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US007746916B2
(12) Ulllted States Patent (10) Patent N0.: US 7,746,916 B2 Han et al. (45) Date of Patent: Jun. 29, 2010
(54) METHOD AND APPARATUS FOR (56) References Cited GENERATING AND TRANSMITTING CODE SEQUENCE IN AWIRELESS U.S. PATENT DOCUMENTS
COMMUNICATION SYSTEM 7,426,175 B2 * 9/2008 Zhuang et a1. ............ .. 370/203 2003/0156624 A1* 8/2003 Koslar ...................... .. 375/131
(75) Inventors: Seung Hee Han, Seoul (KR); Min Seok ggiygttzlt 31' Noh, Seoul (KR); Yeon Hyeon KWon, '
Anyang-Si (KR); Hyllll W00 Lee, EP 1065855 1/2001 Anyang-si (KR); Dong Cheol Kim, KR 10-2007-0103917 10/2007 UiWang-si (KR) WO 9605668 2/1996
WO 2003049295 6/2003
(73) Assignee: LG Electronics Inc., Seoul (KR) W0 W0 03/075500 9/2003 W0 WO 2005/104412 11/2005
( * ) Notice: Subject to any disclaimer, the term of this OTHER PUBLICATIONS
Patent 15 extended Or adJusted under 35 Texas Instruments “On allocation of Uplink Pilot Sub-Channels in U~S-C- 154(1)) by 580 days- Eutra SC-FDMA”, 3GPP TSG-RAN WGl, El-050922, Aug. 29,
2005. (21) Appl. N0.: 11/563,909 _ _
* c1ted by exammer
(22) Filed: NOV‘ 28’ 2006 Primary ExamineriDavid C Payne _ _ _ Assistant ExamineriAdolf DsouZa
(65) Pnor Pubhcatlon Data (74) Attorney, Agent, or FirmiLee, Hong, Degerman, Kang US 2007/0177682 A1 Aug. 2, 2007 & Waimey
(30) Foreign Application Priority Data (57) ABSTRACT
Nov. 28, 2005 (KR) .................... .. 10-2005-0114306 A method of generating a code sequence in a Wireless com Jul. 4, 2006 (KR) .................... .. 10-2006-0062467 munication system is disclosed- More speci?cally, the Jul. 7, 2006 (KR) .................... .. 10-2006-0064091 method includes recognizing a desired length of the code
sequence, generating a code sequence having a length differ (51) Int. Cl. ent from the desired length, and modifying the length of the
H04B 1/00 (2006.01) generated code sequence to equal the desired length. Here, (52) US. Cl. ..................... .. 375/142; 370/203; 370/208; the step of modifying includes discarding at least one element
375/131; 375/140; 375/146; 375/148 of the generated code sequence or inserting at least one null (58) Field of Classi?cation Search ............... .. 370/203; element to the generated code sequence
375/131, 142 See application ?le for complete search history. 11 Claims, 18 Drawing Sheets
19
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US. Patent Jun. 29, 2010 Sheet 1 0f 18 US 7,746,916 B2
as 6950
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US. Patent Jun. 29, 2010 Sheet 3 0f 18 US 7,746,916 B2
FIG. 3
Start
F
Generate code sequence having length M _n_ 8301 based on code generating algorithm
1
Generate code sequence having length N by removing (M-N) number of elements
from each code sequence for N number of code sequence (M>N )
~ S302
} End
US. Patent Jun. 29, 2010 Sheet 4 0f 18 US 7,746,916 B2
FIG. 4
1000
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sequence 0
llillirii , , ,
1000
500
Code Index
M d » U 0 O 0 @353,“
Time Index
US. Patent Jun. 29, 2010 Sheet 5 0f 18 US 7,746,916 B2
FIG. 5
sequence 0
$535
Time Index
US. Patent Jun. 29, 2010 Sheet 6 6f 18 US 7,746,916 B2
FIG. 6
. 1
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Value of Correlation
US. Patent Jun. 29, 2010 Sheet 8 0f 18 US 7,746,916 B2
FIG. 8
Required CAZAC length=L U
Generated CAZAC length=X>L, X=prime number
Truncated CAZAC length=L
FIG. 9
Required CAZAC length=L
qIEHBI'HtBd CAZAC length=X<L, X=prime numbe; l |
generated CAZAC 1ength=L
"if" h“ C1 JL 0 .ELL 7//
US. Patent Jun. 29, 2010 Sheet 9 0f 18 US 7,746,916 B2
FIG. 10
Original CAZAC seq. M
Delaycd CAZAC seq. W
US. Patent Jun. 29, 2010 Sheet 10 0f 18 US 7,746,916 B2
FIG. 11
Required SBQUBHCE length, L
| .
' Delayed CAZAC sequence length, L '
US. Patent Jun. 29, 2010 Sheet 11 0f 18 US 7,746,916 B2
FIG. 12
[i Required sequence length, L :i l [120
i: A CAZAC sequence with prime length XZL _ i
1202 ,f
”””” F;"""“# 1203
r / |__ :| ' Basie CAZAC sequence length, X; L '
11204 T Truncated CAZAC sequence length, L .4
US. Patent Jun. 29, 2010 Sheet 12 0f 18 US 7,746,916 B2
FIG. 13
}_ Required sequence length, L :
if 1301
A CAZAC sequence with prime length X; L I Ff :_|
[1302
L Truncated CAZAC sequence length, L I“ " |
\\ j 1303
i p 2 H e "'"iii../"“H Bedding *" ‘F’ 1304
2\\ I L. L ._J
Delayed CAZAC sequence length, l; 1
padding
US. Patent Jun. 29, 2010 Sheet 13 0f18
FIG. 14
Required sequence length, L
US 7,746,916 B2
1 [140
A CAZAC sequence with prime length XéL r:
2 [140
Basic CAZAC sequence length, XQL
Generated CAZAC sequence length, L
US. Patent Jun. 29, 2010 Sheet 14 0f 18 US 7,746,916 B2
FIG. 15
generated CAZAC 1ength=L
t?////////////¢7/I$ W padding Padding
C2
US. Patent Jun. 29, 2010 Sheet 15 0f 18 US 7,746,916 B2
FIG. 16
Transmitting End Receiving End TrnnsmittingUnit
_.___Y L Sequence SIP . ' Y ; Y___ Selection C ' a Unit overter Y Y
1602 1603
1601
FIG. 1'?
Basic Code Sequence Generation Unit 5 Code Sequence Length Adjustment Unit
Code Circular ' gté‘lvll‘llgsilf Sequence Cl _ Shi? C2 f Control Unit g 5 Generation Application Unit Unit Unit Padding C4
Unit
1701a 1701b 1702a 1702c
1701 1702
US. Patent Jun. 29, 2010 Sheet 16 6f 18 US 7,746,916 B2
FIG. 1B
_ I —-— Truncated ~>shifl _
..____ shi? -> Truncated
US. Patent Jun. 29, 2010 Sheet 18 0f 18 US 7,746,916 B2
FIG. 20
:_ Required CAZAC length=L i '_|
Puwerper tone=11 ///r7/L
L _
X |
Power per WHEEL/X]: ’//Z////Z ,- ' W /§“51 310139‘? . //,1 padding
US 7,746,916 B2 1
METHOD AND APPARATUS FOR GENERATING AND TRANSMITTING CODE
SEQUENCE IN A WIRELESS COMMUNICATION SYSTEM
This application claims the bene?t of Korean Application No. P2005-114306, ?led on Nov. 28, 2005, Korean Applica tion No. P2006-62467, ?led on Jul. 4, 2006, and Korean Application No. P2006-64091, ?led on Jul. 7, 2006, Which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to a method of generating and
transmitting code sequence, and more particularly, to a method and apparatus for generating and transmitting code sequence in a Wireless communication system.
2. Discussion of the RelatedArt Usually, a pilot signal or a preamble of a Wireless commu
nication system is referred to as a reference signal used for initial synchronization, cell search, and channel estimation. Further, the preamble is comprised of a code sequence, and the code sequence is further comprised of orthogonal or quasi-orthogonal Which represent good correlation proper ties.
For example, a Hadamard matrix of 128x128 is used in a portable intemet (PI) to insert the code sequence to the fre quency domain. In so doing, 127 types of code sequences are used.
Although the Hadmard code sequence and a poly-phase Constant Amplitude Zero Auto-Correlation (CAZAC) code sequence are orthogonal codes, a number of codes used to maintain orthogonality is limited. For example, a number of N orthogonal codes in a N><N Hadamard matrix is N, and a number of N orthogonal codes that can be expressed by the CAZAC codes is N and a prime number smaller than N (David C. Chu, “Polyphase Codes With Good Periodic Cor relation Properties,” Information Theory IEEE Transaction on, vol. 18, issue 4, pp. 531-532, July 1972). With respect to CAZAC sequence types, GCL CAZAC and Zadoff-Chu CAZAC are often used.
If the code sequence is generated using the Hadamard codes, N number of sequence types corresponding to the entire length of the codes is generated. HoWever, the if the code sequence is generated using the CAZAC codes, only half or N/ 2 number of sequence types are generated.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method and apparatus for generating and transmitting code sequence in a Wireless communication system that substantially obvi ates one or more problems due to limitations and disadvan tages of the related art. An object of the present invention is to provide a method of
generating a code sequence in a Wireless communication system.
Another object of the present invention is to provide an apparatus for generating a code sequence in a Wireless com munication system.
Additional advantages, objects, and features of the inven tion Will be set forth in part in the description Which folloWs and in part Will become apparent to those having ordinary skill in the art upon examination of the folloWing or may be learned from practice of the invention. The objectives and other advantages of the invention may be realiZed and
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60
65
2 attained by the structure particularly pointed out in the Written description and claims hereof as Well as the appended draW ings.
To achieve these objects and other advantages and in accor dance With the purpose of the invention, as embodied and broadly described herein, a method of generating a code sequence in a Wireless communication system includes rec ogniZing a desired length of the code sequence, generating a code sequence having a length different from the desired length, and modifying the length of the generated code sequence to equal the desired length. Here, the step of modi fying includes discarding at least one element of the gener ated code sequence or inserting at least one null element to the generated code sequence.
In another aspect of the present invention, method of gen erating a code sequence in a Wireless communication system includes a recogniZing a desired length of a ?rst code sequence, generating a second code sequence having a length different from the desired length of the ?rst code sequence, and modifying the length of the second code sequence to equal the desired length of the ?rst code sequence. Here, the step of modifying includes discarding at least one element of the modi?ed code sequence if the length of the modi?ed code sequence is longer than the desired length of the ?rst code sequence or inserting at least one null element to the modi?ed code sequence if the length of the modi?ed second code sequence is shorter than the desired length of the ?rst code sequence.
In a further aspect of the present invention, an apparatus for generating a code sequence in a Wireless communication system includes a sequence selection unit for recogniZing a desired length of the code sequence, generating a code sequence having a length different from the desired length, and modifying the length of the generated code sequence to equal the desired length, Wherein the sequence selection unit discards at least one element of the generated code sequence or inserts at least one null element to the generated code sequence in modifying the length of the generated code sequence, and a transmitting unit for transmitting the modi ?ed generated code sequence via at least one antenna.
It is to be understood that both the foregoing general description and the folloWing detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying draWings, Which are included to pro vide a further understanding of the invention and are incor porated in and constitute a part of this application, illustrate embodiment(s) of the invention and together With the descrip tion serve to explain the principle of the invention. In the draWings;
FIG. 1 illustrates a structure of an apparatus for transmit ting data using Orthogonal Frequency Division Multiplexing (OFDM) or OFDM Access (OFDMA) scheme;
FIG. 2 illustrates a structure of an apparatus for receiving data using OFDM/OFDMA scheme;
FIG. 3 is a How diagram illustrating adjusting a code sequence;
FIG. 4 illustrates cross-correlation properties of the gener ated code sequence;
FIG. 5 illustrates a generated CAZAC sequence