CA2384168A1

CA2384168A1 - System and method for automatically determining when to answer incoming packet data calls in a wireless communication network

Info

Publication number: CA2384168A1
Application number: CA002384168A
Authority: CA
Inventors: Nischal Abrol
Original assignee: Qualcomm Incorporated; Nischal Abrol
Current assignee: Qualcomm Inc
Priority date: 1999-09-08
Filing date: 2000-09-07
Publication date: 2001-03-15
Also published as: JP2011055528A; JP2003509917A; KR20020029783A; CN1437829A; CA2384162C; JP4846948B2; WO2001019027A9; WO2001019099A9; WO2001019099A2; WO2001019027A2; AU7357700A; CA2384162A1; WO2001019099A3; WO2001019027A3; CN100361541C; WO2001019027A8; CN1387732A; IL148477A0

Abstract

A system and method for determining when to answer an incoming packetized data call generated from a base station in a wireless communication network. The system includes a communication device (MT2), which interfaces with the wireless communication network, and a terminal device (TE2), which is electronically coupled to the communication device and is capable of transmitting and receiving packetized data. The communications device (MT2) answers (530) the incoming packetized data call from the base station in response to detecting a control signal or control information indicating the ready-state of the terminal device. This terminal device ready-state indicator may include control signals such as a high-state data transmit ready signal or the low-state to high-state transition of the data transmit ready signal after a ring-indicator signal has been activated to alert a subscriber of the incoming call. the ready-state indicator may also include control information such as a point-to-point protocol packetized data indicator flag, embedded in the data stream generated from the terminal device, or other information indicating that a point-to-point protocol packet was sent by the terminal device.

Description

SYSTEM AND METHOD FOR AUTOMATICALLY DETERMINING
WHEN TO ANSWER INCOMING PACKET DATA CALLS IN A
WIRELESS COMMUNICATION NETWORK
BACKGROUND OF THE INVENTION
I. Field of the Invention This invention generally relates to the field of wireless communications.
More particularly, the present invention relates to a novel and improved method and system for automatically answering incoming packet data calls in a wireless communication network.
II. Description of Related Art Recent innovations in wireless communication and computer-related technologies, as well as the unprecedented growth of Internet subscribers, have paved the way for mobile computing. In fact, the popularity of mobile computing has placed greater demands on the current communications infrastructure to provide mobile users with more support. A cruaal part of meeting these demands and providing users with the necessary support is the use of Code Division Multiple Access (CDMA) technology in wireless communication systems.
CDMA is a digital radio frequency (RF) channelizafion technique that is defined in the Telecommunications Industry Association/Electronics Industries Association Interim Standard-95 (TIA/EIA IS-95), entitled "MOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL MODE
W IDEBAND SPREAD SPECTRUM CELLULAR SYSTEM", published in July 1993 and herein incorporated by reference. W ireless communication systems employing this technology assign a unique code to communication signals and spread these communication signals across a common wideband spread spectrum bandwidth. As longas the receiving apparatus in a CDMA system has the correct code, it can sucressfully detect and select its communication signal from the other

2 signals concurrently transmitted over the same bandwidth. The use of CDMA
produces an increase in system traffic capacity, improves overall call quality and noise reduction, and provides a reliable transport mechanism for data service traffic.
FIG. 1 illustrates a simplified block diagram depicting some of the basic elements of such a wireless data communication system 100. Artisans of ordinary skill will readily appreciate that these basic elements, along with their associated interfaces, may be modified, augmented, or subjected to various standards known in the art, without limiting their scope or function. System 100 allows a mobile terminal equipment, TE2 device 102 (e.g., the terminal equipment such as laptop or palmtop computer) to communicate with an Interworking Function (IWF) 108. System 100 includes a wireless communication device, MT2 device 104 (e.g., wireless telephone), and a Base Station/Mobile Switching Center (BS/MSC) 106. The IWF 108 serves as a gateway between the wireless network and other networks, such as the Public Switched Telephone Network and wireline packet data networks providing Internet- or Intranet-based access. An L interface couples IWF 108 to BS/MSC
106. Often the IWF 108 will be co-located with the BS/MSC 106. The TE2 device 102 is electronically coupled to the MT2 device 104 via the Rn, interface. The MT2 device 104 communicates with the BS/MSC 106 via the wireless interface Um. The TE2 device 102 and the MT2 device 104 may be integrated into a single unit or may be separated out, as in the case of an installed mobile phone unit in which a laptop is the TE2 device 102 and the transceiver is the MT2 device 104.
It is important to note that, as indicated by FIG. 2, the combination of the device 102 and the MT2 device 104, whether integrated or separate, is generally referred to as a mobile station (MS) 103.
The ability of CDMA system to accommodate data service traffic has been recognized in the TIA/EIA IS-707.5 standard, entitled "DATA SERVICE
OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: PACKET DATA
SERVICES," published in February 1998 and herein incorporated by reference.

3 This standard defines the requirements for supporting packet data transmission on TIA/EIA IS-95 wideband spread spectrum systems and provides a suite of packet data bearer services. Similarly,the TIA/EIA IS-707-A.5 standard, entitled "DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: PACKET
DATA SERVICES," and the TIA/EIA IS-707-A.9 standard, entitled "DATA
SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: HIGH-SPEED
PACKET DATA SERVICES," both published in March 1999 and incorporated by reference, also define requirements for packet data transmission support o n TIA/EIA IS-95 systems.
These standards provide that certain packet data service options may be used to communicate between the TE2 device 102 and IWF 108 via BS/MSC
106. In doing so, IS-707.5 introduces two protocol option models, which specify the packet data protocol requirements for the Rm interface. FIG. 2 depicts one of the protocol option models, the Relay Layer Interface Protocol Option model 200, in which the application running on the TE2 device 102 manages the packet data services as well as the network addressing.
At the far left of FIG. 2 is a protocol stack, shown in conventional vertical format that depicts the protocol layers running on the TE2 device 102. The TE2 protocol stack is logically connected to the protocol stack of the MT2 device over the Rm interface. The Rn, interface may comply, for example, with the TIA/EIA-232-F standard, entitled "INTERFACE BETWEEN DATA TERMINAL
EQUIPMENT AND DATA CIRCUIT-TERMINATING EQUIPMENT
EMPLOYING SERIAL BINARY DATA INTERCHANGE", published in October 1997 and herein incorporated by reference. It is to be understood that other standards or protocols known to artisans of ordinary skill in the art may be used to define the transmission across the Rm interface. For example, other applicable Rm interface standards include, the "UNIVERSAL SERIAL BUS
(USB) SPECIFICATION, Revision 1.1", published in September 1998, and the "BLUETOOTH SPECIFICATION VERSION 1.0A CORE, published in July 1999, both incorporated by reference.

4 By way of illustration, the TIA/EIA-232-F standard is shown in FIG. 2 as specifying the Rm interface. The TIA/EIA-232-F standard describes both the physical interface as well as the communications protocol for relatively low-speed serial data communication between the Data Terminal Equipment (DTE) (i.e., the TE2 device 102) and the Data Circuit-Terminating Equipment (DCE) (i.e., the MT2 device 104). FIG. 3A depicts the physical interface and lists the corresponding signals defined by the TIA/EIA-232-F standard.
FIG. 3B briefly illustrates the communications protocol provided by the TIA/EIA-232-F standard. According to the standard, the TE2 device 102 generates a Data-Terminal-Ready (DTR) signal 320, which transitions from a low state to a high state, to indicate that it is ready to transmit data.
Similarly, the MT2 device 104 generates a Data-Set-Ready (DSR) signal 306, which transitions from a low state to a high state, to indicate that it is ready to receive data. The TE2 device 102 Request-to-Send (RTS) signal 304 and the MT2 device 104 Clear-to-Send (CTS) signal 305 are used to control the flow of data between the TE2 device 102 and the MT2 device 104. To establish a link with a remote DCE device (e.g., communications equipment at the BS/MSC 106), the MT2 device 104 activates a signal carrier. This signal carrier activation triggers the MT2 device 104 Data-Carrier-Detect (DCD) signal 308 to transition from low-to-high, which notifies the TE2 device 102 that it is ready to exchange data.
While the DCD signal 308 is high, data is transmitted and received by the Transmit Data (TXD) 302 and Receive-Data (RXD) 303 signals, respectively.
Central to the IS-707.5 Relay Layer Interface Protocol Option is the notion that the principal link layer connection is established between the TE2 device 102 and the IWF 108. As such, the MT2 device 104 simply behaves as a pipe transmitting the TE2 device 102 frames over the Um interface and the IWF 108 frames over the Rm interface. As indicated in FIG. 2, the Relay Layer Interface Protocol Option implements the Point-to-Point Protocol (PPP) as its link layer protocol 208, 232 at both ends of the link. PPP is described in detail in Request for Comments 1661 (RFC 1661), entitled "THE POINT-TO-POINT PROTOCOL (PPP)", dated May 1992 and herein incorporated by reference. Essentially, the PPP
protocol configures, tests, and establishes the data link connection. In addition, the PPP protocol encodes the packets coming from upper protocol layers of the TE2102 device, "serializing" them to facilitate transmission.

5 To support packet data services on CDMA systems, the IS-707.5 standard provides that the IWF 108 and the MS 103 (i.e., the combination of the TE2 device 102 and the MT2 device 104) utilize the link layer connection, as typified by the Relay Layer Interface Protocol Option model, to facilitate the transmission of packet data. For example, the IWF 108 link layer 232 must be open and the IWF 108 must request the activation of a link layer connection for packet data calls destined to the TE2 device 102. Such activation requests are achieved by directing the BS/MSC 106 to connect to the TE2 device 102 via the MT2 device 104 with a packet data service option.
Generally, the BS/MSC 106 initiates the connect operation by transmitting a Page Message to the MT2 device 104 and requesting a packet data service option. As per the IS-95 standard, Page messaging is used to notify the MT2 device 104 of incoming calls, including incoming packet calls, and is incorporated in the overhead Paging Channel of the forward link channel. If the MT2 device 104 replies with a Page Response Message having a valid service option number, the BS/MSC 106 assigns the MT2 device 104 a Traffic Channel. The Page Response Message is transmitted over the Access Channel of the reverse link channel. With this said, it is important to note that other protocols may implement methods, other than Page messaging, to notify the MT2 device 104 of incoming calls. For example, under certain circumstances a message protocol operating on the Um interface may directly provide the BS/MSC 106 with a Traffic Channel, without having to notify the MT2 device 104 of incoming calls.
The Traffic Channel accommodates the transfer of packet data between the BS/MSC 106 and the TE2 device 102 and comprises a combination of Forward and Reverse Traffic Channel Frames. The Traffic Channel assignment

6 is established by first initializing the channel for the MT2 device 104, followed by negotiating the connection of a packet data service option with the TE2 device 102, and then further negotiating the requested service configuration with the TE2 device 102.
FIG. 4 is a high-level state diagram depicting the general interchange between the MT2 device 104 and the BS/MSC 106 after the Traffic Channel has been assigned. After the assignment, the IS-95 standard specifies that the BS/MSC 106 transmits an "ALERT WITH INFORMATION MESSAGE" to the MT2 device 104 on the forward link channel. The ALERT W I T H
INFORMATION MESSAGE contains signaling information from the BS/MSC
106, which prompts the MT2 device 104 to notify the subscriber of an incoming call (e.g., ringing with possibly different tones and patterns).
As indicated in FIG. 4, receipt and processing of the ALERT W I T H
INFORMATION MESSAGE places the MT2 device 104 in a "WAITING FOR
MOBILE STATION ANSWER SUBSTATE" 410. Upon entering substate 410, the MT2 device 104 sets a substate timer for a maximum of Tssm seconds. The MT2 device 104 then waits for the subscriber to answer the incoming call by responding to the signaling information processed by the MT2 device 104 (i.e., audible "ringing" patterns, visual "flashes" on a screen, etc.). If the subscriber answers the signaling MT2 device 104 within the T53m second time limit, the MT2 device 104 transmits a "CONNECT ORDER" to the BS/MSC 106. This places the MT2 device 104 in the "CONVERSATION SUBSTATE" 430. The MT2 device 104 then proceeds to communicate with the BS/MSC 106 by processing Forward and Reverse Traffic Channel Frames. On the other hand, if the subscriber does not answer the signaling MT2 device 104, the substate timer expires, which results in the MT2 device 104 entering the "TRANSMITTER
DISABLED SUBSTATE" 420. In substate 420, the MT2 device 104 disables the transmitter, releases the Traffic Channel, and terminates the call.
As stated above, once the MT2 device 104 is in the WAITING FOR
MOBILE STATION ANSWER SUBSTATE 410, the MT2 device 104 must accept

7 and process the ALERT WITH INFORMATION MESSAGE. Typically, for voice calls, the processing of this message is relatively automatic and results in the ringing of the MT2 device 104. The subscriber then answers the ringing MT2 device 104 by picking up the handset or pressing a pre-programmed function key.
Unlike incoming voice calls, however, there is no clearly defined procedure that specifies how the MT2 device 104 responds to an incoming packet data call. For example, instead of simply ringing or flashing to notify the subscriber, the MT2 device 104, in processing packet data calls, has to consider an additional element - the TE2 device 102 - which is the ultimate destination of the incoming packet data call. As stated above, the TE2 device 102 may be a laptop or palmtop computer that is electrically coupled to the MT2 device 104 via the Rm (EIA-232F) interface. Thus, before the MT2 device 104 can accept and process the ALERT WITH INFORMATION MESSAGE transmitted by the BS/MSC 106, the MT2 device 104 has to determine whether the TE2 device 102 is ready, or even capable, of connecting and exchanging packet data.
Therefore, what is needed is a novel method and system that enables the wireless communication device to determine when to answer an incoming packet data call.
SUMMARY OF THE INVENTION
The present invention addresses the need identified above by providing a system and method that enables a wireless communication device to determine when to answer an incoming packet data call generated from a base station in a wireless communication network.
Systems and methods consistent with the principles of the present invention as embodied and broadly described herein include a communication device, which interfaces with the wireless communication network, and a terminal device, which is electronically coupled to the communication device and is capable of transmitting and receiving packetized data. The

8 communications device answers the incoming packetized data call from the base station in response to detecting a control signal or control information indicating the ready-state of the terminal device. This terminal device ready-state indicator may include control signals such as a high-state data transmit ready signal or the low-state to high-state transition of the data transmit ready signal after a ring-indicator signal has been activated to alert a subscriber of the incoming call. The ready-state indicator may also include control information such as a point-to-point protocol packetized data indicator flag, embedded in the data stream generated from the terminal device, or other information indicating that a point-to-point protocol packet was sent by the terminal device.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this Specification, illustrate an embodiment of the invention and, together with the description, explain the objects, advantages, and principles of the invention. In the drawings:
FIG. 1 is a high level block diagram depicting various elements of a wireless communication system.
FIG. 2 schematically describes the protocol stacks of a wireless communication system.
FIGs. 3A, 3B describe the TIA/EIA-232-F protocol.
FIG. 4 is a state diagram depicting the operation of a wireless communication device.
FIG. 5 is a state diagram illustrating an embodiment of the invention.

9 PCT/L1S00/24622 DETAILED DESCRIPTION OF THE PREFERRED
EMBODIMENTS
The following detailed description of the present invention refers to the accompanying drawings that illustrate preferred embodiments consistent with this invention. Other embodiments are possible and modifications may be made to the embodiments without departing from the spirit and scope of the invention. Therefore, the following detailed description is not meant to limit the invention. Rather the scope of the invention is defined by the appended claims.
It will be apparent to one of ordinary skill in the art that an embodiment of the present invention, as described below, may be realized in a variety of implementations, including the software, firmware, and hardware of the entities illustrated in the figures (i.e., TE2 device 102, MT2 device 104, BS/MSC
106 and IWF 108). The actual software code or control hardware used to implement the present invention is not limiting of the present invention.
Thus, the operation and behavior of the present invention will be described without specific reference to the actual software code or hardware components.
Such non-specific references are acceptable because it is clearly understood that a person of ordinary skill in the art would be able to design software and control hardware to implement the embodiment of the present invention based on the description herein.
FIG. 5 is a high-level state diagram of an embodiment of the present invention. As such, FIG. 5 details the operation of the MT2 device 104 for determining whether to accept, process, and answer incoming packet data calls.
The MT2 device 104 begins in the "IDLE STATE" 510. In this state, there is no Traffic Channel established between the BS/MSC 106 and the MT2 device 104 to accommodate packet data traffic. Therefore, the MT2 device 104 is free to originate or receive any type of call.

WO 01/19099 PCT/~IS00/24622 As stated above, the MT2 device 104 is coupled to the TE2 device 102 via the Rm interface and signaling between the two devices can be achieved in accordance with such standards as the TIA/EIA-232-F or the USB. These standards provide control information or control signals that indicate the 5 ready-state of the TE2 device 102. Examples of such TE2 device 102 ready-state control information include USB packets embedded with ready-state information as well as the TIA/EIA-232-F DTR signal. Moreover, in some conventional implementations, the MT2 device 104 has been configured to detect ready-state control information. In other implementations, the MT2

10 device 104 has not been specifically instructed to ignore the ready-state control signals (e.g., the Hayes standard dialing command string 'AT&DO' has not been set to disregard the TIA/ EIA-232-F DTR signal). In either case, the present embodiment exploits such ready-state control information by using it to trigger the MT2 device 104 to answer the incoming packet data call. For example, if the MT2 device 104 receives a Page Message from the BS/MSC 106 that requests a packet data service option, the MT2 device 104 will automatically answer the incoming packet data call if it detects ready-state control information/signal.
This automatic answer is executed by the MT2 device 104 sending a CONNECT
ORDER to the BS/MSC 106, consistent with IS-95 procedure (see FIG. 4). This order places the MT2 device 104 into the "CALL ACTIVE STATE" 530.
If the MT2 device 104 receives a Page Message with a packet data service option and the MT2 device 104 is not capable of detecting the pertinent ready-state control information/signal (e.g., the DTR signal) or otherwise detects the ready-state control signal in a "low state" (e.g., the TE2 device 102 is not physically connected to the MT2 device 104), the MT2 device 104 progresses to the PROCESS PAGE STATE 520. This state is analogous to the WAITING FOR
MS ANSWER SUBSTATE defined in the IS-95 standard (see FIG. 4).
Because a low ready-state control signal fails to indicate the presence of an awaiting TE2 device 102, the MT2 device 104, in state 520, will toggle the Ring Indicator signal (RI) on the Rm interface to signify the existence of an

11 incoming packet data call. This RI toggling can be configured to trigger an alert signal (e.g., audible tones/patterns or visual flashes/messages) to notify a subscriber of the incoming packet data call. If, after the RI toggling, and within the Tssm second time limit of the WAITING FOR MS ANS WER S UBSTATE 430 Ts3m timer, the MT2 104 device detects a low-to-high ready-state control signal transition (i.e., DTR signal transition) or detects PPP packets on the Rm interface, the MT2 104 advances to the "CALL ACTIVE STATE" 530.
The ready-state control signal transition and the existence of PPP packets can occur, for example, if the TE2 device 102 was previously disconnected from the MT2 104 device and the audible or visual signal produced by the RI
toggling reminded the subscriber to reconnect the two devices. After reconnecting the two devices, the TE2 device 102 packet data application drives the ready-state control signal to a high state and, after the usual Rm interface negotiation, the TE2 device 102 transmits PPP packets to the MT2 104 device. By detecting the control signal transition coming from the TE2 device 102, the MT2 device 104 is notified of an awaiting TE2 device 102. Moreover, in the event that the MT2 104 device cannot detect the ready-state control information/signal or is instructed to ignore such signals (e.g., by sending the AT dialing command string 'AT&DO' to ignore the DTR signal), the MT2 104 device can still detect PPP
packets by examining byte streams on the Rm interface and looking for the PPP
flag (i.e., Ox7E character) at the beginning of a packet. Accordingly, if, within the Tssm time limit, the MT2 104 device detects either (1) the ready-state control signal transition or (2) the PPP packet flag, it answers the incoming packet data call by sending a CONNECT ORDER to the BS/MSC 106, consistent with IS-95 procedure (see FIG. 4).
If, on the other hand, the MT2 device 104 does not detect the ready-state control signal transition or the PPP flag within the T53m time limit, the MT2 device times out and returns to the IDLE STATE 510. As stated above, in this state the MT2 device 104 is free to originate or receive any type of call.

12 Whenever the MT2 device 104 answers the call by sending a CONNECT
ORDER to the BS/MSC 106, the MT2 device 104 enters into the CALL ACTIVE
STATE 530. This state is analogous to the CONVERSATION SUBSTATE 430 described in the IS-95 standard. In state 530, the MT2 device 104 exchanges packet data traffic with the BS/MSC 106 by processing Forward and Reverse Traffic Channel Frames.
This embodiment, therefore, provides a system and method that enables the MT2 device 104 to determine when to answer an incoming packet data call.
The foregoing description of preferred embodiments of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the grease form disdosed.
Modifications and variations are possible consistent with the above teadzings or may be acquired from practice of the invention. Accordingly, the scope of the invention is defined by the claims and their equivalents.
What is claimed is:

Claims

1. A system for determining when to answer an incoming packetized data call in a wireless communication network, said system comprising:
a communication device for interfacing with said wireless communication network; and a terminal device, coupled to said communication device, for transmitting and receiving packetized data;
wherein said communication device answers said incoming packetized data call in response to detecting a ready-state indicator generated by said terminal device.

2. The system of Claim 1, wherein said ready-state indicator includes a high-state data transmit ready signal.

3. The system of Claim 2, wherein said ready-state indicator includes a low-state to high-state transition of a data transmit ready signal after a ring-indicator signal on said communication device has been activated to alert a subscriber of said incoming packetized data call.

4. The system of Claim 3, wherein said ready-state indicator includes information in a data stream generated from said terminal device indicating a transmission of point-to-point protocol packetized data.

5. A method for determining when to answer an incoming packetized data call in a wireless communication network, said method comprising:
interfacing a communication device with said wireless communication network;

coupling a terminal device to said communication device, said terminal device capable of transmitting and receiving packetized data;
detecting, by said communication device, a ready-state indicator generated by said terminal device; and answering, by said communication device, said incoming packetized data call, in response to said detection of said ready-state indicator.

6. The method of Claim 5, wherein said ready-state indicator includes a high-state data transmit ready signal.

7. The method of Claim 6, wherein said ready-state indicator includes a low-state to high-state transition of a data transmit ready signal after a ring-indicator signal on said communication device has been activated to alert a subscriber of said incoming packetized data call.

8. The method of Claim 7, wherein said ready-state indicator includes information in a data stream generated from said terminal device indicating a transmission of point-to-point protocol packetized data.

9. A communication device capable of determining when to answer a packetized data call in a wireless communication network, said communication device comprising:
means for interfacing with said wireless communication network;
means for being coupled to a terminal device, said terminal device capable of transmitting and receiving packetized data;
means for detecting a ready-state indicator generated by said terminal device; and means for answering said incoming packetized data call in response to said detection of said ready-state indicator.

10. The communication device of Claim 9, wherein said ready-state indicator includes a high-state data transmit ready signal.

11. The communication device of Claim 10, wherein said ready-state indicator includes a low-state to high-state transition of a data transmit ready signal after a ring-indicator signal on said communication device has been activated to alert a subscriber of said incoming packetized data call.

12. The communication device of Claim 11, wherein said ready-state indicator includes information in a data stream generated from said terminal device indicating a transmission of point-to-point protocol packetized data.

13. A machine-readable medium encoded with a plurality of processor-executable instructions for performing a process comprising:
enabling a communication device to interface with a wireless communication network;
enabling said communication device to communicate with a terminal device, said terminal device capable of transmitting and receiving packetized data;
detecting, by said communication device, a ready-state indicator generated by said terminal device; and answering, by said communication device, an incoming packetized data call in response to said detection of said ready-state indicator.

14. The machine-readable medium of Claim 13, wherein said ready-state indicator includes a high-state data transmit ready signal.

15. The machine-readable medium of Claim 14, wherein said ready-state indicator includes a low-state to high-state transition of a data transmit ready signal after a ring-indicator signal on said communication device has been activated to alert a subscriber of said incoming packetized data call.

16. The machine-readable medium of Claim 14, wherein said ready-state indicator includes information in a data stream generated from said terminal device indicating a transmission of point-to-point protocol packetized data.