(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0123485 A1
`(43) Pub. Date:
`Jul. 3, 2003
`Yi et al.
`
`US 2003.01.23485A1
`
`(54) METHOD FORTRANSMITTING PACKET
`DATA IN COMMUNICATION SYSTEM
`(76) Inventors: Seung-June Yi, Seoul (KR);
`Woon-Young Yeo, Kyungki-Do (KR);
`So-Young Lee, Kyungki-Do (KR)
`Correspondence Address:
`FLESHNER & KIM, LLP
`P.O. BOX 221200
`CHANTILLY, VA 20153 (US)
`(21) Appl. No.:
`10/303,059
`(22) Filed:
`Nov. 25, 2002
`(30)
`Foreign Application Priority Data
`
`Nov. 24, 2001 (KR)....................................... 73640/2001
`Nov. 24, 2001 (KR)....................................... 74774/2001
`Publication Classification
`
`(51) Int. Cl." ........................................................ H04J 3/18
`
`(52) U.S. Cl. ........................... 370/477; 370/521; 370/389
`
`(57)
`
`ABSTRACT
`
`In the preferred embodiment, the transmission of a packet
`with one of full-header or compressed header is determined
`according to the report of a lower layer, and preferably,
`regardless of any request from the receiver. Preferably, the
`determination is done in PDCP layer, and the lower layer is
`RLC layer. In one embodiment, the attachment of a full
`header to a packet is triggered by the RLC report of
`transmission failure of prior packet. In another embodiment,
`one of the trigger of attachment of a full-header to a packet
`is excluded by the RLC report of transmission success of
`prior full-header packet. The transmission of full-header
`packets is preferably controlled based on feedback informa
`tion of a lower layer indicating whether a previously trans
`mitted full-header packet was Successfully received by the
`receiver. The feedback information may be delivered from a
`data link layer Such as an RLC layer to a header compression
`layer, which is preferably included in a PDCP layer.
`
`
`
`Uu
`
`RNL-1
`
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`Patent Application Publication
`
`Jul. 3, 2003 Sheet 1 of 13
`
`US 2003/0123485 A1
`
`FIG 1
`RELATED ART
`
`FULL, HEADER PACKET
`
`COMPRESSED HEADER PACKET
`
`FIG 2
`RELATED ART
`
`DATA
`
`SYSTEM
`
`HEADER COMPRESSION
`CONTROL UNIT
`
`10
`
`:
`
`HEADER
`COMPRESSION UNIT
`14
`
`DATA
`TRANSMISSION UNIT
`
`FULL HEADER OR
`COMPRESSED HEADER
`CONTROL INFORMATION
`PACKET
`Rio------------ 16
`: TRANSMISSION
`BUFFER AND
`CONTROL
`TRANSMISSIONH
`UNIT
`UNIT
`
`DELIVERY TO
`LOWER LAYER
`
`
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`Patent Application Publication
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`Jul. 3, 2003 Sheet 2 of 13
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`US 2003/0123485 A1
`
`FIG 3
`RELATED ART
`
`O
`
`1.
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`CID
`
`FIG. 4
`
`RELATED ART
`
`8 BITS
`
`
`
`
`
`
`
`
`
`
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`Patent Application Publication
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`Jul. 3, 2003. Sheet 3 of 13
`
`US 2003/0123485 A1
`
`FIG 5
`RELATED ART
`
`TRANSMIT FULL
`HEADER PACKET
`
`
`
`TRANSMIT COMPRESSED
`HEADER PACKET
`
`CNT. CNT+ 1
`
`
`
`
`
`
`
`
`
`
`
`INT-INT*2
`
`
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`Patent Application Publication
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`Jul. 3, 2003 Sheet 4 of 13
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`US 2003/0123485 A1
`
`FIG 6
`
`
`
`
`
`– ~~~~ ---- – – – – – – – – – – – – – – + – – – – – – – – – – – – +
`
`UTRAN
`
`
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`Patent Application Publication
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`Jul. 3, 2003 Sheet 5 of 13
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`US 2003/0123485 A1
`
`FIG. 7
`
`CONTROL, PLANE
`
`USER PLANE
`
`RRC
`(THIRD LAYER)
`
`PDCP
`(SECOND LAYER)
`
`PDCP ECF ce
`CP
`2. He is
`r RLC
`RLC
`RLC
`:
`i
`(SECOND LAYER)
`t H LOGICAL CHANNEL
`
`P
`
`Hsi-cid-ce
`
`
`
`O
`
`-
`
`w
`
`MAC
`
`MAC
`
`(SECOND LAYER)
`TRANSPORT CHANNEL
`PHY
`(FIRST LAYER)
`
`
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`Patent Application Publication
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`Jul. 3, 2003 Sheet 6 of 13
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`US 2003/0123485 A1
`
`
`
`
`
`TERMINAL
`
`FIG 8
`
`
`
`UDP/IP
`L2
`Ll L.
`
`FIG 9
`
`32 BITS
`
`- - - - - - - - - - - - - -
`
`-
`
`
`
`
`
`CHECKSUM
`OPTIONS
`
`WINDOW
`
`URGENT POINTER
`PADDING
`
`
`
`
`
`IPv6
`HEADER
`
`TCP
`HEADER
`
`
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`Patent Application Publication
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`Jul. 3, 2003 Sheet 7 of 13
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`US 2003/0123485 A1
`
`FIG 1 OA
`
`32 BITS
`
`VERSION: TRAFFIC CLAS
`ISBOF PACKET
`SEQUENCE NUMBER
`
`PO
`
`OFFSET
`
`UAP RSF
`
`OPTIONS
`
`PADDING
`
`
`
`IPv6
`HEADER
`
`TCP
`HEADER
`
`
`
`
`
`
`
`
`
`
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`Patent Application Publication
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`Jul. 3, 2003 Sheet 8 of 13
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`US 2003/0123485 A1
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`FIG 1 OB
`
`COMPRESSED TOP FORMAT
`
`CID
`R O I P S A. W. U
`
`TCP CHECKSUM
`
`RANDOM FIELDSF ANY
`, I
`R-OCTET
`
`
`
`
`
`IPv4 DENTIFICATION DELTA
`OPTIONS
`
`(if I=1)
`(if O=1)
`
`FIG 1 OC
`
`COMPRESSED TOP NONDELTA FORMAT
`
`RANDOM FIELDS, IF ANY
`WHOLE TCP HEADER EXCEPT FOR PORT NUMBERS
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
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`Patent Application Publication
`
`Jul. 3, 2003 Sheet 9 of 13
`
`US 2003/0123485 A1
`
`FIG 11
`
`H - BS -
`VERSION TRAFFIC CLASS
`FLOWLABEL
`Hop LIMIT
`
`IPv6
`HEADER
`
`DESTINATION ADDRESS:
`
`:SOURCE PORT
`LENGTH
`
`DESTINATION PORT
`CHECKSUM
`
`
`
`UDP
`HEADER
`
`
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`Patent Application Publication
`
`Jul. 3, 2003 Sheet 10 of 13 US 2003/0123485 A1
`
`FIG 12A
`32 BITS
`
`GENERATION
`
`IPv6
`IIEADER
`
`UDP
`HEADER
`
`CHECKSUM
`
`FIG 12 B
`
`COMPRESSED NON-TCP FORMAT,8BIT CID
`
`
`
`
`
`D
`
`CENERATION
`
`
`
`FIG 12C
`
`COMPRESSED NON-TCP FORMAT, 16BIT CID
`
`
`
`MSB OF CID
`
`GENERATION
`
`D
`
`
`
`
`
`
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`Patent Application Publication
`
`Jul. 3, 2003 Sheet 11 of 13 US 2003/0123485 A1
`
`FIG. 13A
`
`
`
`
`
`REPORTNC
`TIME
`
`THE PDCP SEND A FULL
`HEADER PACKET
`
`FULL HEADER PACKET
`
`COMPRESSED HEADER PACKET
`
`IF RLC REPORT THAT THE
`TRANSMISSION OF THIS
`PACKET IS FAILED,
`
`FIG 13B
`
`THE PDCP DOES NOT SEND
`A FULL HEADER PACKET
`
`
`
`IF RLC REPORT THAT THE TRANSMISSION
`OF THIS PACKET IS FAILED,
`THE PDCP SEND A FULL
`HEADER PACKET
`
`
`
`RECEIVING RLC REPORT
`AT THIS TIME
`IF RLC REPORT THAT THE TRANSMISSION
`OF THIS PACKET IS SUCCESSFUL,
`RECEIVING RLC REPORT
`AT THIS TIME
`FIG 13C
`
`PACKET--PACKET ID+Discard Req+?
`
`
`
`
`
`
`
`
`
`
`
`
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`Patent Application Publication
`
`Jul. 3, 2003. Sheet 12 of 13 US 2003/0123485 A1
`
`FIG 14.
`
`DATA
`
`SYSTEM
`
`
`
`HEADER COMPRESSION
`CONTROL UNIT
`
`1.
`O
`
`HEADER
`COMPRESSION UNIT
`14
`
`FULL HEADER OR
`COMPRESSED HEADER
`PACKET
`
`TRANSMISSION
`CONTROL
`UNIT
`
`BUFFER AND
`TRANSMISSION
`UNIT
`
`DELIVERY TO
`LOWER LAYER
`
`TRANSMISSION FAILURE
`DISCRIMINATING UNIT
`
`CONTROL/
`STATUS PDU
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
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`Patent Application Publication
`
`Jul. 3, 2003. Sheet 13 of 13 US 2003/0123485 A1
`
`FIG 15
`
`TRANSMIT FULL
`HEADER PACKET
`
`S90
`
`CNT- O
`
`S91
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`S98
`
`YES
`
`IS
`TRANSMISSION OF
`FUII, HEADER PACKET IS
`SUCCESSFUL 2
`
`
`
`
`
`
`
`TRANSMISSION OF FULL
`HEADER PACKET IS
`SUCCESSFUL
`
`STOP CNT OPERATION - - S99
`
`NO
`
`INT-INT+ 2 - S97
`
`TRANSMIT COMPRESSED - s100
`HEADER PACKET
`
`S101
`
`
`
`DOES ANY
`ADDITIONAL PACKET
`EXIST
`
`NO
`
`END
`
`
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`US 2003/O123485 A1
`
`Jul. 3, 2003
`
`METHOD FORTRANSMITTING PACKET DATA
`IN COMMUNICATION SYSTEM
`
`BACKGROUND OF THE INVENTION
`0001) 1. Field of the Invention
`0002 The present invention generally relates to the trans
`mission of packet data in a communications System, and
`more particularly to a System and method for Sending packet
`data which includes header information.
`0003 2. Background of the Related Art
`0004 AS mobile communications technology continues
`to evolve, wireleSS phone Sets are expected to become more
`widely used than standard wired telephone sets. Wired sets,
`however, remain the terminal of choice for Some applica
`tions. For example, radio mobile communications technol
`ogy significantly lags behind the performance of existing
`wired communications Systems when it comes to transmit
`ting large amounts of data and Voice traffic between termi
`nals. Several wireleSS communications Standards have been
`proposed to address this problem. One Standard called
`IMT-2000 allows large amounts of data to be communicated
`between terminals and therefore has been promoted in many
`countries. In fact, international cooperation is currently
`underway for developing a single Standard for this technol
`Ogy.
`0005 Recently, this cooperative effort has resulted in an
`initiative known as the third generation partnership project
`(3GPP). The 3GPP initiative has been established for the
`purpose of Standardizing, among other things, a third-gen
`eration IMT-2000 system based on a communications plat
`form adopted in Europe. The Standard, known as the uni
`versal mobile telecommunications system (UMTS), has
`received contributions from a variety of national, interna
`tional, and local Standardization institutions Such as TTA in
`Korea, CWTS in China, T1 in the U.S.A., and ARIB/TTC in
`Japan.
`0006. The UMTS adopts a wideband code division mul
`tiple access (WCDMA) technique as a radio access network
`technique, and is being developed to include a general
`packet radio Service (GPRS) based on a packet-Switching
`network and a global System for a mobile communication
`(GSM) based on a circuit switching network. UMTS is also
`being developed to provide multimedia Services Such as
`Voice, image and data.
`0007. The 3GPP project includes five technical specifi
`cation groups (TSG) each of which handles development,
`approval and management of the Standard in a related field.
`0008. The radio access network (RAN) group (TSG
`RAN) manages the development of functional requirements
`and a Standard for an interface between wireless terminals
`and a UMTS terrestrial radio access network (UTRAN). The
`core network (CN) group (TSG-CN) manages the develop
`ment of the functions of the core network, and the require
`ments and the Standard of an interface which allows the
`UTRAN to access a circuit-switching backbone network or
`a packet-Switching backbone network.
`0009. The full-header plays a critical role in the header
`compression technique of the related art packet-Switching
`backbone network. If the full-header is not transmitted
`properly, every packet received thereafter cannot be decom
`
`pressed and is discarded. In order to Solve this problem when
`a non-TCP protocol such as UDP/IP is used, the related art
`System requires a transmitting party to transmit a full-header
`packet that can be used to construct a context to the
`receiving party multiple times within the same data Stream
`according to certain regulations.
`0010. In the Compressed non-TCP compression tech
`nique, that is, the header compression technique used for the
`UDP/IP protocol, a full-header packet is transmitted at least
`once in each exponentially increasing period, which is called
`compression slow-start (CSS). According to the CSS
`method, if the full-header information is changed or a fresh
`header compression technique is applied, the transmission
`interval for the same full-header is shortened at an initial
`Stage and then gradually increased thereafter.
`0011 FIG. 1 is a diagram showing a transmission inter
`vals for transmitting full-header information in accordance
`with the CSS method. As shown, the transmission intervals
`for the full-header packet increase exponentially, and the
`number of compressed header packets transmitted between
`neighboring full-header packets (i.e., within each interval) is
`increased by 1, 2, 4, 8, . . . The transmission interval is not
`infinitely increased but maintained at the same interval when
`it reaches a transmission interval threshold value, which is
`usually set by 256. For reference, the full-headers transmit
`ted by the CSS method have the same CID (context iden
`tifier) value and generation number. That is, the full-header
`packet is transmitted in an exponential period for a packet
`Stream with the same CID and generation value.
`0012 AS previously discussed, if a header compression
`technique is used, the header size of the packet can be
`considerably reduced. Especially, in the case where a normal
`packet is transmitted through a radio interface, Since the
`header of the packet is too big to be neglected compared
`with the payload size (a data portion of the packet), the
`header needs to be compressed.
`0013 FIG. 2 is a block diagram of a packet transmission
`System of the related art which uses a header compression
`technique. The System includes a header compression unit
`10, provided in the PDCP layer, which compresses a header
`of data received from an upper layer under control of a
`header compression control unit 12. The full-header packet
`or the compressed header packet converted by the header
`compression unit 10 is delivered to the RLC layer through
`a data transmission unit 14. A buffer and transmission unit
`16 of the RLC layer stores the full-header packet or the
`compressed header packet received from the data transmis
`sion unit 14 of the PDCP and/or transmits it to a receiving
`party.
`0014 Operation of the system will now be explained.
`First, in a case of using Compressed TCP as the header
`compression technique, a transmitting party first transmits a
`full-header packet for a packet Stream to construct a context
`at a receiving party. One or more compressed headers are
`then transmitted indicating differences between Successive
`packets.
`0015 If the full-header packet is not successfully trans
`mitted from the transmitting party, Since the context is not
`properly constructed at the receiving party, the receiving
`party fails to restore Subsequently received compressed
`headers. In addition, even in the case where a compressed
`
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`
`Jul. 3, 2003
`
`header packet is Successfully transmitted, Since the context
`of the receiving party is not properly updated, the following
`compressed headers cannot be restored, just as in the case
`where the full-header packet is lost. Since the damaged
`context can be recovered only by receiving a new full
`header of a corresponding context, the receiving party
`transmits a context-State packet requesting transmission of a
`new full-header of the corresponding context from the
`transmitting party.
`0016 FIG. 3 shows a structure of a context-state packet
`in accordance with the related art. This packet includes a
`plurality of CID fields, each of which Signifies one damaged
`context, that is, one damaged packet Stream. Such a context
`State packet is not used whenever one context is damaged,
`but is transmitted to the transmitting party when more than
`a predetermined number of contexts are damaged. In addi
`tion, transmission of the context-state packet itself from the
`receiving party to the transmitting party wastes radio
`resources, So that its frequency of use is limited in RFC
`2507.
`0.017. In transmitting packet data using the Compressed
`TCP header compression technique, if a full-header packet
`or a compressed header packet is lost, it takes a large amount
`of time to restore a corresponding context by the receiving
`party. Moreover, the transmitting party is not aware that the
`corresponding context has been damaged. Thus, the follow
`ing compressed header packets are uselessly transmitted,
`which results in wasting radio resources.
`0018 FIG. 4 shows a structure of a compressed header
`used in a UDP/IP protocol. As previously discussed, in
`performing UDP/IP header compression, the generation
`value of corresponding header information as well as the
`CID value is used to discriminate packet Streams. Thus, the
`compressed header only contains the CID field, the genera
`tion field, and the checksum field and as a result has a total
`length of about 4-5 octets.
`0019. In the compressed header of FIG. 4, if an 8bit CID
`is used, CID(2) positioned at the third octet is not necessary.
`If a 16 bit CID is used, 8 bits are allocated to CID(1) and the
`other 8 bits are allocated to CID(2). Considering that the size
`of a full-header is 48 octets, it is noted that the Same purpose
`can be achieved by transmitting a very Small amount.
`0020. In transmitting packet data using the Compressed
`TCP header compression technique following the TCP/IP
`Header Compression Algorithm (RFC 2507 Compressed
`TCP), a full-header packet is transmitted at the first packet
`of a packet Stream. The following packets are transmitted
`with compressed header containing the variance from pre
`viously transmitted headers of a packet Stream. The context
`of the packet Stream is continuously updated with the
`compressed header in the reference of previously received
`packet headers.
`0021. In transmitting packet data using another Com
`pressed TCP header compression technique following the
`TCP/IP Header Compression Algorithm (RFC 2507 Com
`pressed TCP nondelta), a full-header packet is transmitted at
`the first packet of a packet Stream. The following packets are
`transmitted with compressed header containing the variance
`from previously transmitted full header of the packet Stream.
`The context of the packet Stream is continuously updated
`with the compressed header in the reference of previously
`received full header.
`
`0022. In transmitting packet data using UDP/IP Header
`Compression Algorithm (Compressed non-TCP, Compres
`sion Slow-Start, hereinafter referred to CSS), full-header
`packets are transmitted at the first packet and Some of
`following packets of a packet Stream in a predetermined
`rule. FIG. 5 is a flow chart of a related art method for
`transmitting a full-header packet and a compressed header
`packet according to the CSS method. In this figure, an INT
`(Interval) value indicates the number of compressed header
`packets that can be transmitted between two consecutively
`transmitted full-header packets, and a CNT (Count) value
`indicates the number of transmitted compressed header
`packets.
`0023. According to this method, a compressed header
`packet is transmitted, and when the CNT value and the INT
`value become the Same, the full-header packet is transmitted
`instead of the compressed header packet. The INT value is
`updated at the time when the full-header is to be transmitted.
`When the INT value reaches a MaxINT, which corresponds
`to a transmission interval threshold value, the INT value is
`no longer increased and the MaxINT is maintained. The
`process is terminated when all data in a packet Stream are
`transmitted or when the full-header information is changed.
`The transmission method will now be described in greater
`detail.
`0024 First, the minimum number (INT) of compressed
`header packets that can be transmitted between the full
`header packetS is Set to an initial value of 1.
`0025. When a header packet transmission operation is
`initiated, the full-header packet is first transmitted (S80), and
`then the CNT indicating the number of the transmitted
`compressed header packets is initialized to a value of 0
`(CNT=0) (S81). Next, the compressed header packet is
`transmitted (S82) and then the CNT indicating the number
`of transmitted compressed header packets is increased by 1
`(CNT=CNT+1) (S83).
`0026. Next, the INT value and the CNT value are com
`pared (S84), and if the two values are different a compressed
`header packet is additionally transmitted and steps S82-S84
`are repeatedly performed. If the two values are the same, it
`is checked whether the INT value is greater than the Max
`INT (in the present invention, MaxINT=256) (S85). If the
`INT value is smaller than the MaxINT, steps S80-S85 are
`repeatedly performed while increasing the INT value by the
`unit of multiple of 2 (1, 2, 4, 8, 16,..., 256). If, however,
`the INT value is the same or greater than the MaxINT value,
`the INT value is no longer increased and the same trans
`mission interval is maintained.
`0027 Transmitting full-header packets using the CSS
`method of the related art is advantageous in at least two
`respects. First, even if the full-header packet is lost during
`transmission, the compressed header can be recovered by
`using the next-transmitted full-header packet. Second, in the
`case where the Same packet is broadcast to Several users
`through a multicast technique, even if a new user is con
`nected in the course of broadcasting, the new user can
`receive data normally after receiving the full-header packet
`(e.g., the new user can receive compressed packets and then
`recover them based on information in a next-transmitted
`full-header packet). These advantages lend a measure of
`stability to the system.
`0028. In spite of these advantages, the CSS method of the
`related art has a number of drawbacks. For example, Since
`
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`Jul. 3, 2003
`
`the full-header is much larger than the compressed header,
`repeated transmission of a considerable number of full
`header packets within a Same data Stream Substantially
`degrades transmission efficiency. This is especially true if
`the full-header packet is Successfully transmitted at the
`initial Stage. Under these circumstances, the related art
`method will continue to intermittently transmit full-header
`packets in the data System even though the initial full-header
`packet was Successfully transmitted. AS will become more
`apparent below, the Inventors of the present invention have
`determined that every full-header packet transmitted after an
`initial full-header packet has been Successfully received may
`be considered to be an unnecessarily transmitted one.
`0029. The Compressed TCP header compression tech
`nique following the TCP/IP Header Compression Algorithm
`of the related art also has a number of drawbacks. For
`example, the context of a packet of compressed header is
`recovered in the reference of the full-header directly or
`indirectly. If, one of the headers of a packet in a Stream is not
`received Successfully or the full-header is not received
`Successfully, Several packets following that packet could not
`be recovered for a time being. That is, the transmission of
`packet data using the Compressed TCP header compression
`technique, if a full-header packet or a compressed header
`packet is lost, it takes a large amount of time to restore a
`corresponding context by the receiving party. Moreover, the
`transmitting party is not aware that the corresponding con
`text has been damaged. Thus, the following compressed
`header packets are uselessly transmitted, which results in
`Wasting radio resources. If the receiver transmits the request
`of Sending a full-header packet to the transmitter immedi
`ately, the traffic load for the request might be a burden to the
`radio channel.
`
`SUMMARY OF THE INVENTION
`0.030. An object of the invention is to solve at least the
`above problems and/or disadvantages and to provide at least
`the advantages described hereinafter.
`0031. It is another object of the present invention to
`achieve the aforementioned object by providing a System
`and method which controls the transmission of packets in a
`communications System in a manner which is faster and
`more efficient than other systems/methods which have been
`proposed.
`0032. It is another object of the present invention is to
`achieve the aforementioned object by Substantially increas
`ing the efficiency of recovering the context of the header
`information and the packets transmitted in the System while
`at the same time decreasing the request of Sending a full
`header packet to the transmitter in any given data Stream
`compared with other proposed Systems.
`0033. It is another object of the present invention to
`achieve the aforementioned object using an improved header
`compression Scheme which optimizes the transmission of
`full-header packets and minimizes the number of request of
`Sending a full-header packet in any given data Stream,
`thereby improving transmission efficiency compared with
`other proposed Systems.
`0034.
`It is another object of the present invention is to
`achieve the aforementioned object by Substantially decreas
`ing the number full-header packets transmitted in the System
`
`while at the Same time increasing the number of compressed
`header packets in any given data Stream compared with
`other proposed Systems.
`0035) It is another object of the present invention to
`achieve the aforementioned object using an improved header
`compression Scheme which minimizes the number of full
`header packets and maximizes the number of compressed
`header packets transmitted in any given data Stream, thereby
`improving transmission efficiency compared with other pro
`posed Systems.
`0036. It is another object of the present invention is to
`provide a packet data transmitting System method which
`improves a transmission efficiency and decompression effi
`ciency of a packet when a Compressed TCP compression
`technique is used in a UMTS system.
`0037. It is another object of the present invention is to
`provide a packet data transmitting method in which, when a
`full-header packet of a Specific packet Stream is repeatedly
`transmitted periodically or non-periodically, transmission of
`the full-header packet is controlled to thereby increase a
`transmission efficiency.
`0038. To achieve these and other objects and advantages,
`there is provided a packet data transmitting method of a
`communication System in which, with respect to one packet
`Stream, a header compression layer of a transmitting party
`determines the transmission of a full-header packet with a
`full-header or a compressed header packet with a com
`pressed header through a data link layer in the reference of
`the transmission status of the previous data packet in the data
`link layer.
`0039. In the packet data transmitting method of the
`present invention, preferably, in the header compression
`layer of a communication System transmitting party includ
`ing the Steps of receiving a packet data Stream from upper
`layer; transmitting a full-header packet having full-header
`information of the packet data Stream through a lower layer;
`transmitting a compressed header packet having a com
`pressed header holding a portion of the full-header infor
`mation through the lower layer, detecting the packet has
`been received by the receiving party with the report of the
`lower layer; and transmitting a packet to be transmitted as a
`full-header packet if it is detected that the packet has not
`been received.
`0040. In the packet data transmitting method of the
`present invention, preferably, in the detecting Step includes
`Steps of detecting whether a data link layer detects a packet
`transmission failure; and receiving the detected transmission
`failure information from the data link layer.
`0041. In the packet data transmitting method of the
`present invention, preferably, the transmission failure infor
`mation contains ID information and/or transmission failure
`indicating information of the corresponding packet.
`0042. In the packet data transmitting method of the
`present invention, preferably, the predetermined compres
`Sion method is that a context is updated by the header of
`present packet in the reference of the previous packet header
`Successively updated from the full-header.
`0043. In the packet data transmitting method of the
`present invention, preferably, the compression method
`updated with the header of present packet in the reference of
`
`
`Ex.1012 / Page 17 of 30Ex.1012 / Page 17 of 30
`
`TESLA, INC.TESLA, INC.
`
`

`

`US 2003/O123485 A1
`
`Jul. 3, 2003
`
`the previous packet header Successively updated from the
`full-header is a Compressed TCP technique.
`0044) In the packet data transmitting method of the
`present invention, preferably, the predetermined compres
`Sion method is that a context is updated by the header of
`present packet in the reference of the previous full-header.
`0.045. In the packet data transmitting method of the
`present invention, preferably, the compression method that a
`context is updated with the full-header packet is a Com
`pressed TCP nondelta technique.
`0046. In the packet data transmitting method of the
`present invention, preferably, the header compression layer
`is a packet data convergence protocol (PDCP) layer and the
`data link layer is a radio link control (RLC) layer.
`0047. In the packet data transmitting method of the
`present invention, preferably, an upper layer at the control
`plane of the RLC layer is an RRC layer which manages a
`radio resource, and the RRC layer Sets a radio bearer Such
`that information of an SDU discarded from the RLC is
`provided to the PDCP layer.
`0.048. In the packet data transmitting method of the
`present invention, preferably, when the PDCP layer delivers
`a PDCPPDU to the RLC layer, the PDCP layer instructs the
`RLC layer to inform the PDCP layer about a transmission
`failure result on the corresponding PDU.
`0049. In the packet data transmitting method of the
`present invention, preferably, when the PDCP layer delivers
`the PDCP PDU to the RLC layer, the PDCP layer transmits
`a transmission failure report indicator together with the
`corresponding PDU.
`0050. To achieve these and other objects and advantages,
`there is provided a packet data transmitting method of a
`communication System in which, with respect to one packet
`Stream, a header compression layer of a transmitting party
`transmits a full-header packet with a full-header or a com
`pressed header packet with a compressed header through a
`data link layer and a header compression layer of a receiving
`party recovers compressed header information of the com
`pressed header packet by using full-header information of
`the full-header packet, including the Steps of receiving a
`packet data Stream using an Internet protocol; transmitting a
`full-header packet having full-header information of the
`packet data Stream; transmitting a compressed header packet
`having a compressed header holding a portion of the full
`header information; detecting whether the packet has been
`received by the receiving party; and transmitting a packet to
`be transmitted the very next as a full-header packet if it is
`detected that the packet has not been received.
`0051. In the packet data transmitting method of the
`present invention, preferably, the detecting Step includes
`Steps of detecting whether a data link layer detects a packet
`transmission failure; and delivering the detected transmis
`Sion failure information to the header compression layer.
`0.052
`In the packet data transmitting method of the
`present invention, preferably, the transmission failure infor
`mation contains ID information and/or transmission failure
`indicating information of the corresponding packet.
`0053. In the packet data transmitting method of the
`present invention, preferably, the predetermined compres
`
`Sion method is that a context is updated by the header of
`present packet in the reference of the previous packet header
`Successively updated from the full-header.
`0054.
`In the packet data transmitting method of the
`present invention, preferably, the compression method
`updated with the header of present packet in the reference of
`the previous packet header Successively updated from the
`full-header is a Compressed TCP technique.
`0055. In the packet data transmitting method of the
`present invention, preferably, the predetermined compres
`Sion method is that a context is updated by the header of
`present packet in the reference of the previous full-header.
`0056. In the packet data transmitting method of the
`present invention, preferably, the compression method that a
`context is updated with the full-header packet is a Com
`pressed TCP nondelta technique.
`0057 The packet data transmitting method of the present
`invention, preferably, further includes a step of delivering a
`fresh full-header packet to the transmitting party of the data
`link layer if the transmission failure information is received
`from the data link layer.
`0058. In the packet data transmitting method of the
`present invention, preferably, when the header compression
`layer receives the transmission failure information, the
`header compression layer compresses a following first
`packet using the same CID with the transmission-failed
`packet to a full-header packet and transmits it.
`0059. In the packet data transmitting