Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/14—Relay systems
  • H04B7/15—Active relay systems
  • H04B7/155—Ground-based stations
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/14—Relay systems
  • H04B7/15—Active relay systems
  • H04B7/155—Ground-based stations
  • H04B7/15528—Control of operation parameters of a relay station to exploit the physical medium
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13098—Mobile subscriber
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13174—Data transmission, file transfer
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13191—Repeater
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13291—Frequency division multiplexing, FDM
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13342—Arrangement of switches in the network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13367—Hierarchical multiplexing, add-drop multiplexing

Definitions

• the invention relates to a data transmission system for the digital transmission of data, for which purpose i.a. also heard language.
• a packet-wise data transmission between the stations of a data transmission network is also known from the Internet.
• data on packets are bundles and these packets are transmitted separately via the cheapest transmission path.
• Such a packet transmission there are considerable delays which correspond at least to the time required for the transmission of a packet.
• Such a packet transmission is disadvantageous for a telephone system because of the delays involved.
• the delays would add up according to the number of stations involved in the transmission.
• the invention has for its object to provide a decentralized digital data transmission system that allows the use of different transmission channels between two stations and keeps the delays extremely low.
• the data transmission system is characterized in that in each station the received signals are converted from the reception channels to at least one transmission channel that differs therefrom. This means that every symbol stream arriving on a receive channel is converted to the send channels.
• information packages are formed that consist of only one symbol.
• a symbol is a bit. However, it can also consist of a plurality of bits that belong together, such as a letter symbol represented by 8 bits.
• the number of bits per symbol position is constant during a transmission. At the start of the transmission, the number of bits per symbol is determined depending on the required or desired degree of transmission quality.
• the symbol-wise implementation means that only a delay in the order of one symbol position of the symbol stream is required at each station.
• This delay is due to the fact that there is normally no synchronization of the symbol sequence on the incoming channels and on the outgoing channels, so that a certain waiting time is required before the outgoing signal can be transmitted in synchronization with the transmission channels.
• this delay is minimal. In practice, it is about one to two symbol positions. The delays of the individual stations add up. Because of the small delay of each individual station, the resulting total transmission delay is still acceptable.
• the transmission channels are divided into subchannels, each of which is suitable for the transmission of a symbol stream, the symbols of all subchannels of a transmission channel being transmitted synchronously.
• each station can receive incoming signals in all channels.
• the outgoing subchannels can be broadcast concentrated in a single channel or in a few selected channels.
• the symbol positions of all subchannels are transmitted synchronously in each channel, which consists of a predetermined number of subchannels.
• Each subchannel is suitable for unidirectional data flow.
• the data arrives the station in each subchannel of the entire channel system in a continuous data stream without being broken down into "frames" or "packets". As a result, the data stream does not need any headers or other ordering elements. Rather, each symbol of the data stream is converted to the subchannel selected for transmission within a very short time and transmitted in synchronization with the transmission channel.
• the subchannels are allocated to a transmission channel between two stations in such a way that the transmission frequency range is dynamically adapted to the information content to be transmitted. This means that the number of subchannels per channel can vary.
• the allocation of channels intended for the transmission is preferably carried out at a station in such a way that all transmitting subchannels of this station lie within a few channels. This significantly reduces the number of channels to be used. It should be borne in mind that if a station transmits on a channel, this channel must not be used by neighboring stations in order to avoid interference or other interference. If only one subchannel is used by a station in a channel, the entire channel is reserved for this station. Therefore, all connections that run through a particular station are preferably distributed to subchannels that are all contained in the same channel.
• the contents of the data are synchronized in a preferred embodiment of the invention.
• corresponding error correction bits are added to the symbol positions of the subchannels of a channel, an error correction being carried out in the receiving station.
• error correction methods such as the FEC method (Forward Error Correction) or the ARQ method (Automatic Re-transmission Request).
• FEC method Forward Error Correction
• ARQ method Automatic Re-transmission Request
• the peculiarity in the present case is that the contents of the symbol positions of the subchannels of a channel which are transmitted synchronously are used for error correction, information contents which are completely independent of one another flowing in the subchannels. This means that the error correction is carried out on the basis of bits which belong to different information and which are merely randomly located in the channel at the same time.
• an error correction method only makes sense if a bit error rate of about 10 "3 is to be undershot. For higher bit error rates, mere error detection is sufficient to at least obtain information about the quality of the connection between the two stations involved.
• Such an error detection can by means of a redundant fuse attachment (for example parity bit), this attachment being added to the symbol locations of all subchannels of a channel which are transmitted synchronously. the successive information content of this subchannel corresponds, with an error detection taking place in the receiving station.
• FIG. 4 shows an example of data streams which pass through the coupling matrix from FIG. 3, and
• FIG. 5 shows a representation of the successive symbol positions in a channel with error correction bits and error detection bits.
• the data transmission system consists of numerous distributed stations S, each station representing a subscriber station. Each station contains a transmitting and receiving device. Two frequency bands of 12.8 MHz each are available for radio transmission of the data. Both frequency bands are separated by a duplex spacing. One frequency band is called an uplink and the other as Called downlink. To establish a connection, a channel in the uplink is used for the connection in one direction and a channel in the downlink in the connection in the other direction, so that the frequency of the two directions is completely decoupled from one another.
• the two frequency bands are divided into a total of 1,280 channels with a spacing of 20 kHz. Of these channels, some channels are used as an information channel for connection establishment and other purposes.
• Each of the stations can receive and transmit on any of the available channels.
• the example of an established connection shown in FIG. 2 provides that the information transmission from S61 takes place in the channel C1, the information transmission from S60 to S63 in a channel C25 and the information transmission from S63 to the destination station S65 in a channel C12.
• routing that is to say the selection of the stations via which the connection is to be established, and the selection of the channels is moreover carried out by means of a dialogue which the participating stations carry out among themselves. Routing and the establishment of a connection are not the subject of the present invention.
• each symbol position represented as a box is assumed to consist of one bit.
• Each station contains a channel register CR-1 ... CR-n for each channel Cl ... Cn.
• the channel register CR-1 contains eight information symbol positions 1 ... 8, each of these symbol positions corresponding to a subchannel SC.
• Channel Cl is thus divided into eight subchannels 1 ... 8.
• Each subchannel has a bandwidth of 20 kHz, with the frequencies of all subchannels 1-8 immediately following one another.
• a unidirectional data connection can run via a subchannel SC.
• FIG. 3 shows the time slots for the subchannels 4 and 5 of the channel C1, in which symbols are transmitted into the channel register 1.
• the transmission takes place at the frequency of 20 kHz in an uninterrupted symbol stream.
• the time-synchronously received symbols (here: bits) of the subchannels of a channel reach a receive register ER1 ... ERn and from there they are transferred to the respective channel register with a delay of two symbol times CR-1 ... CR-n transmitted.
• the channel registers CR-1 ... CR-n are each connected to the columns of the coupling matrix.
• the coupling matrix contains n rows and m columns, each row and each column being assigned to a different subchannel or a different frequency.
• the lines of the coupling matrix KM each correspond to a subchannel or a transmission frequency.
• a channel register CR-1 ... CR-n is provided for each channel, which contains a symbol position for each subchannel 1 ... 8.
• the symbol positions of all transmission-side channel registers are connected to the lines of the coupling matrix KM.
• a transmission register SR1 ... SRn is assigned to each transmission-side channel register CR-1 ... CR-n.
• the coupling matrix KM is designed using integrated circuit technology, the nodes at the connection points of a row and a column being able to be switched through by means of corresponding control signals. The relevant node remains switched through during a connection.
• FIGS. 4 shows an example of the temporal course of signals which are received in the subchannels of channels C1, C2 and C3.
• the signals received there and intended for forwarding are implemented on channel C25.
• the station S60 it was previously determined in dialogue with the neighboring stations that the channel C25 is available for data transmission.
• station S60 receives from station S61 in channel C1 those data which it is to pass on to station S63. Accordingly, this data is converted to channel C25 in station S60. In station S63, the same data is converted to another channel, for example C12, and transmitted to target station S65.
• the station S60 considered here receives signals in channel C2 in the selected example from station S62. These signals are to be passed on to station S64. Channel C25 is also selected for this. Finally, signals from station S60 are to be transmitted to station S61, for which purpose another subchannel of channel C25 is selected. Everything that station S60 transmits is done on channel C25, in different subchannels. 4 shows the implementation of the data in station S60, which are received by stations S61 and S62 in channels C1 and C2. This data is converted to channel C25 in different subchannels. The time axis is designated t in each case. It can be seen from the upper line in FIG.
• subchannels 1 ... 8 which transmit the information
• three further bit positions for error correction bits A, B, C are added to each channel.
• the contents of these further bit positions are evaluated in the receive register ER1 ... ERn and used for error correction of the information bits that were received simultaneously within one channel. Only the corrected information bits are entered into the corresponding channel register CR-1 ... CR-n.
• error detection bits A, B, C are added to the eight information symbols of a channel before the entire bit set is sent. These error detection bits are generated in accordance with the content of the information symbol locations using an error detection algorithm. In the same way error reception follows after receipt of the total signal using the algorithm.
• FIG. 5 shows the individual symbol positions for a channel with regard to their temporal profiles, the numbers 1 to 8 denoting the information symbol positions and representing subchannels. These subchannels have different frequencies.
• the frequency f increases with increasing atomic number in FIG. 5 from left to right.
• the three error correction bit positions A, B, C are added to the last subchannel (channel "8").
• a further symbol position P is added to the channel after a total of eight consecutive symbols, which symbol position also contains a parity bit for each subchannel that serves for error detection.
• the addition of the error detection bits and the error correction bits and the evaluation of these bits on the basis of the information content take place separately for each transmission link. These additional bits do not participate in the frequency conversion.
• the assignment of the subchannels to the frequencies can be changed after each symbol step. This ensures that a jammer cannot permanently jam a subchannel.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
• Radio Relay Systems (AREA)
• Data Exchanges In Wide-Area Networks (AREA)
• Communication Control (AREA)
• Time-Division Multiplex Systems (AREA)
• Detection And Prevention Of Errors In Transmission (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7840681

Family Applications (1)

Country Status (11)

Families Citing this family (7)

Citations (3)

• 1997
  • 1997-08-29 DE DE19737897A patent/DE19737897C2/de not_active Expired - Fee Related
• 1998
  • 1998-08-27 CA CA002302501A patent/CA2302501A1/en not_active Abandoned
  • 1998-08-27 CN CN98808619A patent/CN1269076A/zh active Pending
  • 1998-08-27 HU HU0002405A patent/HUP0002405A3/hu unknown
  • 1998-08-27 EP EP98951322A patent/EP1010261A1/de not_active Withdrawn
  • 1998-08-27 KR KR1020007002090A patent/KR20010023447A/ko not_active Application Discontinuation
  • 1998-08-27 IL IL13426598A patent/IL134265A0/xx unknown
  • 1998-08-27 JP JP2000509171A patent/JP2001515297A/ja active Pending
  • 1998-08-27 CZ CZ2000672A patent/CZ288768B6/cs not_active IP Right Cessation
  • 1998-08-27 AU AU97395/98A patent/AU9739598A/en not_active Abandoned
  • 1998-08-27 WO PCT/EP1998/005451 patent/WO1999012279A1/de not_active Application Discontinuation

Patent Citations (3)

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