I lllll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111
`US007075917B2
`
`c12) United States Patent
`Herrmann
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,075,917 B2
`Jul. 11, 2006
`
`(54) WIRELESS NETWORK WITH A DATA
`EXCHANGE ACCORDING TO THE ARQ
`METHOD
`
`(75)
`
`Inventor: Christoph Herrmann, Aachen (DE)
`
`(73) Assignee: Koninklijke Philips Electronics N.V.,
`Eindhoven (NL)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 984 days.
`
`(21) Appl. No.: 09/973,312
`
`(22) Filed:
`
`Oct. 9, 2001
`
`(65)
`
`Prior Publication Data
`
`US 2002/0075867 Al
`
`Jun. 20, 2002
`
`(30)
`
`Foreign Application Priority Data
`
`Oct. 11, 2000
`
`(DE)
`
`................................ 100 50 117
`
`(51)
`
`Int. Cl.
`H04L 12128
`(2006.01)
`H04L 12156
`(2006.01)
`H04L 1118
`(2006.01)
`(52) U.S. Cl. ....................... 370/349; 370/394; 370/471
`(58) Field of Classification Search ................ 370/349,
`370/394, 471, 474
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`2001/0036169 Al* 11/2001 Ratzel ........................ 370/338
`2003/0157927 Al*
`8/2003 Yi et al ...................... 455/411
`2004/0246917 Al* 12/2004 Cheng et al.
`............... 370/328
`
`OTHER PUBLICATIONS
`
`By Balachandran K. et al: Entitled: "GPRS-136: High-Rate
`Packet Data Service for North American TDMA Digital
`
`Cellular Systems" IEEE Personal Communications Society,
`US Bd. 6, Jun. 3, 1999, pp. 34-47.
`By Lockitt J.A. et al. "A Selective Repeat ARQ Systems"
`Proceedings of the International Conference on Digital
`Satellite Communications. Kyoto, Japan, Nov. 11-13, 1975,
`pp. 189-195.
`By Sophia Antipolis, 3RD Generation Partnership Project;
`Entitled: Technical Specification Group Radio Access Net(cid:173)
`work; Report on HybridARQ Type II/III (Release 2000), 3G
`TR 25.835 Vo.0.2, TSG-RAN Working Group 2 (Radio L2
`and Radio L3, France, Aug. 15-21, 2000.
`* cited by examiner
`Primary Examiner-Melvin Marcelo
`
`(57)
`
`ABSTRACT
`
`The invention relates to a wireless network comprising a
`radio network controller and a plurality of assigned termi(cid:173)
`nals, which are provided for exchanging data according to
`the hybrid ARQ method of type II or III and each form a
`receiving and/or transmitting side. A physical layer of a
`transmitting side is arranged for
`storing coded transport blocks in a memory, which blocks
`contain at least a packet data unit delivered by the
`assigned radio link control layer and can be identified
`by a packet data unit sequence number,
`storing abbreviated sequence numbers whose length
`depends on the maximum number of coded transport
`blocks to be stored and which can be shown unam(cid:173)
`biguously shown in a packet data unit sequence num(cid:173)
`ber, and for
`transmitting coded transport blocks having at least the
`assigned abbreviated sequence numbers.
`a physical layer of a receiving side is provided for testing
`the correct reception of the coded transport block and
`for sending a positive acknowledge command to the
`transmitting side over a back channel when there is
`correct reception and a negative acknowledge com(cid:173)
`mand when there is error-affected reception.
`
`10 Claims, 3 Drawing Sheets
`
`TTI
`
`TB1
`
`TTI
`
`TB4
`
`TTI
`
`TBO
`
`TB2
`
`TB3
`
`PHC
`
`ACK
`
`ACK, ACK,
`NACK
`
`BC
`
`RF
`
`Page 1 of 10
`
`

`

`U.S. Patent
`U.S. Patent
`
`Jul. 11,2006
`Jul. 11, 2006
`
`Sheet 1 of 3
`Sheet 1 013
`
`US 7,075,917 B2
`US 7,075,917 B2
`
`8
`
`9
`
`7
`
`:0» fi/ fi”
`r118 &1 j
`05/
`fig
`
`3
`
`5
`
`1
`
`6
`
`FIG. 1
`FIG. 1
`
`Page 2 of 10
`
`Page 2 of 10
`
`

`

`U.S. Patent
`
`Jul. 11, 2006
`
`Sheet 2 of 3
`
`US 7,075,917 B2
`
`RRC
`
`..__ 14
`
`I RLC 1
`I RLC
`I RLCI
`RLCI
`
`I RLCl
`I RLCI
`RLCI
`I RLCI
`
`+-13
`
`+-12
`
`\
`11
`
`""
`
`10
`
`MAC
`
`PHY
`
`FIG. 2
`
`Page 3 of 10
`
`

`

`U.S. Patent
`
`Jul. 11, 2006
`
`Sheet 3 of 3
`
`US 7,075,917 B2
`
`<11
`
`TTI
`
`TB1
`
`~ ..
`
`TTI
`
`TB4
`
`ti:-
`
`TTI
`
`TBO
`
`TB2
`
`TB3
`
`TB2 TBO TB2 TBO 1
`
`'!ACK, ACK, 'I
`_NACK:
`_BC
`
`RF
`
`FIG. 3
`
`Page 4 of 10
`
`

`

`US 7,075,917 B2
`
`1
`WIRELESS NETWORK WITH A DATA
`EXCHANGE ACCORDING TO THE ARQ
`METHOD
`
`2
`The object is achieved by the following features by the
`wireless network mentioned in the opening paragraph which
`comprises a radio network controller and a plurality of
`assigned terminals which are each provided for exchanging
`data and which form each a receiving and/or transmitting
`The invention relates to a wireless network comprising a
`side:
`radio network controller and a plurality of assigned termi(cid:173)
`A physical layer of a transmitting side is provided for
`nals, which are each provided for exchanging data and
`storing coded transport blocks in a memory, which blocks
`which form a receiving and/or transmitting side.
`contain at least a packet data unit which is delivered by
`Such a wireless network is known from the document "3rd 10
`the assigned radio link control layer and can be iden(cid:173)
`Generation Partnership Project; Technical Specification
`tified by a packet data unit sequence number,
`Group Radio Access Network; Report on Hybrid ARQ Type
`storing abbreviated sequence numbers whose length
`II/III (Release 2000), 3G TR 25.835 V0.0.2, TSG-RAN
`depends on the maximum number of coded transport
`Working Group 2 (Radio L2 and Radio L3), Sophia Anti(cid:173)
`blocks to be stored and which can be shown unam(cid:173)
`polis, France, 21-15 August 2000". For the secured trans- 15
`biguously in a packet data unit sequence number, and
`mission of data a method is used here which is called the
`for
`hybrid ARQ-method type II or III (ARQ=Automatic Repeat
`transmitting coded transport blocks having at least the
`Request). The data sent in Packet Data Units (PDU) by the
`assigned abbreviated sequence number and
`Radio Link Control layer (RLC layer) are additionally
`a physical layer of a receiving side is provided for testing
`provided for the error correcting coding with an error control 20
`the correct reception of the coded transport block and
`through repetition of transmission. This means that in the
`for sending a positive acknowledge command to the
`case of an error-affected reception of a packet data unit
`transmitting side over a back channel when there is
`packed in a transport block coded by one of the assigned
`correct reception and a negative acknowledge com(cid:173)
`physical layers, the received packet data unit affected by
`mand when there is error-affected reception.
`error is sent anew. With the hybrid ARQ method type I the 25
`The wireless network according to the invention may be,
`received packet data unit affected by error is rejected and an
`for example, a radio network according to the UMTS
`identical copy is requested anew. With the hybrid ARQ
`standard (UMTS=Universal Mobile Telecommunication
`methods types II and III the received packet data unit
`System). With this system, when, for example, data are
`affected by error is buffered and, after additional incremental
`transmitted according to the ARQ method of type II or III,
`redundancy relating to the received packet data unit,
`30 the transmission of an acknowledge command over a back
`decoded together with the received packet data unit affected
`channel unknown thus far between a physical layer of a
`by error. Since only incremental redundancy and not the
`transmitting side (for example, a radio network controller)
`whole error-affected packet data unit is transmitted anew, the
`and the physical layer of a receiving side (for example, a
`amount of data to be transmitted anew is reduced. With the
`terminal) provides that a correct or error-affected transmis-
`ARQ method type II the incremental redundancy is useless
`35 sion of a transport block is announced to the transmitting
`without the buffered (error-affected) packet, with the ARQ
`side much more rapidly than known until now. As a result,
`method type III the incremental redundancy can be decoded
`a repetition of transmission with incremental redundancy
`also without the buffered (error-affected) packet. The coded
`may be effected rapidly. This enables the receiving side to
`transport blocks are sent over at least one transport channel.
`buffer the received coded transport block affected by error
`A message about the error-free reception in said document
`40 clearly more briefly, because the additional redundancy
`is sent only when the receiving RLC layer establishes on the
`necessary for the correct decoding is available at an earlier
`basis of the so-called RLC sequence number that packet data
`instant. In this manner, the memory capacity or memory area
`units are lacking, even if the physical layer has already
`needed on average for buffering received coded transport
`recognized the packet data unit as being error-affected. This
`blocks affected by error is also reduced.
`means that the packet data unit is to be buffered over long 45
`The use of abbreviated sequence numbers reduces the
`time spaces until an incremental redundancy is requested
`extent of information that is required to be additionally
`and then, after a successful decoding, the reception may be
`transmitted for managing the transport blocks and packet
`acknowledged as correct, especially when the receiving side
`data units and simplifies the assignment of the received
`is the network side, while the physical layer and the RLC
`acknowledge command to the stored transport blocks. The
`layer are usually located on different hardware components. 50 physical layer of a receiving side is provided here for
`In addition to the packet data units contained in the transport
`sending a positive or negative acknowledge command with
`blocks, the RLC sequence numbers of the packet data unit
`the abbreviated sequence number of the correctly or
`and a redundancy version are to be transmitted in synchro(cid:173)
`received transport block affected by error over the return
`nism with the coded transport block when the hybrid ARQ
`channel.
`methods of type II or III are implemented. This transmission 55
`In lieu of transmitting the abbreviated sequence number,
`is generally effected over a clearly better protected transport
`an abbreviated sequence number of a transport block which
`channel to safeguard that this information is error-free
`a received acknowledge command relates to can also implic(cid:173)
`already at first reception. The information is decisive if after
`itly be determined based on the length of time between the
`a repetition of transmission with incremental redundancy the
`transmission of the transport block and the reception of the
`buffered (error-affected) packet data unit is decoded together
`60 acknowledge command and on the transmission sequence of
`with the incremental redundancy, because the incremental
`the acknowledge command in case of a plurality of received
`redundancy is to be assigned to the respective packet data
`acknowledge commands. This is made possible in a simple
`unit via the redundancy version.
`manner in that a transmission of the transport blocks is
`It is an object of the invention to provide a wireless
`provided in radio frames and in that the transmission of an
`network in which error-affected data repeatedly to be trans(cid:173)
`65 acknowledge command from the transmitting side to the
`receiving side is provided in the F'h radio frame at the
`mitted according to the ARQ method of the type II or III are
`earliest after the radio frame that contains the respective
`buffered for a shorter period of time on average.
`
`Page 5 of 10
`
`

`

`US 7,075,917 B2
`
`20
`
`25
`
`3
`transport block (with F ~ 1 ). The order of a plurality of
`acknowledge connnands corresponds to the order of the
`transmission of transport blocks in a preceding radio frame.
`If the physical layer of a transmitting side has received a
`negative acknowledge connnand, the physical layer once
`again requests the radio link control layer to transmit the
`packet data unit that has been transmitted affected by error
`via the coded transport block. After a packet data unit has
`been received, the physical layer forms therefrom a coded
`transport block which contains an incremental redundancy. 10
`The invention also relates to a radio network controller
`and a terminal in a wireless network which exchange data
`according to the hybrid ARQ method.
`These and other aspects of the invention are apparent
`from and will be elucidated with reference to the embodi- 15
`ments described hereinafter.
`In the drawings:
`FIG. 1 shows a wireless network comprising a radio
`network controller and a plurality of terminals,
`FIG. 2 shows a layer model for explaining different
`functions of a terminal or of a radio network controller and
`FIG. 3 shows a plurality of radio frames which contain
`data to be transmitted over the radio path between radio
`network controller and terminals.
`FIG. 1 shows a wireless network, for example, radio
`network, including a radio network controller (RNC) 1 and
`a plurality of terminals 2 to 9. The radio network controller
`1 is responsible for controlling all the components taking
`part in the radio traffic such as, for example, the terminals 2
`to 9. An exchange of control and useful data takes place at
`least between the radio network controller 1 and the termi(cid:173)
`nals 2 to 9. The radio network controller 1 sets up a
`respective link for the transmission of useful data.
`As a rule, the terminals 2 to 9 are mobile stations and the
`radio network controller 1 is fixedly installed. A radio
`network controller 1 may, however, also be movable or
`mobile, as appropriate.
`In the wireless network are transmitted, for example,
`radio signals in accordance with the FDMA, TDMA or
`CDMA method
`(FDMA=frequency division multiple 40
`access, TDMA=time division multiple access, CDMA=code
`division multiple access), or in accordance with a combina(cid:173)
`tion of the methods.
`In the CDMA method, which is a special code-spreading
`method, binary information (a data signal) coming from a
`user is modulated with a respective code sequence. Such a
`code sequence includes a pseudo-random square-wave sig(cid:173)
`nal (pseudo-noise code), whose rate, also called chip rate, is
`generally considerably higher than that of the binary data.
`The length of time of a square-wave pulse of the pseudo(cid:173)
`random square-wave signal is referred to as a chip interval
`Tc- l!Tc is the chip rate. The multiplication or modulation
`respectively, of the data signal by the pseudo-random
`square-wave signal has a spreading of the spectrum by the
`spreading factor Nc=T!Tc as a result, where Tis the length
`of time of the square-wave pulse of the data signal.
`Useful data and control data are transmitted between at
`least one terminal (2 to 9) and the radio network controller
`1 over channels predefined by the radio network controller
`1. A channel is determined by a frequency range, a time 60
`range and, for example, in the CDMA method, by a spread(cid:173)
`ing code. The radio link from the radio network controller 1
`to the terminals 2 to 9 is referred to as the downlink and from
`the terminals to the base station as the uplink. Thus data are
`sent over downlink channels from the base station to the 65
`terminals and over uplink channels from the terminals to the
`base station.
`
`4
`For example, a downlink control channel may be pro(cid:173)
`vided which is used for broadcasting, prior to a connection
`setup, control data coming from the radio network controller
`1 to all the terminals 2 to 9. Such a channel is referred to as
`downlink broadcast control channel. For transmitting con(cid:173)
`trol data from a terminal 2 to 9 to the radio network
`controller 1 prior to a connection setup, for example, an
`uplink control channel assigned by the radio network con-
`troller 1 can be used which, however, may also be accessed
`by other terminals 2 to 9. An uplink channel that can be used
`by various terminals or all the terminals 2 to 9 is referred to
`as a connnon uplink channel. After a connection setup, for
`example, between a terminal 2 to 9 and the radio network
`controller 1, useful data are transmitted by a downlink and
`an uplink user channel. Channels that are set up between
`only one transmitter and one receiver are referred to as
`dedicated channels. As a rule, a user channel is a dedicated
`channel which may be accompanied by a dedicated control
`channel for transmitting link-specific control data.
`For exchanging useful data between the radio network
`controller 1 and a terminal, it is necessary for a terminal 2
`to 9 to be synchronized with the radio network controller 1.
`For example,
`it
`is known from
`the GSM system
`(GSM=Global System for Mobile connnunication),
`in
`which a combination ofFDMAand TDMAmethods is used,
`that after a suitable frequency range is determined based on
`predefined parameters, the position in time of a frame is
`determined (frame synchronization), with the aid of which
`30 frame the order in time for transmitting data is determined.
`Such a frame is always necessary for the data synchroniza(cid:173)
`tion of terminals and base station in TDMA, FDMA and
`CDMA methods. Such a frame may contain several sub(cid:173)
`frames, or together with various other successive frames,
`35 form a superframe.
`The exchange of control and useful data via the radio
`interface between the radio network controller 1 and the
`terminals 2 to 9 can be explained with the layer model or
`protocol architecture shown by way of example in FIG. 2
`(compare for example 3rd Generation Partnership Project
`(3GPP); Technical Specification Group (TSG) RAN; Work-
`ing Group 2 (WG2); Radio Interface Protocol Architecture;
`TS 25.301 V3.2.0 (1999-10)). The layer model comprises
`three protocol layers: the physical layer PHY, the data link
`45 layer having the sub-layers MAC and RLC (in FIG. 2
`various objects of the sub-layer RLC are shown) and the
`layer RRC. The sub-layer MAC is equipped for Medium
`Access Control, the sub-layer RLC for Radio Link Control
`and the layer RRC for Radio Resource Control. The layer
`50 RRC is responsible for the signaling between the terminals
`2 to 9 and the radio network controller 1. The sub-layer RLC
`is used for controlling a radio link between a terminal 2 to
`9 and a radio network controller 1. The layer RRC controls
`the layers MAC and PHY via control links 10 and 11. By
`55 doing this, the layer RRC can control the configuration of
`the layers MAC and PHY. The physical layer PHY offers
`transport links 12 to the layer MAC. The layer MAC renders
`logic connections 13 available to the layer RLC. The layer
`RLC can be reached by applications via access points 4.
`In such a network a method of securely transmitting data
`is used, which is called the hybrid ARQ (ARQ=Automatic
`Repeat Request) method. The data sent in packet data units
`PDU are additionally provided for a forward error correction
`by means of an error control via repetitions of transmissions.
`This means that in case a packet data unit is received
`affected by error, the received packet data unit affected by
`error is sent anew. With the hybridARQ methods of type II
`
`Page 6 of 10
`
`

`

`US 7,075,917 B2
`
`25
`
`5
`or III it is possible to send only certain parts of the data of
`an error-affected transmission once again. This is referred to
`as incremental redundancy.
`The packet data units are formed in the RLC layer and
`packed to transport blocks in the MAC layer, which trans(cid:173)
`port blocks are transmitted by the physical layer from the
`radio network controller to a terminal or vice versa over the
`available transport channels. In the physical layer the trans(cid:173)
`port blocks are provided with a cyclic redundancy check
`(CRC) and coded together. The result of this operation is 10
`referred to as a coded transport block. The coded transport
`blocks contain a packet data unit and control information.
`Coded transport blocks affected by error that were trans(cid:173)
`mitted are buffered in the physical layer of the receiving side
`for the conversion according to the hybrid ARQ method of
`type II or III until the incremental redundancy required
`afterwards makes an error-free decoding possible. It is
`known that at least the RLC sequence number or packet data
`unit sequence number, which features a packet data unit, and
`a redundancy version is to be transmitted, in parallel with the
`coded transport block or the incremental redundancy
`required afterwards, as so-called side information (compare:
`"3rd Generation Partnership Project; Technical Specification
`Group Radio Access Network; Report on Hybrid ARQ Type
`II/III (Release 2000), 3G TR 25.835 V0.0.2, TSG-RAN
`Working Group 2 (Radio L2 and Radio L3), Sophia Anti(cid:173)
`polis, France, 21-15 August 2000"), so that the receiving
`side can detect which coded transport block is concerned or
`which buffered coded transport block the additionally trans- 30
`mitted redundancy refers to when a coded transport block
`affected by error or additional incremental redundancy
`affected by error is received. The redundancy version indi(cid:173)
`cates whether it is a first-time sent incremental redundancy
`or which next incremental redundancy possibly repeated 35
`several times is concerned.
`According to the invention, an abbreviated sequence
`number in lieu of the RLC sequence number is used for the
`transmission of the side information over the radio interface,
`the length of which abbreviated sequence number is clearly
`shorter than the RLC sequence number. This abbreviated
`sequence number is determined by the number of M coded
`transport blocks which, on the receiving side, can at most be
`buffered simultaneously, and consists of [ld M l bits. ([ld
`Ml means the logarithm to the base of 2 rounded to the next
`higher natural number).
`For this purpose, the transmitting physical layer generates
`an abbreviated sequence number from the RLC sequence
`number locally received as side information from the RLC
`layer. The physical layer contains another table or a memory
`which stores the abbreviated sequence number and the RLC
`sequence number, so that an image of the RLC sequence
`number follows the abbreviated sequence number. If the
`physical layer receives from the RLC layer a transport block
`containing side
`information, but all
`the abbreviated
`sequence numbers have already been issued, this transport
`block cannot be transmitted and the RLC layer is to be
`informed of this queue situation. In another case the physical
`layer selects a non-issued abbreviated sequence number,
`writes the relation to the RLC sequence number in the table
`and codes the transport block and sends it as a coded
`transport block with the side information via the radio
`interface. For an incremental redundancy to be sent after(cid:173)
`wards, which relates to this coded transport block, again this
`abbreviated sequence number is taken from the table and
`sent in the side information in parallel with the incremental
`redundancy.
`
`6
`To inform the transmitting side (transmitting terminal or
`radio network controller) of the fact that a transport block
`has not been transmitted error-free, according to the inven(cid:173)
`tion a fast back channel is provided which is inserted directly
`between the receiving physical layer and the sending physi(cid:173)
`cal layer and not between the RLC layers concerned. The
`back channel is built up if a terminal and the radio network
`controller have agreed that data are transmitted according to
`the hybrid ARQ method of type II or III. The receiving
`physical layer checks whether the coded transport block has
`been transmitted correctly. If it has, a positive acknowledge
`signal ACK is sent to the sending physical layer over the
`back channel. Conversely, if the coded transport block has
`not been received error-free, a negative acknowledge com-
`15 mand NACK is sent to the sending physical layer.
`The positive and negative acknowledge commands ACK
`and NACK may each contain the abbreviated sequence
`number of the correctly or erroneously received coded
`transport block. The sending side can also identify the
`20 transmitted transport block affected by error on account of
`the number of a radio frame, which contains the positive or
`negative acknowledge command. The acknowledge com(cid:173)
`mands in a radio frame of the back channel relate to coded
`transport blocks which were transmitted in transmission
`time intervals TTI which ended in a radio frame that
`preceded by exactly F radio frames (with F ~ 1) the radio
`frame containing the acknowledge commands. FIG. 3 shows
`this. A transport time interval TTI indicates the time which
`a transport block lasts and corresponds at least to the length
`of time of one radio frame RF which determines the time
`necessary for the transport blocks to be sent over the radio
`link or radio interface. The numbers of the radio frames are
`generally broadcast to the mobile stations via a broadcast
`channel. In FIG. 3 are shown various transport blocks TBO
`to TB4 which are to be transmitted for the length of time of
`two radio frames RF. The transport block TBO in this
`example is not transmitted according to the hybrid ARQ
`method of type II or III, whereas the other transport blocks
`are to be transmitted indeed according to the hybrid ARQ
`40 methods of type II or III. The announcement about a correct
`or error-affected transmission thus only occurs for the trans(cid:173)
`port blocks TBl to TB4 via a positive or negative acknowl(cid:173)
`edge command over the physical back channel.
`The transmission time interval TTI of the transport blocks
`45 TBl and TB4 is equal to the length of time of a single radio
`frame RF and the transmission time interval TTI of the
`transport blocks TBO, TB2 and TB3 is equal to two radio
`frames RF. A first part of the transport blocks TB2, TB3 and
`TBO and transport block TBl are used for transmitting coded
`50 transport blocks during a first radio frame RF and a second
`part of the transport blocks TB2, TB3 and TBO and transport
`block TB4 during a second subsequent radio frame RF over
`the physical channel PHC. It is assumed that the transport
`blocks TBl, TB2 and TB4 have been received correctly and
`55 the transport block TB3 from a terminal or from the network
`controller. The correct or error-affected reception is checked
`in a radio frame RF which comes after the ended Transmis(cid:173)
`sion Time Interval (TTI) and is announced to the sending
`side (F=2) in the next radio frame RF via the back channel
`60 BC. FIG. 3 shows in the third radio frame RF the positive
`acknowledge command ACK for the transport block TBl
`and in the fourth radio frame RF the positive acknowledge
`command ACK for the transport blocks TB4 and TB2 and
`the negative acknowledge command NACK for the transport
`65 block TB3. No acknowledge command is sent for the
`transport block TBO, because this command is not transmit(cid:173)
`ted according to an ARQ method of type II or III. The
`
`Page 7 of 10
`
`

`

`US 7,075,917 B2
`
`7
`acknowledge commands are sorted in the sequence in which
`the transport blocks have been sent. The acknowledge
`command can, however, also be sent during a later radio
`frame RF. The number F of radio frames RF which occur
`between the reception of a transport block (i.e. after the
`transmission time interval has ended) or a number of trans(cid:173)
`port blocks (i.e. after their transmission time intervals have
`ended, ending all at the same frame boundary) and the
`sending of an acknowledge command should be selected so
`that the receiving side has enough time to decode all 10
`co-transmitted transport blocks and check them for errors.
`The transmission of the transport blocks TBO to TB4 is
`accompanied with data called side information, which con(cid:173)
`tain at least information about the redundancy version and
`about the abbreviated sequence number of a transport block. 15
`This side information is referred to as SI in FIG. 3.
`If a sending side receives a negative acknowledge com(cid:173)
`mand NACK, additional
`incremental
`redundancy
`is
`prompted to be sent. The physical layer that has received the
`negative acknowledge command (NACK) for one or more
`received coded transport blocks affected by errors, deter(cid:173)
`mines the RLC sequence number of the packet data unit
`which the negative acknowledge commands relate to and
`announces to the associated RLC layer the RLC sequence
`numbers of the error-affected packet data units. At the same
`time, the receiving physical layer stores the RLC sequence
`numbers of the packet data units that have been announced
`to be error-affected. The RLC layer then sends each one of
`these packet data units again, as in the case where the
`opposite RLC layer requests to send a packet data unit again
`(hybrid ARQ method type I). The MAC layer generates a
`transport block from the packet data unit, which transport
`block is then transferred with the side information to the
`physical layer. The physical layer compares the RLC
`sequence number contained in the side information with the
`buffered sequence number and recognizes that this transport
`block is to be sent as a repetition of transmission. The
`physical layer generates a coded transport block which
`contains the necessary incremental redundancy and no
`longer the whole coded packet data unit-as defined by the
`hybrid ARQ method type II or III.
`If the physical layer has received a positive acknowledge
`command ACK, it deletes the stored RLC sequence number.
`Via this RLC sequence number the physical layer can also
`acknowledge the correct reception of the packet data unit to
`the associated RLC layer, which RLC layer then deletes the
`packet data unit that has this RLC sequence number from its
`buffer. This is particularly possible in the case of the
`downlink direction, when physical layer and RLC layer are
`not accommodated on separate hardware components in the
`receiving mobile station. On the other hand, it may be more
`favorable forthe sending RLC layer to wait forthe acknowl(cid:173)
`edgement of receipt from the RLC layer on the receiving
`side, because it is still possible for transmission errors to
`occur when the transport block is transferred from the 55
`receiving physical layer to the receiving RLC layer (more
`particularly in the uplink direction, because here the receiv(cid:173)
`ing physical layer and the receiving RLC layer are accom(cid:173)
`modated on different hardware components).
`
`The invention claimed is:
`1. A wireless network comprising a radio network con(cid:173)
`troller and a plurality of assigned to signals, which are each
`provided for exchanging data according to the hybrid ARQ
`method an which form a receiving and/or transmitting side, 65
`in which a physical layer of a transmitting side is arranged
`for
`
`8
`storing coded transport blocks in a memory, which blocks
`contain at least a packet data unit which is delivered by
`an assigned radio link control layer and can be identi(cid:173)
`fied by a packet data unit sequence number,
`storing abbreviated sequence numbers whose length
`depends on the maximum number of coded transport
`blocks to be stored and which can be shown unam(cid:173)
`biguously in a packet data unit sequence number, and
`for
`transmitting coded transport blocks having at least an
`assigned abbreviated sequence number and
`a physical layer of a receiving side is provided for testing
`the correct reception of the coded transport block and
`for sending a positive acknowledge command to the
`transmitting side over a back channel when there is
`correct reception and a negative acknowledge com-
`mand when there is error-affected reception.
`2. A wireless network as claimed in claim 1, characterized
`in that the radio network controller and the assigned termi-
`20 nals are provided for exchanging data according to the
`hybrid ARQ method of type II or III.
`3. A wireless network as claimed in claim 1, characterized
`in that the physical layer of a receiving side is provided for
`sending a positive or negative acknowledge command with
`25 the abbreviate sequence number of the transport block
`received correctly or affected by error.
`4. A wireless network as claimed in claim 1, characterized
`in tat the physical layer of one of a sending side or
`transmitting side, after the reception of a positive or negative
`30 acknowledge command, is provided for determining the
`abbreviated sequence number of the respective coded trans(cid:173)
`port block transmitted correctly or affected by error based on
`the length of time between transmission of the transport
`block and reception of the acknowledge command and the
`35 sending sequence of the ack