser number of interfaces. In one embodiment, network packet switch 204 is coupled to a single network interface that couples to both an IP network (not shown) and a RAN. In another embodiment, the network packet switch 204 is incorporated into the control processor 202 such that the control processor 202 communicates directly with the network interface.

Control processor 202 exchanges information packets with RAN interface 208 when required to interface with an MS (not shown). After control processor 202 receives the packet indicating that an attachment to the MS is required, control processor 202 conducts a PPP session with the MS. To conduct the PPP session, control processor 202 generates and sends PPP frames to RAN interface 208 and interprets responses from the MS received from RAN interface 208. The types of frames generated by control processor 202 include LCP frames, IPCP frames, and CHAP frames. The MS may be authenticated according to the method described in U.S. application No. (serial No. yet designated) entitled "method and apparatus for authentication in a wireless communication system," filed on 3.12.1999, assigned to the assignee of the present invention and incorporated herein by reference.

Control processor 202 generates packets for exchange with an AAA server (not shown) and a mobile IP (also not shown). In addition, control processor 202 compresses and decompresses IP packets for each established PPP session. Those skilled in the art will appreciate that the control processor 202 may be implemented using Field Programmable Gate Arrays (FPGAs), Programmable Logic Devices (PLDs), Digital Signal Processors (DSPs), one or more microprocessors, an Application Specific Integrated Circuit (ASIC), or any other device capable of performing the PDSN functions described above.

In one embodiment, the packet is sent to a network packet switch 204, which in turn sends the packet to an IP network interface 206 for transmission to an IP network. The IP network interface 206 transports packets over the physical interface. In one embodiment, the physical interface is T3 and the standard data telecommunications interface has a 45Mbps transmission rate. The physical T3 interface can be replaced by a T1 interface, an ethernet interface, or any other physical interface for data networking. The IP network interface 206 is also preferably capable of receiving packets on the same physical interface.

As shown in fig. 3A, MS 300 sends packet data over an IP network (not shown) by establishing PPP instance 302 with PDSN 304. The MS 300 sends packets across an RF interface, such as a CDMA interface, to a packet control function or base station (PCF/BS) 306. PCF/BS306 establishes a PPP instance 302 with PDSN 304. Another PPP instance 308 may be established at the same time (e.g., if both the phone and the laptop require a connection). Depending on the particular PPP instances 302, 308, data packets are sent from the PDSN 304 to an HA (not shown) over an IP network (not shown). Packets destined for MS 300 are sent from the HA to PDSN 304 through the IP network, from PDSN 304 to PCF/BS306 through PPP instances 302, 308, and from PCF/BS306 to MS 300 through the RF interface. PCF/BS306 includes a PCF/BS table 310. PCF/BS table 310 includes a series of MS identifiers (MS _ IDs), service reference identifiers (SR _ IDs), and RAN-TO-PDSN interface (R-P) identifiers (R-P IDs). PDSN 304 includes a PDSN table 312. PDSN table 312 includes a series of IP addresses, MS _ IDs, SR _ IDs, and R-P IDs. The PDSN 304 may have more than one PCF/BS306 serving, but for simplicity only one PCF/BS306 is shown coupled to the PDSN 304.

When the MS 300 is idle (i.e., not in a telephone call), the MS 300 sends a short data burst as a PPP frame. Each such PPP frame includes an srid identifying which of the PPP instances 302, 308 is the destination of the PPP frame. PPP frames compress other protocols as known to those skilled in the art. In an exemplary embodiment, the PPP frame compresses a Transmission Control Protocol (TCP) frame and identifies the protocol of the compressed TCP frame. The TCP frame compresses an IP frame and identifies the protocol of the IP frame. IP frames compress a frame, such as an RLP frame, and also include a source header and a destination header. RLP frames may compress a data frame configured as IS-95B.

When the MS 300 leaves the vicinity of the PDSN 304 and enters the vicinity of another PDSN314, the MS 300 issues an origination message. If the MS 300 is in a data call, the call is "handed off" from the first PCF/BS306 to a second PCF/BS316 coupled to a second PDSN 414. One exemplary handoff process is described in U.S. patent No. 5,267,261, assigned to the assignee of the present invention and incorporated herein by reference. The MS 300 then sends an origination message informing the second PDSN314 of its new location and requesting to establish or reconnect the PPP instance associated with the call. In addition, the PPP instances 302, 308 are static, and the MS 300 performs a static transfer and then sends a source message informing the second PDSN314 of the new location of the MS 300. Those skilled in the art will recognize that the second PDSN314 may have more than one PCF/BS316 serving. But for simplicity only one PCF/BS316 and PDSN314 connection is shown. Although the network is informed of the new location of the MS 300, the MS 300 still needs to initialize two new PPP instances (since the MS 300 has two static srids subordinate to the static PPP services 302, 308). The new PCF/BS316 and PDSN306 do not have tables to list the SR _ ID or R-P ID since the two necessary PPP instances are not established. Thus, data packets destined for the MS 300 will be sent to the first PDSN 304 because the MS 300 has not established a PPP instance with the new PDSN 314. Therefore, packets destined for the MS 300 will be lost.

As shown in fig. 3B, in one embodiment, an MS 318 moves from the vicinity of a first PDSN 320 and associated PCF/BS322 to the vicinity of a second PDSN 324 and associated PCF/BS326 and informs the second PDSN 324 of the number and identity of PPP instances that must be established. The first PDSN 320 has established two PPP instances 328, 330 between the PDSN 320 and the PCF/BS322 that are static (i.e., not used to carry traffic channel data). Tables 332, 334 of PDSN 320 and PCF/BS322, respectively, contain the various established connections and addresses. The number (2) and identifiers of the two newly requested PPP instances 336, 338 are preferably included in the origination message sent by MS 318. For simplicity, only one PCF/BS322, 326 is shown serving each respective PDSN 320, 324, but it will be understood that there may be multiple PCFs/BSs serving each PDSN 320, 324. The source message preferably contains a "data ready to send" (DRS) flag that may be set to zero to identify the identifier and total number of static packet services for PDSN 324, thereby enabling PDSN 324 to establish the necessary R-P links between PPP instances 336, 338 and PDSN 324 and PCF/BS 326. If a data call is in progress, the MS 318 sets the DRS flag to 1 and requests a reconnection or establishment of a PPP instance 328, 330 associated with the call. If the call is not in progress, the MS 318 sets the DRS flag to 0 and reports the SR _ IDs (SR _ IDs 1 and 2) of all static PPP service instances 328, 330 associated with the MS 318. PCF/BS326 then sends a message to PDSN 324 containing the SR _ ID and MS _ ID lists. The PDSN 324 establishes two PPP instances 336, 338 and two (the number of srjds reported by the MS 318) R-P connections. PDSN 324 and PCF/BS326 then update their respective tables 340, 342. Thus, the list of static SR _ IDs informs the PDSN 324 how many PPP instances 336, 338 need to be initialized and provides the PCF/BS326 with enough information to update its R-P/SR _ ID table 342.

In one embodiment, when an MS (not shown) moves away from the vicinity of a PDSN and into the vicinity of a neighboring PDSN (also not shown), it performs the method steps shown in fig. 4. In step 400, the MS determines whether it has reached a new PDSN. If the MS does not reach the new PDSN, the MS returns to step 400. On the other hand, if the MS arrives at the new PDSN, the MS proceeds to step 402. In step 402, the MS determines whether it is in a data call. If the MS is in a data call, the MS proceeds to step 404. On the other hand, if the MS is not in a data call, the MS proceeds to step 408.

The MS is in handoff in step 404. The MS then proceeds to step 406. In step 406, the MS sends a source message to the new PDSN informing the PDSN of its location. The DRS flag is set to 1 in the source message and the MS requests a reconnection or a PPP instance associated with the data call to be established. In step 408, the MS is in a static handoff. Then, the MS proceeds to step 410. The MS sends a source message to the new PDSN informing of its own location in step 410. The DRS flag in the source message is set to 0 and the MS contains the number of PPP instances to be established (the number of static PPP instances associated with the MS) and a srid associated with each such PPP instance.

Thus, a novel and improved method and apparatus for requesting PPP instances from a packet data service network is described. Those of skill in the art would 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. Various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans will recognize the interchangeability of hardware and software under these circumstances, and how best to implement the described functionality for each particular application. For example, the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented or performed with a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGAs), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components such as registers and FIFO, a processor executing a series of firmware instructions, any conventional programmable software module and processor, or any combination thereof. The processor is preferably a microprocessor, and in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The software modules may reside in RAM memory, flash memory, ROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Those of skill would further appreciate that the data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description are advantageously described by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The preferred embodiments of the present invention have been shown and described. It will be apparent to those skilled in the art that various changes can be made in the embodiments disclosed herein without departing from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the following claims.

Claims (8)

1. A method of notifying a packet data services network of dormant network connections associated with a mobile station when the mobile station moves from a first infrastructure element of the packet data services network to a second infrastructure element of the packet data services network, the method comprising the steps of:

a message is sent from the mobile station that includes the number of dormant point-to-point protocol instances associated with the mobile station and a list of identifiers associated with dormant network connections in a packet control function or base station.

2. The method of claim 1, wherein the first and second infrastructure elements comprise packet data service nodes.

3. The method of claim 1, wherein the list of identifiers in the packet control function or base station associated with the static network connection contains a service reference identifier.

4. The method of claim 1, wherein the message comprises an origination message that includes an indication that the static network connection is static.

5. A mobile station configured to notify a packet data services network of dormant network connections associated with the mobile station when the mobile station moves from a first infrastructure element of the packet data services network to a second infrastructure element of the packet data services network, the mobile station comprising:

means for sending a message from the mobile station, the message containing the number of dormant point-to-point protocol instances associated with the mobile station and a list of identifiers associated with dormant network connections in a packet control function or base station.

6. The mobile station of claim 5, the first and second infrastructure elements comprising packet data service nodes.

7. The mobile station of claim 5, the list of identifiers in the packet control function or base station associated with the dormant network connection contains a service reference identifier.

8. The mobile station of claim 5, the message comprising an origination message, the origination message including an indication that the dormant network connections are dormant.