Europllsches
`Patentamt
`European
`Patent Office
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`des brevets
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`111111111111111111111111111111111111111111111111111111111111111111111111111
`EP 1 793 639 81
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`(11)
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`EUROPEAN PATENT SPECIFICATION
`
`(45) Date of publication and mention
`of the grant of the patent:
`11.01.2012 Bulletin 2012/02
`
`(21) Application number: 06024560.2
`
`(22) Date of filing: 28.11.2006
`
`(51) Int Cl.:
`H04W 28/16r2009·01J
`
`H04L 12/56(2006.01J
`
`(54) Call admission control device and call admission control method
`
`Vorrichtung und Verfahren fur Rufzugangskontrolle
`
`Dispositif et precede pour contr61er !'admission d'appels
`
`(84) Designated Contracting States:
`DEGB
`
`(30) Priority: 30.11.2005 JP 2005346319
`
`(43) Date of publication of application:
`06.06.2007 Bulletin 2007/23
`
`(73) Proprietor: NTT DoCoMo, Inc.
`Chiyoda-Ku
`Tokyo 100-6150 (JP)
`
`(72) Inventors:
`• Ishii, Hiroyuki,
`NTT DoCoMo, Inc.
`Chiyoda-ku,
`Tokyo 100-6150 (JP)
`• Hanaki, Akihito,
`NTT DoCoMo, Inc.
`Chiyoda-ku,
`Tokyo 100-6150 (JP)
`
`(74) Representative: Sparing Rohl Henseler
`Patentanwalte
`European Patent Attorneys
`Postfach 14 04 43
`40074 Dusseldorf (DE)
`
`(56) References cited:
`EP-A 1- 1 033 849
`EP-A1-1126 734
`EP-A 1- 1 227 695
`US-A1- 2004 082 363
`
`EP-A 1- 1 100 283
`EP-A1-1189 472
`WO-A2-02/067619
`
`• KOLDING TE ET AL: "High Speed Downlink
`Packet Access: WCDMA Evolution" IEEE
`VEHICULARTECHNOLOGY SOCIETY NEWS, XX,
`XX, 1 February 2003 (2003-02-01), pages 4-10,
`XP002307537
`• PEDERSEN KI: "Quality based HSDPA access
`algorithms" VEHICULAR TECHNOLOGY
`CONFERENCE, 2005. VTC-2005-FALL. 2005 IEEE
`62ND DALLAS, TX, USA 25-28 SEPT., 2005,
`PISCATAWAY, NJ, USA,IEEE LNKD- DOI:
`10.1109NETECF.2005.1558999, vol. 4, 25
`September 2005 (2005-09-25), pages 2498-2502,
`XP010878903 ISBN: 978-0-7803-9152-9
`• ZBIGNIEW DZIONG ET AL: "Adaptive Traffic
`Admission for Integrated Services in CDMA
`Wireless-Access Networks" IEEE JOURNAL ON
`SELECTED AREAS IN COMMUNICATIONS, IEEE
`SERVICE CENTER, PISCATAWAY, US, vol.14,
`no. 9, 1 December 1996 (1996-12-01),
`XP011054571 ISSN: 0733-8716
`• YOSHIHIRO ISHIKAWA ET AL: "Capacity Design
`and Performance of Call Admission Control in
`Cellular CDMA Systems" IEEE JOURNAL ON
`SELECTED AREAS IN COMMUNICATIONS, IEEE
`SERVICE CENTER, PISCATAWAY, US, vol.15,
`no. 8, 1 October 1997 (1997-10-01), XP011054711
`ISSN: 0733-8716
`
`Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent
`Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the
`Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been
`paid. (Art. 99(1) European Patent Convention).
`
`,-
`a.
`w
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`Printed by Jouve, 75001 PARIS (FR)
`
`

`

`Description
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`EP 1 793 639 B1
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`[0001] The present invention relates to a call admission control device and call admission control method, and more
`specifically to a call admission control device and call admission control method for controlling the admission of a call
`in a packet communication system in mobile communications.
`[0002] A mobile communication system performs a communication using finite resources (frequencies and power).
`There is an upper limit to the communication capacity. Therefore, it is necessary to limit the number of mobile stations
`in a cell depending on the communication capacity. Practically, when a new mobile station starts communications in the
`cell, it is necessary to judge whether or not the new mobile station can start a communication in the cell. The control is
`referred to as call admission control. The status in which a new mobile station cannot start a communication in the cell,
`that is, the status in which the communication capacity is being used substantially 100%, is referred to as a capacity limit.
`[0003] The conventional call admission control is a control method of, for example, allowing a new mobile station to
`start communications when the total number of mobile stations being communicating in the cell does not exceed a
`predetermined threshold value, and not allowing a new mobile station to start communications when the total number
`of mobile stations being communicating in the cell exceeds the predetermined threshold value.
`[0004] Relating to the standardization of a third generation mobile communication system, what is called IMT (Inter(cid:173)
`national Mobile Telecommunications)-2000, the standard specifications related to the W-CDMA system and the cdma
`2000 system are prescribed respectively for the 3GPP (Third-Generation Partnership Project) and 3GPP2 (Third-Gen(cid:173)
`eration Partnership Project 2).
`[0005]
`In the 3GPP, with the recent fast spread of the Internet, based on the prediction that high speed and large
`capacitance traffic by the download, etc. from a database and a Web site especially in the downlink, the specification
`of the "HSDPA (High Speed Downlink Packet Access)" as a high speed packet transmission system in the downlink
`direction is prescribed (for example, refer to "3GPP TR25.848 v4.0.0"). As for the 3GPP2, from a similar point of view,
`the specification of the "1 x EV-DO" as a high speed dedicated transmission system in the downlink direction is prescribed
`(for example, refer to "3GPP2 C.S0024 Rev.1.0.0"). In the CDMA 2000 1 x EV-DO, the DO means "Data only".
`[0006] Further described below is the HSDPA.
`[0007] The HSDPA is a system for performing communications by sharing one shared channel or more than two
`channels among a plurality of mobile stations, and a radio base station selects a mobile station which uses the shared
`channel from among the plurality of mobile stations for each TTI (Time Transmission lnteival, 2 ms for the HSDPA) for
`transmission of a packet. In this case, depending on the occurrence of data traffic, there is a difference in number of
`mobile stations in a cell when a capacity limit is reached. For example, when the case where all mobile stations download
`data using an FTP (File Transfer Protocol) is compared with the case where all mobile stations perform Web browsing,
`the number of mobile stations in the cell when the capacity limit is reached is larger in the latter case because there are
`all the time packets to be transmitted to the mobile stations in downloading data using the FTP, while, in the case of the
`35 Web browsing, a user has reading time to browse Web pages and there is time when no packet to be transmitted to a
`mobile station exists. That is, in the case of the Web browsing, since there is a low frequency at which one mobile station
`uses a shared channel, more mobile stations can share one shared channel. As a result, in the HSDPA, the number of
`mobile stations that can be accumulated in a capacity limit fluctuates depending on the occurrence of data traffic.
`[0008]
`In the HSDPA, a modulation system of a radio channel and a system of controlling a coding rate (in the HSDPA,
`it is called an AMCS (adaptive modulation and coding scheme)) are adopted depending on the radio channel quality
`between a mobile station and a radio base station, and the transmission data rate fluctuates depending on the radio
`channel quality (for example, signal-to-interference power ratio (SIR)) between the mobile station and the radio base
`station. On the other hand, the radio channel quality (SIR) largely depends on the mode of a cell such as an outdoor
`environment and an indoor environment, an urban area and a suburb, etc. That is, in the HSDPA, the number of mobile
`stations that can be accumulated at the capacity limit fluctuates depending also on the mode of a cell.
`[0009]
`In such HSDPA, when the call admission control in the above-mentioned conventional method, that is, the call
`admission control based on the number of mobile stations currently performing communications in a cell, is performed,
`the number of mobile stations performing communications in the cell in a capacity limit is constant. Therefore, the
`transmission data rate of each mobile station in a capacity limit depends on the position of each mobile station or the
`mode in a cell. For example, since there is little interference from another cell in an indoor environment, and the radio
`channel quality is high, the transmission data rate of each mobile station in a capacity limit is high. However, since there
`is much interference in an outdoor environment, and the radio channel quality is not high, it is considered that the
`transmission data rate of each mobile station in a capacity limit is low.
`[0010] However, the transmission data rate of each mobile station in a capacity limit is to be determined by the
`serviceability of the communications provided using the HSDPA, and it is desired that the speed is constant regardless
`of the mode of a cell or the position of each mobile station.
`[0011] Described below is the scheduling in the HSDPA. As described above, the HSDPA is a system for performing
`communications by sharing one channel or more than two channels to be shared among a plurality of mobile stations,
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`a radio base station selects a mobile station that uses the shared channel from among the plurality of mobile stations
`for each TII (Time Transmission Interval, 2 ms in the HSDPA), and transmits a packet. Selecting a mobile station that
`uses the shared channel for each TII by a radio base station is referred to as scheduling.
`[0012] An well known algorithm of the scheduling is a round robin scheduler for controlling the transmission order of
`a transmission allocation packet of a downlink shared channel in order (for example, the mobile station #1 ~ #2 ~ #3
`~ ... )on the mobile station which are connected to a radio base station device. Furthermore, a Proportional Fairness
`scheduler and a MAX C/1 (Maximum C/1) scheduler for controlling the transmission order of a packet waiting for trans(cid:173)
`mission based on a radio channel quality of each mobile station and an average transmission data rate of each mobile
`station are also well known.
`[0013] For example, the Proportional Fairness scheduler performs scheduling by calculating the evaluation function
`Cn = Rn/avrgRn relating to each mobile station, and allocating a packet to a mobile station having the largest evaluation
`function Cn. Rn indicates a momentary radio channel quality of each mobile station, and avrgRn indicates an average
`transmission data rate of each mobile station.
`[0014] The Proportional Fairness scheduler can be expected to obtain higherthroughputthan the round robin scheduler
`because transmission allocation is performed in a state in which downlink radio channel quality is relatively good in each
`mobile station. Then, the value of the evaluation function expression of a mobile station having a high average transmission
`data rate is reduced by performing a division by an average transmission data rate of each mobile station, thereby
`realizing allocation with high fairness in time.
`[0015] Furthermore, from a view point of serviceability, a method of providing Proportional Fairness scheduling with
`the minimum transmission data rate taken into account is proposed by, for example, JP2005-130053A.
`In
`JP2005-130053A, it is proposed that Cn = Rn/(avrgRn - targetR) is to be used instead of Cn = Rn/avrgRn as an evaluation
`function Cn. In the equation, targetR indicates the minimum transmission data rate.
`In the 3GPP, the specification of the Evolved UTRA and UTRAN (also referred to as Long Term Evolution or
`[0016]
`Super 3G) as a further high-speed packet communication system is defined. However, the Evolved UTRA and UTRAN
`(also referred to as Long Term Evolution or Super 3G) has almost the same characteristics, that is, using a shared
`channel, performing the AMC, performing scheduling about the allocation of the shared channel, etc., as the above(cid:173)
`mentioned HSDPA.
`In JP2002-232941 A, the amount of uplink interference and the total downlink transmission power when a call
`[0017]
`is admitted are estimated, and it is determined whether or not the estimated amount of uplink interference is equal to or
`higher than a threshold value of an amount of interference, whether or not the total downlink transmission power is equal
`to or higher than a transmission power threshold value, and whether or not the remaining and unused expansion code
`resources are equal to or lower than an expansion code threshold value. Depending on the determination result, it is
`controlled whether or not a call admission request is to be recognized.
`In JP2002-223239A, depending on the type of service or the priority, the admission of a new call is controlled.
`[0018]
`[0019] JP2002-217956A controls the admission of a new call depending on the resource use status and the number
`of packet users.
`[0020] As described above, there is a method of not admitting a call of a new mobile station when a total number of
`mobile stations performing communications in a corresponding cell exceeds a predetermined threshold value as a call
`admission control method in a communication system which transmits a packet to a plurality of mobile stations.
`[0021] However, the above-mentioned conventional call admission control method has the disadvantage of not able
`to appropriately controlling admission of a call depending on the method of generating packet data and the mode of a
`cell. That is, when the conventional call admission control method is used, there occurs the problem that the transmission
`data rate of a mobile station in a capacity limit depends on the method of generating packet data and the mode of a cell.
`[0022] Known from EP 1 189 472 A 1 is a method of determining transmission rate from a mobile station to a base
`station in a wireless communication system, wherein it is determined when a request for a higher transmission rate
`should be granted to a mobile station that currently has access to a communication system to facilitate the maintenance
`of a performance target of the reverse link. The disclosure of EP 1 189 472 A 1 forms the preamble of claims 1 and 12.
`[0023] Known from WO 02/067619 A2 is a call admission control device in a communications system and a method
`for controlling call admission in a communications system according to the preamble of claims 1 and 10, respectively.
`[0024] Known from EP 1 126 734 A 1 is a mobile radio telecommunication system, wherein a method is disclosed to
`allocate resources by the steps of determining the current proportion of each rate traffic in a telecommunications cell;
`and applying a threshold to the loading level in said cell in accordance with said determined proportion.
`[0025] Known from EP 1 033 849 A 1 is a process for controlling access to radio resource for uplink packet transmission
`in a wireless communication network, wherein each user equipment is allowed to access the resource at a reduced
`transmission rate for a given time period.
`[0026] Known from US 2004/0082363 A 1 is a system and a method for wireless network admission control based on
`quality of service. An admission controller accesses a "QoS penalty" that would be incurred if a prospective new user
`is admitted based on the extent to which admitting the new user might cause the network to not meet QoS guarantees
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`for current users.
`[0027] Known from the article "High Speed Downlink Packet Access: WCDMA Evolution" by T.E. Kolding et al., IEEE
`Vehicular Technology Society News, 1 February 2003, pages 4-10 is an overview of the high speed downlink packet
`access (HSDPA) concept.
`[0028] Known from the article "Quality based HSDPA access algorithms" by K-1. Pedersen, Vehicular Technology
`Conference, Dallas, TX, USA, 25-28 September 2005, IEEE LNKD-DOI: 10.1109/VETECF, vol, 4, 25 September 2005,
`pages 2498-2502, ISBN: 978-0-7803-9162-9 is an algorithm which is designed so that it takes both priority and minimum
`bit rate requirements into account in the decision process.
`[0029] Known from EP 1 227 695 A 1 is a call admission control method communication system. In communication in
`which calls of a plurality of services having mutually different degrees of priority are present and respective calls perform
`access with shared resources it is disclosed that for the plurality of services, a plurality of corresponding call admission
`threshold values are set beforehand in accordance with the respective degrees of priority, and in respect of a requested
`call, the resource use condition of a predetermined resource designated as the subject of monitoring and the call
`admission threshold value corresponding to the service in this call are compared and new call admission in respect of
`the requested call is restricted in accordance with the comparison result.
`[0030] Known from EP 1 100 283 A 1 is a method for adjusting the call admission control threshold(s) and call admission
`control method using the same, wherein for each cell the instantaneous loading level of the considered cell is determined
`and this value is compared with a maximum tolerated cell load value for the considered cell, and the maximum allowed
`cell load can be modified in response to the comparison step.
`[0031] Known from the article "Adaptive Traffic Admission for Integrated Services In CDMA Wireless-Access Networks"
`by Zbigniew Dziong et al., IEEE Journal on selected Areas in Communications, vol, 14, no. 9, 1 December 1996, pages
`1737-1747 is a framework for adaptive connection admission in the up-link direction. It is based on estimation of the
`interference at the base station receivers.
`[0032] Known from the article "Capacity Design and Performance of Call Admission Control in Cellular CDMA Systems"
`by Yoshihiro Ishikawa et al., IEEE Journal on selected Areas in Communications, vol. 15, no. 8, 1 October 1997, pages
`1627-1635 is a capacity design method based on the grade of service (GoS), i.e., the blocking rate, and a quality of
`service (QoS), i.e., the loss probability of communication quality. Theoretical expressions for Gos and QoS as functions
`of traffic intensity and call admission control thresholds are first derived from the traffic theory viewpoint, and then a
`design method using these expressions is presented.
`[0033] The present invention has been developed to solve the above-mentioned problems of the conventional tech(cid:173)
`nology, and the advantage of the present invention is to provide a call admission control device and call admission
`control method capable of adaptively controlling call admission on the method of generating packet data and the mode
`of a cell, and efficiently admitting a new call.
`[0034] A call admission control device in a communication system for transmitting a packet to a plurality of mobile
`stations is provided according to claim 1.
`[0035] Additionally, a call admission control method in a communication system for transmitting a packet to a plurality
`of mobile stations is provided according to claim 12.
`[0036] As described above, the present invention has the effect of realizing appropriate call admission control regard(cid:173)
`less of the mode of a corresponding cell and data traffic by controlling call admission by estimating the congestion of
`the cell based on the number or the ratio of the mobile stations whose values of average transmission data rates have
`been initialized.
`[0037] Further objects, advantages and embodiments may be taken from the following description.
`[0038] The invention will now be described in connection with embodiments illustrated in the attached drawings.
`
`FIG. 1 shows an example of the configuration of the mobile communication system using a radio base station as a
`call admission control device according to the mode for embodying the present invention;
`FIG. 2 is a block diagram of the function showing an example of the configuration of the radio base station shown
`in FIG. 1;
`FIG. 3 is a block diagram of the function showing the configuration of the function of the baseband signal processing
`unit of the radio base station shown in FIG. 2;
`FIG. 4 is a function block diagram of the configuration showing the function configuration of the MAC-hs processing
`unit of the radio base station shown in FIG. 3;
`FIG. 5 is a function block diagram showing the function configuration of the radio network controller shown in FIG. 1;
`FIG. 6 is a flowchart of a call admission judging operation by the MAC-hs processing unit;
`FIG. 7 is a flowchart showing an example of a scheduling operation by the MAC-hs processing unit;
`FIG. 8 is a flowchart showing another example of a call admission judging operation by the MAC-hs processing unit;
`FIG. 9 is a flowchart showing an example of a call admission judging operation by the MAC-hs processing unit;
`FIG. 10 shows an example of the configuration of the mobile communication system using a radio base station as
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`a call admission control device according to another mode for embodying the present invention;
`FIG. 11 is a block diagram showing the functions of a configuration example of the radio base station shown in FIG. 1 O;
`FIG. 12 is a block diagram of the functions showing the configuration of the functions of the baseband signal
`processing unit of the radio base station shown in FIG. 11;
`FIG. 13 is a block diagram of the functions showing the configuration of the functions of the MAC processing unit
`of the radio base station shown in FIG. 12;
`FIG. 14 is a flowchart showing the call admission judging operation of the MAC processing unit;
`FIG. 15 is a flowchart showing an example of the scheduling operation of the MAC processing unit;
`FIG. 16 is a flowchart showing another example of the call admission judging operation of the MAC processing unit;
`and
`FIG. 17 is a flowchart showing the call admission judging operation of the MAC processing unit.
`
`[0039] The mode for embodying the present invention is explained below by referring to the attached drawings. In the
`explanation below, each figure shows a component common with other figures by assigning the same reference numeral.
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`[0040] The mode 1 for embodying the present invention is explained below by referring to the attached drawings.
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`[0041] FIG. 1 shows an example of the configuration of the mobile communication system using the call admission
`control device according to the mode 1 for embodying the present invention.
`In FIG. 1, the mobile communication system is constituted by a plurality of mobile stations 1 Oto 12 and 21, a
`[0042]
`radio base station 100 as a call admission control device, and a radio network controller 300 for controlling them, and
`the above-mentioned HSDPA is applied to the system. A cell 1000 is an area in which the radio base station 100 can
`provide communications. The mobile stations 1 Oto 12 are in the state in which communications are being performed
`using the radio base station 100 and the HSDPA in the cell 1000, and the mobile station 21 is in the state in which a
`new communication using the radio base station 100 and the HSDPA is to be newly started in the cell 1000.
`[0043] Since the mobile stations 10 to 12 that are performing communications using the HSDPA has the same con(cid:173)
`figuration, function, and status, it is explained as a mobile station n (n is an integer equal to or more than 1) unless
`otherwise specified. Additionally, the mobile station 21 is used as an example of a mobile station in a state in which a
`new communication is to be started using the HSDPA.
`[0044] A communication channel in the HSDPA is explained below. In the downlink in the HSDPA, a downlink shared
`physical channel HS-POSCH (High Speed Physical, Downlink Shared Channel; HS-DSCH or High Speed Downlink
`Shared Channel in terms of a transport channel) shared by each of the mobile stations 1 O to 12, a downlink shared
`control channel HS-SCCH (High Speed Shared Control Channel) shared by each mobile station, and a downlink asso(cid:173)
`ciated dedicated channel (A-DPCH: associated Dedicated Physical Channel) associated with the shared physical channel
`dedicated to each mobile station are used. In the uplink, in addition to the uplink associated dedicated channel A-DPCH
`dedicated to each mobile station, a control channel HS-DPCCH (High Speed-Dedicated Physical Control Channel) for
`the HSDPA dedicated to each mobile station is used. In the downlink, using the downlink associated dedicated channel,
`a transmission power control command, etc. for the uplink associated dedicated channel is transmitted, and user data
`is transmitted using the shared physical channel. On the other hand, in the uplink, a pilot symbol and a power control
`command (TPC command) for downlink associated dedicated channel transmission are transmitted in addition to the
`user data using the uplink associated dedicated channel, downlink radio channel quality information used for the AMCS
`(adaptive modulation/coding) and the scheduling of a shared channel, and acknowledgement information of downlink
`shared channel HS-DSCH are transmitted using the dedicated control channel for the HSDPA (HS-DPCCH).
`
`(Configuration Example of Radio Base Station)
`
`[0045] FIG. 2 is a block diagram of the function showing an example of the configuration of the radio base station 100
`shown in FIG. 1.
`In FIG. 2, the radio base station 100 is constituted by a transmission/reception antenna 101, an amplification
`[0046]
`unit 102, a transmission/reception unit 103, a baseband signal processing unit 104, a call processing unit 105, and a
`transmission line interface 106. The downlink packet data is input from the radio network controller 300 positioned above
`the radio base station 100 to the baseband signal processing unit 104 through the transmission line interface 106. The
`baseband signal processing unit 104 performs retransmission control (Hybrid Automatic Repeat Request (HARO))
`processing, scheduling, transmission format selection, channel coding, and a spreading process, and the result is trans-
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`ferred to the transmission/reception unit 103. The transmission/reception unit 103 performs a frequency converting
`process of converting a baseband signal output from the baseband signal processing unit 104 into a radio frequency
`band. Then, the resultant signal is amplified by the amplification unit 102 and transmitted through the transmission/
`reception antenna 101.
`[0047] On the other hand, as for the uplink data, the radio frequency signal received by the transmission/reception
`antenna 101 is amplified by the amplification unit 102, and the transmission/reception unit 103 frequency-converts it into
`a baseband signal. The baseband signal is processed by the baseband signal processing unit 104 for de-spreading,
`RAKE combining, and error correction decoding, and then transferred to the radio network controller 300 through the
`transmission line interface 106.
`[0048] The call processing unit 105 communicates a call processing control signal with the radio network controller
`300, manages the status of the radio base station 100, and allocates resources.
`
`(Configuration Example of Baseband Signal Processing unit)
`
`[0049] FIG. 3 is a function block diagram showing the configuration of the function of the baseband signal processing
`unit 104.
`[0050]
`In FIG. 3, the baseband signal processing unit 104 is constituted by a layer 1 processing unit 111, and a MAC(cid:173)
`hs (short for Medium Access Control-HSDPA) processing unit 112. Each of the layer 1 processing unit 111 and the
`MAC-hs processing unit 112 in the baseband signal processing unit 104 is connected to the call processing unit 105. In
`the layer 1 processing unit 111, the processes of downlink data channel coding, uplink data channel decoding, trans(cid:173)
`mission power control of uplink and downlink dedicated channels, RAKE combining, spreading/de-spreading processing
`are performed.
`[0051] The layer 1 processing unit 111 receives the information about the downlink radio channel quality reported
`along the dedicated physical channel (HS-DPCCH) for the uplink HSDPA from each mobile station, and notifies the
`MAC-hs processing unit 112 of the information. The MAC-hs processing unit 112_performs the HARO operation and
`the scheduling of packets waiting for transmission for the downlink shared channel in the HSDPA. Additionally, the MAC(cid:173)
`hs processing unit 112 judges call admission as to whether or not the mobile station 21 can newly start communications
`using the HSDPA in a corresponding cell 1000 as described later.
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`[0052] FIG. 4 shows an example of the configuration showing the function of the MAC-hs processing unit 112 shown
`in FIG. 3. In FIG. 4, the MAC-hs processing unit 112 is constituted, for example, by the following function blocks.
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`(1) flow control unit 120
`(2) MAC-hs resource calculation unit 130
`(3) scheduler unit 140
`(4) TFR (Transport Format and Resource) selection unit 150
`(5) mobile station transmission data rate initialization unit 160
`(6) mobile station transmission data rate calculation unit 170
`(7) evaluation function calculation unit 180
`(8) minimum transmission data rate setting unit 190
`(9) HS call admission judge unit 200
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`[0053] The flow control unit 120 of (1) above has the function of adjusting the transmission data rate of a signal received
`from the radio network controller 300 through the transmission line interface 106 based on the implemented buffer
`capacity and the like. Each of the flow controls (#1 to #N) 121 1 to 121 N monitors the amount of packets, and when the
`amount of packets increases and the space of memory of the queue buffer decreases, the amount of transmission of
`packets is reduced.
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`(MAC-hs Resource Calculation Unit)
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`[0054] The MAC-hs resource calculation unit 130 of (2) above includes an HS-DSCH power resource calculation unit
`131 and an HS-DSCH code resource calculation unit 132 for calculating the radio resources (power resource, code
`resource, hardware resource, etc.) to be allocated to the HS-DSCH.
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`50
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`55
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`6
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`(Scheduler Unit)
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`EP 1 793 639 B1
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`5
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`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`[0055] The scheduler unit 140 of (3) above includes N priority queues (#1 to #N) 141 1 to 141 N• N reordering units (#1
`to #N) 1421 to 142N, and N HARO units (#1 to #N) 1431 to 143N. The priority queues (#1 to #N) 141 1 to 141 N are queues
`for each connection. Normally, one user has one priority queue. However, when one user has a plurality of connections,
`one user has a plurality of priority queues. The priority queues (#1 to #N) 141 1 to 141 N receive downlink data, and
`accumulate the data until it is selected in the scheduling. The reordering units (#1 to #N) 1421 to 142N allocate a sequence
`number to data so that the mobile station n can control the downlink reception order in the retransmission control in the
`HARO, and perform window control so that the reception buffer of the mobile station n cannot overflow. The HARO units
`(#1 to #N) 1431 to 143N perform retransmission control of the HARO based on the uplink Ack/Nack (Acknowledgment/
`Negative Acknowledgment) feedback using a stop and wait protocol of the M process where M indicates the number of
`processes.
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`(TFR Selection Unit)
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`[0056] The TFR selection unit 150 of (4) above includes N TFR select functions (#1 to #N) 151 1 to 151 N· These N
`TFR select functions (#1 to #N) 151 1 to 151 N determine the transmission format (Number of codes, modulation scheme,
`coding rate) of the downlink transmission channel and the transmission power based on the CQI (Channel Quality
`Indicator) of the user selected by the scheduler unit 140, and the radio resource (power resource, code resource,
`hardware resource), etc. to be allocated to the HS-DSCH calculated by the MAC-hs resource calculation unit. The
`transmission format and the transmission power of the downlink transmission channel determined by the TFR select
`function are noticed to the layer 1 processing unit.
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`(Mobile Station Transmission data rate Initialization Unit)
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`[0057] The mobile station transmission data rate initialization unit 160 of (5) above receives the av