WO2003024049A1 - Methode de codage de source permettant de reduire le brouillage - Google Patents

Methode de codage de source permettant de reduire le brouillage Download PDF

Info

Publication number
WO2003024049A1
WO2003024049A1 PCT/US2002/028210 US0228210W WO03024049A1 WO 2003024049 A1 WO2003024049 A1 WO 2003024049A1 US 0228210 W US0228210 W US 0228210W WO 03024049 A1 WO03024049 A1 WO 03024049A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
low energy
length
encoding
computer code
Prior art date
Application number
PCT/US2002/028210
Other languages
English (en)
Inventor
Haruhiko H. Asada
Chun-Hung Liu
Erin Cem
Kai-Yeung Siu
Original Assignee
Massachusetts Institute Of Technology
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
Application filed by Massachusetts Institute Of Technology filed Critical Massachusetts Institute Of Technology
Publication of WO2003024049A1 publication Critical patent/WO2003024049A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
    • H04J11/0023—Interference mitigation or co-ordination
    • H04J11/0026—Interference mitigation or co-ordination of multi-user interference
    • H04J11/0036—Interference mitigation or co-ordination of multi-user interference at the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits
    • H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
    • H04L25/4906—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using binary codes
    • H04L25/4908—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using binary codes using mBnB codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/10—Code generation

Definitions

  • the present invention relates to multiple access systems and more specifically to encoding techniques for multiple access systems.
  • the multiple access interference (MAI) in each receiver increases along with the number of users in the system and therefore the capacity of a given frequency is limited.
  • a method of encoding a transmission signal to reduce multiple access interference at a receiver A data source signal including a plurality of source symbols is received into a transmitter. The source symbols are encoded using low energy encoding forming encoded codewords. An identifying pattern is applied to the encoded codewords forming a transmission signal. In one embodiment, the identifying pattern is a unique pseudo-random pattern identifying the data source. Once the pattern has been added, multiple transmission signals can be summed together and then modulated onto a carrier wave. The transmission signals are then transmitted on the carrier wave which is at a pre-selected frequency.
  • the low energy encoding format is such that a sequence of signals forming codewords is created wherein the length of the codewords is greater than a traditional binary format such that the length of the codewords in an alphabet of 256 source symbols would be greater than 8bits.
  • Each sequence of signals is characterized by an energy and normally a high bit consumes energy whereas a low bit requires substantially less energy.
  • the redundant bits allow for the creation of codes that reduce the number of transmitted high bits and therefore reduce the multiple access interference.
  • each codeword signifies a specified source symbol on the basis of a mapping between source symbols and codewords mapped such that each symbol of lower probability of occurrence is associated with a codeword of at least equal energy.
  • a modulated signal having multiple transmitted signals thereon is received wherein each transmitted signal is encoded using low energy encoding.
  • the receiver identifies a transmitted signal according to a unique identifying pattern within the signal and the transmitted signal is decoded using low energy decoding.
  • the methodology as described may be used with a code division multiple access system.
  • the capacity of a frequency in a code division multiple access system is determined by selecting a length for low energy encoding. Then based upon the system's bit energy to noise ratio a maximum number of transmitters can be determined. Such a capacity can be communicated to a control module so that transmitters will limit- assignment to selected frequencies such that the number of transmission signals is below that of the maximum determined.
  • the length of the codewords may be determined based upon system parameters and the number of source symbols in the alphabet.
  • the length of a codeword may be determined by obtaining a signal to noise ratio for a frequency and determining a binary length based upon the number of source symbols.
  • a critical length is then determined.
  • the critical length can be determined by substituting the binary length and the signal to noise ratio into a formula or through a look-up table.
  • the codeword length for low energy encoding is set at or below the critical length. It should be understood that other system parameters may be used to calculate the critical length such as the number transmission signals for a frequency and the bit energy to noise ratio fro the system.
  • the method as described may be embodied on a computer program product for use with a computer wherein the computer program product has computer readable code thereon.
  • the method may also be embodied in a system wherein the system includes a low energy data source encoder for encoding a data source into codewords using low energy encoding. Additionally the system has a pseudo-random pattern generator wherein each pseudorandom generator adds a pseudorandom signal to the codewords for the data source forming a transmission signal and a modulator for modulating each transmission signal on a carrier frequency.
  • the system also includes a summer module for summing transmission signals prior to modulation.
  • the system may include a plurality of pseudorandom pattern generators and a plurality of low energy encoding modules so that parallel processing may occur.
  • a decoder system that includes a signal receiver that receives the modulated signal and performs demodulation.
  • the decoder system also has low energy decoder module.
  • a desired transmission signal is identified by its unique pseudorandom signal and is sent through a correlation process. After the desired transmission signal is separated out, the decoder decodes the transmission signal and the original source symbols are retrieved from the codewords using a look-up table.
  • Fig. 1 graphically represents the principle of the encoding technique which will be referred to as low energy encoding.
  • Fig. 2 shows the entire set of usable codewords sorted by the number of high bits for low energy encoding.
  • Fig. 3 is flow chart of a method for encoding a code division multiple access signal in order to reduce multiple access interference that more formally explains one embodiment of the invention
  • Fig. 4 is a graphic showing multiple data signals being transmitted at the same time using low energy encoding such that very few high bits are transmitted simultaneously thereby reducing the MAI at the receiver;
  • Fig. 5 shows one embodiment of a system for transmission of a code division multiple access signal encoded with low energy encoding;
  • Fig. 6 shows one embodiment of a system for receiving a modulated signal transmitted by the system of Fig. 5;
  • Fig. 7 is a flow chart showing one embodiment for calculating a length for the low energy encoded codewords.
  • Fig. 8 is a graph showing the ratio of LJL b versus Eb/N 0 .
  • a pseudo-random pattern generator adds a unique pseudo-random pattern to each data source signal in order to provide an identifier of the data source at the receiver. This unique pattern is added prior to all data sources being combined and prior to the combined data sources being transmitted to a receiver.
  • This pseudo-random pattern is a spreading signal that has a chip rate that is orders of magnitude greater than the bit rate of the source.
  • Each data source has its own unique pseudo-random pattern that is approximately orthogonal to all other patterns. This allows the receiver in such a system to perform a time correlation operation to detect only the specific desired pattern and thus identify the data source. All other patterns appear as noise due to decorrelation. The receiver can then demodulate the chip pattern from the data source and the data source is recovered.
  • a further encoding technique is employed prior to adding the pseudo-random pattern in order to reduce multiple access interference.
  • multiple access interference occurs as more and more data sources are added at the transmission side of a code division multiple access system.
  • the data sources other than the desired data source appear as noise.
  • the noise floor is increased and at a point the noise floor becomes so high that the desired data source cannot be identified from the noise. The increased noise occurs as the result of multiple data sources sending high bits of information at the same time.
  • the additional coding technique reduces the number of sent high bits and thus decreases the amount of MAI, therefore allowing the number of data sources to be increased for a single transmission carrier frequency without the need for changing the receiver or increasing the signal power to increase the signal to noise ratio.
  • the encoding provides a lower energy transmission per codeword on average as compared to a standard binary transmission system (e.g. an 8bit codeword corresponds to 256 possible source symbols in a standard binary transmission).
  • the additional encoding technique is based on on-off keying. In on- off keying power is consumed when a high bit is transmitted. In this encoding technique additional bits are added as compared to that of a standard binary transmission.
  • Figure 1 graphically represents the principle of the encoding technique which will be referred to as low energy encoding.
  • Low energy encoding is generated through two distinct steps which are codebook optimality and coding optimality. The former step requires determining a set of codewords, minimizing the high bits, and the latter step requires assigning codewords having less high bits to symbols with higher probability of occurrence.
  • codewords abounding in high bits are not preferred. For example,
  • Fig. 3 is flow chart that more formally explains one embodiment of the invention.
  • First a data source signal is received 300.
  • the data source signal contains a number of source symbols within the signal.
  • the source symbols may be ASCI symbols or letters of the alphabet for example.
  • Associated with each source symbol is a known probability of occurrence.
  • the known probability may be statistically based upon other data sources or more locally determined based upon the actual data source.
  • the system then encodes the source signal using the low energy encoding technique 310.
  • a length is first calculated for the codewords. The length should be longer than that of a standard binary encoder. Adopting an excessively long codeword results in traffic congestion within the communication network and increases the error probability that a codeword will be decoded incorrectly by the receiver.
  • codewords are associated with source symbols.
  • the source symbol having the highest probability of occurrence is provided with the codeword exhibiting the least amount of energy. For example, if the length of the codewords is 1 Obits the source symbol having the highest probability of occurrence would be associated with a code word of all zeros having the lowest power transmission (0000000000). Similarly a source symbol having the next highest probability of occurrence would be associated with a codeword that had only one high bit.
  • next nine source symbols having the next nine highest probabilities of occurrence would be associated with codewords with only one high bit (0000000001, 0000000010, 0000000100, 0000001000, etc.) It could be imagined that other keying could be used in place of on-off keying, but in any event the highest probability source symbol should be associated with the codeword that produces the lowest power output when transmitted.
  • a pseudo-random number signal is added to the low energy encoded signal 320. This is achieved by using a unique chip signal that has a frequency that is much greater than that of the encoded data source. This unique chip signal allows multiple data sources to be transmitted on the same frequency. Once the low energy encoded signal and the pseudo-random chip pattern are integrated, the resulting encoded signal is modulated onto the carrier frequency for transmission into the transmission channel 330. It should be understood that each low energy encoded data source is assigned a unique pseudo-random chip signal for identification purposes and that multiple data sources are combined and modulated on the same frequency.
  • Fig. 4 shows multiple data signals that have been low energy encoded being transmitted at the same time such that very few high bits are transmitted simultaneously thereby reducing the MAI at the receiver.
  • d(t) represents the original data source data encoded by low-energy encoding
  • c(t) represents the unique pseudo-random chirping pattern signal
  • cos ⁇ t is the carrier frequency used for transmitting the signals to the receiver.
  • FIG. 5 A system for transmitting a CDMA signal that is low energy encoded is shown in Fig. 5.
  • Multiple data sources 505 are provided to the transmission system 500.
  • Each data source is passed to a low energy encoder module 510.
  • the low energy encoder module 510 associates the source symbols of the data source with codewords.
  • First a codeword length is determined. This length may be predetermined and associated with the low energy encoder or it may be calculated by the low energy encoder.
  • the method for determining the length of the codewords is provided below with respect to Fig. 7.
  • the codewords are assigned such that the energy of the codeword is associated in reverse order with the probability of occurrence of the source symbol.
  • the code word source symbol association would be (35% 0000), (25% 0001), (20% 0010), (10% 0100), (7% 1000) and (3% 0011).
  • the association is such that higher probabilities are associated with lower energies.
  • the source symbol having a 25% probability could have just as easily been associated with codeword 0010.
  • the low energy encoder module 510 may maintain in a look-up table a listing of the probability of occurrence for a source symbol.
  • the probability of occurrences may be transmitted in conjunction with the data source or the low energy encoder may determine the probability of occurrence based upon the received data source by tabulating the occurrence of each source symbol as the source symbols is processed.
  • the assignment of codewords and source symbols is performed each time a data source is presented to the system for transmission and the association is then stored in a look-up table (LUT). In other embodiments, this association between codewords and source symbols is predetermined and stored in a LUT.
  • the low energy encoder module 510 identifies the source symbols received in the data source signal stream.
  • the low energy encoding module 510 accesses the LUT and selects the appropriate codeword based upon the identified source symbol.
  • the codeword is then passed in a streaming fashion to the pseudo-random pattern generator module 520.
  • the pseudo-random pattern generator module multiples 520 the encoded data source signal with a unique chip signal c(t) that aids in identifying the data source upon decoding. Pseudo-random pattern generator modules are known to those of ordinary skill in the art and need not be elaborated on here.
  • a summer module 530 which in turn passes the summed signals to a modulator 540 for placing the summed signals on a carrier frequency.
  • the modulator 540 than transmits the modulated signal into a network channel.
  • Fig. 6 shows the system for receiving the modulated signal from the transmission system of Fig. 5.
  • a receiver module 610 of the receiver system 600 receives the modulated signal.
  • the receiver 610 demodulates the summed signal from the carrier frequency and passes the summed signal to a demodulator 620.
  • a pseudo-random pattern generator 630 which operates in the same manner as the pseudo-random pattern generator in the transmitter produces a unique pattern for a desired data source. That unique pattern is then used in the demodulation process.
  • the pseudo-random pattern generator 630 For instance, if data source 1 is to be identified and demodulated the pseudo-random pattern generator 630 generates the same pseudorandom pattern that was used to encode data source 1 originally.
  • the demodulator 620 performs a correlation whereby the only signal that is retrieved is the signal for data source 1 and the other data source signals appear as noise.
  • the data source signal is then passed to a low energy decoder module 640.
  • the low energy decoder module 640 performs the inverse task of the encoder and associates the identified codewords in the stream with the source symbols.
  • the low energy decoder module 640 include a LUT which has the same associations between codewords and source symbols as that of the receiver.
  • the low energy decoder 640 therefore identifies the codeword in the stream, performs a look-up function with the LUT and then outputs a source symbol that corresponds to the codeword.
  • the stream of source symbols that is output from the low energy decoder 640 is associated with a particular data source such as data source 1 as shown in the Fig 6.
  • the length of the codewords could continually be extended in order to reduce the likelihood that multiple transmitters would be transmitting high bits simultaneously.
  • factors such as network congestion and transmission error counter such an extension.
  • the length needs to be based in part on the necessary transmission rate and should balance the probability of codeword error with the benefit of reduced MAI.
  • the length therefore is based upon the given system performance and the transmission rate.
  • a theoretical model for the performance of a DS-CDMA system with BPSK modulation and MAI cancellation has been developed with regard to average bit error probability Y.C. Yoon, R. Kohno and H. Imai, "Spread- spectrum multi-access system with co-channel interference cancellation for multipath fading channel," IEEE J. Selected Areas Communication, Vol. 11, No.7, pp. 1067-1075, May 1992 which is incorporated by reference herein in its entirety.
  • the error probability per bit which for a low energy encoded system can be
  • L is the minimum length for a binary representation of the possible source symbols. For example if there are 8 source symbols, the binary length would be 3.
  • ⁇ is the percentage of high bits for the data source d ⁇ during a transmission duration of T
  • Fig. 7 is a flow chart showing the steps that are necessary for determining the length of the codewords.
  • the bit energy to noise ratio for the system is selected (700). This value may be predefined as a result of the transmitter and receiver design.
  • the number of different source symbols is also determined ( ⁇ ) (710). Again this value is likely predefined and is dependent on the communication scheme.
  • the total number of transmitters is selected (M) (720).
  • the critical length can be determined (730).
  • the S ⁇ R LE is determined with the variable N M and E ⁇ /No for a given a . Knowing the SNR LE , a simple substitution produces a value for L c .
  • the codeword length is selected to be equal to or less than the critical length (740).
  • the length of a L ⁇ codeword can be determined based on the rule: L LE ⁇ min ( 10 4 Z fc , ? min ⁇ ) where 7 ⁇ is the bit duration.
  • the length depends on the system design parameters and the transmission rate.
  • presuming a length of the codewords and the transmitting a high bit the number of possible transmitters for a given system can be calculated.
  • logic may be partitioned into different logic blocks (e.g., programs, modules, functions, or subroutines) without changing the overall results or otherwise departing from the true scope of the invention.
  • logic elements may be added, modified, omitted, performed in a different order, or implemented using different logic constructs (e.g., logic gates, looping primitives, conditional logic, and other logic constructs) without changing the overall results or otherwise departing from the true scope of the invention.
  • the present invention may be embodied in many different forms, including, but in no way limited to, computer program logic for use with a processor (e.g., a microprocessor, microcontroller, digital signal processor, or general purpose computer), programmable logic for use with a programmable logic device (e.g., a Field Programmable Gate Array (FPGA) or other PLD), discrete components, integrated circuitry (e.g., an Application Specific Integrated Circuit (ASIC)), or any other means including any combination thereof.
  • a processor e.g., a microprocessor, microcontroller, digital signal processor, or general purpose computer
  • programmable logic for use with a programmable logic device
  • FPGA Field Programmable Gate Array
  • ASIC Application Specific Integrated Circuit
  • Source code may include a series of computer program instructions implemented in any of various programming languages (e.g., an object code, an assembly language, or a high-level language such as Fortran, C, C++, JAVA, or HTML) for use with various operating systems or operating environments.
  • the source code may define and use various data structures and communication messages.
  • the source code may be in a computer executable form (e.g., via an interpreter), or the source code may be converted (e.g., via a translator, assembler, or compiler) into a computer executable form.
  • the computer program may be fixed in any form (e.g., source code form, computer executable form, or an intermediate form) either permanently or transitorily in a tangible storage medium, such as a semiconductor memory device (e.g., a RAM, ROM, PROM, EEPROM, or Flash-Programmable RAM), a magnetic memory device (e.g., a diskette or fixed disk), an optical memory device (e.g., a CD-ROM), a PC card (e.g., PCMCIA card), or other memory device.
  • the computer program may be fixed in any form in a signal that is transmittable to a computer using any of various communication technologies, including, but in no way limited to, analog technologies, digital technologies, optical technologies, wireless technologies, networking technologies, and internetworking technologies.
  • the computer program may be distributed in any form as a removable storage medium with accompanying printed or electronic documentation (e.g., shrink wrapped software or a magnetic tape), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the communication system (e.g., the Internet or World Wide Web.)
  • printed or electronic documentation e.g., shrink wrapped software or a magnetic tape
  • a computer system e.g., on system ROM or fixed disk
  • a server or electronic bulletin board over the communication system (e.g., the Internet or World Wide Web.)
  • Hardware logic including programmable logic for use with a programmable logic device
  • implementing all or part of the functionality previously described herein may be designed using traditional manual methods, or may be designed, captured, simulated, or documented electronically using various tools, such as Computer Aided Design (CAD), a hardware description language (e.g., VHDL or AHDL), or a PLD programming language (e.g., PALASM, ABEL, or CUPL.)
  • CAD Computer Aided Design
  • a hardware description language e.g., VHDL or AHDL
  • PLD programming language e.g., PALASM, ABEL, or CUPL.

Abstract

L'invention concerne un méthode de codage d'un signal de transmission, permettant de réduire le brouillage induit par plusieurs accès au niveau d'un récepteur. Cette méthode consiste à recevoir un signal de source de données comprenant une pluralité de symboles source dans un émetteur, à coder ces symboles source par codage à faible énergie pour former des mots codés et à appliquer un schéma d'identification aux mots codés pour former un signal de transmission. Dans un mode de réalisation, le schéma d'identification est un schéma pseudoaléatoire unique identifiant la source de données. Une fois le schéma ajouté, plusieurs signaux de transmission peuvent être additionnés, puis modulés sur une onde porteuse. Les signaux de transmission sont ensuite transmis sur l'onde porteuse ayant la fréquence présélectionnée. Le format de codage à faible énergie permet de créer la séquence de mots codés formant les signaux. Chaque séquence de signaux est caractérisée par une énergie. En principe, un débit binaire élevé consomme de l'énergie, alors qu'un faible débit binaire requiert sensiblement moins d'énergie.
PCT/US2002/028210 2001-09-06 2002-09-05 Methode de codage de source permettant de reduire le brouillage WO2003024049A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US31769101P 2001-09-06 2001-09-06
US60/317,691 2001-09-06

Publications (1)

Publication Number Publication Date
WO2003024049A1 true WO2003024049A1 (fr) 2003-03-20

Family

ID=23234836

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2002/028210 WO2003024049A1 (fr) 2001-09-06 2002-09-05 Methode de codage de source permettant de reduire le brouillage

Country Status (1)

Country Link
WO (1) WO2003024049A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11363633B2 (en) 2016-03-30 2022-06-14 Sony Corporation Device and method in radio communication system, and radio communication system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000011845A1 (fr) * 1998-08-21 2000-03-02 Massachusetts Institute Of Technology Protocole de communication puissant
EP1069798A1 (fr) * 1999-07-12 2001-01-17 Lucent Technologies Inc. Réseau de système universel de télécommunications mobiles (UMTS) avec procédé amelioré d'adaptation de débit

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000011845A1 (fr) * 1998-08-21 2000-03-02 Massachusetts Institute Of Technology Protocole de communication puissant
EP1069798A1 (fr) * 1999-07-12 2001-01-17 Lucent Technologies Inc. Réseau de système universel de télécommunications mobiles (UMTS) avec procédé amelioré d'adaptation de débit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEN T-T ET AL: "TCM/SSMA COMMUNICATION SYSTEMS WITH CASCADED SEQUENCES AND PAM/QAM SIGNAL SETS", IEEE TRANSACTIONS ON COMMUNICATIONS, IEEE INC. NEW YORK, US, vol. 46, no. 7, 1 July 1998 (1998-07-01), pages 950 - 956, XP000779693, ISSN: 0090-6778 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11363633B2 (en) 2016-03-30 2022-06-14 Sony Corporation Device and method in radio communication system, and radio communication system

Similar Documents

Publication Publication Date Title
EP0712219B1 (fr) Méthode et dispositif pour la détection d'un débit variable d'une transmission de données
EP0439925B1 (fr) Décodage au maximum de vraisemblance avec détection d'interférence, pour systèmes de modulation codée à évasion de fréquence
JP4915450B2 (ja) ネットワーク符号化方法およびネットワーク符号化装置
IL102766A (en) An orthogonal coding device in communication systems
RU96112180A (ru) Способ и устройство для передачи цифровых данных с переменной скоростью передачи
KR20030025298A (ko) 라디오 통신 네트워크에서의 복수 입력 복수 출력 송신시스템
US7376105B2 (en) Source coding for interference reduction
WO2002065724A1 (fr) Procede de modulation de niveaux multiples, procede de demodulation de niveaux multiples, et procede de modulation/demodulation de niveaux multiples
CN100546203C (zh) 在结合无线电接入网使用的设备中的速率匹配方法、设备和系统
KR102111975B1 (ko) 희소 코딩을 이용한 정보 전송 방법 및 장치
TWI389487B (zh) 通信站及無線通信方法
US11539463B2 (en) Methods and computing device for facilitating multiple access in a wireless communication network
US6134696A (en) Encoding and decoding rate-1/n convolutional codes and their punctured versions
KR100704350B1 (ko) 확산 스펙트럼 계수 가변의 다중 사용자 복조 방법
WO2003024049A1 (fr) Methode de codage de source permettant de reduire le brouillage
Vlachos et al. Performance study of hybrid spread-spectrum random-access communications
CN112311711B (zh) 一种m-fsk调制方法、装置及系统
US7769077B2 (en) Diversity transmitter-receiver in CDMA system using space-time code, and method thereof
EP1444797A1 (fr) Codulation de polarisation d'antenne
CN101764667A (zh) 无线发送设备、方法和无线接收设备、方法
KR100640923B1 (ko) 전송 포맷 조합 식별자 엔코딩 방법
KR100761669B1 (ko) 유사직교부호화 송신 및 수신 시스템
Ahmed Block-size estimation and application to BTFD for 3GPP UMTS
KR102509820B1 (ko) 적어도 두 개의 송신기들에 의해 수신기들로 독립 데이터를 전송하는 방법 및 시스템
Park et al. Multistage decision-directed channel estimation scheme for DS-CDMA system with M-ary orthogonal signaling

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FR GB GR IE IT LU MC NL PT SE SK TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP