Apple Inc. v. Samsung Electronics Co. Ltd. et al

Filing 662

EXHIBITS re #660 Administrative Motion to File Under Seal Apple Inc.'s Notice of Motion and Motion for Partial Summary Judgment Exhibits to Mueller Declaration ISO Apple's Motion for Partial Summary Judgment [660-9] filed byApple Inc.(a California corporation). (Attachments: #1 Exhibit Mueller Decl Exhibit 26, #2 Exhibit Mueller Decl Exhibit 27, #3 Exhibit Mueller Decl Exhibit 28, #4 Exhibit Mueller Decl Exhibit 29, #5 Exhibit Mueller Decl Exhibit 30, #6 Exhibit Mueller Decl Exhibit 31, #7 Exhibit Mueller Decl Exhibit 32, #8 Exhibit Mueller Decl Exhibit 33, #9 Exhibit Mueller Decl Exhibit 34, #10 Exhibit Mueller Decl Exhibit 35, #11 Exhibit Mueller Decl Exhibit 36, #12 Exhibit Mueller Decl Exhibit 37, #13 Exhibit Mueller Decl Exhibit 38, #14 Exhibit Mueller Decl Exhibit 39, #15 Exhibit Mueller Decl Exhibit 40, #16 Exhibit Mueller Decl Exhibit 41)(Related document(s) #660 ) (Selwyn, Mark) (Filed on 1/25/2012)

Mueller Exhibit 25

US007675941B2

(12) United States Patent

(lO) Patent No.:
US 7,675,941 B2
(45) Date of Patent:
Mar. 9, 2010

Kim et al.
(54)

(75)

METHOD AND APPARATUS FOR
TRANSMITTING/RECEIVING PACKET DATA
USING PRE-DEFINED LENGTH INDICATOR
IN A MOBILE COMMUNICATION SYSTEM

2002/0041567 A1
2002/0048281 A1
2002/0174276 A1 *
2004/0160937 A1 *
2006/0072494 A1 *

Inventors: Soeng-Hun Kim, Suwon-si (KR);

(73) Assignee:

Samsung Electronics Co., Ltd.,
Suwon-Si (KR)

(*) Notice:

Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 908 days.

(21) Appl. No.: 11/417,219
Filed:

(65)

May 4, 2006

(KR) ...................... 10-2005-0037774

(51) Int. Cl.
¯ I04J 3/DO
(2006.01 )
(52) U.S. CI ......................... 3701473; 370/474; 370/329
(58) Field of Classification Search ................. 370/281,
370/295,344, 252, 349, 470, 474, 469
See application file for complete search history.
(56)

References Cited
U.S. PATENT DOCUMENTS

2002/0001314 A1 *
2002/0024972 A1

1/2002 Yi et al .......................
2/2002 Yi et al.

1 276 282 A
2204215
WO 00/21253
WO021253

1/2003
5/2003
4/2000
4/2000

OTHER PUBLICATIONS
"Universal Mobile Telecommunications System (UMTS); Radio
Link Control (RLC) protocol specification (3GPP TS 25.322 version
6.3.0 Release 6); ETSI TS 125 322" ETSI Standards, European
Telecommunications Standards Institute, Sophia-Antipo, FR, vol.
3-R2, No. V630, Mar. 2005, XP014027660; ISSN: 0000-0001; sections 11.1.2.2 and 11.2.2.2.

Primary Examine~Ricky Ngo
Assistant Examiner David Oveissi
(74) Attorney, Agent, or Firm Roylance, Abrams, Berdo &
Goodman, LLP

Foreign Application Priority Data

May 4, 2005

EP
RU
WO
WO

* cited by examiner

Prior Publication Data
US 2007/0060139 A1 Mar. 15, 2007

(30)

710/105
370/349
370/328

FOREIGN PATENT DOCUMENTS

Gert-Jan Van Lieshout, Middlesex
(GB); Himke Van Der Velde, Middlesex
(GB)

(22)

4/2002 Yi et al.
4/2002 Yi et al.
11/2002 Jiang ..........................
8/2004 Jiang ..........................
4/2006 Matusz .......................

(57)

ABSTRACT

A method and apparatus for enabling efficient use of radio
resources by reducing an RLC PDU size in a mobile communication system supporting voice service over a packet network are provided. An RLC layer constructs an RLC PDU
without inserting information indicating the start and end of
an SDU or indicating the use or non-use of padding. The RLC
layer sets an LI in a header to indicate inclusion of an intermediate SDU segment in the data field of the RLC PDU.
Therefore, the resulting decrease of overhead arising from
packet transmission facilitates the efficient use of limited
radio resources.

370/469

18 Claims, 9 Drawing Sheets

415

425 ----

DATA FIELD

430 --"

APLNDC-WH-A 0000018762

RNC

!

123 --~

PDCP

122~
121

RLC
MAC/PHY

120

I4O

-.1t

NODE Bi~ 110

105 ---104 ---103 ---102 ---101 ---

CODEC
IP/UDP/RTP
PDCP

O0

RLC
MAC/PHY

FIG.1
(CONVENTIONAL ART)

U.S. Patent

Mar. 9, 2010

US 7,675,941 B2

Sheet 2 of 9

TRANSMITTER
HIGHER LAYER
RLC LAYER
LOWER LAYER
RADIO CHANNEL

t._205

F 210
F 215
I

FIG..2A
(CONVENTIONAL ART)

I
I
I
I

RECEIVER
HIGHER LAYER

,.t,
RLC LAYER

f
LOWER LAYER

F 207
L 212
~-- 217

f
RADIO CHANNEL I

FIG.2B
(CONVENTIONAL ART)

APLNDC-WH-A 0000018764

RLC SDU
IP PACKET
I\

I\
I \
I
\
I

\\\

RLC PDU
230

~,-240

SEQUENCE NUMBER
LI

DATA FIELD

FIG.2C
(CONVENTIONAL ART)

E
E

U.S. Patent

Mar. 9, 2010

Sheet 4 of 9

US 7,675,941 B2

315 -320
325 -RLC SDU = 35 byte

DATA FIELD : RLC SDU

FIG.3
{CONVENTIONAL ART}

425 ---"

DATA FIELD

430 ----

FIG.4

APLNDC-WH-A 0000018766

U.S. Patent

Mar. 9, 2010

Sheet 5 of 9

US 7,675,941 B2

SN

DATA PART = RLC SDU

FIG.5A

DATA PART

FIG.5B
APLNDC-WH-A 0000018767

U.S. Patent

Mar. 9, 2010

Sheet 6 of 9

US 7,675,941 B2

605
RLC SDU

610

s, =x ~i~i~

615

SN =x+l 1~,o,~

LI = 1111 100

FIRST SEGMENT

INTERMEDIATE SEGMENT

620
SN =x+2 ~.1,~
LI = e.g. 0100 010

LAST SEGMENT

FIG.6A
625
RLC SDU

630

635

640

SN = x
LI = 0000 000

SN =x+l ~11"~.
LI = new predefined value

LI = e.g.0100 011

FIRST SEGMENT

INTERMEDIATE SEGMENT

LAST SEGMENT

FIG.6B

APLNDC-WH-A 0000018768

U.S. Patent

Mar. 9, 2010

US 7,675,941 B2

Sheet 7 of 9

START)
IRECEIVE RLC SDU

~-705

INFORM LOWER LAYER |
OF SIZE AND NUMBER OF
RLC SDUs

~

710

715

~YES
SET F = 0

L725

SETF= 1

/

INSERT SDU INTO DATA FIELD
|
OF RLC PDU WITHOUT LI ~730
SEND RLC PDU TO
LOWER LAYER

|
~735

INSERT PRE-DEFINED LI

SEND RLC PDU TO LOWER LAYER h750

I

/

FIG.7

APLNDC-WH-A 0000018769

~- START ~)
RECEIVE RLC PDU

F 805
STORE RLC PDU
ACCORDING TO SN

II
~

~YES
RLC PDU INCLUDES
INTERMEDIATE SEGMENT

~

.]
"]

"*
FORWARD RLC SDU TO
HIGHER LAYER

815

~

850

820

~NO

~

830

yE£835 N°

REASSEMBLE RLC SDU
BASED ON LIE AND SN

FIG.8

~

840

WAIT FOR NEXT RLC PDU

F845

U.S. Patent

Mar. 9, 2010

US 7,675,941 B2

Sheet 9 of 9

/905

/930
PDU SIZE
CONTROLLER

ITRANSMISSION
BUFFER ~
/-925

~ .~9~°

F SETTER

RLC’HEADER i
INSERTER

/920
TRANSMISSION I1_,
PART

I

~ /915
I LIINSERTERI

FIG.9

REASSEMBLER

1010
RLC HEAOER
AND LI
REMOVER
025
REASSEMBLY
CONTROLLER

1015
RECEPTION
BUFFER
1020
RECEPTION
PART

FIG.10
APLNDC-WH-A 0000018771

US 7,675,941 B2
1

2

METHOD AND APPARATUS FOR
TRANSMITTING/RECEIVING PACKET DATA
USING PRE-DEFINED LENGTH INDICATOR
IN A MOBILE COMMUNICATION SYSTEM

and sending it to a Core Network (CN) 130. The IP/UDP/RTP
packet is sent to the other party, for example, a receiving UE
(not shown) via an IP network 140. The receiving UE a layer
structure analogous to that of the transmitting UE 100 and
recovers the original voice signal by processing the IP/UDP/
PRIORITY
RTP packet in the reverse order. The RLC layers 102 and 122
function as follows.
This application claims the benefit 35 U.S.C. § 119(a) of
In general, the RLC layer works in Unacknowledged Mode
Korean Patent Application filed in the Korean Intellectual
(UM), Acknowledged Mode (AM), or Transparent Mode
Property Office on May 4, 2005 and assigned Serial No. 10 (TM). VoIP operates in the RLC UM.
2005-37774, the entire disclosure of which is hereby incorIn the transmitter, the RLC UM layer segments, concatporated by reference.
enates, or pads RLC Service Data Units (SDUs) received
from a higher layer to a size suitable for transmission on a
BACKGROUND OF THE INVENTION
radio channel. The RLC UM layer constructs an RLC PDU
15 suitable for transmission on the radio channel by inserting
1. Field of the Invention
segmentation!concatenation!padding information and a
The present invention relates generally to a mobile comsequence number into the resulting data and provides the
munication system supporting packet service. More particuRLC PDU to a lower layer.
larly, the present invention relates to a method and apparatus
In the receiver, the RLC UM layer recovers data by interwhich efficiently use radio resources by reducing the header 2o preting the sequence number and segmentation!concatenasize of a Protocol Data Unit (PDU) to be transmitted on a
tion/padding information of an RLC PDU received from a
radio link.
lower layer and re-constructs an RLC SDU by concatenating
2. Description of the Related Art
or segmenting the data, in correspondence with the operation
Today’s mobile communication systems are evolving
of the transmitter. The reconstructed RLC SDU is provided to
toward high-speed and high-quality wireless data packet 25 a higher layer. Processing an RLC SDU received from the
communication systems. These systems are capable of prohigher layer to a size suitable for transmission on a radio
viding data service and multimedia service in addition to the
channel is called ’RLC framing’.
traditional voice service. A 3rd generation mobile communiFIG. 2A illustrates conventional RLC framing in a transcation system using Wideband Code Division Multiple
mitter.
Access (WCDMA) based on the European Global System for 30
In FIG. 2, an RLC layer 210 frames data received from a
Mobile communications (GSM) system and General Packet
higher layer 205 to a suitable data size for transmission on a
Radio Services (GPRS), Universal Mobile Telecommunicaradio channel. A lower layer 215 sends the framed data to a
tion Service (UMTS) provides mobile subscribers or comreceiver on the radio channel. The higher layer 205 correputer users with a uniform service of transmitting packetsponds to a PDCP layer and the lower layer 215 corresponds
based text, digitized voice, and video and multimedia data at 35 to a MAC layer. The data exchanged between the RLC layer
or above 2 Mbps regardless of their locations around the
210 and the higher layer 205 is an ’RLC SDU’ and the data
world. With the introduction of the concept of virtual access,
exchanged between the RLC layer 210 and the lower layer
the UMTS system allows access to any end point within a
215 is an ’RLC PDU’.
network all the time. The virtual access refers to packetFIG. 2B illustrates conventional RLC framing in a receiver.
switched access using a packet protocol like Internet Protocol 4o
Referring to FIG. 2B, an RLC layer 212 recovers the origi(IP).
nal data from data received from a lower layer 217 and proRegarding voice service, a standardization organization for vides the recovered data to a higher layer 207. The higher
UMTS, 3rd Generation Partnership Project (3GPP) is dislayer 207 corresponds to a PDCP layer and the lower layer
cussing Voice over IP (VoIP). VoIP is a technology for send217 corresponds to a MAC layer. The data exchanged
ing a voice frame generated from an audio Coder and Decoder 45between the RLC layer 212 and the higher layer 207 is an
(CODEC) in the form of an IP/User Datagram Protocol
’RLC SDU’ and the data exchanged between the RLC layer
(UDP)/Real-time Transport Protocol (RTP) packet. VoIP
212 and the lower layer 217 is an ’RLC PDU’.
facilitates the provision of voice service over a packet netFIG. 2C illustrates a conventional operation for constructwork.
ing RLC PDUs by framing ofRLC SDUs in the RLC layer of
EIG. 1 illustrates the configuration of a typical mobile 5o the transmitter.
communication system supporting VoIE
With reference to FIG. 2C, the RLC layer of the transmitter
Referring to EIG. 1, a User Equipment (UE) 100 includes
receives an RLC SDU 225 of a particular size, for example, a
a CODEC 105 for converting a voice signal to a voice frame,
100-byte IP packet from the higher layer. If a data size transan IP/UDP/RTP layer 104 for converting the voice frame to an
mittable on a radio channel is 40 bytes, the RLC layer segIP/UDP/RTP frame, a Packet Data Convergence Protocol 55 ments the RLC SDU 225 into three RLC PDUs 230, 235 and
(PDCP) layer 103 for compressing the header of the IP/UDP/
240. Each RLC PDU may have 40 bytes. Each RLC PDU also
RTP packet, a Radio Link Control (RLC) layer 102 for conincludes an RLC header 245.
verting the header-compressed IP/UDP/RTP packet to be
The RLC header 245 includes a Sequence Number (SN)
suitable for transmission on a radio channel, and a Medium
250, an E field 255, and at least one of a plurality of pairs of
Access Control (MAC)/Physical (PHY) layer 101 for sending 6o Length Indicator (LI) field 260 and E field 265. The LI field
the output of the RLC layer 102 on the radio channel.
260 is included according to segmentation. The SN field 250
Radio data from the UE 100 is delivered to a Radio Netindicates a 7-bit SN which increases monotonously by 1 for
work Controller (RNC) 120 via the PHY layer (not shown) of
every RLC PDU. SNs indicate the sequence of the RLC PDUs
a Node B 110 on the radio channel. Like the UE 100. The
230,235 and 240. The E field 255, which is one bit, indicates
RNC 120 is analogous to the UE 100 because it includes a 65 whether the following field is a Data field or an LI-E pair field.
MAC layer 121, an RLC layer 122, and a PDCP layer 123, for
The LI field 260 is 7 bits or 15 bits in size depending on
converting the radio data to the original IP/UDP/RTP packet
RLC framing. It indicates the position of a segment of the

APLNDC-WH-A 0000018772

US 7,675,941 B2

3

4

RLC SDU 225 in a Data field 270 of the RLC PDU. The LI
process, the RLC layer recognizes from the second LI that the
remaining bits of the Data field of the RLC PDU 240 are
field 260 indicates the start and end of the RLC SDU 225
padded bits.
within the Data field 270 of the RLC PDU. The LI field 260
The conventional scheme in which the last byte of an RLC
may also indicate whether padding is used. The LI field 260 is
set to a value expressed in bytes, indicating the number of 5 SDU is indicated by an LI is efficient in cases where one RLC
SDUI is segmented to a plurality ofRLC PDUs or a plurality
bytes to the end of an RLC SDU from an RLC header. For
ofRLC SDUs are concatenated to one RLC PDU. However,
simplicity, the LI field 260 is assumed to be 7 bits.
one concrete RLC SDU frequently corresponds to one RLC
In the first byte of the first RLC PDU 230, the SN is set to
a predetermined value ’x’ and the first E is set to ’1 ’, which PDU without any segmentation!concatenation!padding in
implies that an LI-E pair resides in the following byte. In the 10 view of the nature of VoIP packets.
In cases where a 12.2-kbps Adaptive Multi-Rate (AMR)
second byte of the RLC PDU 230, the LI field indicates that
CODEC is widely used in 3GPP, this AMR CODEC creates a
the RLC SDU 225 starts from the first byte of the Data field of
7-byte or 32-byte voice frame every 20 msec. The voice frame
the RLC PDU 230. This allows the LI field to be used in other
is encapsulated with an IP/UDP/RTP header, header-cornways rather than just indicating the position of the last byte of
15 pressed in the PDCP layer, and then delivered to the RLC
the RLC SDU. This LI is called ’pre-defined LI’. Pre-defined
layer. The compressed header is typically 3 bytes, or occaLIs are discussed below.
sionally ranges from 4 to 12 bytes.
’ 1111 100’: the first byte of the Data field in the RLC PDU
Consequently, the size of an RLC SDU ranges from 10 to
is the first byte of the RLC SDU.
19 bytes, or from 35 to 44 bytes. This RLC SDU is provided
’0000 000’: although the last byte of the RLC SDU is 2o to the RLC layer of the transmitter every 20 msec. The RLC
included in the previous RLC PDU, an LI indicating that it is
layer reconstructs one concrete RLS SDU to one RLC PDU
not included in the previous RLC PDU.
and sends it on a radio channel. As stated above, since the
’ 1111 111’: the remainder of the Data field of the RLC
compressed header is usually 3 bytes in length, most RLC
PDU are padding bits.
SDUs are 10 or 35 bytes. Accordingly, it is preferable to
Hence, the first LI field is set to the pre-defined LI ’ 1111 25 determine an RLC PDU size such that RLC SDUs of the most
100’ and ’0’ is inserted in the second E field to indicate that the frequent size can be efficiently processed.
If the RLC PDU size is defined based on the most frequent
next byte belongs to the Data field in the RLC PDU 230.
RLS SDU size, most ofRLS SDUs are framed to RLC PDUs
Accordingly, a 38-byte Data field of the 40-byte RLC PDU
without segmentation/concatenation/padding. In this case,
230, except for the first two bytes, is used to carry the first 38
30 the conventional framing is not efficient.
bytes of the RLC SDU 225.
FIG. 3 illustrates a problem encountered with the convenIn the second RLC PDU 235, the SN is set to ’x+l’ and the
tional framing.
E is set to ’0’ indicating that the next byte is for the Data in the
Referring to FIG. 3, a 35-byte RLC SDU 305 is created and
first byte. Since the RLC PDU 235 does not include the first
the size of an RLC PDU 310 is 38 bytes. The RLC SDU 305
byte or the last byte of the RLC SDU 225, there is no need to
include an LI field. Therefore, the remaining 39 bytes of the 35 is framed to one RLC PDU 310. In the RLC PDU 310, a first
LI 315 is set to ’ 1111 100’ which indicates that the first byte
Data field carry 39 bytes of the RLC SDU 225, from byte 39
of the RLS SDU 305 corresponds to the first byte of a Data
to byte 77.
field 325 and a second LI 320 is set to ’0100 011’ which
In the third RLC PDU 240, the SN is set to ’x+2’ and the E
indicates that the last byte of the RLS SDU 305 corresponds
is set to ’ 1’ indicating that the next byte is an LI-E pair in the 4o to the 35th byte of the Data field 325. The Data field 325
first byte. In the second byte, the LI is set to ’0010 111(23)’
carries the entire 35-byte RLC SDU 305.
indicating that the last byte of the RLC SDU 225 corresponds
Transmission of the 35-byte is accompanied by a 3-byte
to the 23th byte (’100’-’77’) of the Data field, and the E field
overhead, two bytes of which are used for the LI fields.
is set to’ 1 ’. The Data field of the RLC PDU 240 still has room
As described above, compared to typical packet commuto carry data, after loading the last segment of the 100-byte 45 nications, packet data needs to be processed in real time and
RLC SDU 225. Therefore, the second E field is set to ’ 1’ and
one RLC SDU is created at every predetermined time interval
the second LI field is set to’ 1111 111 ’, which implies that bits
in VoIR More specifically, one RLC SDU is converted to one
following the position indicated by the first LI field are padRLC PDU without segmentation or concatenation in VoIP
ded. The third E field is set to ’0’. Consequently, the Data field
communications. Nonetheless, the conventional RLC framof the RLC PDU 240 is filled with the last 23 bytes of the RLC 50 ing always requires at least two LI fields, i.e. an LI indicating
SDU 225 and a 14-byte padding.
the start of an RLC SDU and another LI indicating the end of
In accordance with the above RLC layer operation of the
the RLC SDU for an RLC PDU. When necessary, an LI
transmitter, the RLC layer of the receiver operates as follows.
indicating whether a Data field is padded is additionally
The RLC layer of the receiver receives the RLC PDUs 230,
inserted.
235 and 240 and sequentially orders them based on their SNs. 55
Therefore, the conventional RLC framing leads to ineffiSpecifically, the RLC layer determines that the Data field of
cient use of limited radio resources in VoIP due to the use of
the first RLC PDU 230 corresponds to the first segment of the
unnecessary LI fields.
RLC SDU 225 referring to the LI field of the RLC PDU 230,
Accordingly, there is a need for an improved system and
and the Data field of the second RLC PDU 235 corresponds to
method to efficiently use radio resources.
the second segment of the RLC SDU 225 referring to the LI 60
field of the RLC PDU 235, thus considering that reconstrucSUMMARY OF THE INVENTION
tion of the RLC SDU 235 is yet to be completed. Then the
RLC layer determines from the first LI field of the RLC PDU
An aspect of exemplary embodiments of the present inven240 that 23 bytes of the Data field of the RLC PDU 240 are the
tion is to address at least the above problems and/or disadlast segment of the RLC SDU 225, and completes reconstruc- 65 vantages and to provide at least the advantages described
tion of the RLC SDU 225 by combining the segments
below. Accordingly, an aspect of exemplary embodiments of
the present invention is to provide a method and apparatus for
extracted from the three RLC PDUs 230,235 and 240. In this

APLNDC-WH-A 0000018773

US 7,675,941 B2
5

6

efficiently using radio resources by reducing the header size
a following segment, if the LI field is set to a predetermined
of an RLC PDU in an RLC layer in a mobile communication value indicating inclusion of an intermediate segment of an
SDU in a data field of the PDU. If the one-bit field indicates
system supporting packet service.
An exemplary embodiment of the present invention also the presence of the LI field, a header and LI remover extracts
provides a method and apparatus for segmenting a higher- 5 an intermediate segment from the data field of the PDU by
layer packet into a plurality of RLC PDUs.
eliminating the SN field, the one-bit field, and the LI field. A
According to one aspect of an exemplary embodiment of reassembler receives the intermediate segment from the
header and LI remover and constructing the SDU by combinthe present invention, in a method of transmitting data using
a pre-defined LI in a mobile communication system, an SDU ing the intermediate segment with at least one previous segis received from a higher layer and a determination is made as 10 ment extracted from a data field of at least one previous PDU
to whether the SDU can be included in one PDU. If the SDU and at least one following segment extracted from a data field
cannot be included in one PDU, the SDU is segmented into a
of at least one following PDU.
plurality of segments according to a transmittable PDU size.
Other objects, advantages, and salient features of the invenA plurality of PDUs are constructed, which include the segtion will become apparent to those skilled in the art from the
ments in data fields. Each PDU has a header with an SN field, 15 following detailed description, which, taken in conjunction
at least one-bit field indicating the presence of an LI field, and with the annexed drawings, disclose exemplary embodiments
the LI field. An LI field of a PDU with an intermediate of the invention.
segment of the SDU in a data field is set to a predetermined
BRIEF DESCRIPTION OF THE DRAWINGS
value indicating the presence of the intermediate segment.
The PDUs are sent to a receiver.
20 The above and other exemplary objects, features and
According to another aspect of an exemplary embodiment
of certain exemplary embodiments
of the present invention, a PDU is received from a transmitter advantageswill become more apparent from of the present
invention
the following
in a method of receiving data using a pre-defined LI in a
mobile communication system. An SN field and a one-bit detailed description when taken in conjunction with the
field indicating the presence or absence of a following LI field 25 accompanying drawings in which:
FIG. 1 illustrates the configuration of a conventional
are detected from a header of the PDU. If the one-bit field mobile communication system supporting VoIP;
indicates the presence of the LI field, the following LI field is
FIG. 2A illustrates a conventional transmission operation;
detected from the header of the PDU. A determination is
FIG. 2B illustrates a conventional reception operation;
made as to whether the LI field is set to a predetermined value
FIG. 2C illustrates a
constructindicating inclusion of an intermediate segment of an SDU in 30 .lng RLC PDUs with conventional operation offraming in a
an RLC SDU by RLC
a data field of the PDU. If the LI field is set to the predetermined value, the PDU is stored until the PDU can be transmitter;
FIG. 3 illustrates a problem encountered with the convenassembled with a previous segment and a following segment.
tional RLC framing;
The SDU is constructed by combining the intermediate segment from the data field of the PDU with at least one previous 35 an FIG. 4 illustrates the structure of an RLC PDU according to
exemplary embodiment of the present invention;
segment extracted from a data field of at least one previous
FIG. 5A illustrates the structure of an RLC PDU according
PDU and at least one following segment extracted from a data to an exemplary embodiment of the present invention, in
field of at least one following PDU.
cases where an RLC SDU corresponds to an RLC PDU withAccording to a further aspect of an exemplary embodiment
segmentation!concatenation!padding;
of the present invention, in an apparatus for transmitting data 4o outFIG. 5B illustrates the structure of an RLC PDU according
using a pre-defined LI in a mobile communication system, a to an exemplary embodiment of the present invention, in
transmission buffer receives an SDU from a higher layer, cases where an RLC SDU is framed to an RLC PDU by
determines whether the SDU can be included in one PDU, segmentation/concatenation/padding;
and reconstructs the SDU to at least one segment according to
FIG. 6A illustrates segmentation of one
a transmittable PDU size. A header inserter constructs at least 45 plurality ofRLC PDUs by the conventionalRLC SDU into a
RLC framing;
one PDU including the at least one segment in a data field and
FIG. 6B illustrates segmentation of one RLC SDU into a
including an SN field and a one-bit field in a header. A one-bit plurality ofRLC PDUs using a new pre-defined LI according
field setter sets the one-bit field of the at least one PDU to
to an exemplary embodiment of the present invention;
indicate the presence or an absence of a following LI field. An
is a flowchart illustrating an operation
LI inserter inserts an LI field after the one-bit field in the at 5o FIG. 7PDU in an RLC layer according to for sending an
RLC
an exemplary
least one PDU if the SDU cannot be included in one PDU, and embodiment of the present invention;
sets an LI field to a predetermined value indicating inclusion
is a flowchart illustrating an operation for receiving
of an intermediate segment in a PDU including an interme- anFIG. 8 PDU in the RLC layer according to an exemplary
RLC
diate segment of the SDU in a data field. A transmitter sends
the at least one PDU received from the LI inserter to a 55 embodimentaof the present invention;
FIG. 9 is block diagram of a transmitter according to an
receiver.
exemplary embodiment of the present invention; and
According to still another aspect of an exemplary embodiFIG. 1D is a block diagram of a receiver according to an
ment of the present invention, in an apparatus for receiving
exemplary embodiment of the present invention.
data using a pre-defined LI in a mobile communication sysThroughout
drawings,
same
tem, a reception buffer receives a PDU from a transmitter and 6o numerals willthe understood therefer todrawing reference
be
to
the same elements,
stores the PDU. A reassembly controller detects an SN field
features, and structures.
and a one-bit field indicating the presence or absence of a
following LI field from a header of the PDU and interprets the
DETAILED DESCRIPTION OF EXEMPLARY
following LI field from the header of the PDU, if the one-bit
EMBODIMENTS
field indicates the presence of the LI field. The reassembly 65
controller also controls the reception buffer to store the PDU
The matters defined in the description such as a detailed
until the PDU can be assembled with a previous segment and
construction and elements are provided to assist in a compre-

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hensive understanding of the embodiments of the invention.
RLC PDU without segmentation/concatenation/padding, it
Accordingly, those of ordinary skill in the art will recognize sets the F field to ’0’ and inserts the RLC SDU in the Data field
that various changes and modifications of the embodiments
of the RLC PDU.
described herein can be made without departing from the
If the F field of a received RLC PDU is ’0’, a receiver
scope and spirit of the invention. Also, descriptions of well- 5 extracts the Data field from the RLC PDU, considering that
known functions and constructions are omitted for clarity and
the Data field follows the F field, and provides the Data field
conciseness.
as an RLC SDU to the higher layer.
Exemplary embodiments of the present invention are
FIG. 5B illustrates the structure of an RLC PDU according
directed to framing for efficient use of radio resources in a
to an exemplary embodiment of the present invention, in
mobile communication system for providing packet service. 10 cases where an RLC SDU is framed to an RLC PDU by
An exemplary embodiment of the present invention will be segmentation/concatenation/padding.
described below in the context of an operation in an RLC
Referring to FIG. 5B, when the transmitter needs to perlayer, particularly an RLC UM operation in a UMTS system, form segmentation/concatenation/padding for RLC framing,
to which the exemplary embodiment of the present invention it constructs an RLC PDU including an F field set to’ 1’ and LI
is not limited. For simplicity, an RLC header is defined to15 fields and a Padding field which are needed for segmentation/
include an SN, the first E, and at least one LI-E pair in an RLC concatenation/padding.
PDU with packet data from a higher layer. That is, the remainIf the F field of a received RLC PDU is ’ 1’, the receiver
der of an RLC PDU, except a Data field, is an RLC header. determines that an LI field and an E field reside in one byte
In accordance with an exemplary embodiment of the following the F field and reconstructs one or more RLC SDUs
present invention, two kinds of framing are considered. One is 2o out of the Data field of the RLC PDU according to the value
that the RLC layer frames an RLC SDU of the most frequent of the LI field.
size to an RLC PDU without using any LI, and the other is that
The requirements for using the conventional first E field as
the RLC layer frames an RLC SDU of any other size to an an F field are discussed below.
RLC PDU or RLC PDUs using an LI field.
Conventionally, If an RLC PDU comprises a segment of an
The former framing does not use any LI field. It is used in25 RLC SDU and the start and the end of the RLC SDU is not
cases where the size of an RLC SDU is equal to that of the included in the RLC PDU, there is no LI in the RLC PDU.
Data field of an RLC PDU and thus there is no need for
Alternatively, no LI field is used when an RLC SDU is
segmentation!concatenation!padding.
framed to one RLC PDU without segmentation!concatenaThe latter framing requires an LI field. It is used in cases
tion/padding. It is necessary to indicate that the RLC PDU
where the size of an RLC SDU is different from that of the30 does not include one concrete RLC SDU and thus does not
Data field of an RLC PDU and therefore segmentation!con- include the start or end of the RLC SDU in FIG. 5A.
catenation/padding is needed.
FIG. 6A illustrates segmentation of one RLC SDU into a
Hence, a different framing scheme may apply to each plurality of RLC PDUs by the conventional RLC framing.
higher-layer packet. A transmitter notifies a receiver of the
Referring to FIG. 6A, an RLC SDU 605 is segmented into
framing scheme used for the packet.
35 three RLC PDUs 610, 615 and 620 with SN ’x’, ’x+l’ and
In an exemplary embodiment of the present invention, the
’x+2’, respectively. A pre-defined LI value of ’1111 100’ is
framing scheme applied to an RLC PDU is indicated by one inserted in the first RLC PDU 610, thereby indicating that the
bit of an RLC header, particularly one bit of the first E field. first byte of the Data field of the RLC PDU 610 corresponds
The first E field is called an F field, to be distinguished from to the first byte of the RLC SDU 605.
other E fields.
40 Since the start and the end of the RLC SDU 605 are not
FIG. 4 illustrates the structure of an RLC PDU according to included in the second RLC PDU 615, the first E field of the
second RLC PDU 615 is set to ’0’ and any LI field not is
an exemplary embodiment of the present invention.
Referring to FIG. 4, the RLC PDU includes an SN field inserted. An LI value of ’0100 010’, for example, is inserted
405, an F field 410, an LI field 415, an E field 420, a Data field in the third RLC PDU 620 in order to indicate that the end of
425, and a Padding 430. The LI field 415, the E field 420, and the RLC SDU 605 corresponds to the 34th byte of the Data
45
the Padding 430 may or may not be included depending on
field of the RLC PDU 620.
Regarding the RLC PDU 615 with no LI field due to the
situations. However, the SN field 405, the F field 410, and the
Data field 425 always exist. The SN field 405, the LI field 415, absence of the start or end of the RLC SDU, the receiver
the E field 420, the Data field 425, and the Padding 430 may cannot determine whether the segment in the Data field of the
have functionalities analogous to those of a conventional 50 RLC PDU 615 is one concrete RLC SDU or forms one concrete RLC SDU together with the previous and following
RLC PDU.
The F field 410 indicates a framing scheme used for an RLC PDUs. Therefore, in an exemplary embodiment of the
RLC PDU, such as the presence or absence of the LI field 415. present invention, a novel LI value is defined to indicate an
The F field 410 also indicates whether an RLC SDU has been RLC PDU that does not include the start or the end of an RLC
framed to the RLC PDU 415 without segmentation!concat- 55 SDU (hereinafter, referred to as an intermediate PDU). The
enation/padding. If the F field 410 is set to ’0’, the RLC PDU novel LI can be ’ 1111 110’, for example. An RLC PDU with
415 does not have the LI field 415 and the Data field 425 is the novel LI value is considered an intermediate RLC PDU.
eventually the one concrete RLC SDU. If the F field 410 is set The Data field of the intermediate RLC PDU includes an RLC
to ’ 1 ’, the RLC PDU 415 has the LI field 415 and the size of SDU segment between the start and end of the RLC SDU.
the Data field 425 is not equal to that of the RLC SDU. Thus, 6o FIG. 6B illustrates segmentation of one RLC SDU into a
the LI field 415 indicates the start or end of the RLC SDU.
plurality ofRLC PDUs using a new pre-defined LI according
FIG. 5A illustrates the structure of an RLC PDU according to an exemplary embodiment of the present invention.
to an exemplary embodiment of the present invention, in
Referring to FIG. 6B, an RLC SDU 625 is segmented into
cases where an RLC SDU corresponds to an RLC PDU with- three RLC PDUs 630, 635 and 640 with SN ’x’, ’x+l’ and
out segmentation/concatenation/padding.
65 ’x+2’, respectively. The F field is set to ’1’ and a pre-defined
Referring to FIG. 5A, when a transmitter (an RLC layer in LI value of’ 1111 100’ is inserted in the first RLC PDU 630,
the transmitter) can frame one concrete RLC SDU to one thereby indicating that the first byte of the Data field of the

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pre-defined LI value is set by a system or a designer. In step
RLC PDU 630 corresponds to the first byte of the RLC SDU
750, the RLC layer sends the RLC PDU to the lower layer, for
625. Since neither the start nor the end of the RLC SDU 625
transmission to the receiver.
is included in the second RLC PDU 635, the F field of the
second RLC PDU 635 is set to ’0’ and the new pre-defined LI
FIG. 8 is a flowchart illustrating an RLC operation in the
value of ’111 110’ is inserted to the second RLC PDU 635, 5 receiver according to an exemplary embodiment of the
thereby indicating the RLC PDU 635 is an intermediate RLC
present invention.
PDU.
Referring to FIG. 8, the RLC layer of the receiver receives
An LI value of ’0100 011’, for example, is inserted in the an RLC PDU from the lower layer in step 805 and checks the
third RLC PDU 640 to serve as an indication that the end of
first E field (F field) of the RLC PDU in step 810. If the F field
the RLC SDU 625 corresponds to the 35th byte of the Data 10 is ’1 ’, the RLC layer goes to step 820. If the F field is ’0’, the
field of the RLC PDU 640.
RLC layer proceeds to step 815.
Now a description will be made of an operation and an
If the F field is ’0’, this implies that segmentation!concatapparatus structure according to exemplary embodiments of
enation!padding was not applied to the RLC PDU. Thus, the
the present invention. Since concatenation in the RLC layer is
RLC layer eliminates an RLC header (such as SN and F) from
beyond the scope of exemplary embodiments of the present 15 the RLC PDU and reconstructs one concrete RLC SDU with
invention, an operation and apparatus structure associated
the remaining Data field in step 815. The Data field of the
with the concatenation will not be described. It is clear that in
RLC PDU becomes one concrete RLC SDU. In step 850, the
case of concatenation, if the first E field (i.e. F field) is ’ 1 ’, at RLC layer provides the RLC SDU to the higher layer.
least one LI field exists.
If the F field is ’1’, this implies that segmentation!concatFIG. 7 is a flowchart illustrating an RLC operation in the 2o enation!padding was applied to the RLC PDU and at least one
transmitter according to an exemplary embodiment of the
LI field exists. In step 820, the RLC layer buffers the RLC
present invention.
PDU according to its SN in a reception buffer.
Referring to FIG. 7, upon receipt of at least one RLC SDU
In step 825, the RLC layer checks to determine whether the
from the higher layer in step 705, the RLC layer of the
first LI field of the RLC PDU is the new pre-defined value
transmitter notifies the lower layer of the number and the size 25 ’ 1111 110’. In case of LI ’ 1111 110’, the RLC layer goes to
of the at least one RLC SDU in step 710. The lower layer can
step 830. Otherwise, it goes to step 835. The RLC layer
be the MAC layer. When LI ’0000 000’ for transmission of
determines that the RLC PDU includes an intermediate segthe RLC SDU, the RLC layer notifies the lower layer of ’the
ment of the RLC SDU in step 830 and determines whether an
size of the RLC SDU’+I.
RLC SDU can be reassembled, such as, recovered by checkIn step 715, the RLC layer waits until the lower layer 30 ing the SNs and LIs ofRLC PDUs buffered in the reception
reports the size and number of RLC PDUs to be transmitted
buffer in step 835. Ifn RLC PDUs (n is an integer larger than
for the next transmission interval. The lower layer determines
1) among buffered RLC PDUs with consecutive SNs fulfills
the most efficient RLC PDU size based on the received RLC
the following conditions, the RLC SDU can be reassembled.
SDU information and the radio channel condition for the next
Condition 1 : The last LI field of the first of the n RLC PDUs
transmission interval and notifies the RLC layer of the RLC 35 indicates the start of a new RLC SDU.
PDU size.
Condition 2: The second to (n-1)th RLC PDUs each
In step 720, the RLC layer determines whether the notified
include one LI field set to ’ 1111 110’.
RLC PDU size matches to the RLC SDU size. At the same
Condition 3: The first LI field of the last (such as nth) RLC
time, the RLC layer determines whether LI ’0000 000’ in a
PDU indicates the position of the last byte of the RLC SDU.
current RLC PDU according to whether the previous RLC 4o If there are n buffered RLC PDUs fulfilling the above
PDU has an LI field indicating the last byte of the previous
conditions, the RLC layer goes to step 840 and otherwise, it
RLC SDU. If the RLC PDU size matches to the RLC SDU
goes to step 845 and waits until a new RLC PDU is received.
size and it is unnecessary to send an LI of’0000 000’, the RLC
The RLC layer reassembles an RLC SDU, referring to the
layer goes to step 725. When the sum of the RLC SDU size
SNs and LIs of the RLC PDUs in step 840 and provides the
and a minimum RLC header size is equal or approximate to 45 RLC SDU to the higher layer in step 850.
the RLC PDU size, not greater than the RLC PDU size, it is
FIG. 9 is a block diagram of a transmitter acting as a
said that the RLC SDU size matches to the RLC PDU size. In
transmitting RLC layer according to an exemplary embodiment of the present invention.
other words, when the first E field (F field) of the RLC PDU
is set to ’0’ and LI fields indicating the start and end of the
Referring to FIG. 9, the transmitter includes a transmission
RLC SDU are not used, the entire RLC SDU is carried in the 5o buffer 905, an RLC header inserter 910, an LI inserter 915, a
Data field of the RLC PDU.
transmission part 920, an F setter 925, and a PDU size conLI ’0000 000’, when the end of the previous RLC PDU
troller 930.
perfectly corresponds to the end of the previous RLC SDU
The transmission buffer 905 buffers at least one RLC SDU
and, LI field indicating the end of the previous RLC SDU is
received from the higher buffer and notifies the PDU size
not included in the previous RLC PDU.
55 controller 930 of the size and number of the at least one RLC
The RLC layer sets the F field of the current RLC PDU to
SDU. The PDU size controller 930 determines an RLC PDU
’0’ in step 725, inserts the entire RLC SDU in the Data field of
size to ensure the highest transmission efficiency and notifies
the RLC PDU without including any LI field in step 730, and
the transmission buffer 905 of the RLC PDU size.
sends the RLC PDU to the lower layer, for transmission to the
The transmission buffer 905 reconstructs the at least one
receiver in step 735.
6o RLC SDU to the RLC PDU size. If the size of an RLC SDU
Alternatively, if the RLC PDU size does not match to the
is equal to that of the Data field of an RLC PDU, the transRLC SDU size or LI ’0000 000’, the RLC layer sets the F bit
mission buffer 905 simply provides the RLC SDU to the RLC
of the current RLC PDU to ’ 1’ in step 740. In step 745, the
header inserter 910 without any processing. The F setter 925
RLC layer determines whether there is an intermediate RLC
controls the RLC header inserter 910 to set the F field of the
PDU generated from the RLC SDU. When an intermediate 65 RLC PDU to ’0’ if the RLC SDU size is equal to the size of the
RLC PDU exists, the only LI field of the intermediate RLC
Data field. The RLC header inserter 910 inserts the F field and
PDU is set to a novel pre-defined value’ 1111 110’. The novel
an SN into the data received from the transmission buffer 905

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wherein if the data field of the PDU contains an intermeunder the control of the F setter 925. If the F field is set to ’0’,
diate segment of the SDU, the LI field in the PDU
the LI inserter 915 does not insert an LI field into the data
contains the intermediate segment of the SDU is set to a
received from the RLC header inserter 910. Alternatively, if
predefined value indicating that the PDU contains neithe F field is ’1’, the LI inserter 915 inserts an LI field. The
ther a first segment nor a last segment of the SDU; and
transmission part 920 sends RLC PDUs created in the above 5
procedure on a radio channel.
sending the PDUs to a receiver.
FIG. 10 is a block diagram of a receiver operating as a
2. The method of claim 1, further comprising the step of, if
receiving RLC layer according to an exemplary embodiment the SDU is comprised in one PDU, constructing one PDU
of the present invention.
comprising a header and a data field,
Referring to FIG. 10, the receiver includes a reception part 10 wherein the header comprises a SN field, and a one-bit field
1020, a reception buffer 1015, an RLC header and LI remover
indicating that the PDU contains the entire SDU in the
1010, a reassembler 1005, and a reassembly controller 1025.
data field.
The reception part 1020 provides an RLC PDU received
3. The method of claim 1, further comprising the step of, if
from the lower layer to the reception buffer 1015. The recepa PDU size except the SN field and the one-bit field for a next
tion buffer 1015 buffers the RLC PDU until it is reassembled 15 transmission interval matches to the size of the SDU, deterto an RLC SDU. The reassembly controller 1025 determines
mining the PDU size according to the size of the SDU and a
whether an RLC SDU assembly is possible by interpreting
radio channel condition, determining that the SDU can be
the Fs and LIs ofRLC PDUs buffered in the reception buffer
comprised in one PDU.
1015, and controls the reception buffer 1015 to provide an
4. The method of claim 1, wherein LI fields of PDUs
RLC PDU that can be reassembled to the RLC header and LI 20
comprising the first and last segments of the SDU in data
remover 1010.
fields are set to values indicating inclusion of the first segment
The RLC header and LI remover 1010 eliminate an RLC
of the SDU and inclusion of the last segment of the SDU.
header and an LI (LIs) from the RLC PDU. If the RLC PDU
5. The method of claim 1, wherein the SDU comprises an
has an F field set to ’0’, which implies that there is no LI field,
internet protocol (IP) packet.
only the RLC header is eliminated.
25
6. A method of receiving data in a mobile communication
The reassembler 1005 reassembles an RLC SDU using the
system, comprising:
RLC PDU from which the RLC header and LI(s) are removed
receiving a protocol data unit (PDU) from a transmitter and
and provides the RLC SDU to the higher layer. For an RLC
detecting a sequence number (SN) field and a one-bit
PDU with an F set to ’0’, the reassembler 1005 constructs one
30
field indicating whether the PDU contains an entire serconcrete RLC SDU with data extracted form the Data field of
vice data unit (SDU) in its data field from the header;
the RLC PDU. For an RLC PDU with an F set to ’ 1’ and only
if the one-bit field indicates that the PDU does not contain
one LI set to’ 1111 110’, the reassembler 1005 constructs one
an entire SDU in its data field, detecting the following
RLC SDU by combining an intermediate SDU segment
length indicator (LI) field from the header of the PDU,
extracted from the Data field of the RLC PDU with SDU
and determining whether the LI field is set to a value
segments extracted from the previous and following RLC
indicating that the PDU contains an intermediate segPDUs.
ment that is neither a first segment nor a last segment of
As described above, exemplary embodiments of the
the SDU;
present invention facilitate the efficient use of limited radio
transmission resources by eliminating the need to insert addistoring the PDU until the PDU can be assembled with a
tional information indicating the start/end/padding of an RLC 4o
previous segment and a following segment, if the LI field
SDU by use of one-bit information indicating the existence of
is set to the predefined value; and
one concrete RLC SDU in the Data field of an RLC PDU.
constructing the SDU by combining the intermediate segSince an LI with a new pre-defined value is set in an RLC
ment from the data field of the PDU with at least one
PDU including only an intermediate segment of the RLC
previous segment extracted from a data field of at least
SDU, RLC SDU segmentation is facilitated.
45
one previous PDU and at least one following segment
While the present invention has been shown and described
extracted from a data field of at least one following PDU.
with reference to certain exemplary embodiments thereof, it
7. The method of claim 6, further comprising, if the one-bit
will be understood by those skilled in the art that various
field indicates that the PDU contains the entire SDU in its data
changes in form and details may be made therein without
field, acquiring the entire SDU from the data field of the PDU.
departing from the spirit and scope of the invention as defined 50
8. The method of claim 6, wherein the storing comprises
by the appended claims and their equivalents.
the steps of storing the PDU in a reception buffer according to
the SN field of the PDU.
What is claimed is:
9. The method of claim 8, wherein the constructing com1. A method of transmitting data in a mobile communicaprises constructing the SDU by combining segments
tion system, comprising:
55
receiving a service data unit (SDU) from a higher layer and extracted from data fields of a set of PDUs stored in the
reception buffer, if the first of the PDUs comprises an LI field
determining whether the SDU can be comprised in one
indicating inclusion of the first segment of the SDU, if at least
protocol data unit (PDU);
one intermediate PDU among the PDUs comprises an LI field
if the SDU is not comprised in one PDU, segmenting the
SDU into a plurality of segments according to a trans- 6o set to the value, and if the first LI field of the last of the PDUs
indicates the position of the last byte of the SDU.
mittable PDU size, and constructing one or more PDUs,
each PDU comprising a header and a data field,
10. An apparatus for transmitting data in a mobile commuwherein the data field comprises a segment of the SDU,
nication system, comprising:
wherein the header comprises a serial number (SN) field, a
a transmission buffer for receiving a service data unit
one-bit field indicating that the PDU does not contain an 65
(SDU) from a higher layer, determining whether the
entire SDU in the data field and at least one Length
SDU can be comprised in one protocol data unit (PDU)
segmenting the SDU into a plurality of segments accordIndicator (LI) field,

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ing to a transmittable PDU size if the SDU does not be
a reception buffer for receiving a protocol data unit (PDU)
comprised in one PDU, and constructing one or more
from a transmitter and storing the PDU;
a reassembly controller for detecting a sequence number
PDUs;
(SN) field and a one-bit field indicating whether the
a header inserter for constructing a header of each PDU,
PDU contains an entire service data unit (SDU) in its
wherein the header comprises a serial number (SN) field, 5
data field from the header, detecting the following length
a one-bit field, at least one Length Indicator (LI) field;
indicator (LI) field from the header of the PDU and
a one-bit field setter for setting the one-bit field of the at
determining whether the LI field is set to a predefined
least one PDU to indicate whether the PDU contains an
value indicating that the PDU contains an intermediate
entire SDU in the data field;
10
segment that is neither a first segment nor a last segment
an LI inserter for inserting an LI field after the one-bit field
of the SDU if the one-bit field indicates that the PDU
in the at least one PDU if the SDU is not comprised in
does not contain an entire SDU in its data field;
one PDU, and setting an LI field to a predefined value
a header and LI remover for eliminating the SN field, the
indicating that the PDU contains neither a first segment
one-bit field, and the LI field if the one-bit field indicates
nor a last segment of the SDU to contain the intermediate
15
that the PDU does not contain the entire SDU in its data
segment of the SDU; and
field,; and
a transmitter for sending the PDUs to a receiver.
a reassembler for receiving the intermediate segment from
11. The apparatus of claim 10, wherein if the SDU is
the header and LI remover and constructing the SDU by
comprised in one PDU, constructing one PDU comprising a
combining the intermediate segment with at least one
header and a data field,
2o
previous segment extracted from a data field of at least
wherein the header comprises a SN field, and a one-bit field
one previous PDU and at least one following segment
indicating that the PDU contains the entire SDU in the
extracted from a data field of at least one following PDU.
data field.
16. The apparatus of claim 15, wherein the header and LI
remover eliminate the SN field and the one-bit field from the
12. The apparatus of claim 10, wherein ifa PDU size except
the SN field and the one-bit field for a next transmission 25 PDU and acquire the entire SDU from the data field of the
interval matches to the size of the SDU, the PDU size being
PDU if the one-bit field indicates that the PDU contains the
determined according to the size of the SDU and a radio
entire SDU in its data field.
channel condition, the transmission buffer determines that the
17. The apparatus of claim 15, wherein the reception buffer
SDU can be comprised in one PDU.
stores the PDU according to the SN field of the PDU.
18. The apparatus of claim 17, wherein the reassembler
13. The apparatus of claim 10, wherein the LI inserter sets 30
constructs the SDU by combining segments extracted from
LI fields of PDUs comprising the first and last segments of the
data fields of a set of PDUs stored in the reception buffer, if the
SDU in data fields to values indicating inclusion of the first
first of the PDUs comprises an LI field indicating inclusion of
segment of the SDU and inclusion of the last segment of the
the first segment of the SDU, if at least one intermediate PDU
SDU.
14. The apparatus of claim ll), wherein the SDU comprises 35 among the PDUs comprises an LI field set to the value, and if
the first LI field of the last of the PDUs indicates the position
an internet protocol (IP) packet.
of the last byte of the SDU.
15. An apparatus for receiving data in a mobile communication system, comprising:

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