WO2001030094A1

WO2001030094A1 - Mobile station execution of packet control channel (pcch) transition during broadcast control channel (bcch) update

Info

Publication number: WO2001030094A1
Application number: PCT/IB2000/001484
Authority: WO
Inventors: Ari Uistola
Original assignee: Nokia Mobile Phones Ltd; Nokia Inc
Current assignee: Nokia Oyj; Nokia Inc
Priority date: 1999-10-21
Filing date: 2000-10-11
Publication date: 2001-04-26
Anticipated expiration: 2002-04-21
Also published as: AU7810900A

Abstract

A method is provided for use with a packet data terminal (24) of a wireless communications system (10), the method being intended to respond to a receipt of a broadcast control channel message (BCCH) when camped on a digital control channel (DCCH). The method includes a first step of determining if the received BCCH contains a message that pertains to acquiring a packet control channel (PCCH). As presently specified, this message is a Beacon PCCH Parameters message. If it does, a next step initiates a PCCH event only if certain criteria are fulfilled. In a presently preferred embodiment of the invention, the certain criteria are selected from a set of criteria including a Queued Originate indicator not being set; packet data service being enabled and a determination that the packet data service of an acceptable Network Type is supported by the current DCCH; and packet data service being enabled and a determination that PCCH parameters found in the message are acceptable. Upon initiating the PCCH event, a next step of the method performs a PCCH selection operation with a PCCH that was specified in the message and, if the PCCH selection operation is successful, a further step transitions from the DCCH to the PCCH.

Description

MOBILE STATION EXECUTION OF PACKET CONTROL CHANNEL (PCCH) TRANSITION DURING BROADCAST CONTROL CHANNEL (BCCH) UPDATE

FIELD OF THE INVENTION:

This invention relates generally to mobile stations operable with a digital wireless network and, in particular, to mobile stations operable with a packet data channel and with an associated packet control channel

(PCCH) .

BACKGROUND OF THE INVENTION:

Modern wireless mobile stations, such as radiotelephones and personal communicators operable with a time division, multiple access (TDMA) air interface protocol, are capable of transmitting packet data to and receiving packet data from a wireless network infrastructure. Internet access is but one important mobile station application that uses network packet data services.

One exemplary air interface standard that specifies packet data services is known as TIA/EIA-136. In a recent publication TIA/EIA-136-123-B (13 September 1999) a method was proposed for a mobile station to acquire the PCCH. The PCCH must be acquired by the mobile station prior to utilizing a particular network's packet data services (the mobile station may have a choice of several networks offering packet data services.) However, the inventor has realized that this proposal does not address a problem that would arise of acquiring the PCCH when a network Broadcast Control Channel (BCCH) Update procedure has been invoked. The BCCH Update procedure may result in a change in an indication of available candidate networks and their respective PCCHs . This information is proposed to be conveyed in a BCCH Update message referred to as a Beacon PCCH Parameters message. The Beacon PCCH Parameters message

CONFIRMATION G0r*Y contains information for enabling the mobile station to locate and acquire PCCHs. However, if the mobile station fails to properly respond to a Beacon PCCH Parameters message, it may be unable to use available packet data service (s), which is clearly an undesirable condition.

More particularly, and as presently proposed in Section 4.17 (BCCH Update) of the TIA/EIA-136-123-B publication, while in a camping state the mobile station is expected to respond to different conditions. One of these conditions is a receipt of a Forward Digital Control Channel (FDCCH) Indication primitive that is received containing a BCCH message. When this condition occurs the BCCH Update procedure is invoked. The BCCH Update procedure can involve a receipt of one of a number of different messages including, but not limited to, messages relating to DCCH Structure, Access Parameters, Control Channel Selection Parameters, and Registration Parameters.

A message of most interest to this invention is the Beacon PCCH Parameters message, which contains the information relating to the PCCH channels. However, Section 4.17 of the TIA/EIA-136-123-B publication does not provide any guidance as to how the mobile station is to respond to the receipt of a Beacon PCCH Parameters message, should one be received during the BCCH Update procedure. If not properly responded to, as was indicated above, the mobile station may not be able to acquire a PCCH when packet data service is desired.

OBJECTS AND ADVANTAGES OF THE INVENTION:

It is a first object and advantage of this invention to provide an improved BCCH Update procedure for enabling a mobile station to respond to a receipt of a message that pertains to packet data service operation.

It is another object and advantage of this invention to provide an improved BCCH Update procedure for enabling a mobile station to respond to a receipt of a Beacon PCCH Parameters message.

SUMMARY OF THE INVENTION

The foregoing and other problems are overcome and the objects are realized by methods and apparatus in accordance with embodiments of this invention.

More specifically, a method is provided for use with a packet data terminal of a wireless communications system, the method being intended to respond to a receipt of a broadcast control channel message (BCCH) when camped on a digital control channel (DCCH) . The method includes a first step of determining if the received BCCH contains a message that pertains to acquiring a packet control channel (PCCH) . If it does, a next step initiates a PCCH event only if certain criteria are fulfilled. In a presently preferred, but not limiting, embodiment of the invention, the certain criteria are selected from a set of criteria including a Queued Originate indicator not being set; packet data service being enabled and a determination that the packet data service of an acceptable Network Type is supported by the current DCCH; and packet data service being enabled and a determination that PCCH parameters found in the message are acceptable. Upon initiating the PCCH event, a next step of the method performs a PCCH selection operation with a PCCH or PCCHs specified in the message and, if the PCCH selection operation is successful, a further step transitions from the DCCH to a PCCH.

More specifically still, the method includes a first step of (a) detecting a receipt of a FDCCH Indication primitive containing a broadcast control channel (BCCH) message; (b) invoking a BCCH Update procedure; (c) determining if the BCCH message contains a Beacon PCCH Parameters message and, if it does, (d) generating a Go_PCCH event if a Queued Originate indicator is not set and if both of the following conditions are true: (A) the packet data terminal has packet data service enabled and determines that the packet data service of an acceptable Network Type is supported by the current DCCH; and (B) the packet data terminal has packet data service enabled and determines that the PCCH parameters found in the Beacon PCCH Parameters message are acceptable. In response to generating the Go_PCCH event, a next step (e) receives a candidate PCCH that is indicated in the received Beacon PCCH Parameters message and invokes a Packet Control Channel Selection Procedure. A next step determines whether the Packet Control Channel Selection Procedure returns a success indication or a failure indication. In response to a success indication being returned by the Packet Control Channel Selection Procedure, the method generates a DCCH to PCCH Transition event and enters a Camping-Restricted state. In response to a failure indication being returned by the Packet Control Channel Selection Procedure, the method instead marks the PCCH(s) as ineligible and continues the BCCH Update procedure.

A packet data terminal that operates in accordance with these methods is also disclosed, and forms a part of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above set forth and other features of the invention are made more apparent in the ensuing Detailed Description of the Invention when read in conjunction with the attached Drawings, wherein:

Fig. 1 is block diagram of a wireless digital communications network, having packet data capabilities, that is suitable for practicing this invention; Fig. 2 is a logic flow diagram of a presently preferred embodiment of a method for responding to a Beacon PCCH Parameters message; and

Fig. 3 illustrates a proposed format of a Beacon PCCH Parameters message, which is one of a plurality of Optional forward BCCH messages.

DETAILED DESCRIPTION OF THE INVENTION

A description is first made of the wireless digital communications network 10, having packet data capabilities, that is shown in Fig. 1. The network 10 includes at least one network infrastructure portion 12 having a mobile switching center (MSC) 14 for connection to public switched telephone network (PSTN) 16 and possibly one or more packet data networks, a plurality of base transceiver stations (BTSs) 18, and one or more base station controllers (BSCs) 20. It is assumed for the purposes of this description that the network infrastructure portion 12 is a TDMA system that is capable of transmitting and receiving packet data, and is compatible with the TIA/EIA-136 air interface standard or a similar standard. To this end a packet data control system (PDCS) 22 is shown coupled to the network infrastructure portion 12. It should be realized at the outset, however, that the teachings of this invention are not limited for use with only this particular TDMA air interface standard, nor are the teachings of this invention restricted for use only in TDMA systems. By example only, the teachings of this invention can be applied to other types of networks and air interface standards, such as both narrowband and wideband code division, multiple access (CDMA) networks. It should be further realized that a plurality of network infrastructure portions 12 may serve the same geographical area.

The network 10 also includes a plurality of mobile stations 24, only one of which is shown. The mobile station 24 includes a mobile station controller 24A, typically a suitably programmed microprocessor, a memory 24B for storing packet data and other data, including operating programs and the like, and a transceiver 24C for transmitting to and receiving from various frequency channels. The frequency channels are assumed to be partitioned physically and logically into one or more digital control channels (DCCHs), broadcast control channels (BCCHs) , Packet Control Channels (PCCHs), voice and packet data traffic channels, etc. The mobile station 24 may be a radiotelephone having packet data capability, or it may be a wireless device intended specifically for packet data use. As such, the mobile station 24 may be referred to hereafter interchangeably as a packet data terminal, which term is intended to encompass all wireless devices (fixed or mobile) that are capable of at least transmitting packet data in accordance with the air interface protocol of interest (e.g., TIA/EIA-136).

Referring now to Fig. 2, a description will now be made of the operation of the controller 24A in implementing a presently preferred embodiment of a method in accordance with the teachings of this invention. The packet data terminal 24 is assumed to be in a camping state on a digital control channel (DCCH) , and capable of receiving the above-mentioned FDCCH Indication primitive from the network infrastructure portion 12.

At Step A the controller 24A detects a receipt of a FDCCH Indication primitive containing a BCCH message. At Step B the controller 24A invokes a BCCH Update procedure. At Step C the controller 24A determines if the BCCH message contains a Beacon PCCH Parameters message. The proposed format of the Beacon PCCH Parameters message is shown in Fig. 3, where the fields of most interest to this discussion are the Channels, PCCH Slot Configuration and the Network Type fields. In other embodiments of this invention more or less information may be provided, and the information may be arranged in another format. The proposed message structure shown in Fig. 3 is simply exemplary of one suitable PCCH-related message structure that can be used by the teaching of this invention.

If at Step C the controller 24A determines that the BCCH message does not contain a Beacon PCCH Parameters message, control passes to Step D to service the received BCCH message in accordance with, for example, the procedure already described in the above-referenced Section 4.17 (BCCH Update) of the TIA/EIA-136-123-B (13 September 1999) . By example, the BCCH message may contain an Access Parameters update message, and/or a Mobile Assisted Channel Allocation update message, and/or a Neighbor Cell update message, and/or any one of the various types of update messages described in Section 4.17.

However, if a Step C the controller 24A determines that the BCCH message does contain a Beacon PCCH Parameters message, and if certain criteria are met (as described below) , then control passes instead to Step E.

At Step E the controller 24A generates a Go_PCCH event if the certain criteria were found to be met at Step C. In this embodiment the certain criteria are a Queued Originate indicator is not set, and both of the following conditions or criterion are true: (A) the mobile station 24 has packet data service enabled and determines that the packet data service of an acceptable Network Type is supported by the current DCCH; and (B) the mobile station 24 has packet data service enabled and determines that the PCCH parameters found in the Beacon PCCH Parameters message are eligible (i.e., not found in a list of ineligible PCCHs). If these criteria are not found to be true, the mobile station 24 continues BCCH Update processing (transitions from Block C to Block D) .

The state of the Queued Originate indicator is tested because this flag is set when an originated call attempt has been queued by the network (for example, due to a lack of available traffic channels.) Once the originated call is placed in the queue it will be connected by the network when resources are available. As such, if the Queued Originate indicator is set it is implied that the mobile station has attempted to place a call, and the Go_PCCH state is thus inhibited.

Assuming that the Queued Originate indicator is not set and that both of the foregoing conditions (A) and (B) are true (i.e., the Go_PCCH event has been generated at Step E) , control passes to Step F where the controller 24A tunes the receiver of the transceiver 24C to receive a candidate PCCH that is indicated in the received Beacon PCCH Parameters message, and then invokes a Packet Control Channel Selection Procedure, such as one already defined in TIA/EIA-136-335. The Packet Control Channel Selection Procedure is assumed, for the purposes of this invention, to handle all PCCHs that are received in the Beacon PCCH Parameters message.

At Step G the controller 24A determines whether the Packet Control Channel Selection Procedure returns a success indication or a failure indication. Assuming first that a success indication is returned, control passes to Step H where the controller 24A performs the following procedures:

( 1 ) stop a DCCH Re-Registration Timer;

( ϋ ) display to the user any alpha tags (descriptive text) for the selected packet service;

( iϋ ) generate a DCCH to PCCH Transition event; and

( iv) enter a 136 Mobility Management (MM) Camping- Restricted state (as defined in EIA/TIA-136- 336) . This state primarily performs procedures for packet data services mobility management and for teleservices by tunneling TIA/EIA-136 messages .

The DCCH Re-Registration Timer is stopped as it is used for DCCH registration purposes. Since in this situation the mobile station 24 is transitioning from the DCCH to the PCCH state, and since these states have different registration requirements, the DCCH Re-Registration Timer is not used in the PCCH state.

Returning to Step G, if the controller 24A instead determines that the Packet Control Channel Selection Procedure returns a failure indication, control passes to Step I where the controller 24A marks the PCCH(s) received in the Beacon PCCH Parameters message as ineligible, and then processes any remaining BCCH messages (i.e., it continues the BCCH Update procedure until all BCCH messages have been processed. )

Based on the foregoing it can be seen that the inventor has not only recognized the deficiencies in the currently proposed BCCH Update procedure, but has also provided a method to respond to the presence of the Beacon PCCH Parameters message in the BCCH Update state, thereby avoiding the possibility that the packet data terminal 24 will miss an important Beacon PCCH Parameters message and be unable to acquire a PCCH.

Although described in the context of a presently preferred embodiment, those skilled in the art should realize that modifications to these teachings could be made, and that the resulting methods and apparatus would still fall within the scope of the teachings of this invention. As but one example, at Step H at least the sub-step (ii) of displaying alpha tags to the user could be eliminated, or it could be executed, for example, before the sub-step (i) of stopping the DCCH Re_Registration Timer. Also, the processing of the Beacon PCCH Parameters message need not be the first action performed during the BCCH Update procedure, as one or more other BCCH message (s) could be processed first.

Thus, while the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope and spirit of the invention.

Claims

CLAIMSWhat is claimed is:

1. In a packet data terminal of a wireless communications system, a method for responding to a receipt of a broadcast control channel message (BCCH) when camped on a digital control channel (DCCH), comprising steps of:

determining if the received BCCH contains a message that pertains to acquiring a packet control channel (PCCH) ;

if yes, initiating a PCCH event only if certain criteria are fulfilled;

upon initiating the PCCH event, performing a PCCH selection operation with a desired PCCH that was specified in the message; and

if the PCCH selection operation is successful, transitioning from the DCCH to the desired PCCH.

2. A method as in claim 1, wherein the certain criteria are selected from a set of criteria comprised of a Queued Originate indicator not being set; packet data service being enabled and a determination that the packet data service of an acceptable Network Type is supported by the current DCCH; and packet data service being enabled and a determination that PCCH parameters found in the message are acceptable.

3. In a packet data terminal of a wireless communications system, a method for operating a packet data terminal when camped on a digital control channel (DCCH) , comprising steps of: detecting a receipt of a FDCCH Indication primitive containing a broadcast control channel (BCCH) message;

invoking a BCCH Update procedure;

determining if the BCCH message contains a Beacon PCCH Parameters message and, if it does, generating a Go_PCCH event if a Queued Originate indicator is not set, and if both of the following criterion are true: (A) the packet data terminal has packet data service enabled and determines that the packet data service of an acceptable Network Type is supported by the current DCCH; and (B) the packet data terminal has packet data service enabled and determines that the PCCH parameters found in the Beacon PCCH Parameters message are acceptable;

in response to generating the Go_PCCH event, receiving at least one candidate PCCH that is indicated in the received Beacon PCCH Parameters message and invoking a Packet Control Channel Selection Procedure;

determining whether the Packet Control Channel Selection Procedure returns a success indication or a failure indication;

in response to a success indication being returned by the Packet Control Channel Selection Procedure, generating a DCCH to PCCH Transition event; and

entering a Camping-Restricted state;

in response to a failure indication being returned by the Packet Control Channel Selection Procedure, marking the received PCCH(s) as ineligible and continuing the BCCH Update procedure.

4. A packet data terminal operable with a wireless communications system, said terminal comprising a wireless transceiver and a controller, said controller being responsive to a receipt of a broadcast control channel message (BCCH) , when camped on a digital control channel

(DCCH) , and to a condition wherein the received BCCH contains a message that pertains to acquiring a packet control channel (PCCH), for initiating a PCCH event only if certain criteria are fulfilled, and upon initiating the PCCH event, said controller performing a PCCH selection operation with a PCCH that was specified in the message and, if the PCCH selection operation is successful, for transitioning from the DCCH to the desired PCCH.

5. A packet data terminal as in claim 4, wherein the certain criteria are selected from a set of criteria comprised of a Queued Originate indicator not being set; packet data service being enabled and a determination that the packet data service of an acceptable Network Type is supported by the current DCCH; and packet data service being enabled and a determination that PCCH parameters found in the message are acceptable.