+

WO2008066348A1 - Méthode d'émission et réception d'un signal dans un système de communication - Google Patents

Méthode d'émission et réception d'un signal dans un système de communication Download PDF

Info

Publication number
WO2008066348A1
WO2008066348A1 PCT/KR2007/006141 KR2007006141W WO2008066348A1 WO 2008066348 A1 WO2008066348 A1 WO 2008066348A1 KR 2007006141 W KR2007006141 W KR 2007006141W WO 2008066348 A1 WO2008066348 A1 WO 2008066348A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
code
equation
spreading code
communication system
Prior art date
Application number
PCT/KR2007/006141
Other languages
English (en)
Inventor
Mun-Geon Kyeong
Woo-Goo Park
In-Cheol Jeong
Jae-Sang Cha
Original Assignee
Electronics And Telecommunications Research Institute
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020070042510A external-priority patent/KR100862726B1/ko
Application filed by Electronics And Telecommunications Research Institute filed Critical Electronics And Telecommunications Research Institute
Priority to US12/517,175 priority Critical patent/US20100142595A1/en
Publication of WO2008066348A1 publication Critical patent/WO2008066348A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H04B1/7115—Constructive combining of multi-path signals, i.e. RAKE receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2201/00—Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
    • H04B2201/69—Orthogonal indexing scheme relating to spread spectrum techniques in general
    • H04B2201/707—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
    • H04B2201/7097—Direct sequence modulation interference
    • H04B2201/709709—Methods of preventing interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/0055—ZCZ [zero correlation zone]
    • H04J13/007—LAS, i.e. LA, LS and LAS codes

Definitions

  • the present invention relates to a signal transmitting and receiving method of a communication system. More particularly, the present invention relates to a signal transmitting and receiving method using a pre-rake method.
  • a terminal When a conventional pre-rake transmission method is applied to a base station of the code division multiplexing (CDM)/ code division multiple access (CDMA) system using time division duplexing (TDD), a terminal can acquire the same diversity effect as that of a rake receiver without any additional diversity synthesis circuit.
  • CDMA code division multiplexing
  • CDMA code division multiple access
  • the pre-rake transmission method transmits signals of multiple paths compared to the general CDM/CDMA method that transmits the signals through a single path
  • the pre-rake transmission method is greatly influenced by multi-path interference (MPI) or multiple access interference (MAI) that the wireless communication system originally has. Therefore, when the pre-rake transmission method is applied to the communication system, the bit error rate (BER) of the communication system is substantially degraded and the data reception efficiency is worsened.
  • MPI multi-path interference
  • MAI multiple access interference
  • the present invention has been made in an effort to provide a signal transmitting and receiving method of a communication system having advantages of reducing the interference that occurs when the pre-rake transmission method is used.
  • a method for transmitting a signal through a multipath channel in a communication system includes generating a continuously orthogonal spreading code for a user, generating a spreading- modulated signal for a user signal by using the continuously orthogonal spreading code, and performing a pre-rake combining on the spread signal and transmitting the pre-rake combined signal.
  • a channel impulse response for the multipath channel may be combined with the spread signal to perform the pre-rake combining.
  • the continuously orthogonal spreading code may be continuously orthogonal for a predetermined time interval or it has an autocorrelation value and a cross-correlation value as 0 for a predetermined time interval.
  • the continuously orthogonal spreading code may include one of a zero correlation duration (ZCD) code, a zero correlation zone (ZCZ) code, and a large area synchronous (LAS) code.
  • ZCD zero correlation duration
  • ZCZ zero correlation zone
  • LAS large area synchronous
  • a method for receiving a signal through a multipath channel in a communication system includes receiving a pre- rake combined transmission signal through the multipath channel, and processing the received signal by using a matched filter for one path.
  • a method for transmitting a signal through a multipath channel in a communication system includes spreading modulation for a user signal by a spreading code having a continuously orthogonal characteristic for a predetermined time interval, combining a channel impulse response for the multipath channel and the spreading-modulated signal, and transmitting the channel impulse response combined spread signal.
  • FIG. 1 shows a block diagram of a communication system according to an exemplary embodiment of the present invention.
  • FIG. 2 is a block diagram of a transmitter of a communication system shown in FlG. 1.
  • FIG. 3 shows a flowchart of a method for a transmitter according to an exemplary embodiment of the present invention to generate a transmission signal.
  • FIG. 4 shows an autocorrelation characteristic and a cross-correlation characteristic of a binary ZCD spread code.
  • FIG. 5 shows bit error rate performance of the CDM/CDMA wireless communication system in which the pre-rake method is applied to the Walsh- Hadamard spreading code with 32 chips in the Rayleigh fading condition having three paths and the multiple access condition.
  • FIG. 6 shows bit error rate performance of the CDM/CDMA wireless communication system in which the pre-rake method is applied to the continuously orthogonal spreading code with 32 chips in the Rayleigh fading condition having three paths and the multiple access condition.
  • each block in the present specification represents a unit for processing at least one function or operation, which can be realized by hardware, software, or combination of hardware and software.
  • FIG. 1 shows a block diagram of a communication system according to an exemplary embodiment of the present invention.
  • the communication system includes a transmitter 100 and a receiver 200 connected through a multipath channel 300.
  • the transmitter 100 can be formed in a base station, and it spreading-modulates an input signal, performs a pre-rake combining process on the spreading-modulated signal, and outputs a resultant signal.
  • the receiver 200 can be formed in a terminal, and it receives the signal from the transmitter 100 through the multipath channel 300 and restores the received signal.
  • the transmitter 100 and a method for the transmitter 100 to perform a pre- rake combining on the input signal and output a resultant signal will now be described with reference to FIG. 2 and FIG. 3.
  • FIG. 2 is a block diagram of a transmitter 100
  • FIG. 3 shows a flowchart of a method for the transmitter 100 to generate a transmission signal.
  • the transmitter 100 includes a first modulator 110, a continuously orthogonal spreading code generator 120, a spreading modulator 130, a pre-rake combiner 140 and a transmit antenna 150.
  • the first modulator 110 modulates data for a predetermined user (S310) by using various digital modulation methods including phase shift keying (PSK) modulation, quadrature phase shift keying (QPSK) modulation, and quadrature amplitude modulation (QAM).
  • the continuously orthogonal spreading code generator 120 generates a spreading code that has a continuously orthogonal characteristic for a predetermined time (hereinafter, a continuously orthogonal spreading code) (S320), and the spreading modulator 130 spreading-modulates the data symbol value modulated by the first modulator 110 by using the continuously orthogonal spreading code (S330).
  • the pre-rake combiner 140 converts the spreading-modulated transmission signal into a pre- rake combined signal and outputs the resultant signal through the transmit antenna 150 (S340).
  • the spread modulator 130 of the transmitter 100 spread- modulates the input signal modulated by the first modulator 110, and the pre-rake combiner 140 performs a pre-rake combining on the spreading modulated signal, and outputs a transmission signal that is expressed in Equation 1.
  • U t ⁇ where s s (t) is a spread signal that is generated by the spreading- modulation for the input signal by the spreading modulator 130, ⁇ is a value found by time inverting a channel impulse response, and ⁇ * ⁇ is the conjugated complex of ⁇ .
  • U is a normalizing factor, is used to control power of the pre-rake combined output signal to be constant, and is expressed as Equation 2.
  • Equation 3 the spread signal s s (t) is combined with the channel impulse response that is time inverted by the pre-rake combiner 140, and a channel impulse response h k (t) of the multipath channel 300 shown in FIG. 1 can be expressed as Equation 3.
  • Equation 3 L is the number of channel paths, ⁇ k , ⁇ is a path gain and is an independent identically distributed (i.i.d.) Rayleigh random variable for all k's and I's, ⁇ kt represents a phase and is uniformly distributed in [O, ⁇ r), T 0 is a one-chip interval of the spreading code, and E[ ⁇ k , ⁇ ] is assumed to be 1.
  • the base station receives the signals from the terminals during the uplink time interval by using the rake receiver to estimate the channel impulse response l ⁇ (t) for the user k.
  • Equation 4 The transmitted signal of Equation 1 that is received as a received signal by the receiver 200 through the multipath channel 300 is expressed in Equation 4.
  • Equation 6 the transmitted signal S k (t) of Equation 1 can be expressed as Equation 6.
  • U k is a normalizing factor, it maintains transmission power irrespective of the number of paths, and is expressed in Equation 7.
  • the signal ⁇ (t) received from the receiver 200 of the terminal user i during a downlink time slot is expressed as Equation 8 according to the additive white Gaussian noise n(t) and the multipath channel 300.
  • Equation 6 Y It) u s k (t-jT JexpOV u ) where n(t) is additive white Gaussian noise with a power spectrum density of No/2.
  • the output Z of the matched filter of the user 1 is expressed in Equation 9.
  • ⁇ is a Gaussian random variable with a variance of NoT/4
  • D is an item desired by the received signal
  • S is multipath interference, that is, self interference
  • A is multiple access interference, that is, multi-user interference.
  • Equation 12 Equation 12
  • Equation 13 Equation 13
  • Equation 13 respective terms are uncorrelated since the average of each term is 0 for all j's and m's and their phase values are independent. Therefore, the variance of S is expressed as Equation 14. (Equation 14)
  • Equation 15 The multiple access interference A generated by the other user can be given by setting k>1 in Equations 6, 8, and 9, and is expressed in Equation 15. (Equation 15)
  • Equation 16 cos( ⁇ kJ - ⁇ ⁇ Jb ⁇ k C k ⁇ (0)
  • Equations 16 and 17 have averages of 0 and all the terms are uncorrelated.
  • Equation 18 the variance of the multiple access interference A is expressed in Equation 18.
  • Equation 20 All C 2 k,i(m)'s in Equations 14 and 18 can be expressed as expectations in Equation 20.
  • a random spread code can be used so as to induce Equation 20 in the case of using a general one-point orthogonal code.
  • the code used by the transmitter 100 is a continuously orthogonal spreading code such as a ZCD code and a ZCZ code, or a LAS code.
  • Equation 21 is applied to the continuously orthogonal spreading region.
  • the BER characteristic for the case of using a continuously orthogonal spreading code in the transmitter 100 will be described with reference to FIG. 4 to FIG. 6.
  • the ZCD spread code will be exemplified for the continuously orthogonal spreading code in FIG. 4 to FIG. 6, and other continuously orthogonal spreading codes are also applicable to the exemplary embodiment of the present invention.
  • FIG. 4 shows an autocorrelation characteristic and a cross-correlation characteristic of a binary ZCD spreading code.
  • Equation 22 the periodic correlation function and the aperiodic correlation function for the time shift (T) are respectively given as Equations 22 and 23.
  • Equations 24 and 25 the generation equations of the binary ZCD spreading code and the ternary ZCD spreading code having the continuously orthogonal characteristic can be expressed as Equations 24 and 25.
  • N is the period of a spreading code
  • '+' and '-' are '+1' and '-1'
  • A, B, C, and D are respectively a chip configuration formed by '+1' and '-1' in the spreading code
  • Zi is the number of O's that are inserted into the tertiary ZDC spreading code.
  • the maximum ZCD interval of the binary ZCD spreading code generated from Equation 24 is 0.5N+1
  • the maximum ZCD interval of the ternary ZCD spreading code generated from Equation 25 is 0.75N+1.
  • FIG. 4 shows the autocorrelation function and the cross-correlation function of the one pair of binary ZCD spreading codes having the period of 64 chips, in this instance, it is determined that the cross-correlation between the two codes is 0 in the interval that corresponds to (N/2+1) of the 64 th chip, that is, the 33 rd chip corresponding to (64/2+1 ). Also, the autocorrelation is 0 at the side lobe near the peak value of the autocorrelation in the above-noted interval.
  • Equation 20 is applied to in the communication system using the random spreading variable. Therefore, the BER characteristics are expressed as Equation 26 when Equation 20 is applied to Equations 14 and 18, the receiver output (Z) of Equation 9 is assumed to be a Gaussian random variable, and the
  • Equation 26 Y is the signal to interference plus noise ratio (SINR) including noise and interference, and is given as D 2 /2var(Z), and var(Z) is the variance of the Gaussian random variable (Z). Therefore, Y is expressed as Equation 27.
  • Equation 28 Equation 28
  • Equation 21 is applied to Equation 14 and Equation 18, and resultantly, interference components in Equation 27 become 0 and Equation 29 is acquired.
  • Equation 29 That is, the multipath interference S and the multiple access interference A become 0, and influences caused by the interference are removed.
  • FIG. 5 and FIG. 6 are obtained when the BER performance is measured by using the parameters of Table 1 so as to check the performance of the communication system having combined the continuously orthogonal spreading code and the pre-rake combining method according to the exemplary embodiment of the present invention.
  • FIG. 5 shows the BER performance of the CDM/CDMA wireless communication system in which the pre-rake method is applied to the Walsh- Hadamard spreading code with 32 chips in the Rayleigh fading condition having three paths and the multiple access condition.
  • FIG. 6 shows the BER performance of the CDM/CDMA wireless communication system in which the pre- rake method is applied to the continuously orthogonal spreading code with 32 chips in the Rayleigh fading condition having three paths and the multiple access condition.
  • the BER performance of the CDM/CDMA wireless communication system having combined the pre-rake method with the continuously orthogonal spreading code (binary ZCD spread code) having 32 chips in the Rayleigh fading condition having 3 paths and the multiple access condition according to the exemplary embodiment of the present invention can remove the influence of the interference component such as the multipath fading interference or multiple access interference because of the continuously orthogonal correlation characteristics for a predetermined time interval even when the number of users is increased, and the excellence of the BER performance is confirmed.
  • the interference component such as the multipath fading interference or multiple access interference
  • the CDM/CDMA system using TDD has been described in the exemplary embodiment of the present invention, and the embodiment thereof is also applicable to another TDD or frequency division duplex (FDD) system for feeding channel information provided by the terminal back to the base station.
  • FDD frequency division duplex
  • the pre- rake method is applied to the spreading code having the continuously orthogonal characteristic for a predetermined time interval so that a spread code that has 0 within a predetermined time is generated to thus remove interference without increasing system complexity.
  • the BER performance of the existing pre-rake system is degraded since the multipath fading interference and the multiple access interference are increased because of a plurality of multipaths compared to the general system using a rake receiver, and according to the exemplary embodiment of the present invention, the pre-rake method is applied to the spreading code having the continuously orthogonal characteristic for a predetermined time interval, and hence the BER is reduced and excellent low noise sensitivity is provided.
  • the above-described embodiment can be realized through a program for realizing functions corresponding to the configuration of the embodiment or a recording medium for recording the program in addition to through the above- described device and/or method, which is easily realized by a person skilled in the art.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Un système de communication produit un code orthogonal d'étalement continu pour un utilisateur, un signal d'utilisateur modulé en étalement utilise lesdits codes continus, puis le signal d'étalement est combiné par prémélange et transmis. Un récepteur traite ensuite le signal reçu en utilisant un filtre adapté à une voie.
PCT/KR2007/006141 2006-12-01 2007-11-30 Méthode d'émission et réception d'un signal dans un système de communication WO2008066348A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/517,175 US20100142595A1 (en) 2006-12-01 2007-11-30 Method of transmitting and receiving signal in communication system

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20060120647 2006-12-01
KR10-2006-0120647 2006-12-01
KR10-2007-0042510 2007-05-02
KR1020070042510A KR100862726B1 (ko) 2006-12-01 2007-05-02 통신 시스템의 신호 송신 방법 및 수신 방법

Publications (1)

Publication Number Publication Date
WO2008066348A1 true WO2008066348A1 (fr) 2008-06-05

Family

ID=39468082

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2007/006141 WO2008066348A1 (fr) 2006-12-01 2007-11-30 Méthode d'émission et réception d'un signal dans un système de communication

Country Status (1)

Country Link
WO (1) WO2008066348A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120093200A1 (en) * 2010-10-14 2012-04-19 Electronics And Telecommunications Research Institute Continuous orthogonal spreading code based ultra-high performance array antenna system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11331124A (ja) * 1998-05-12 1999-11-30 Matsushita Electric Ind Co Ltd Ｃｄｍａ方式通信機
US6963601B1 (en) * 1999-02-04 2005-11-08 Samsung Electronics Co., Ltd. Apparatus and method for spreading channel data in CDMA communication system using orthogonal transmit diversity
US7002901B2 (en) * 1999-12-02 2006-02-21 Samsung Electronics Co., Ltd. Apparatus and method for transmitting and receiving data in a CDMA communication system
US7116649B2 (en) * 2000-11-10 2006-10-03 Sony Corporation Multiple-user CDMA wireless communication system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11331124A (ja) * 1998-05-12 1999-11-30 Matsushita Electric Ind Co Ltd Ｃｄｍａ方式通信機
US6963601B1 (en) * 1999-02-04 2005-11-08 Samsung Electronics Co., Ltd. Apparatus and method for spreading channel data in CDMA communication system using orthogonal transmit diversity
US7002901B2 (en) * 1999-12-02 2006-02-21 Samsung Electronics Co., Ltd. Apparatus and method for transmitting and receiving data in a CDMA communication system
US7116649B2 (en) * 2000-11-10 2006-10-03 Sony Corporation Multiple-user CDMA wireless communication system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120093200A1 (en) * 2010-10-14 2012-04-19 Electronics And Telecommunications Research Institute Continuous orthogonal spreading code based ultra-high performance array antenna system

Similar Documents

Publication Publication Date Title
EP0925652B1 (fr) Demodulation coherente avec estimation de canal a commande decisionnelle pour communication numerique
US7133459B2 (en) Space-time transmit diversity
US7218666B2 (en) Method and system for transmission and frequency domain equalization for wideband CDMA system
US7778355B2 (en) Space-time transmit diversity
US6721293B1 (en) Unsupervised adaptive chip separation filter for CDMA terminal
US20060153283A1 (en) Interference cancellation in adjoint operators for communication receivers
US7496128B2 (en) Multi-user interference resilient ultra wideband (UWB) communication
US7340009B2 (en) Space-time coding for multi-antenna ultra-wideband transmissions
Lee et al. Comparison of multicarrier DS-CDMA broadcast systems in a multipath fading channel
CN101467380B (zh) 用于估计噪声变化量的方法和设备
US7558309B2 (en) Low-interference UWB wireless communication system and processing method thereof and storage medium recorded program of the same
US8594154B2 (en) Apparatus and method for transmitting and receiving signal in multi-antenna communication system
KR100862726B1 (ko) 통신 시스템의 신호 송신 방법 및 수신 방법
WO2008066348A1 (fr) Méthode d'émission et réception d'un signal dans un système de communication
US20160173207A1 (en) Method and Apparatus for Implementing Wireless Body Area Network
Wang High-Speed Wireless Communications: Ultra-wideband, 3G Long Term Evolution, and 4G Mobile Systems
KR101320779B1 (ko) 다중 안테나 통신 시스템의 신호 송수신 장치 및 방법
Mahmood et al. Rayleigh fading channel estimation using MMSE estimator for MIMO-CDMA system
KR101425859B1 (ko) Ｉｒ-ｕｗｂ 시스템 기반의 성능 향상 방법과 그를 위한 ｕｗｂ 수신 장치
Kumaratharan et al. STSIC detection for multi-user MIMO MC-CDMA systems
Taban Space-time coding for CDMA-based wireless communication systems
Huang et al. A more accurate analysis of interference for rake combining on DS-CDMA forward link in mobile radio
D'Amours et al. Permutation spreading for asynchronous MIMO-CDMA systems using Hadamard codes and gold scrambling sequences
Stefanovic et al. Simulation models of RAKE receiver in DS-CDMA multipath propagation environment
Dahmane et al. Parity bit selected spreading for MIMO-CDMA using Hadamard codes and Gold scrambling sequences

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07851163

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07851163

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 12517175

Country of ref document: US

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载