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

A method and apparatus for requesting PPP instances from a packet data services network includes a mobile station configured to send an origination message to a packet data service node (PDSN) at which it has arrived upon leaving the vicinity of another PDSN. The message informs the new PDSN of the new location of the mobile station and indicates both the number of dormant PPP instances associated with the mobile station and a service reference identifier for each such PPP instance. A flag within the message may be used to indicate whether the PPP instances are dormant (i.e., whether the mobile station is engaged in a call).

BACKGROUND OF THE INVENTION

I. Field of the Invention

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

With the increasing popularity of both wireless communications and Internet applications, a market has arisen for products and services that combine the two. As a result, various methods and systems are under development to provide wireless Internet services that would allow a user of a wireless telephone or terminal to access email, web pages, and other network resources. Because information on the Internet is organized into discrete “packets” of data, these services are often referred to as “packet data services.”

Among the different types of wireless communication systems to be used to provide wireless packet data services are code division multiple access (CDMA) systems. The use of CDMA modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. The framing and transmission of Internet Protocol (IP) data through a CDMA wireless network is well known in the art and has been described in TIA/EIA/IS-707-A, entitled “DATA SERVICE OPTIONS 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 schemes such as amplitude companded single sideband (ACSSB) modulation are known in the art. These techniques have been standardized to facilitate interoperation between equipment manufactured by different companies. CDMA communications systems have been standardized in the United States in 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 recently requested the submission of proposed methods for providing high-rate data and high-quality speech services over wireless communication channels. A first of these proposals was issued by the Telecommunications Industry Association, entitled “The cdma2000 ITU-R RTT Candidate Submission,” and hereinafter referred to as cdma2000. A second of these proposals was issued by the European Telecommunications Standards Institute (ETSI), entitled “The ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT Candidate Submission,” also known as “wideband CDMA,” and hereinafter referred to as W-CDMA. A third proposal was submitted by U.S. TG 8/1, entitled “The UWC-136 Candidate Submission,” hereinafter referred to as EDGE. The contents of these submissions are public record and are well known in the art.

Several standards have been developed by the Internet Engineering Task Force (IETF) to facilitate mobile packet data services using the Internet. Mobile IP is one such standard, and was designed to allow a device having an IP address to exchange data with the Internet while physically travelling throughout a network (or networks). Mobile IP is described in detail in IETF request for comments (RFC), entitled “IP Mobility Support,” and incorporated by reference.

Several other IETF standards set forth techniques referred to in the above-named references. Point-to-Point Protocol (PPP) is well known in the art and is described in IETF RFC 1661, entitled “The Point-to-Point Protocol (PPP)” and published in July 1994, hereinafter referred to as PPP. PPP includes a Link Control Protocol (LCP) and several Network Control Protocols (NCP) used for establishing and configuring different network-layer protocols over a PPP link. One such NCP is the Internet Protocol Control Protocol (IPCP), well known in the art and described in IETF RFC 1332, entitled “The PPP Internet Protocol Control Protocol (IPCP),” published in May of 1992, and hereinafter referred to as IPCP. Extensions to the LCP are well known in the art and described in IETF RFC 1570, entitled “PPP LCP Extensions,” published in January 1994, and hereinafter referred to as LCP.

Mobile stations, such as, e.g., cellular or PCS telephones with Internet connections, typically transmit packet data over a network by establishing a PPP connection (or PPP instance, or PPP session), with a packet data service node (PDSN). The mobile station sends packets across an RF interface such as, e.g., a CDMA interface, to a base station or packet control function. The base station or packet control function establishes the PPP instance with the PDSN. More than one such PPP instance may be established contemporaneously (e.g., if a phone and a laptop each require a connection). Data packets are routed from the PDSN to a home agent (HA) via an IP network in accordance with the particular PPP instance. Packets being sent to the mobile station are routed from the HA via the IP network to the PDSN, from the PDSN to the base station or packet control function via the PPP instance, and from the base station or packet control function to the mobile station via the RF interface.

When a mobile station leaves the vicinity of a PDSN and enters the vicinity of another PDSN, the mobile station sends an origination message. If the mobile station is engaged in a data call, the origination message requests reconnection or establishment of the associated PPP instance. Otherwise, the origination message informs the new PDSN of the new location of the mobile station. Nevertheless, any data packets being sent to the mobile station will be routed to the old PDSN because the mobile station does not have a PPP instance established with the new PDSN. Accordingly, packets destined for the mobile station will become lost. Thus, there is a need for a method of informing a PDSN of the number and identities of PPP instances to be established for a newly arriving mobile station.

SUMMARY OF THE INVENTION

The present invention is directed to a method of informing a PDSN of the number and identities of PPP instances to be established for a newly arriving mobile station. Accordingly, in one aspect of the invention, a method of informing 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 is provided. The method advantageously includes the step of transmitting from the mobile station a message including 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 configured to inform 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 is provided. The mobile station advantageously includes an antenna; a processor coupled to the antenna; and a processor-readable medium accessible by the processor and containing a set of instructions executable by the processor to modulate and transmit from the mobile station a message including 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 configured to inform 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 is provided. The mobile station advantageously includes a device configured to transmit from the mobile station a message including 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 configured to inform 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 is provided. The mobile station advantageously includes means for transmitting from the mobile station a message including a number of dormant network connections associated with the mobile station and a list of identifiers associated with the dormant network connections.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment a wireless communication system100for performing packet data networking includes the elements shown inFIG. 1. A mobile station (MS)102is advantageously capable of performing one or more wireless packet data protocols. In one embodiment the MS102is a wireless telephone running an IP-based Web-browser application. In one embodiment the MS102is not connected to any external device, such as a laptop. In an alternative embodiment, the MS102is a wireless telephone that is connected to an external device, wherein a protocol option is used that is equivalent to the Network Layer RmInterface Protocol Option described in IS-707. In another alternative embodiment, the MS102is a wireless telephone that is connected to an external device, wherein a protocol option is used that is equivalent to the Relay Layer RmInterface Protocol Option described in the aforementioned IS-707.

In a particular embodiment, the MS102communicates with an Internet Protocol (IP) network104via wireless communications with a radio access network (RAN)106. The MS102generates IP packets for the IP network104and encapsulates the IP packets into frames destined for a Packet Data Serving Node (PDSN)108. In one embodiment the IP packets are encapsulated using a point-to-point protocol (PPP) and the resultant PPP byte stream is transmitted through a code division multiple access (CDMA) network using a Radio Link Protocol (RLP).

The MS102sends the frames to the RAN106by modulating and transmitting the frames through an antenna110. The frames are received by the RAN106through an antenna112. The RAN106sends the received frames to the PDSN108, at which the IP packets are extracted from the received frames. After the PDSN108extracts the IP packets from the data stream, the PDSN108routes the IP packets to the IP network104. Conversely, the PDSN108can send encapsulated frames through the RAN106to the MS102.

In one embodiment the PDSN108is coupled to a Remote Authentication Dial In User Service (RADIUS) server114for authenticating the MS102. The PDSN108is also coupled to a Home Agent (HA)116for supporting the Mobile IP protocol. The HA116advantageously includes entities capable of authenticating the MS102and for granting the MS102the use of an IP address when Mobile IP is to be used. One skilled in the art would recognize that the RADIUS server114could be replaced with a DIAMETER server or any other Authentication, Authorization, and Accounting (AAA) server.

In one embodiment the MS102generates IP packets, and the PDSN108is coupled to the IP network104. One skilled in the art would recognize that alternate embodiments could use formats and protocols other than IP. In addition, the PDSN108may be coupled to a network capable of employing protocols other than IP.

In one embodiment the RAN106and the MS102communicate with each other using wireless spread spectrum techniques. In a particular embodiment, the data is wirelessly transmitted using CDMA multiple access techniques, as described in U.S. Pat. Nos. 5,103,459 and 4,901,307, which are assigned to the assignee of the present invention and fully incorporated herein by reference. One skilled in the art would recognize that the methods and techniques described herein may be used in conjunction with several alternate modulation techniques, including TDMA, cdma2000, W-CDMA, and EDGE.

In one embodiment the MS102has the ability to perform RLP, PPP, Challenge Handshake Authentication Protocol (CHAP), and Mobile IP. In a particular embodiment, the RAN106communicates with the MS102using RLP. In one embodiment the PDSN108supports PPP functionality, including Link Control Protocol (LCP), CHAP, and the PPP Internet Protocol Control Protocol (IPCP). In one embodiment the PDSN108, RADIUS server114, and HA116are physically located in different physical devices. In an alternate embodiment, one or more of these entities can be located in the same physical device.

In one embodiment PDSN200includes a control processor202, a network packet switch204, an IP network interface206, and an RAN interface208, as shown inFIG. 2. The IP network interface206is coupled to the network packet switch204. The network packet switch204is coupled to the control processor202and to the RAN interface208. The RAN interface208receives data packets from an RAN (not shown). The RAN interface208receives the packets over a physical interface. In one embodiment the physical interface is T3, a standard digital telecommunications interface that has a forty-five Mbps transfer rate. The physical T3interface could be replaced with a T1interface, an Ethernet interface, or any other physical interface used for data networking.

The RAN interface208delivers the received packets to the network packet switch204. In an exemplary embodiment, the connection between the network packet switch204and the RAN interface208comprises a memory bus connection. The connection between the RAN interface208and the network packet switch204could be an Ethernet or any other of a variety of communications links that are well known in the art. The RAN interface208is also advantageously capable of receiving packets from the network packet switch204over the same connection and transmitting the packets to the RAN.

The network packet switch204is advantageously a configurable switch that is capable of routing packets between a variety of interfaces. In one embodiment the network packet switch204is configured such that all packets received from the RAN interface208and the IP network interface206are routed to the control processor202. In an alternate embodiment, the network packet switch204is configured such that a subset of received frames from the RAN interface208are delivered to the IP network interface206and a remaining subset of received frames from the RAN interface208are delivered to the control processor202. In one embodiment the network packet switch204delivers packets to the control processor202via a shared memory bus connection. The connection between the RAN interface208and the network packet switch204could be an Ethernet or any other of a variety of well known types of communications links. While the network packet switch204is coupled to the RAN interface208and the IP network interface206, one skilled in the art would appreciate that the network packet switch204could be coupled to a smaller or larger number of interfaces. In an embodiment in which the network packet switch204is coupled to a single network interface, that network interface is coupled to both an IP network (not shown) and an RAN. In an alternate embodiment, the network packet switch204is incorporated into the control processor202such that the control processor202communicates directly with the network interface(s).

The control processor202exchanges information packets with the RAN interface208when a connection with an MS (not shown) is desired. After the control processor202receives an information packet indicating that a connection with an MS is desired, the control processor202negotiates a PPP session with the MS. To negotiate the PPP session, the control processor202generates PPP frames and sends the PPP frames to the RAN interface208, and then interprets responses from the MS received from the RAN interface208. The types of frames generated by the control processor202include LCP frames, IPCP frames, and CHAP frames. The MS may be authenticated in accordance with a method described in a U.S. Application filed Dec. 3, 1999, serial number not yet assigned, entitled METHOD AND APPARATUS FOR AUTHENTICATION IN A WIRELESS TELECOMMUNICATIONS SYSTEM, assigned to the assignee of the present invention, and fully incorporated herein by reference.

The control processor202generates packets for exchange with AAA servers (not shown) and Mobile IP Has (also not shown). Additionally, for each established PPP session, the control processor202encapsulates and unencapsulates IP packets. One skilled in the art would recognize that the control processor202may 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 packets are delivered to the network packet switch204, which, in turn, delivers the packets to the IP network interface206for delivery to the IP network. The IP network interface206transmits the packets over a physical interface. In one embodiment the physical interface is T3, a standard digital telecommunications interface that has a forty-five Mbps transfer rate. The physical T3interface could be replaced with a T1interface, an Ethernet interface, or any other physical interface used for data networking. The IP network interface206is also advantageously capable of receiving packets over the same physical interface.

An MS300transmits packet data over an IP network (not shown) by establishing a PPP instance302with a PDSN304, as shown inFIG. 3A. The MS300sends packets across an RF interface such as, e.g., a CDMA interface, to a packet control function or base station (PCF/BS)306. The PCF/BS306establishes the PPP instance302with the PDSN304. Another PPP instance308may be established contemporaneously (e.g., if a phone and a laptop each require a connection). Data packets are routed from the PDSN304to an HA (not shown) via an IP network (also not shown) in accordance with the particular PPP instance302,308. Packets being sent to the MS300are routed from the HA via the IP network to the PDSN304, from the PDSN304to the PCF/BS306via the PPP instance302,308, and from the PCF/BS306to the MS300via the RF interface. The PCF/BS306includes a PCF/BS table310. The PCF/BS table310includes a list of MS identifiers (MS_IDs), service reference identifiers (SR_IDs), and RAN-to-PDSN interface (R-P) identifiers (R-P IDs). The PDSN304includes a PDSN table312. The PDSN table312includes a list of IP addresses, MS_IDs, SR_IDs, and R-P IDs. The PDSN304may be served by more than one PCF/BS306, but for simplicity only one PCF/BS306is shown coupled to the PDSN304.

While the MS300is idle (i.e., not engaged in a telephone call), the MS300sends short data bursts as PPP frames. Each such PPP frame includes an SR_ID that identifies which PPP instance302,308is to be the destination for the PPP frame. As understood by those of skill in the art, the PPP frames encapsulate other protocols. In an exemplary embodiment, the PPP frame encapsulates a Transport Control Protocol (TCP) frame and identifies the protocol of the encapsulated TCP frame. The TCP frame encapsulates an IP frame and identifies the protocol of the IP frame. The IP frame encapsulates a frame such as an RLP frame and also includes a source header and a destination header. The RLP frame may encapsulate a data frame configured in accordance with, e.g., IS-95B.

When the MS300leaves the vicinity of the PDSN304and enters the vicinity of another PDSN314, the MS300sends an origination message. If the MS300is engaged in a data call, the call is “handed off” from the first PCF/BS306to a second PCF/BS316coupled to the second PDSN314. An exemplary handoff procedure is described in U.S. Pat. No. 5,267,261, which is assigned to the assignee of the present invention and fully incorporated herein by reference. The MS300then sends an origination message informing the second PDSN314of its new location and requesting the establishment or reconnection of the PPP instance associated with the call. Otherwise, the PPP instances302,308are “dormant” and the MS300performs a dormant handoff and then sends an origination message that informs the second PDSN314of the new location of the MS300. It would be understood by those of skill that the second PDSN314may also be served by more than one PCF/BS316, but for simplicity only one PCF/BS316is shown coupled to the PDSN314. Although the network has been informed of the new location of the MS300, the MS300requires that two new PPP instances be initiated (because the MS300has two dormant SR_IDs pertaining to the dormant PPP service instances302,308). The new PCF/BS316and PDSN306do not have tables listing SR_IDs or R-P IDs because the two necessary PPP instances have not been established. Accordingly, data packets being sent to the MS300will be routed to the first PDSN304because the MS300does not have a PPP instance established with the new PDSN314. Hence, packets destined for the MS300will become lost.

In one embodiment, as shown inFIG. 3B, an MS318travels from the vicinity of a first PDSN320and associated PCF/BS322to the vicinity of a second PDSN324and associated PCF/BS326and informs the second PDSN324of the number and identities of PPP instances that must be established. The first PDSN320had established two PPP instances328,330between the PDSN320and the PCF/BS322, which were dormant (i.e., not being used to transmit traffic channel data). The various established connections and addresses are included in the respective tables332,334for the PDSN320and the PCF/BS322. The number (two) of, and identifiers for, two newly required PPP instances336,338are advantageously included in the origination message transmitted by the MS318. For simplicity, only one PCF/BS322,326is shown serving each respective PDSN320,324, but it would be understood that there could be multiple PCF/BSs serving each PDSN320,324. The origination message advantageously includes a Data-Ready-to-Send (DRS) flag that may be set to zero to identify to the PDSN324the identity and total number of packet services that are dormant, thereby allowing the PDSN324to establish PPP instances336,338and the requisite R-P links between the PDSN324and the PCF/BS326. If a data call is in progress, the MS318sets the DRS flag to one and requests reconnection or establishment of the PPP instance328,330associated with the call. If no call is in progress, the MS318sets the DRS flag to zero and reports the SR_IDs for all dormant PPP service instances328,330(SR_IDs1and2) associated with the MS318. The PCF/BS326then sends a message to the PDSN324that includes the list of SR_IDs and the MS_ID. The PDSN324establishes two PPP instances336,338and two (the number of SR_IDs reported by the MS318) R-P connections. The PDSN324and the PCF/BS326then update their respective tables340,342. Thus, the list of dormant SR_IDs informs the PDSN324how many PPP instances336,338need to be initiated and also gives the PCF/BS326enough information to update its R-P/SR_ID table342.

In one embodiment, as shown inFIG. 3C, an MS366travels from the vicinity of a first PDSN354and associated PCF/BS362to the vicinity of a second PDSN356and associated PCF/BS364and informs the second PDSN356of the number and identities of PPP instances to be established. The first PDSN354had established two PPP instances as illustrated between the PDSN354and the PCF/BS362, which were dormant (i.e., not being used to transmit traffic channel data). The various established connections and addresses are included in the respective tables350,358for the PDSN354and the PCF/BS362, respectively. The number (two) of, and identifiers for, two newly required PPP instances372,374are advantageously included in the origination message transmitted by the MS366. For simplicity, only one PCF/BS362,364is shown serving each respective PDSN354,356, but it would be understood that there could be multiple PCF/BSs serving each PDSN354,356. The origination message advantageously includes a Data-Ready-to-Send (DRS) flag that may be set to zero to identify to the PDSN356the identity and total number of packet services that are dormant, thereby allowing the PDSN356to establish PPP instances372,374and the requisite R-P links between the PDSN356and the PCF/BS364. If a data call is in progress, the MS366sets the DRS flag to one and requests reconnection or establishment of the PPP instance associated with the call. If no call is in progress, the MS366sets the DRS flag is set to zero and reports the SR_IDs for all dormant PPP service instances372,374(SR_IDs1and2) associated with the MS366. The PCF/BS364then sends a message to the PDSN356from the table360storing the R-P IDs, SR_IDs and MS_ID. The PDSN356establishes two PPP instances372,374and two (the number of SR_IDs reported by the MS318) R-P connections. The PDSN356and the PCF/BS364then update their respective tables352,360. Thus, the list of dormant SR_IDs informs the PDSN356how many PPP instances to initiate and also gives the PCF/BS326enough information to update its R-P/SR_ID table352. Note that the table352includes the R-P IDs, MS_ID, and IP address.

In one embodiment an MS (not shown) performs the method steps illustrated inFIG. 4when leaving the vicinity of a PDSN (also not shown) and entering the vicinity of a neighboring PDSN (also not shown). In step400the MS determines whether it is arriving at a new PDSN. If the MS is not arriving at a new PDSN, the MS returns to step400. If, on the other hand, the MS is arriving at a new PDSN, the MS proceeds to step402. In step402the MS determines whether it is engaged in a data call. If the MS is engaged in a data call, the MS proceeds to step404. If, on the other hand, the MS is not engaged in a data call, the MS proceeds to step408.

In step404the MS engages in handoff. The MS then proceeds to step406. In step406the MS sends an origination message to the new PDSN informing the PDSN of its location. A DRS flag in the origination message is set to one, and the MS is requesting reconnection or establishment of a PPP instance associated with the data call. In step408the MS engages in dormant handoff. The MS then proceeds to step410. In step410the MS sends an origination message to the new PDSN informing the PDSN of its location. The DRS flag in the origination message is set to zero, and the MS includes the number of PPP instances to establish (the number of dormant PPP instances associated with the MS) and an SR_ID associated with each such PPP instance.

Thus, a novel and improved method and apparatus for requesting PPP instances from a packet data services network have been described. Those of skill in the art would understand 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. The various illustrative components, blocks, modules, circuits, and steps have been described generally in terms of their functionality. Whether the functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans recognize the interchangeability of hardware and software under these circumstances, and how best to implement the described functionality for each particular application. As examples, 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 (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components such as, e.g., registers and FIFO, a processor executing a set of firmware instructions, any conventional programmable software module and a processor, or any combination thereof. The processor may advantageously be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The software module could 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 represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Preferred embodiments of the present invention have thus been shown and described. It would be apparent to one of ordinary skill in the art, however, that numerous alterations may be made to the embodiments herein disclosed without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited except in accordance with the following claims.