(12) United States Patent
`Suumiiki et al.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,847,610 B1
`Jan. 25, 2005
`
`US006847610B1
`
`(54) METHOD FOR OPTIMIZING DATA
`TRANSMISSION IN A PACKET SWITCHED
`WIRELESS DATA TRANSMISSION SYSTEM
`
`(75) Inventors: Jan Suumaki, Tampere (FI); Juha
`Kalliokulju, Vesilahti (Fl)
`
`(73) Assignee: Nokia Mobile Phones Ltd., Espoo (FI)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 679 days.
`
`(21) Appl. No.: 09/649,770
`(22) Filed:
`Aug. 28, 2000
`(30)
`Foreign Application Priority Data
`
`Aug. 30, 1999
`
`(F1) ........................................... .. 19991834
`
`(51) Int. Cl.7 ................................................. .. H04J 3/16
`(52) US. Cl. ................... .. 370/230.1; 370/352; 370/468
`(58) Field of Search ............................... .. 370/229—232,
`370/342, 465, 468, 329, 352
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`6,347,091 B1 * 2/2002 Wallentin et al. ......... .. 370/437
`6,374,112 B1 * 4/2002 Widegren et al. ...... .. 455/452.2
`6,438,122 B1 * 8/2002 Monrad et al. ........... .. 370/349
`6,542,465 B1 * 4/2003 Wang ....................... .. 370/232
`6,553,006 B1 * 4/2003 Kalliokulju et al. ...... .. 370/310
`6,560,231 B1 * 5/2003 Kawakami et al.
`370/395.43
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`W0
`W0
`
`1 017 207 A1
`WO 98/53576
`WO 99/05828
`
`7/2000
`11/1998
`2/1999
`
`W0
`W0
`W0
`W0
`
`WO 99/12302
`WO 99/16266
`WO 99/41872
`WO 99/48310
`
`* cited by examiner
`
`3/1999
`4/1999
`8/1999
`9/1999
`
`Primary Examiner—Min Jung
`(74) Attorney, Agent, or Firm—Perman & Green, LLP
`(57)
`ABSTRACT
`
`The invention relates to a method for optimizing the transfer
`of information between one or more applications run in a
`mobile terminal (MT) and a packet-switched network
`There are at least two PDP contexts (PDP1—PDP9) available
`in the packet-switched network (NW), which have at least
`partly different data transfer properties, whereby the PDP
`contexts (PDP1—PDP9) can provide at least partly different
`qualities of service for the transfer of information. In this
`method at least one application connection is established for
`at least one of said applications, for which application
`connection a quality of service is speci?ed. In addition, this
`method is characterized in that at least one data ?ow is
`formed of the information to be transferred in the application
`connection, and one of the PDP contexts (PDP1—PDP9) is
`selected for each data ?ow of the application connection.
`The method is also characterized in that when the quality of
`service speci?ed for the application connection changes, it is
`examined on the basis of the properties of the PDP contexts
`(PDP1—PDP9) available in the packet-switched network
`(NW) which of the PDP contexts (PDP1—PDP9) is suitable
`for use by the application connection with the changed
`quality of service, and the one of the PDP contexts
`(PDP1—PDP9), the data transfer properties of which are
`closest to the changed quality of service is selected for the
`application connection.
`
`20 Claims, 7 Drawing Sheets
`
`@ 3G-GGSN
`
`I
`
`Need to modify the PDP
`context of the mobile terminal
`Change Bearer Request
`2
`[QoSP, NSAPI] g
`412
`413
`
`PDP context of the
`radio network modi?ed
`
`414
`
`Bearer changed
`[QOSPIBJD] 2
`415
`
`Update PDP Context Request
`[QoSP] 2
`416 Performing the settings of the
`gateway GPRS support node
`
`41 7
`
`M d’ PDP C
`0 Ify
`ont:ext Request
`[Qosp' BJD’ NSAPI]
`
`S419
`
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`[QOSP] 2
`41 8
`
`Modify PDP Context Request accepted
`
`[NSAPI]
`422
`
`421
`
`S423
`
`Setting of the data transfer ?lter
`l
`
`420
`
`PDP context of the
`mobile terminal modi?ed
`
`f th d t
`8 tti
`e ng o e a a
`transfer filter if required
`C
`T
`
`Petitioner's Exhibit 1004
`Page 1 of 17
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`U.S. Patent
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`Sheet 1 0f 7
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`US 6,847,610 B1
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`Petitioner's Exhibit 1004
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`Jan. 25, 2005
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`US. Patent
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`Jan. 25,2005
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`

`

`US 6,847,610 B1
`
`1
`METHOD FOR OPTIMIZING DATA
`TRANSMISSION IN A PACKET SWITCHED
`WIRELESS DATA TRANSMISSION SYSTEM
`
`2
`neously via one or several base stations Node-B. In addition,
`the UMTS packet netWork includes gateWay GPRS support
`nodes 3G-GGSN. The serving GPRS support nodes
`3G-SGSN and the gateWay GPRS support nodes 3G-GGSN
`are connected to an UMTS backbone netWork UBN for data
`transmission.
`An essential difference betWeen a GPRS packet netWork
`and an UMTS packet netWork is the fact that in the GPRS
`system, data transfer at the radio interface Um is based on
`time division multiple access (TDMA). In the UMTS
`system, data transfer at the radio interface Uu is based on
`code division multiple access (CDMA), such as Wideband
`CDMA (WCDMA) or a combined time division and code
`division multiple access (TD-CDMA).
`FIG. 2a illustrates data transfer on the user level in an
`UMTS packet netWork as a protocol stack description.
`Correspondingly, FIG. 2b illustrates data transfer on the
`control level in an UMTS packet netWork as a protocol stack
`description. Data transfer by means of a mobile terminal MT
`and a radio access netWork RAN is carried out in the
`physical layer as radio frequency signals. These signals can
`be, for instance, Wideband CDMA signals or signals With
`combined time division and code division multiple access
`(TD-CDMA). Data transfer on the radio path is controlled
`With the operations of the MAC layer. Bursts for transmis
`sion to the radio path are formed In this MAC layer, and in
`reception, these bursts are correspondingly converted into
`packets of the upper layer. The layer above the MAC layer
`in this radio interface Uu is the RLC layer. The tasks of the
`RLC layer include segmentation of the SDU data packets of
`the upper level so as to make them suitable for the radio
`interface. In addition, the RLC layer transfers the SDU data
`packets of the user in such a manner that the parts of the
`packets that Were segmented during reception can be
`restored to the right order. In addition, the operations of this
`RLC layer can be used to support different qualities of
`service (QoS), for instance so that the mode of operation and
`the number of retransmissions are selected in this RLC layer.
`With regard to the packet sWitched connection, the RLC
`layer can operate either in an unacknoWledged mode,
`Whereby no retransmission is carried out for defective
`packets, or in an acknoWledged mode, Whereby retransmis
`sion of the packets is performed if required, When an error
`has occurred.
`In the protocol stack of the control level, the layer above
`the MAC layer is the RRC layer, the tasks of Which include
`radio resource control. The above mentioned layers RRC,
`RLC, MAC and the physical layer have been implemented
`both in the mobile terminal MT and the radio netWork RAN
`to be used in data transfer at the radio interface Uu.
`Data transfer in an UMTS packet netWork betWeen a
`radio access netWork RAN, a serving support node
`3G-SGSN and a gateWay support node 3G-GGSN can also
`be divided into similar layer structures, of Which a preferred
`eXample is shoWn in the FIGS. 2a and 2b. HoWever, the
`placement of different layers in these protocol stacks need
`not be the same as in the FIGS. 2a, 2b, but it can vary in
`practical applications. For instance, conversions from the
`protocols of the radio interface Um, Uu (L3CE, RLC,
`MAC, .
`.
`. ) to the protocols of the GPRS backbone netWork
`(GTP, UDP, IP, .
`.
`. ) can be carried out in the serving support
`node 3G-SGSN instead of the radio access netWork RAN.
`The operations of these layers Will not be described in more
`detail in this connection, because in Wireless data transfer
`the most important interface that has an effect-on the quality
`of service is typically the radio interface Um, Uu.
`The mobility management of a mobile terminal MT is
`controlled by the operations of the MM (Mobility
`
`The present invention relates to a method set forth in the
`preamble of claim 1 for optimising data transmission in a
`packet switched Wireless data transmission system. The
`invention also relates to a Wireless data transmission system
`as set forth in the preamble of claim 12, and a Wireless data
`terminal as set forth in the preamble of claim 20 for use in
`a Wireless data transmission system according to the inven
`tion.
`In addition to the circuit sWitched connections, packet
`sWitched connections are being developed for Wireless data
`transfer systems, such as GSM and UMTS. In a packet
`sWitched connection, it is not necessary to allocate resources
`to the connection for its entire duration, but only for the time
`When there is transferable information present in the con
`nection. This information to be transferred is converted into
`one or several packets, Which are transmitted in the data
`transfer system. FIG. 1a illustrates a packet sWitched data
`transmission system developed for the GSM system, the
`General Packet Radio Service (GPRS), Which Will be called
`the GPRS packet netWork in this speci?cation.
`Correspondingly, FIG. 1b illustrates a packet sWitched data
`transmission system being developed for the UTMS
`(Universal Mobile Telecommunications System), Which Will
`be called the UMTS packet netWork in this speci?cation.
`The GPRS packet netWork consists of base station sub
`systems (BSS) of the GSM mobile communication netWork
`and a subscriber data base, such as a home location register
`(HLR). The base station subsystem BSS consists of base
`transceiver stations BTS and base station controllers BSC.
`In addition, the GPRS packet netWork includes serving
`GPRS support nodes (SGSN) and gateWay GPRS support
`nodes (GGSN). The serving GPRS support nodes SGSN and
`the gateWay GPRS support nodes GGSN are connected to a
`GPRS backbone netWork GBN for data transmission.
`Interfaces betWeen different units of the GPRS system
`are also shoWn in FIG. 1a. The radio interface Um is the
`interface betWeen a Wireless mobile terminal MT and a base
`transceiver station BTS of the base station subsystem BSS.
`In this radio interface Um, data transmission is carried out
`as radio frequency signals. The base transceiver station BTS
`and the base station controller BSC are interconnected by a
`BTS-BSC interface called Abis. The serving support nodes
`SGSN can communicate With other serving support nodes
`SGSN. Data transmission betWeen a GPRS packet netWork
`and other netWorks takes place via an external connection
`interface Gi and gateWay support nodes GGSN. The base
`station subsystem is connected to the serving support node
`SGSN via a BSS-SGSN interface Gb.
`The UMTS packet netWork shoWn in FIG. 1b includes
`blocks Which have similar functions as those of the GPRS
`packet netWork. A notable difference in the UMTS packet
`netWork is the structure of the base station subsystems. The
`base stations Node-B and the radio netWork controllers
`(RNC) Which control them constitute a radio access netWork
`(RAN). Each base station Node-B is connected to one radio
`netWork controller RNC via a Node-B-RNC interface lub.
`Correspondingly, the radio netWork controllers RNC are
`connected to the serving UMTS support node via a
`3G-SGSN lu interface. The radio netWork controllers RNC
`can be connected to other radio netWork controllers RNC via
`an lur interface. An arrangement like this enables carrying
`out data transmission betWeen a mobile terminal MT and the
`UMTS packet netWork via the radio interface Uu simulta
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`Management) layer of the protocol stack. This MM layer is
`implemented in the mobile terminal MT and the serving
`GPRS support node 3G-SGSN. Correspondingly, the ses
`sion management operations are carried out in the SM
`(Session Management) layer, which is also implemented in
`the protocol stacks of the mobile terminal MT and the
`serving GPRS support node 3G-SGSN.
`In the user level protocol stack there is, above the RLC
`layer, an L3CE layer, which is implemented in the mobile
`terminal MT and preferably in the radio access network
`RAN. This L3CE (Layer-3 Compatibility Entity) corre
`sponds to the SNDCP protocol of the GPRS system. The
`L3CE layer is used to control the operation of the radio
`interface Uu. The L3CE protocol is a so-called compatibility
`protocol for the network layer, and one of its purposes is to
`enable the operation of the system in connection with
`different services and network layer protocols. This L3CE
`layer can support many network layer protocols. These
`supported network layer protocols include, for instance, the
`Internet protocols 4 (IPv4) and 6 (IPv6), but the use of other
`network layer protocols can also be enabled by making
`changes mainly in the IBCE layer (Layer-3 Compatibility
`Entity). In this case, adding a new network layer protocol
`does not require making changes in the lower level proto
`cols. The IBCE layer also provides operations by which the
`reliability of the information to be transferred and the
`ef?ciency of the use of the channel can be improved. This
`can be implemented by various methods of optimisation,
`such as compressing the header ?elds and/or data ?elds of
`the packets.
`In the following description, mainly the UMTS packet
`network will be used as an example of a packet network, but
`naturally the invention can also be applied to other packet
`networks, in which it is possible to select different qualities
`of service for the packet switched connection.
`Some terms used in connection with the description of
`the method and the operation of the data transfer system
`according to the invention will be de?ned in the following.
`Firstly, the DP context relates to the data transfer connection
`(packet switched connection) established for the transmis
`sion of the data packets of one or several applications. The
`PDP context has mainly two tasks: Firstly, it is used for
`reserving a PDP address, such as an IPv4 connection
`address, for a user, and secondly, for establishing a logical
`connection in a packet switched network with a certain
`quality of service (QoS). A packet switched network may
`provide many such PDP contexts, in which at least some of
`the parameters are different. In addition, a default PDP
`context can be de?ned in a packet switched network. The set
`of quality of service parameters de?ned for each PDP
`context is called a quality of service pro?le (QoSP, QoS
`Pro?le). One or several applications can use a certain PDP
`context, whereby the quality of service is the same for each
`application using the same PDP context. Secondly, the
`application connection is connected to a logical connection
`formed for one application preferably between a mobile
`terminal and a gateway GPRS support node of a packet
`network with a certain quality of service. The application
`connection can comprise one or several data ?ows.
`In order to initiate an application connection, a connec
`tion is created at ?rst. When creating a connection, a suitable
`PDP context is selected for the application connection on the
`basis of the quality of service wanted and the PDP address.
`The quality of service parameters of the new application
`connection are taken into account in the selected PDP
`context, and the quality of service pro?le of the PDP context
`is modi?ed if required. If there is no suitable PDP context,
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`it is possible to activate one according to the parameters of
`the application connection and thus create a new packet
`switched connection. If the application connection does not
`specify any quality of service parameters, the default PDP
`context is selected. An UMTS packet network can contain
`several packet switched connections, or PDP contexts, for
`one PDP address. On the other hand, in the phase 1 reali
`sation of the GPRS packet network there can be only one
`packet switched connection for each PDP address. In the
`packet network discussed in this speci?cation, this type of a
`connection forms a logical link with a certain quality of
`service between two terminal points. These two terminal
`points are preferably a mobile terminal MT and a gateway
`GPRS support node 3G-GGSN.
`If there are several packet switched connections available
`for one PDP address, these different packet switched con
`nections can also have different quality of service pro?les.
`For saving information, a PDP context comprises a database
`or the like, containing information, which has been saved for
`each packet switched connection and which is needed when
`a packet switched connection is established, such as the type
`of connection (e.g. IPv4), PDP address (eg IPv4 address),
`the requested quality of service pro?le including the quality
`of service parameters requested by the user, and the quality
`of service pro?le including the quality of service parameters
`given by the packet network. If the packet network includes
`a default PDP context, it is selected preferably in a situation
`where none of the other PDP contexts available is suitable
`for the requested application connection.
`The term data How is used to denote data transfer of
`packets which have the same source and target. For instance,
`in the Internet data network, packets using the IP protocol,
`which have the same source and target address and the same
`source and target gate number, constitute one data ?ow. Data
`?ows are unidirectional, and each application having a data
`transfer connection from a mobile terminal to a packet
`network has at least one data ?ow. An example of these
`applications is a web browser, by means of which the user
`of a mobile terminal (MT) can browse, for instance, the
`home pages of service providers having a data transfer
`connection to the Internet. When a web browser is used, the
`target address and the gate number can change very quickly,
`whereby there can be many data ?ows simultaneously. In
`order to identify different data ?ows, it is not necessary to
`use the above mentioned source and target address and the
`source and target gate number, but the identi?cation can also
`be carried out in other ways, as known as such in the art. In
`this speci?cation, this identi?cation information is referred
`to by the common name data How identi?er, which can thus
`be constructed in many different ways.
`A bearer is basically a logical data transfer channel
`between two terminal points of a packet network. This
`bearer has certain properties, such as a certain quality of
`service (QoS). There are many different types of bearers in
`an UMTS packet network, such as an UMTS Bearer and a
`Radio Access Bearer. The UMTS bearer provides a logical
`data transfer channel between a mobile terminal MT and a
`gateway GPRS support node 3G-GGSN. UMTS bearers can
`be connected to certain PDP contexts, because a PDP
`context provides a certain quality of service between these
`terminal points (MT, 3G-GGSN).
`In order to provide data transfer services for applications
`which require different data transfer properties, UMTS bear
`ers with different data transfer properties have been speci?ed
`in the UMTS packet network. At the time of ?ling this
`application, the UMTS bearers are divided into four different
`traf?c classes, namely TC1—TC4 (Conversational,
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`Page 10 of 17
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`US 6,847,610 B1
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`Streaming, Interactive, Background). Some preferred
`erties of this other PDP context correspond better to the new
`properties wanted for the connection. The method according
`examples of the parameters of these classes are shown in
`Table 1. The differences between these traf?c classes
`to the present invention is characterised in what is set forth
`include, for instance, the length of delay allowed in them.
`in the characterising part of claim 1. The data transfer system
`For example, the ?rst traf?c class TC1 (Conversational) is 5 according to the present invention is characterised in what is
`intended for applications in which long delays in data
`set forth in the characterising part of claim 12. The mobile
`transfer are not allowed. As a contrast to this, the fourth
`terminal according to the present invention is characterised
`traf?c class TC4 (Background) is intended for applications
`in what is set forth in the characterising part of claim 20.
`in which delays in data transfer can be tolerated. Other
`The present invention provides considerable advantages
`properties speci?ed for different traffic classes include bit 10 as compared to the prior art solutions. When the method of
`error rate (BER), maximum bit rate and service precedence.
`the invention is used, the properties of a connection can be
`Naturally, the invention can also be applied to other systems,
`changed so that other simultaneously active connections and
`and the number of traf?c classes need not be four. In
`their properties are not substantially affected. When the
`addition, in practical applications the properties of the traf?c
`method according to the invention is used, the data transfer
`classes can differ from those presented here.
`system can also be used more ef?ciently, because the prop
`
`TABLE 1
`
`Second class
`real time, eg
`video information
`guaranteed capacity
`acknowledgement
`possible
`buffering on the
`application level
`
`Third class
`interactive best effort
`method
`acknowledgement
`web browser, Telnet
`real time control
`channel
`
`Fourth class
`background
`transmission with the
`best effort method
`acknowledgement
`background
`transmission of e-mail
`messages, calendar
`events etc.
`
`First class
`real time, eg a
`telephone conversation
`guaranteed capacity
`no acknowledgement
`
`Tra?ic class
`
`Delay
`
`100 ms, 200 ms, 400 ms <1 s
`
`2 s
`
`N/A
`
`Max. bit rate
`Service
`precedence
`
`0-2 Mbit/s
`High, medium, low
`
`0-2 Mbit/s
`High, medium, low
`
`N/A
`High, medium, low
`
`N/A
`High, medium, low
`
`One problem associated with, for instance, packet net
`works according to phase 1 of the GPRS packet networks is
`the fact that the quality of service speci?ed when the
`application connection is established cannot be changed
`without disconnecting the application connection or without
`affecting the quality of service of other application connec
`tions using the same PDP context simultaneously. However,
`the quality of service needed by an application can vary
`during the use of the application. The user can, for instance,
`by means of a Telnet application, use a mobile terminal as
`a remote terminal for communicating with a computer. Thus
`the user can transfer information from the computer, such as
`program ?les, to the terminal device. Data transfer must then
`be as error free as possible, but the rate of data transfer is not
`an important criterion. However, when a Telnet application
`is used for viewing text ?les saved in the computer, data
`transfer rate should be increased, even if the probability of
`errors would also increase. The home pages viewed with a
`web browser can be very different. Some home pages
`contain a lot of graphic information, the transmission of
`which from the server of the service provider to the mobile
`terminal of the user requires heavy use of resources, if the
`transmission time is to remain relatively short. On the other
`hand, when text information is transmitted, the amount of
`information transmitted at a time is typically much smaller
`than the amount of information contained in the graphics.
`Some home pages also contain video or audio information,
`in which case real time data transmission is an important
`consideration.
`It is an object of the present invention to provide a
`method for changing the properties of the connection, such
`as the quality of service, while the connection is active. The
`invention is based on the idea that when the properties of the
`connection are changed, the PDP context being used for the
`connection is changed to another PDP context, if the prop
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`erties of active connections can be changed during the
`connection. If, for instance, a slower data transfer rate is
`selected during the connection, more data transfer resources
`become available for other simultaneous connections.
`In the following, the present invention will be described
`in more detail with reference to the accompanying drawings,
`in which
`FIG. 1a shows a GPRS data transfer system,
`FIG. 1b shows a UMTS data transfer system,
`FIG. 2a illustrates data transfer on the user level in a
`UMTS data transfer system as a protocol stack description,
`FIG. 2b illustrates data transfer on the control level in a
`UMTS data transfer system as a protocol stack description,
`FIG. 3a illustrates the operation of a mobile terminal
`according to a preferred embodiment of the invention as a
`protocol stack description,
`FIG. 3b shows a mobile terminal according to a preferred
`embodiment of the invention as a simpli?ed block diagram,
`FIG. 4a is a simpli?ed signalling diagram of the activa
`tion of the PDP context in a method according to a preferred
`embodiment of the invention,
`FIG. 4b is a simpli?ed signalling diagram of the chang
`ing of the PDP context as initiated by the packet network in
`a method according to a preferred embodiment of the
`invention, and
`FIG. 5 illustrates a method according to a preferred
`embodiment of the invention for selecting and changing the
`PDP context in a mobile terminal according to a preferred
`embodiment of the invention.
`FIG. 3a illustrates the operation of a mobile terminal MT
`according to a preferred embodiment of the invention in
`connection with a method according to the invention. Some
`layers of the protocol stack and operational blocks are
`shown in the ?gure. All possible protocols and operational
`units are not shown in FIG. 3a; only those which are
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`Page 11 of 17
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`US 6,847,610 B1
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`important for the description of the invention are included.
`The protocols can be divided into tWo main types: internal
`protocols of the packet netWork, and external protocols. The
`internal protocols of the packet netWork include, for
`instance, L3CE and SM. Examples of external protocols that
`may be mentioned in this context are TCP and IP.
`In FIG. 3a, a horiZontal line 301 has been used to make
`a distinction betWeen tWo parts of the system, Which are
`different With regard to the operation of the mobile terminal
`MT. The items shoWn beloW the line are mainly the internal
`protocols of the packet netWork. The items shoWn above the
`line 301 are the essential features of this invention, and
`examples of some external protocols and applications.
`Examples of the applications are e-mail, such as SMTP
`(Simple Mail Transfer Protocol) or IMAP (Internet Message
`Access Protocol); a Web broWser using, for instance, the
`HTTP protocol (Hyper Text Transfer Protocol); and a real
`time data transfer application, such as streaming of video
`programs, in Which the RTP protocol (Real Time Protocol),
`for instance, is used. The applications are connected to an
`interface called SAPI (Socket Application Programming
`Interface). The socket application programming interface
`SAPI has a data transfer connection With the netWork layer
`protocol (NLP) block. The Socket Application Programming
`Interface SAPI performs the conversion of information
`coming from applications, Which is to be sent to the packet
`netWork, into the protocol form used in the transmission
`layer, such as TCP (Transmission Control Protocol) or UDP
`(User Datagram Protocol). In the netWork layer NLP, these
`protocol packets of the transmission layer are converted into
`packets of the netWork layer protocol. One Well-knoWn
`netWork layer protocol used especially in the Internet is IP
`(Internet Protocol). The network layer packets are trans
`ferred to the packet classi?er (PAC), Which maps packets of
`different data ?oWs to the right data transfer queue (PDP
`context). The operation of the packet classi?er PAC Will be
`described in more detail later in this speci?cation.
`FIG. 3a also shoWs the control block QMOC (QoS
`Management & Optimisation Control). The tasks of this
`control block QMOC include controlling the activation of
`application connections and data ?oWs of each application
`and the allocation of the resources required. In addition, the
`control block QMOC performs the changes required by the
`altered needs of the quality of service.
`FIG. 3b shoWs a mobile terminal MT according to a
`preferred embodiment of the invention as a simpli?ed block
`diagram. Some operational blocks that are important for the
`description of the invention are shoWn in the ?gure. A
`mobile terminal MT includes a processor block CONTROL,
`Which can be implemented by one or several processors,
`such as a microprocessor, a digital signal processing unit,
`etc., as knoWn as such in the art. This processor block can
`also be implemented as a part of an Application Speci?c
`Integrated Circuit (ASIC), in Which other operations of a
`mobile terminal can also be carried out. For saving
`information, the mobile terminal MT includes a memory,
`such as read memory, read/Write memory and/or non
`volatile reprogrammable memory. The radio part RF com
`prises means required for carrying our radio data transfer to
`the base station Node-B. In addition, a mobile terminal MT
`preferably includes a keyboard KB, a display DP and a
`display driver DD. In practice, a mobile terminal MT can be
`implemented in many different Ways. A mobile terminal MT
`can be formed as one complete entity, such as the Nokia
`9100 Communicator, or it can comprise a separate data
`transfer device, such as a mobile station, and a data pro
`cessing device, such as a portable computer, Whereby a local
`data transfer connection is arranged betWeen these units.
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`In the folloWing, a method according to a preferred
`embodiment of the invention Will be described in more
`detail With reference to the protocol stack description in FIG.
`3a and the block diagram in FIG. 3b. The mobile terminal
`MT has a data transfer connection With the packet netWork
`NW. In order to use the services of the packet netWork, the
`mobile terminal MT performs at ?rst an attach request, by
`Which it