EP0466785A1 - Procede de transmission d'un signal numerique a bande large - Google Patents

Procede de transmission d'un signal numerique a bande large

Info

Publication number
EP0466785A1
EP0466785A1 EP19900906139 EP90906139A EP0466785A1 EP 0466785 A1 EP0466785 A1 EP 0466785A1 EP 19900906139 EP19900906139 EP 19900906139 EP 90906139 A EP90906139 A EP 90906139A EP 0466785 A1 EP0466785 A1 EP 0466785A1
Authority
EP
European Patent Office
Prior art keywords
receiver
broadband signal
subchannels
flag
digital
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
EP19900906139
Other languages
German (de)
English (en)
Inventor
Hans Carsten Rasmussen
Jens Mikél JENSEN
Jorn Johansen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KJOBENHAVNS TELEFON AS
Original Assignee
KJOBENHAVNS TELEFON AS
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 KJOBENHAVNS TELEFON AS filed Critical KJOBENHAVNS TELEFON AS
Publication of EP0466785A1 publication Critical patent/EP0466785A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/14—Channel dividing arrangements, i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/062—Synchronisation of signals having the same nominal but fluctuating bit rates, e.g. using buffers
    • H04J3/0626—Synchronisation of signals having the same nominal but fluctuating bit rates, e.g. using buffers plesiochronous multiplexing systems, e.g. plesiochronous digital hierarchy [PDH], jitter attenuators

Definitions

  • the invention concerns a method in the transmission of a digital broadband signal from a transmitter to a receiver via a plurality of digital subchannels having arbitrary propagation times, and as stated in the introductory por ⁇ tion of claim 1.
  • US Patent Specification 4 775 987 discloses a digital transmission system which performs such a method, but it does not completely teach how the differences in the pro ⁇ pagation times of the subchannels are compensated.
  • the invention is particularly useful in connection with transmission via the public telephone network, but, as appears from the following, it can also be used in other connections where the bit rate of the available trans ⁇ mission channels is insufficient for transmission of a broadband signal.
  • the public network includes 64 kbits/s transmission channels which are e.g. used for digital telephony.
  • the broadband signal can be divided into a plurality of signals by means of known multiplex technique, each of said signals having a lower bit rate than the broadband signal.
  • These signals will be called subsignals, which can be transmitted between transmitter and receiver on their respective subchannels via the tele ⁇ phone network.
  • An example of this method is leased 2 bits/s connections. This work is expensive and time-consuming, because the necessary number of subchannels often has to be ordered long before they are to be used, just as the manual wiring is time-consum ⁇ ing.
  • the object of the invention is to provide a method enab- ling the use of a plurality of arbitrary, not specially set-up subchannels for multiplex transmission of broadband signals.
  • a further use of the invention is in connection of radio transmission of a 64 kbits/s connection, where a 64 kbits/s signal is now perceived as the broadband signal, which is divided into 8 radio channels of 8 kbits/s each.
  • the method of the invention does not require feedback and is therefore useful for point-to-multipoint transmission. Further, the method can be used modularly so that output signals from one or more devices may be used as input signals for another device.
  • reading-out can take place cyclically by methods according to claims 1 and 2, in con- trast to the method stated in claim 3 where the time de ⁇ lays are established by switching the sequence in which the subsignals are received.
  • Additional signal processing may be desired for some uses before the broadband signal is transmitted further on from the receiver, and in such situations it is expedient to provide for an additional time delay of the received signals, as appears from the method in claim 4.
  • a byte consists of n. bits.
  • An octet is a byte consisting of 8 bits.
  • a frame consists of n f bits.
  • a flag of length n f is a characteristic bit sequence of length n f .
  • a FIFO of length n s consists of a plurality of store locations l.,...,ln .
  • the position i is registered at any time for the next input as well as the position o for the next output.
  • o is counted 1 forwardly modulo ns.
  • a flow buffer of length n is a FIFO of length n , where i-o ;Ls constantly equal to ns. Further, output on other positions may also be possible.
  • fig. 1 shows the functional principle of a transmitter ac ⁇ cording to the invention
  • fig. 2 shows the functional principle of a receiver ac- cording to a first embodiment of the invention
  • fig. 3 shows the functional principle of a receiver ac ⁇ cording to a second embodiment of the invention
  • fig. 4 shows the principle of start in the receiver in fig. 3
  • fig. 5 shows the principle of reestablishing the broadband signal in operation in the receiver in fig. 3
  • fig. 6 shows the functional principle of a receiver ac ⁇ cording to a third embodiment of the receiver
  • fig. 7 shows the principle of start in the receiver in fig. 6,
  • fig. 8 shows the principle of reestablishing the broadband signal in operation in the receiver in fig. 6,
  • figs. 9 and 10 illustrate their respective ones of two possible system configurations for transmission of a video signal.
  • User's broadband signal is here assumed to have a bit rate of 384 kbits/s corresponding to 6 x 8 k o ⁇ tets/s, and this broadband signal is conveyed to part A of the transmitter.
  • Part B of the transmitter receives the 6 x 8 k octets/s, which are divided into individual octets, which are distributed cyclically on the six 8 k octets/s subchannels 11-16.
  • Part A can send either a start sequence or user's broadband signal to part B.
  • the start sequence consists of many idle signals followed by a flag per subchannel.
  • the start sequence is transmitted from part A to part B, and immediately following the completion of this sequence, user's broadband signal is transmitted from part A to part B, where it is distributed on the six output subchannels 11-16.
  • the receiver in fig. 2 comprises a part B and a part A.
  • the six subchannels 11-16 are passed to the part B of the receiver, which has a flag control 21-26 followed by a FIFO 31-36 for each subchannel.
  • the subsignals are con- veyed from the FIFOs to the part A of the receiver where the broadband signal is reestablished.
  • each flag control 21-26 receives a flag which is detected and transmitted to the associated FIFO, which has suffi ⁇ ciently many store locations for the receiver to compen ⁇ sate for the differences between the propagation times of the subchannels occurring in practice. Since six flags are transmitted from the transmitter during start, each buffer receives precisely one flag.
  • the six subchannels are not necessarily received in proper cyclic order, this may be compensated for in that six flags are transmitted from the transmitter, said flags being specific for their respective subchannels and being used in the receiver for identification of the subchannels 11-16, following which the receiver adjusts its output order according to the subchannels on which the individual flags are received.
  • start in the receiver is performed correct ⁇ ly also in case of bit errors, a plurality of start se- quences can be transmitted, each consisting of
  • the receiver tries to recognize flags as soon as at least one reset byte has been recognized. If the broadband test sequence is not recognized, reset is performed upon recog ⁇ nition of at least one reset byte.
  • each subchannel 11-16 can be read out as soon as the following two conditions are satisfied, 1) that the channel in question has one octet next in turn for being read out, and 2) that, apart from the first reading-out attempt, the cyclically preceeding subchannel has been read out. If reading-out is allowed only at spe- cific points of time, reading-out is postponed to the next permitted point of time. After the first cycle in the start phase, where each octet is a flag, reading-out takes place with full broadband bit rate and with the rythm of the transmitter.
  • Fig. 3 shows a second embodiment of the receiver according to the invention.
  • Each subchannel is here associated with a frame number indicator 41-46.
  • a frame consists of an octet from each of the six subchannels 11-16.
  • the received signals are entered frame by frame in an n frame large flow buffer 50.
  • each received octet is examined for whether it is a flag, cf. fig. 4.
  • a frame counter 51 is initialized to zero. After each received frame, the frame counter 51 is counted one forwardly.
  • the frame number indicator 41-46 of this subchannel is set to the actual value of the frame counter 51. This means that the value zero is allocated to the subchannel 11-16 where the first flag was detected.
  • n has been selected such that n is greater than the greatest expected difference in delay between two subchannels measured in frame durations.
  • the octets of the subchannels are arranged in the same order in each frame as in the transmitter.
  • the frames are transferred to the flow buffer for one frame of the broadband signal. A frame of the broadband signal is thus reestablished and can be read out. After reading-out of a frame, the next frame is transferred to the flow buffer for one frame.
  • Figs. 4 and 5 illustrate the conditions in the receiver in fig. 3 during start and operation, respectively. To the left is shown a section of the n frame large flow buffer where each frame contains a byte from each subchannel. The table to the right of the figure indicates from which frame the byte of each subchannel is to be read out, and this is shown by the arrows between the table and the buffer.
  • Figs. 7 and 8 illustrate the conditions in the third em ⁇ bodiment in the receiver in fig. 6 during start and ope ⁇ ration, respectively. It is allowed here that the order of the subchannels is switched during transmission, and six channel-specific flags are transmitted from the trans- mitter on the basis of which the receiver can identify the subchannels.
  • the advantage is that the receiver autono ⁇ mously detects the order in which the transmitter has used these channels by using, in addition to a frame counter, a position counter 53 which is reset for each new frame and is counted one forwardly for each position.
  • a test sequence is transmitted after a flag sequence, as described before.
  • Fig. 8 shows the flags and the octets in the n frame buffer received in the subchannels after the flags imme ⁇ diately after termination of start.
  • a different method of the present type in transmission via subchannels having arbitrary propagation times might be realized by providing each byte in all subsignals in the transmitter with identification, using certain bits in each byte for this purpose. The received bytes are then to be currently sorted in the receiver before the broadband signal is reestablished. In such a method part of the bit rate of the subchannels is employed for identification, and the bit rate available for transmission of the broadband signal is thus reduced.
  • a sorting device is needed in the receiver, which, in addition to adding to the costs of the appara ⁇ tus, increases the delay so much that use in real time is made difficult.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Communication Control (AREA)

Abstract

Un signal numérique à bande large est divisée en une pluralité de sous-signaux par démultiplexage, chacun desdits sous-signaux ayant un débit binaire inférieur à celui du signal de bande large, et étant réparti et transmis dans son sous-canal respectif (16 à 11), tel que par exemple, des canaux téléphoniques numériques ordinaires ayant des temps de propagation arbitraires. Les différences de temps de propagation sont compensées par transmission d'au moins un drapeau dans chaque sous-canal au lancement, et par retardement individuel des signaux reçus dans le récepteur, en réponse aux drapeaux reçus de sorte que l'on peut reconstituer le signal à bande large à partir des sous-signaux par multiplexage. Ce lancement automatique ne nécessite aucun chemin de signal de retour et l'on insère une temporisation minimale afin de permettre le rétablissement dudit signal à bande large.
EP19900906139 1989-04-07 1990-04-06 Procede de transmission d'un signal numerique a bande large Ceased EP0466785A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK1675/89 1989-04-07
DK167589A DK167589A (da) 1989-04-07 1989-04-07 Fremgangsmaade ved transmission af et digitalt bredbaandssignal

Publications (1)

Publication Number Publication Date
EP0466785A1 true EP0466785A1 (fr) 1992-01-22

Family

ID=8107105

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900906139 Ceased EP0466785A1 (fr) 1989-04-07 1990-04-06 Procede de transmission d'un signal numerique a bande large

Country Status (4)

Country Link
EP (1) EP0466785A1 (fr)
AU (1) AU5440290A (fr)
DK (1) DK167589A (fr)
WO (1) WO1990012467A1 (fr)

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5278827A (en) * 1991-05-28 1994-01-11 British Technology Group Ltd. Variable data rate channels for digital networks
US5400328A (en) * 1991-05-28 1995-03-21 British Technology Group Ltd. Variable data rate channels for digital networks
GB2256350B (en) * 1991-05-28 1995-05-17 British Tech Group Variable data rate channels for digital networks
GB9117172D0 (en) * 1991-08-08 1991-09-25 British Telecomm Communication system
US5251210A (en) * 1991-11-01 1993-10-05 Ibm Corporation Method and apparatus for transforming low bandwidth telecommunications channels into a high bandwidth telecommunication channel
SE470039B (sv) * 1992-03-17 1993-10-25 Ellemtel Utvecklings Ab Sätt att i en paketväljare åstadkomma länkgruppering
US5345443A (en) * 1992-04-30 1994-09-06 At&T Bell Laboratories Network-based digital bandwidth-on-demand
NL9400548A (nl) * 1994-04-07 1995-11-01 Nederland Ptt Breedband transmissie systeem.
US5617417A (en) * 1994-09-07 1997-04-01 Stratacom, Inc. Asynchronous transfer mode communication in inverse multiplexing over multiple communication links
US5608733A (en) * 1994-11-29 1997-03-04 Valle; Richard ATM inverse multiplexing
US5987030A (en) 1996-09-27 1999-11-16 Cisco Technology, Inc. Transparent circuit emulation for packet switching network
US6148010A (en) * 1998-06-24 2000-11-14 Qualcomm Incorporated Method and apparatus for distributing and consolidating data packets onto multiple network interfaces
DE10003485A1 (de) * 2000-01-27 2001-08-09 Siemens Ag Verfahren und Vorrichtung zum Ausgleich von Übertragungslaufzeiten bei Datenübertragung über mehrere Übertragungskanäle
US7006509B1 (en) 2000-12-22 2006-02-28 Cisco Technology, Inc. Method and system for graceful slowlink deletion and subsequent fast link addition in an IMA group
US6952434B1 (en) 2000-12-27 2005-10-04 Cisco Technology, Inc. System and method for processing control cells to prevent event missequencing and data loss in IMA groups
US7065104B1 (en) 2000-12-28 2006-06-20 Cisco Technology, Inc. Method and system for managing inverse multiplexing over ATM

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4383316A (en) * 1980-04-14 1983-05-10 Bell Telephone Laboratories, Incorporated Apparatus for and method of collating partitioned time disordered synchronous data streams
GB8407223D0 (en) * 1984-03-20 1984-04-26 British Telecomm Broadband digital transmission systems
US4615040A (en) * 1984-06-14 1986-09-30 Coenco Ltd. High speed data communications system
US4630286A (en) * 1984-10-10 1986-12-16 Paradyne Corporation Device for synchronization of multiple telephone circuits

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9012467A1 *

Also Published As

Publication number Publication date
AU5440290A (en) 1990-11-05
DK167589D0 (da) 1989-04-07
DK167589A (da) 1990-10-08
WO1990012467A1 (fr) 1990-10-18

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