WO2001031823A1 - Acces sans fil a large bande base sur l'acces parallele par repartition de code - Google Patents

Acces sans fil a large bande base sur l'acces parallele par repartition de code Download PDF

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Publication number
WO2001031823A1
WO2001031823A1 PCT/US1999/024778 US9924778W WO0131823A1 WO 2001031823 A1 WO2001031823 A1 WO 2001031823A1 US 9924778 W US9924778 W US 9924778W WO 0131823 A1 WO0131823 A1 WO 0131823A1
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WO
WIPO (PCT)
Prior art keywords
walsh
codes
code
walsh code
user identification
Prior art date
Application number
PCT/US1999/024778
Other languages
English (en)
Inventor
Saleh Faruque
Fereidoun Homayoun
Payam Maveddat
Wing Lo
Original Assignee
Nortel Networks Corporation
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 Nortel Networks Corporation filed Critical Nortel Networks Corporation
Priority to AU11313/00A priority Critical patent/AU1131300A/en
Priority to PCT/US1999/024778 priority patent/WO2001031823A1/fr
Publication of WO2001031823A1 publication Critical patent/WO2001031823A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/16—Code allocation
    • H04J13/18—Allocation of orthogonal codes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/28—Arrangements for preventing distortion of, or damage to, presses or parts thereof
    • B30B15/285—Arrangements for preventing distortion of, or damage to, presses or parts thereof preventing a full press stroke if there is an obstruction in the working area
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16P—SAFETY DEVICES IN GENERAL; SAFETY DEVICES FOR PRESSES
    • F16P3/00—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/004—Orthogonal
    • H04J13/0048—Walsh
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0077—Multicode, e.g. multiple codes assigned to one user

Definitions

  • the present invention relates to radio communications. More particularly, the present invention relates to mobile communication in a code division multiple access system.
  • Multiple access techniques are designed to make efficient use of the limited radio frequency spectrum. They allow users to access the same band of frequency without interfering with each other. Examples of such techniques include time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA).
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • CDMA code division multiple access
  • CDMA wireless technology governed by Electronic Industry Association/Telecommunication Industry Association Interim Specification - 95 (IS- 95), employs a spread spectrum technique for the transmission of information.
  • a spread spectrum system uses a modulation technique that spreads the transmitted signal over a wide frequency band. This frequency band is typically substantially wider than the minimum bandwidth required to transmit the signal.
  • a form of frequency diversity is obtained by spreading the transmitted signal over a wide frequency range. Since only part of a signal is typically affected by a frequency selective fade, the remaining spectrum of the transmitted signal is unaffected. A receiver that receives the spread spectrum signal, therefore, is affected less by the fade condition than a receiver using other types of signals.
  • the spread spectrum technique is accomplished by modulating each base band data signal to be transmitted with a unique wide band spreading code. Using this technique, a signal having a bandwidth of only a few kilohertz can be spread over a bandwidth of more than a megahertz. Typical examples of spread spectrum techniques are found in M.K. Simon, Spread Spectrum Communications, Volume I, pp. 262-358.
  • multiple signals are transmitted simultaneously on the same frequency.
  • a particular receiver determines which signal is intended for that receiver by the unique, orthogonal spreading code, referred to as a Walsh code, in each signal.
  • FIGs. 1A and IB A generic CDMA transmitter and receiver are illustrated in FIGs. 1A and IB respectively.
  • the transmitter in FIG. 1A convolutionally encodes (100) an input data signal.
  • the encoded signal is spread (105) by the Walsh code (106) such that the output of the spreading operation yields the symbol stream of the Walsh code representing "0" and the complement of the Walsh code representing "1". This output is then modulated (110).
  • the receiver of FIG. IB demodulates (115) the received signal.
  • the demodulated signal is then despread (120) using the same Walsh code (116).
  • the de-spread signal is de-interleaved and input to the Viterbi decoder (125).
  • symbol-0 is represented by a
  • Walsh code and symbol- 1 is represented by its complementary Walsh code. Since W l and W , are non-orthogonal to each other, the bit error rate performance of this scheme is solely determined by the forward error control coding.
  • the forward error control coding scheme is well known in the art.
  • IS-95 CDMA cannot reduce interference or improve capacity any further.
  • the symbol stream to be transmitted is the Walsh code and its complement which are always non-orthogonal. Therefore, a conventional IS-95 CDMA receiver correlates with a pair of non-orthogonal signals.
  • the present invention encompasses a multi-orthogonal code division parallel access apparatus for operation in a wireless communication system.
  • the system is comprised of a network of base stations that communicate with wireless devices.
  • the wireless device requests a number of user identification (ID) codes from the base station with which it is communicating.
  • ID user identification
  • the apparatus is comprised of a memory that stores a plurality of 2"-bit Walsh codes.
  • the memory is addressed by the user ID's such that each unique user ID generates a corresponding unique Walsh code from the memory.
  • a Walsh code register is coupled to the memory and the input data stream.
  • the register covers a predetermined number of bits of the input data stream with a predetermined Walsh code to generate a serial symbol stream that is orthogonal to other symbol streams in the communication system.
  • a modulator coupled to the Walsh code register, modulates the symbol stream for transmission over a wireless channel.
  • MSK minimum shift keying
  • the base station of the present invention is a satellite that communicates with terrestrial radiotelephones able to receive satellite signals.
  • terrestrial base stations are used.
  • the present invention may be used in both the base stations and the wireless devices. Alternate embodiments use the present invention in only the base stations or only the wireless devices.
  • FIG. 1A and IB show a block diagram of a typical prior art transmitter and receiver in a CDMA system.
  • FIG. 2 shows a block diagram of the m-orthogonal Walsh code division parallel access apparatus of the present invention.
  • FIG. 3 shows a block diagram of the / ⁇ -orthogonal demodulation and decoding apparatus of the present invention.
  • FIG. 4 shows a quadri-orthogonal code division parallel access apparatus of the present invention.
  • FIG. 5 shows a representation of the Walsh codes and bandwidth in accordance with FIG. 4.
  • FIG. 6 shows an octo-orthogonal code division parallel access apparatus of the present invention.
  • FIG. 7 shows a representation of the Walsh codes and bandwidth in accordance with FIG. 6.
  • FIG. 8 shows a Walsh code representation of a multitasking use of the m- orthogonal Walsh code generation of the present invention.
  • FIG. 9 shows a Walsh code decoding rule in accordance with the present invention.
  • FIG. 10 shows a plot of symbol error rate versus E b/N 0 -
  • FIG. 11 shows a Web Radio system implementation of the present invention.
  • FIG. 12 shows a flowchart of a code division parallel access process used by a wireless device of the present invention.
  • FIG. 13 shows a flowchart of a code division parallel access process used by a base station of the present invention.
  • the /n-orthogonal process and apparatus of the present invention is a parallel access technique that assigns two or more orthogonal codes to each user. This permits orthogonality in two dimensions, between each user in a communication system and within a y user's own signal bursts. The present invention, therefore, lowers the symbol error rate while increasing system capacity.
  • the number of orthogonal codes assigned to each user is variable, depending on the type of information to be transmitted, and proportional to the information rate. Video, data, and voice each have different bandwidth and error requirements that require varying data rates and, thus, varying quantities of orthogonal codes.
  • FIG. 2 illustrates a block diagram of the / ⁇ -orthogonal Walsh code division parallel access apparatus of the present invention.
  • the required number of n.-bit user identifications (IDs) or addresses is transmitted from the base station to the radiotelephone over a paging channel.
  • the user IDs are six bit addresses.
  • the user IDs uniquely identify the radiotelephone to the system in a similar fashion as CDMA user IDs. As is well known in the CDMA art, each radiotelephone recognizes only those received signals that have been covered by orthogonal Walsh codes generated by those particular user IDs.
  • the base station knowing in advance the type of information that will be transmitted to the radiotelephone, transmits to the radiotelephone the required number of user IDs to generate the Walsh codes. This enables the radiotelephone to despread a received signal.
  • the radiotelephone knowing in advance the type of information that it is going to transmit, requests the required number of user ID's from the base station. The radiotelephone then uses these user IDs to generate the Walsh codes required. These Walsh codes are then used to spread the symbols to be transmitted to the base station.
  • the number of orthogonal codes required by the radiotelephone is based on the type of information that the radiotelephone is going to transmit or receive.
  • An example of different types of information and the required number of codes is illustrated in FIG. 8.
  • FIG. 8 illustrates the number of codes required, in the preferred embodiment, for each type of information in a multitasking scheme.
  • Multitasking is a process in which multiple services, such as voice, data, video, and others, are provided over the same channel.
  • the radiotelephone Since voice service has the lowest bit rate of R j . kbps, the radiotelephone is assigned two Walsh codes, Wl and W2, per voice channel. Data has the next highest data rate of 2R j . kbps and is assigned four Walsh codes, W3 - W6, per data channel. Video requires the highest data rate of 4R,. kbps and is assigned eight
  • Walsh codes W7 — W14, per video channel.
  • An orderwire option requires only two Walsh codes, W15 and W16, per channel.
  • orderwire is a special service that might be activated during a radiotelephone call.
  • This special service can include, for example, a customer survey.
  • Walsh code requirements for each type of information is one example. Alternate embodiments assign other quantities of Walsh codes to the various types of information. For example, for lower quality voice data, only one Walsh code may be assigned to the radiotelephone.
  • A-bit address words are generated by splitting the input binary data into A-parallel streams.
  • the A-bit address words generate a spreading bandwidth of:
  • n is the number of bits in the Walsh code
  • R j is the information rate
  • A is the number of parallel streams of input binary data.
  • the received user IDs are used as the n-bit addresses to the 2" x 2 n bit read only memory (ROM) (201).
  • the user IDs are latched into the a dress roist (210) in the order that they arp received.
  • the ROM (201) contains the Walsh codes used in the radiotelephone system.
  • the binary data to be transmitted is input to a data register (215).
  • the input signal is a low speed NRZ data signal having a narrow power spectrum.
  • the data is output at a rate of R b/m kbps, where m is the length of the data register (215).
  • This data rate is required due spreading of each symbol by a Walsh code from the ROM. The spreading occurs in the Walsh code register (205).
  • This register accepts the Walsh codes output from the Walsh code ROM (201) and the binary data to be encoded. This operation generates the spread data for transmission and is output from the Walsh code register (205) at a rate of 2" R ⁇ / kbps.
  • FIGs. 4 and 6, discussed later, illustrate different embodiments for the Walsh code register (205). Another embodiment is an exclusive-OR operation involving the Walsh code and the input binary data.
  • the spread symbols are input to the minimum shift keying (MSK) modulator (220) for modulation to the intermediate frequency before transmission over the channel.
  • MSK minimum shift keying
  • the digital portion (200) of fhe -orthogonal Walsh code generating apparatus in the preferred embodiment, is implemented in a computer.
  • a computer An example of such a computer is the APPLE MACINTOSH POWERBOOK 1400. Other makes and models of computers running different operating systems can also be used.
  • the apparatus can be implemented using discrete logic such as separate registers and memory to perform the illustrated functions.
  • the apparatus is implemented in a digital signal processor.
  • the modulator can be built into a specialized computer. With this set-up, the user does not have to purchase and install any additional parts.
  • Orthogonal decoding is a process of code recovery from the output of the demodulator. The recovery is accomplished by code correlation.
  • the orthogonal decoding process is illustrated in FIG. 3.
  • the incoming impaired Walsh code at a rate of 2"R b kbps, is examined for correlation with one of the 2" bit Walsh codes stored in the Walsh code ROM (301).
  • the recovered code is loaded into the Walsh code shift register (302).
  • the decision threshold used to generate the binary data is illustrated in FIG. 9.
  • the decision threshold is set midway between the two orthogonal codes. Since an orthogonal code has equal numbers of logical l's and logical 0's, a 2"-bit orthogonal code will have 2 7 2 logical l's and 2 72 logical 0's. The distance between two orthogonal codes is also 2 2 and, therefore, the decision threshold is 2 7 .
  • the symbol error rate for a false detection is therefore 2 7 — 1.
  • P e is the symbol error rate.
  • P(W) and P e are plotted in FIG. 10 as a function of ⁇ b/ ⁇ 0 .
  • This plot shows that the symbol error rate approaches 0.25 while the Walsh code error rate also approaches 0.25.
  • the probability of accepting a true Walsh code is equal to the probability of rejecting a false Walsh code which is equal to X .
  • P(W) ⁇ 0.25 the correlator will always detect the valid Walsh code that corresponds to the error free n-bit information.
  • One embodiment of the Walsh code register (205) of FIG. 2 is illustrated in
  • FIG. 4 This embodiment illustrates a quadri-orthogonal code division parallel access apparatus.
  • the radiotelephone has requested four user IDs from the base station.
  • the first user ID is applied to the Walsh code ROM (see FIG. 2) as an address.
  • the 64-bit Walsh code generated from that user ID is loaded into a first shift register (405). This process is repeated for the remaining three user IDs that generate Walsh codes that are loaded into the remaining shift registers (410, 415, and 420).
  • the binary data to be spread is input to a two-bit register (430) or similar device at a rate of 9.6 kbps.
  • the register (430) is coupled to the selection inputs of a multiplexer (425).
  • the data is output from the register (430) to the selection inputs at a rate of 4.8 kbps.
  • the shift registers (405, 410, 415, and 420) with the Walsh codes are coupled to the multiplexer's data inputs.
  • the selection inputs select which data input is coupled to the multiplexer's output.
  • a series of two data bits is used to select a corresponding Walsh code. For example, a data bit sequence of 00 selects Wl, a data bit sequence of 01 selects W2, a data bit sequence of 10 selects W3, and a data bit sequence of 11 selects W4. Alternate embodiments use other logical bit sequences to select Walsh codes Wl - W4.
  • the input data streair. continuously selects the appropriate Walsh code based on each two-bit sequence. This embodiment does not require the exclusive-OR operation to spread each data bit. In this case, every two data bits select an appropriate Walsh code to replace the bits.
  • the multiplexer (425) outputs the selected Walsh codes to the MSK modulator (435) at a rate of 307.2 ksps.
  • the modulator modulates the Walsh code sequences for transmission over the channel.
  • FIG. 5 illustrates a representation of the Walsh code output generated by the apparatus of FIG. 4. There are now four Walsh codes per user at a bandwidth of
  • FIG. 6 illustrates another embodiment of the Walsh code register (205) of FIG. 2.. This figure illustrates an octo-orthogonal code division parallel access apparatus.
  • the radiotelephone has requested eight user IDs from the base station.
  • the first user ID is applied to the Walsh code ROM (see FIG. 2) as an address.
  • the 64 bit Walsh code generated from that user ID is loaded into a first shift register (605). This process is repeated for the remaining seven user IDs that generate Walsh codes that are loaded into the remaining shift registers (606 — 612).
  • the binary data to be spread is input to a three-bit register (620) or similar device at a rate of 9.6 kbps.
  • the register (620) is coupled to the selection inputs of a multiplexer (625).
  • the data is output to the selection inputs at a rate of 3.2 kbps.
  • the shift registers (605 - 612) with the Walsh codes are coupled to the multiplexer's data inputs. As is well known in the art, the selection inputs select which data input is coupled to the multiplexer's output.
  • a series of three data bits is used to select a corresponding Walsh code. For example, a data bit sequence of 000 selects Wl, a data bit sequence of 001 selects W2, a data bit sequence of 010 selects W3, a data bit sequence of 011 selects W4, a data bit sequence of 100 selects W5, a data bit sequence of 101 selects W6, a data bit sequence of 110 selects W7, and a data bit sequence of 111 selects W8.
  • the input data stream continuously selects the appropriate Walsh code based on each three-bit sequence. This embodiment does not require the exclusive-OR operation to spread each data bit. In this case, every three data bits select an appropriate Walsh code to replace the bits.
  • the multiplexer (625) outputs the Walsh code sequence to the MSK modulator (630) at a rate of 153.6 ksps. The modulator (630) modulates the Walsh code sequence for transmission over the channel.
  • FIG. 7 illustrates a representation of the Walsh code output generated by the apparatus of FIG. 6. There are now eight Walsh codes per user at a bandwidth of
  • the registers (620 and 430) of FIGs. 4 and 6 respectively are variable length registers. This enables each apparatus to accept variable length bit sequences for spreading depending on the type of information to be transmitted.
  • FIGs. 4 and 6 are illustrated using discrete components.
  • the digital portions of these embodiments could be implemented in a personal computer.
  • the spread signal from the computer would be output to the MSK modulator for modulation and then transmission.
  • FIG. 11 illustrates an example of an implementation of the code division parallel process of the present invention. This implementation, subsequently referred to as Web Radio, is made possible by the extremely low bit error rates experienced by the present invention.
  • the Web Radio system is comprised of the Web Site (1105) and a Web Radio portion (1110).
  • the Web Site (1105) is comprised of a typical local area network where each device is assigned an Internet Protocol (IP) address.
  • IP Internet Protocol
  • the Web Radio portion (1110) of the system is comprised of a Web Modem
  • Web PCs (1120) and Web Mobiles (1125) are each comprised of an embodiment of the code division parallel access apparatus illustrated above.
  • the destination address of a network device coupled to the network through the Web Modem (1130) is unique to mobile devices. For example, in this embodiment, a block of addresses starting with 150 may be set-aside for mobile devices. This is known to the network router (1135). When it is determined that the destination address is a Web PC (1120) or Web Mobile (1125), the frame is routed to the Web Modem (1130).
  • the Web Modem (1130) comprises one of the code division parallel access embodiments illustrated above.
  • the Web Modem (1130) converts the data into an orthogonal frame for transmission over a channel to a Web PC (1120) or Web Mobile (1125).
  • the process works in reverse for frames transmitted by either the Web PCs (1120) or the Web Mobiles (1125) to the Web Modem (1130).
  • the transmitted orthogonal frames are decoded by the Web Modem (1130) into binary data frames for use by the other devices on the network.
  • FIG. 12 illustrates the process a wireless device uses to communicate in a code division parallel access communication system. Since the wireless device knows what type of information it is going to send (e.g., video, voice, data), it requests (step 1201) the appropriate number of user ID's from the base station with which it is communicating.
  • the wireless device knows what type of information it is going to send (e.g., video, voice, data)
  • it requests (step 1201) the appropriate number of user ID's from the base station with which it is communicating.
  • the base station returns the requested number of user ID's to the wireless device (step 1205).
  • the wireless device uses these user ID's as addresses to address (step 1210) the Walsh code ROM, thus generating a unique, orthogonal Walsh code for each unique user ID.
  • the binary data to be encoded is input to the apparatus of the present invention where it is spread (step 1215) with the Walsh coding.
  • a sequence of input data bits selects a certain Walsh code to replace those data bits as a serial Walsh code symbol stream.
  • the length of the sequence of data bits is determined by the number of Walsh codes used.
  • the Walsh code symbol stream is then modulated (step 1220) for transmission over the wireless channel.
  • This channel in the preferred embodiment, is between a terrestrial wireless device and a satellite base station. Alternate embodiments locate the base station terrestrially.
  • FIG. 13 illustrates the process a base station uses to transmit to a wireless device in a code division parallel access communication system.
  • the base station first determines the type of information to be transmitted to the wireless device (step 1301).
  • the base station then transmits the appropriate number of user ID's to the wireless device that is to receive the information (step 1305).
  • the number of user ID's is based on type of information to be transmitted.
  • the base station generates Walsh codes, from those user ID's, to cover the data to be transmitted to the wireless device (step 1307).
  • the covered data in the form of a Walsh code symbol stream, is transmitted to the wireless device for decoding (step 1310).
  • capacity (N) the number of simultaneous users
  • G s is defined as:
  • the E b/N 0 requirements are low for the radiotelephone system of the present invention due to the symbol error rate. Therefore, from the above equation for capacity, a system using the present invention experiences higher capacity.
  • FIGs. 6 and 7 compare a representation of the prior art to that of the present invention.
  • the prior art system is a system that adheres to the CDMA specification IS-95.
  • the transmission bandwidth using the present invention has been reduced 50% from the 64 channels of the prior art to 32 channels. This is accomplished without any loss in RF capacity.
  • the preferred embodiment of the present invention is used in a satellite- based application.
  • the base station is the satellite while the radiotelephone has the capability to communicate with the satellite over the appropriate frequency spectrum.
  • Alternate embodiments of the present invention operate in a terrestrial cellular radiotelephone system, a home-based communication system, or a building-based communication system.
  • the present invention provides seamless orthogonal transmission and bandwidth on demand. Communications systems using the present invention do not require complex error control techniques normally required in a radio communications system.

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

Abstract

Plusieurs ID d'utilisateur sont attribués à chaque dispositif sans fil. Les divers ID d'utilisateur requis sont basés sur le type d'informations transmises (ex. vidéo, vocales ou de données). Les ID d'utilisateur génèrent les codes de Walsh orthogonaux utilisés pour couvrir un signal de données à transmettre. Chaque code de Walsh présente une longueur de 2n bits et la capacité de mémoire est de 2n x 2n, n étant le nombre de bits dans le code de Walsh. Chaque ID d'utilisation individuel demande à une mémoire de générer un code de Walsh spécifique correspondant seulement audit ID d'utilisateur. Les codes orthogonaux extraits de la mémoire couvrent les informations à transmettre, le signal émis étant orthogonal par rapport aux autres utilisateurs et également au sein des salves de signaux propres à l'utilisateur.
PCT/US1999/024778 1998-01-23 1999-10-22 Acces sans fil a large bande base sur l'acces parallele par repartition de code WO2001031823A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU11313/00A AU1131300A (en) 1999-10-22 1999-10-22 Broadband wireless access based on code division parallel access
PCT/US1999/024778 WO2001031823A1 (fr) 1998-01-23 1999-10-22 Acces sans fil a large bande base sur l'acces parallele par repartition de code

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US7230698P 1998-01-23 1998-01-23
US8688698P 1998-05-27 1998-05-27
PCT/US1999/024778 WO2001031823A1 (fr) 1998-01-23 1999-10-22 Acces sans fil a large bande base sur l'acces parallele par repartition de code

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KR100878802B1 (ko) * 2002-02-28 2009-01-14 엘지전자 주식회사 왈쉬 코드 할당 정보 수신 방법

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US5515396A (en) * 1994-02-25 1996-05-07 Motorola, Inc. Method and apparatus for selecting a spreading code in a spectrum spread communication system
US5781583A (en) * 1996-01-19 1998-07-14 Motorola, Inc. Method and system for communication over multiple channels in a spread spectrum communication system
EP0878930A1 (fr) * 1996-11-07 1998-11-18 Matsushita Electric Industrial Co., Ltd Procede de generation de code et procede de selection de code
WO1999018686A1 (fr) * 1997-10-06 1999-04-15 Telescicom Ltd. Systeme de codage et de modulation
EP0944198A2 (fr) * 1998-03-16 1999-09-22 Mitsubishi Denki Kabushiki Kaisha Procédé et dispositif d'allocation de codes

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EP0878930A1 (fr) * 1996-11-07 1998-11-18 Matsushita Electric Industrial Co., Ltd Procede de generation de code et procede de selection de code
WO1999018686A1 (fr) * 1997-10-06 1999-04-15 Telescicom Ltd. Systeme de codage et de modulation
EP0944198A2 (fr) * 1998-03-16 1999-09-22 Mitsubishi Denki Kabushiki Kaisha Procédé et dispositif d'allocation de codes

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KR100878802B1 (ko) * 2002-02-28 2009-01-14 엘지전자 주식회사 왈쉬 코드 할당 정보 수신 방법

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