WO2004068736A1

WO2004068736A1 - Method and arrangement for transmitting data within an open communication network

Info

Publication number: WO2004068736A1
Application number: PCT/CH2003/000060
Authority: WO
Inventors: Andrew Lunn; Walter Braun; Weilin Liu
Original assignee: Ascom Powerline Communications Ag
Priority date: 2003-01-27
Filing date: 2003-01-27
Publication date: 2004-08-12
Also published as: EP1632038A1; AU2003201589A1

Abstract

The invention relates to a method and an arrangement for transmitting data within an open communication network (8; 23). The data is transmitted by means of a line-bound transmission medium (12; 22), e.g. a power supply network. The transmitting times of at least one transmitter/receiver device (10.1; 25.1) of the open communication network (8; 23) and a transmitter/receiver device (10.2; 25.5) outside the open communication network are synchronised by means of a time signal which is independent from the open communication network (8; 23). By virtue of the fact that the transmission times of the transmitter/receiver device overlap as little as possible with the receiving times of the other transmitter/receiver device, interferences between the transmitter/receiver devices of a different open communication network are minimised, reduction of the waveband is zero or very little and a synchronisation process between transmitter/receiver devices of different open communication networks is prevented.

Description

Method and arrangement for the transmission of data within a

communication composite

Technical field

The invention relates to a method for transmitting data within a communication network with at least a first transceiver and a second transceiver and an external transceiver that is not integrated in the communication network, the data being transmitted via a line-bound transmission medium become. The invention further relates to an arrangement for the transmission of data within such a communication network. State of the art

When transmitting data over a wired transmission network, the number of available transmission channels is usually limited. If one and the same transmission network is used by different communication systems, for example by two or more different groups of transmitters or receivers, interference in data transmission can occur. If the different groups use the same transmission protocols and the same transmission frequencies, interference occurs, for example.

In such cases, the available transmission channels are typically divided among the different groups of transmitters or receivers, so that each group has its own transmission channels on which it does not interfere with the transmission of the other groups.

However, the bandwidth available for data transmission is also divided up among the various groups in this way, which results in a reduced bandwidth for each group.

WO 02 49232 A1 (Ascom Powerline Communications) describes a method in which two transmitters or receivers of two different groups jointly determine a transmission channel that they only use to send data. Such an arrangement prevents one of the transmitters or receivers from receiving data from a subordinate device and at the same time the transmitter or receiver of the other group from transmitting on the same channel, which would interfere with reception.

However, this makes it necessary for one transmitter or receiver to be switched to a special mode in which it can be synchronized with the other transmitter or receiver. The various devices must also be able to receive and decode each other's signals so that synchronization is possible. The described method can also be used in a situation in which two devices different networks, which are not synchronized with each other, interfere with each other, do not use. Finally, only those devices can be synchronized with devices from another group that determine the synchronization of their own group. This step is prevented from subordinate stations experiencing interference from stations in another group, since they would lose synchronization with their superordinate station in the same group.

Presentation of the invention

The object of the invention is to provide a method to be assigned to the technical field mentioned at the outset which minimizes interference between transmitters or receivers of different networks, uses as little bandwidth as possible and avoids a synchronization process between two devices of different groups.

The solution to the problem is defined by the features of claim 1. According to the invention, data is transmitted within a communication network with at least one first transceiver and a second transceiver. An external transceiver is not integrated in the communication network, but transmits on the same line-bound transmission medium as the transceivers of the communication network. The method according to the invention is characterized in that the transmission times of at least the first transceiver are synchronized with the transmission times of the external transceiver by means of a time signal which is independent of the communication network.

The synchronization of the transmission times means that, whenever possible, the devices which are synchronized by the time signal independent of the communication network send at the same time. The probability that one of the devices in the communication network receives data from another device in the communication network and at the same time sends the external device on the same channel and thus interferes with reception is reduced as far as possible. Because the transceivers are synchronized by a time signal that is independent of the communication network, there is no need for a synchronization process between devices from different networks. In particular, it is therefore not necessary for the transmitters / receivers to be able to receive and detect their signals from one another, and it is also not necessary to switch the transmitters / receivers into a special mode for mutual synchronization. Finally, no bandwidth is lost due to the synchronization of the transmission times.

All transceivers advantageously use periodic frames (data frames) of the same structure to transmit the data. In this case, the transmission times of the transceivers are synchronized in that the start time of the frames is determined by the time signal that is independent of the communication network.

Many different data transmission methods known from the prior art are possible for data transmission between the transceivers. For example, the data can be modulated onto a carrier signal using any known type of modulation. The data can optionally also be encoded. Frequency division multiplexing is just as possible as time division multiplexing or spread band technology.

As has been found, data transmission using a time-division multiplex method offers advantages over other techniques, for example with regard to the transmission quality or the achievable data rates. A transmission method is therefore preferably used in which a plurality of transmission channels are made available by a time-division multiplex method. Here, a plurality of transmission frames, hereinafter referred to as frames, are transmitted one after the other, each frame being divided into a plurality of time slots. A transmission channel is formed by one or a plurality of time slots in one or a plurality of frames. I.e. the data to be transmitted are divided into packets of a certain size, which are each accommodated in one or more time slots of one or a plurality of successive frames. Since the various networks use the same line-bound transmission medium, the frame structure can be chosen the same for all transceivers, without any technical disadvantages being expected. It is Z. B. not necessary to adapt the frame structure of the individual networks to local properties of a specific transmission medium. With the synchronization of the start times of the individual frames, e.g. B. by triggering the frame start by the external time signal, the transmission times of the transceivers are then synchronized in a simple manner. It is important that the length of the frames and, if possible, the division of the frames into transmission times and reception times match.

Instead of the start time of the frames, another point in time can be selected for synchronization throughout the system. The method according to the invention is also applicable to communication networks that use non-periodic (system-wide specified) frames, or to communication networks in which the data are organized differently without the use of frames.

The method can be used within a communication network with higher-level (master) and lower-level (slave) transceivers. The first transceiver (master) controls the transmission between it and the second transceiver (slave) by dividing the frame into two - not necessarily contiguous - time segments, the time segments not overlapping and in which first master (downlink) the master and in the second stage (uplink) the slave.

The information about when which slave can use which time slots is transmitted by the master, for example, in a so-called frame header, a special time slot, which is usually located at the beginning of each frame. Of course, multiple time slots can also be used as frame headers. The allocation of the time slots is completely dynamic, ie each slave can be assigned different time slots for sending and receiving in each frame. The order of the first and the second time period and their lengths can in principle be chosen freely. The Periods need not be contiguous, so subsections of the first period can alternate with subsections of the second period within one frame.

Because the frame structure of the devices involved should be the same everywhere, the criteria that the master uses to split the frames into two time segments must be the same everywhere. Because the frames of potentially interfering devices are synchronized by the method according to the invention, the master devices and the slave devices then send or receive in each case in certain time segments which correspond to one another in the different networks as far as possible.

Significant interference between master stations can only occur in the minimally short periods in which the reception time of the master overlaps with the transmission time of the external master.

The situation for the subordinate transceivers (slaves) is as follows: They only send and receive data in the transmission channels assigned to them by the master. For reception, this means that in the first case they either receive signals only from their parent or, in the second case, also receive signals from the external master. The first case is not a problem. In the second case, the subordinate transceiver receives signals from two different sources at the same time, and it must be ensured that the device recognizes which data or which signal originate from the superordinate transceiver and that it only processes these further. This is achieved, for example, with a special coding or an appropriately selected, local division of the transceivers.

The subordinate transceiver is arranged in relation to the superordinate transceiver or the external transceiver, for example, in such a way that the signal level of the signal from the superordinate transceiver is higher than the signal level of the signal from external transceiver. In the case of a line-bound transmission system, this means, for example, that the devices in the network are arranged in such a way that the transmission path from the external transceiver to the subordinate transceiver is greater than the transmission path from the superordinate to the subordinate transceiver, or that it is not the signal path but, for example, the signal attenuation that is greater. Of course, the transmission powers could also be selected such that the signals to be received by the target device arrive there with a higher signal level.

The two time periods are advantageously selected such that the two time periods are in each case contiguous for all transmitting / receiving devices. The first period begins at the beginning of the frame and the second period ends at the end of the frame. This means that the master always occupies the send time (downlink) in the frame from left to right, while it occupies the receive time (uplink) in the frame from right to left.

In this way, there is only an overlap between the transmission time of one master and the reception time of the other master if the frames are heavily occupied and if the relationships between uplink and downlink data traffic in the different networks differ greatly. Otherwise, this - remaining - interference can be kept to a minimum without the bandwidth being restricted and without any additional effort being required to determine the transmission and reception times.

Of course, the order of the transmitting and receiving sections can also be interchanged for all transmitting / receiving devices.

The method according to the invention can also be implemented in such a way that the transceivers used in the communication network and the external transceiver each detect faults caused by a transceiver that is not integrated in the same communication network, eg. B. by periodically determining the bit error rate. After detection of such a disturbance, the frames are divided into two fixed time periods, the transceivers transmitting in the first time period and receiving in the second time period. These time periods are the same for all transceivers that use the same wired transmission medium and can potentially influence each other, e.g. B. stored in a flash EPROM or programmed via dip switches or jumpers. The result of this is that the interference is eliminated between all the transceivers which use the two predetermined time periods. Nevertheless, other devices that do not experience interference due to interference can still freely allocate their transmission and reception times, so that their bandwidth is not restricted in any way. To minimize any interference, even in this non-restricted operation, it is advantageous if the transmission and reception times are also classified according to a system-wide standard.

A possible division of the frames into transmission and reception times is the division into two sections of equal length: transmission during the first half of the frame and reception during the second half of the frame. This division is always advantageous if the specific structure of a network does not mean that interference preferably occurs between certain transceivers and at the same time the data flow has a preferred direction.

An arrangement for the transmission of data within a communications network comprises at least a first transceiver and a second transceiver and an external transceiver that is not integrated in the communications network. All of the transceivers mentioned are connected to a line-bound transmission medium, in particular a power supply network, for the transmission of the data. At least the first transceiver and the external transceiver can also receive a time signal that is independent of the communication network and thereby synchronize their transmission times.

Power supply networks are an example of a transmission medium that can be used by the transceivers for data transmission. In this case, each transceiver is connected to the power supply network via a signal coupler of a known type, for example a low-voltage network known from the prior art Power supply to a building, connected. The transmitting / receiving devices are accordingly equipped with a transmitting / receiving unit, via which data can be coupled into and out of the power supply network. The data which e.g. B. come from a computer connected to the transceiver, a high-frequency carrier signal is modulated for this purpose, which is coupled via a crossover into the so-called. Powerline.

The properties of such a transmission medium are usually heavily frequency-dependent. An advantageous transmission frequency for data transmission via a power supply network is, for. B. in the range of 1 to about 40 MHz. The transmit / receive devices are therefore preferably designed for data transmission in this frequency range.

The time signal, which is independent of the communication network, should be simple and inexpensive to obtain, have a high degree of accuracy and be available in an area in which interference between different transmitting / receiving devices can occur.

These criteria are met in particular by the following time signals:

the phase of the 50 or 60 Hz power supply network; a publicly broadcast radio signal for time reference, e.g. B. the long-wave radio signal DCF 77 of the PTB (Physikalisch-Technische Bundesanstalt, Braunschweig DE); - A navigation signal broadcast by radio, in particular from GPS (Global Positioning System) or GLONASS (Global Orbiting Navigation Satellite System); a time reference signal of a mobile radio network, in particular a GSM, CDMA or UMTS network; or a time reference signal from another communication system on the line-bound transmission medium. A time reference signal from another communication system on the line-bound transmission medium can then be used for synchronization if it can be received in all communication links between which their transceivers are intended to minimize or prevent interference. This is particularly the case if the other communication system has a spatially significantly wider extent than the individual communication networks. If e.g. B. the communication networks include individual buildings, but the other communication system an entire district, a city or region, the time reference signal of the communication system can serve to synchronize the transceivers of the communication networks.

Further advantageous embodiments and combinations of features of the invention result from the following detailed description and the entirety of the claims.

Brief description of the drawings

The drawings used to explain the exemplary embodiment show:

1 shows a power supply network with a plurality of networks;

2 shows a transmission system with two different communication links connected to the same transmission medium;

3 shows a plurality of transmission frames (frames) transmitted one after the other in time;

FIG. 4 shows a transmission frame from FIG. 3 with a plurality of time slots;

5 shows the assignment of transmission and reception times in two transmission frames transmitted at the same time in two communication links; Fig. 6 shows a different assignment of transmission and reception times in two to the same

Time-transmitted transmission frame in two communication links;

Fig. 7 shows another transmission system with two different on the same

Transmission medium connected communication links;

8 shows a fixed assignment of transmission and reception times in a transmission frame;

9 shows a flowchart of a method according to the invention implemented in a transceiver.

In principle, the same parts are provided with the same reference symbols in the figures.

Ways of Carrying Out the Invention

Figure 1 shows a plurality of networks, the transmission medium is a power supply network. A transformer station 1 is shown, in which the voltage of a medium-voltage line 3 is transformed with a transformer 2 into a low voltage, which can be tapped from a busbar 4. Three low-voltage lines 5.1, 5.2, 5.3 are connected to the busbar 4 and supply, for example, three different buildings (not shown) in one neighborhood with electricity. The low-voltage lines 5.1, 5.2, 5.3 each have an inductance 6.1, 6.2, 6.3.

A master station 7.1, 7.2, 7.3 is connected to each low-voltage line 5.1, 5.2, 5.3, which in each case forms a communication network with those slaves (not shown) which are also connected to this low-voltage line 5.

Large interference can occur between the three master stations 7.1, 7.2, 7.3 of the three different networks, since the three master stations are only due to the inductance ten 6.1, 6.2, 6.3 and the busbar 4 are separated. The attenuation of the signals that spread from a master in both directions of the respective low-voltage line is correspondingly low, for example in the range from a few dB to a few dozen dB. The signal attenuation can be so low that the interference from the other masters would be so great that only one master could be used for all three low-voltage lines 5.1, 5.2, 5.3.

Due to the synchronization of masters 7.1, 7.2, 7.3 according to the invention by means of an external time signal and the use of a uniform frame structure, however, it is possible to simultaneously transmit data from the respective master 7.1, 7.2, 7.3 to its slaves on all three low-voltage lines 5.1, 5.2, 5.3 or in the opposite direction. This results in a real increase in transmission capacity. However, if the damping between the masters is too low, i. H. If the ratio between the data signals and the interference signals is too small, the attenuation can be artificially increased, for example, using appropriate filters between the communication links, such as an inductor as a low-pass filter.

The field of application of the method and device according to the invention is not limited to data transmission in power supply networks. It includes other wired transmission media, such as conventional data cables or a broadband cable.

FIG. 2 shows a transmission system with two different communication links 8, 9 connected to the same line-bound transmission medium 12 (e.g. a power supply network). The first communication link 8 comprises a master 10.1 and several slaves 1 1.1, 1 1.2, 1 1.3, data being transmitted within the communication network 8 via a first branch 12.1 of the line-bound transmission medium 12. The second communication network 9 likewise comprises a master 10.2 and a plurality of slaves 1 1.4, 1 1.5, 1 1.6, the master 10.2 and the slaves 1 1.4, 1 1.5, 1 1.6 for data transmission with one another on a two- branch 12.2 of the line-bound transmission medium 12 are connected. Both communication networks 8, 9 use the same transmission channels.

The masters 10.1, 10.2 comprise a receiver and decoder 13.1, 13.2, which can receive and decode a time signal which is emitted by the signal generator 14 and the transmitting device 15 and is independent of the communication network. It can be z. B. is the DCF-77 reference time signal distributed by the Physikalisch-Technische Bundesanstalt in Braunschweig (DE).

The data transmission within a communication network 8, 9, for example between the master 10.1 and its slaves 1 1.1, 1 1.2, 1 1.3, takes place with a frame structure. FIG. 3 shows a plurality of such transmission frames, so-called frames 16.1, 16.2, 16.3, 16.4, which are transmitted one after the other on the branch 12.1 of the transmission medium 12. The data transmission within the communication network 9 takes place with frames of the same duration.

The frame 16.1 is shown in somewhat more detail in FIG. It is divided into a plurality of time slots 17.1, 17.2, 17.3, ..., 17.n, with the subdivision for each frame

16.1 to 16.4 is exactly the same.

Within a communication network 8, 9, the data transmission is controlled by the respective master 10.1, 10.2. For this purpose, each slave 1 1.1 - 1 1.6 with its master 10.1,

10.2 synchronizes and receives from it one or a plurality of reception and one or a plurality of transmission time slots. A slave 1 1.1 - 1 1.6 may only send or receive in the time slots assigned to it.

The assignment is made, for example, by so-called frame headers, which are transmitted from the master to the slaves 1 1.1 - 1 1.6. Such a frame header comprises one or more time slots which are reserved for the master to send messages (broadcast messages) to the slaves. Typically, the first time slot 17.1 or a certain number of time slots at the beginning of each transmission frame 16.1-16.4 are used as frame headers. From the point of view of the first communication network 8, the master 10.2 represents an external transmission device which uses the same transmission medium for data transmission. The same naturally applies to the master 10.1 from the point of view of the second communication network 9. If, for example, the distance between the first and the second communication network 8, 9 or the attenuation between the two communication networks is so small that the signals from one of them also from the devices of the other can be received, data transmission interference within one. Communication network 8, 9 occur, which are caused by interference. I.e. The master 10.1 of the first communication network 8 unintentionally receives signals from the master 10.2 or a slave 1 1.4-1 1.6 of the second communication network 9 in its reception time slots, which accidentally send data in exactly the same transmission channel. The main problem is typically that the master 10.2 is spatially closer to the master 10.1 than (at least partially) its slaves 1 1.1 - 1 1.3. If the master ^'10 .1 receives data simultaneously on a transmission channel, for example from its slave 1 1.3 and from master 10.2, the signal from master 10.2 has a higher signal level, which is why it is difficult for master 10.1 to receive the signal from slave 1 1.3 to determine.

In order to prevent such faults, the two communication groups 8, 9 are synchronized by the time signal which is independent of the communication groups 8, 9 and is present anyway. Since the synchronization of slaves 1 1.1 - 1 1.6 is determined by their respective masters 10.1, 10.2, it is sufficient if only the two masters 10.1, 10.2 are synchronized by the time signal. This takes place in that the start times of the individual frames 16 are determined by the external time signal. For this purpose, the masters 10.1, 10.2 receive the time signal emitted by the transmitting device 15 by means of their receiver and decoder 13.1, 13.2 and decode it. The starting time of the frames is uniquely determined from the decoded time signal by means of a standard which is generally established for all transceivers.

In addition, all masters 10 connected to the transmission medium 12 assign the available time slots 17.1 to 17.n to their slaves 11 according to the same rules, so that the two masters 10.1, 10.2 each receive or send data in the same time slots 17.1 - 17.n if possible. In this way it is achieved that, for example, the master 10.1 receives interfering data from the other master 10.2 as rarely as possible in its reception time slots, because the other master 10.2 sends as little as possible in these time slots, namely only when the data volume is so large that these time slots are absolutely required for transmission.

In a communication network, the transmission medium of which is the power supply network, the situation for the master 10.1 when receiving signals from the slaves 1 1.4-1 1.6 is less critical since the slaves 1 1.4-1 1.6 are typically further away than the own slaves 1 1.1 - 1 1.3. The signal levels are correspondingly lower. Since the master 10.1 also only receives on the transmission channels that it assigned to its slaves 1 1.1 to 1 1.3 for transmission, it is ensured that it never receives signals that only originate from slaves 1 1.4 - 1 1.6. In other words: If he receives signals from these slaves 1 1.4 - 1 1.6, he will always receive signals from his own slaves 1 1.1 - 1 1.3 at the same time, since he does not switch to reception if his slaves 1 1.1 - 1 1.3 do not send. Based on the signal level or other mechanisms, he can, as mentioned, the correct, i.e. H. determine the signals coming from its slaves 1 1.1 - 1 1.3. Since the transmission path from a slave 1 1.1 - 1 1.3 of the first communication network 8 to its master 10.1 is generally shorter than the transmission path to the other master 10.2, conversely it is also ensured for the slaves 1 1.1 - 1 1.3 that the signal level of the signal from the own master 10.1 is greater than the signal level of the signal from the other master 10.2. This makes it possible for a slave 10.1 - 10.3 at any time to find the right one. H. to recognize and receive the signal intended for him.

With the help of FIGS. 5, 6, a possible method is shown how the masters 10 can assign the available time slots to their slaves 11. The assignment follows the rule that the master always occupies the send time (downlink) in the frame from left to right, while it occupies the receive time (uplink) in the frame from right to left. There are z. B. the assignments shown in FIG. 5 of two frames 16.1, 18.1 transmitted at the same time in the communication links 8, 9 on the same transmission channel. The first master 10.1 communicates with its slave 1 1.3 via the same channel as the second master 10.2 with its slave 1 1.5. The master 10.1 assigns the first eight time slots 17.1 - 17.8 to its slave 1 1.3 as downlink 20.1 (slave receives) and the last six time slots 17.15 - 17.20 as uplink 20.2 (slave sends). At the same time, the master 10.2 assigns the first five time slots 19.1 - 19.5 to its slave 1 1.5 as downlink 21.1 and the last eleven time slots 19.10 - 19.20 as uplink 21.2. In this case, the masters experience no interference from the respective other master, because the time periods of the uplinks 20.2, 21.2, in which the respective masters receive data, do not overlap with the downlinks 20.1, 21.1, in which the other master sends data.

FIG. 6 shows other possible assignments of two frames 16.2, 18.2 transmitted simultaneously at a later time in the communication links 8, 9 on the same transmission channel, which lead to interference which is minimal. The first master 10.1 communicates with its slave 1 1.3 again via the same channel as the second master 10.2 with its slave 1 1.5. The master 10.1 now assigns the first twelve time slots 17.1-17.12 to its slave 1 1.3 as downlink 20.3 and the last six time slots 17.15-17.20 as uplink 20.4 (slave sends). At the same time, the master 10.2 assigns the first five time slots 19.1 - 19.5 to its slave 1 1.5 as downlink 21.3 and the last eleven time slots 19.10 - 19.20 as uplink 21.4. In this case, the second master 10.2 simultaneously receives data from its slave 1 1.5 during the time slots 19.10 - 19.12, while the first master 10.1 sends data to its slave 1 1.3: the second master 10.2 of the communication network 9 thus experiences 19.10 during these 3 time slots. 19.12 Interference by the master of the other communication network 8. The time period in which interference occurs is minimal, ie the duration of this time period t _j results

t _j = max (0,? 7 ₁ + D ₂ - t _F , U ₂ + D _X - t _F ), where U _X , U ₂ the durations of the uplinks, D _λ , D ₂ the durations of the downlinks and t _F the duration of the frame. This means that the method according to the invention minimizes the likelihood of interference occurring as far as is possible with a certain amount of data, without thereby reducing the bandwidth.

Of course, several non-contiguous transmission and reception areas can also be agreed by the two masters. It is only important that they are assigned according to the same rules so that the time period in which interference can occur is minimized.

Figure 7 shows another embodiment of the invention. Again, a transmission system with two different communication links 23, 24 connected to the same line-bound transmission medium 22 (e.g. a power supply network) is shown. The first communication network 23 comprises a plurality of transceivers 25.1-25.4, data being transmitted within this first communication network 23 via a first branch 22.1 of the line-bound transmission medium 22. The second communication network 24 likewise comprises a plurality of transceivers 25.5-25.8, the data being transmitted within this second communication network 24 via a second branch 22.2 of the line-bound transmission medium 22. Both communication networks 23, 24 use the same transmission channels.

The data transmission within a communication network 23, 24 takes place with a frame structure (see FIG. 3), the frames of the two communication networks 23, 24 having the same duration.

Each transceiver comprises a receiver and decoder 26.1-26.8, which receives and decodes a time signal emitted by the generator 14 and the transmitting device 15 and is independent of the communication network. It can be z. For example, the DCF-77- used by the Physikalisch-Technische Bundesanstalt in Braunschweig (DE) 11

Act reference time signal. Each individual transceiver 25.1 - 25.8 of the two communication groups 8, 9 is now synchronized by the time signal independent of the communication groups 23, 24. This synchronization in turn takes place in that the start time of the individual frames is determined by the external time signal.

The transmitters / receivers of the communication networks 23, 24 can each exchange any data within their network with other transmitters / receivers. If the transceiver 25.1 receives data from the transceiver 25.4 and at the same time the transceiver 25.5 of the other communication network 24 sends data to the transceiver 25.7 on the same channel, this leads to interference. The receiving device 25.1 of the communication network 23, which is arranged spatially close to the sending device 25.5 of the other communication network 24, receives the transmitted data of the device 25.5 as well as the data to be actually received by the device 25.4, which is spatially the same or even a greater distance to device 25.1.

However, the transceivers 25.1-25.8 according to the invention now include a circuit 28.1-28.8 for detecting interference due to interference. As soon as the device 25.1 detects interference, it switches to a restricted mode by means of a circuit 27.1, in which each frame is divided into fixed transmission and reception times. The structure of a frame in this restricted mode is shown in FIG. 8: the frame 29 is divided into two time segments 31.1, 31.2, each segment accounting for half the frame duration: the first segment 31.1, in which the transceiver 25.1 transmits, comprises the time slots 30.1-30.10, the second section 31.2, in which the transceiver 25.1 receives, comprises the time slots 30.1-1-30.20. If the channel is not fully utilized, not all of the time slots 30.1-30.20 of sections 31.1, 31.2 are occupied.

Because the influences of the interference are typically the same in both directions, the transceiver 25.5 will also experience interference from the transmissions of the transceiver 25.1 and in the same way in the restricted mode switch. As a result of the synchronized frames, the situation arises that the two transceivers 25.1, 25.5 each transmit simultaneously (in the first half of the frames) and receive simultaneously (in the second half of the frames), so that there is no interference between them these two transmitters / receivers of the various communication networks occurs more.

Switching to the restricted mode of a transceiver naturally results in the communicating remote station also being subjected to this mode (the transmission and reception times being exactly the opposite). This is achieved through the usual synchronization between two remote stations. The opposite station of the transmitting / receiving device 25.1, the transmitting / receiving device 25.4 or the opposite station of the transmitting / receiving device 25.5, the transmitting / receiving device 25.7 henceforth transmit and receive in this restricted mode. The other transceivers 25.2, 25.3, 25.6, 25.8, on the other hand, which do not experience any interference, are still free to divide the entire frames depending on the amount of data. The possible loss of bandwidth is therefore kept as small as possible.

FIG. 9 shows a flow diagram of a possible implementation of the method according to the invention in a transceiver 25.1-25.8. At the beginning of the transmission, the time signal independent of the communication system is received (step 32.1), e.g. B. by means of a known antenna and a known receiver. The time signal is usually coded and a signal is modulated onto it, both the coding and the modulation being publicly known. In a next step 32.2, the received signal is demodulated and decoded, so that the time information is obtained in digital form. With the help of this information, the start time of the frames is now determined (step 32.3). This is done according to a system-wide standard, so that all transceivers that can potentially interfere place the start time of the frames at the same time.

First, data is now transmitted in a free mode (step 32.4), ie two transmitting / receiving devices communicating with one another can transmit and receive their data. Arrange times freely, here too the time slots for the transmission from the master to the slaves (downlink) in the frame from left to right and the time slots for the transmission from slaves to the master (uplink) from right to left are occupied. This leads to a reduction in interference even in free mode. This is followed by the detection of interference in the received signals, e.g. B. by determining the bit error rate of the received signals (step 32.5). If this rate exceeds a certain maximum value, which just barely permits reliable transmission of data, the system switches to the so-called restricted mode (step 32.8). This is also communicated to the remote station (step 32.9). From now on, the transceiver and its remote station will use the system-wide transmission and reception times. The device from another communication network that causes the interference will also switch to the restricted mode for the same reasons as the transceiver under consideration. This eliminates the interference that has led to interference and thus a high error rate.

After a time delay by the time period T2 (step 32.10), which, for. B. corresponds to the typical duration of a data transmission between two remote stations in the communication network (and need not be the same system-wide), the system switches back to free mode. The transceiver then again determines the bit error rate and thus recognizes whether the interference is still occurring. If this is the case, the system switches back to the restricted mode for the time period T2.

If the error rate is less than the specified maximum value, there is a time delay of time T1 (step 32.7), after which the error rate is determined again - this periodic evaluation of the received data ensures that interferences are detected quickly, so that in the limited Mode can be switched. The time period T1 can e.g. B. correspond to the time period T2, but it can also be selected differently, in particular shorter.

The maximum values, which correspond to a maximum tolerable error rate, can be selected differently for each device. Instead of the error rate, others can Large sizes are used to detect interference, e.g. B. a measured ratio between the power level of the received signal and also detected interference. The transceiver can - instead of the time delay (step 32.10) by T2 - further include means for detecting possible interference even during the transmission of data in limited mode, e.g. B. by switching periodically to reception in the time period specified for the transmission, so that signals of other transmitters / receivers transmitting in the restricted mode can be detected.

In summary, it can be stated that the method according to the invention for the transmission of data within a communication network minimizes or eliminates the interference between transmitters or receivers of different networks, hardly uses any bandwidth and avoids a synchronization process between two devices of different communication networks.

Claims

claims

1. Method for the transmission of data within a communication network (8; 23) with at least a first transceiver (10.1; 25.1) and a second transceiver (1 1.1; 25.2) as well as one not in the communication network ( 8; 23) integrated external transceiver (10.2; 25.5), the data being transmitted via a line-bound transmission medium (12; 22), in particular a power supply network, characterized in that transmission times of at least the first transceiver (10.1 ; 25.1) and the external transceiver (10.2; 25.5) are synchronized by a time signal that is independent of the communication network (8; 23).

2. The method according to claim 1, characterized in that all transmitting / receiving devices (10, 1 1; 25) use periodic frames (16; 29) for the transmission of the data that all transmitting / receiving devices (10, 1 1 ; 25) has a same structure of the frames (16, 29) use, and that the transmission times of the transmitting / receiving devices (10, 1 1; ^'25) are synchronized by a start time of the frames (16; 29) by the

Communication network (8; 23) independent time signal is determined.

3. The method according to claim 2, characterized in that the first transceiver (10.1) controls the transmission between it and the second transceiver (1 1.1) by the frame (16.1) in one divides the first time period (20.1) and a second time period (20.2), whereby said time periods (20.1, 20.2) do not overlap and transmit the first transceiver (10.1) in the first time period (20.1) and the second transmission in the second time period - / receiving device (1 1.1) sends.

4. The method according to claim 3, characterized in that for all transmitting / receiving devices (10, 1 1) the first time period (20.1) is contiguous and at an arrival beginning of the frame (16.1) begins and the second period (20.2) is contiguous and ends at one end of the frame (16.1).

5. The method as claimed in claim 2, characterized in that at least the first transceiver (25.1) and the external transceiver (25.5) are disturbed by interference which is not integrated in the same communication network (23, 24)

Recognize transceiver, and that after recognizing a fault, they divide the frames (29) into a predetermined first time period (31.1) and a predetermined second time period (31.2), the transceiver (25) in the first period Send (31.1) and receive in the second period (31.2).

6. The method according to claim 5, characterized in that the first time period (31.1) corresponds to a first half of the frame (29) and the second time period (31.2) corresponds to a second half of the frame (29).

7. Arrangement for the transmission of data within a communication network (8; 23) with at least a first transceiver (10.1; 25.1) and a second transceiver (1 1.1; 25.2) as well as an external transmission not integrated in the communication network - / receiving device (10.2; 25.5), wherein all the transmitting / receiving devices (10, 11; 25) mentioned for the transmission of the data are connected to a line-bound transmission medium (12; 22), in particular a power supply network, characterized in that that at least the first

Transceiver (10.1; 25.1) and the external transceiver (10.2; 25.5) are designed in such a way that they receive a time signal that is independent of the communication network (8; 23) and can synchronize their transmission times with it.

8. Arrangement according to claim 7, characterized in that all the transceivers (10, 1 1; 25) use periodic frames (16; 29) to transmit the data that all transceivers (10, 1 1 ; 25) the same structure of the frames Use (16; 29) and that the transmission times of the transceivers (10, 1 1; 25) are synchronized by determining a start time of the frames (16; 29) by the time signal independent of the communication network (8; 23).

9. Arrangement according to claim 8, characterized in that the first transceiver (10.1) is superior to the second transceiver (1 1.1) and is designed such that it is the transmission of data between it and the second transmitter - / Receiver (1 1.1) can be controlled by assigning a first period (20.1) of the frame (16.1) and a second period (20.2) of the frame (16.1), said periods (20.1, 20.2) not overlapping and in the first Period (20.1) transmits the first transceiver (10.1) and in the second period (20.2) transmits the second transceiver (10.2).

10. The arrangement according to claim 9, characterized in that for all transmitting / receiving devices (10, 1 1) the first time period (20.1) is contiguous and begins at the beginning of the frame (16.1) and the second time period (20.2) is related - is given and ends at the end of the frame (16.1).

1 1. Arrangement according to claim 8, characterized in that at least the first transceiver (25.1) and the external transceiver (25.5) comprise means for detecting interference by a transceiver not integrated in the same communication network, and that at least the first transceiver (25.1) and the external transceiver (25.5) after

Detect a fault, divide the frames (29) into a fixed first time period (31.1) and a second time period (31.2), the transceivers (25) transmitting in the first time period (31.1) and in the second time period (31.2 ) received.

12. The arrangement according to claim 1 1, characterized in that the first time period (31.1) corresponds to a first half of the frame (29) and the second time period (31.2) corresponds to a second half of the frame (29).

13. Arrangement according to one of claims 7 to 12, characterized in that the time signal independent of the communication network (8; 23) is selected from the following:

a) a phase of the 50 or 60 Hz power supply network;

b) a publicly broadcast radio signal for time reference;

c) a navigation signal transmitted by radio, in particular from GPS or GLONASS;

d) a time reference signal of a mobile radio network, in particular a GSMCDMA or UMTS network; or

e) a time reference signal from another communication system on the line-bound transmission medium.

14. Transceiver (10.1, 10.2; 25.1, 25.5) for the transmission of data within a communication network (8; 23), in particular for an arrangement according to one of claims 7 to 13, comprising means for connection to a line-bound transmission medium (12 ; 22), in particular the power supply network, characterized by means (13; 26) for receiving a time signal which is independent of the communication network and by means for synchronizing a transmission time of the

Transmitting / receiving device.

15. Transceiver according to claim 14, characterized by means for controlling a transmission of data between it and a second transceiver (1 1.1) which the second transceiver a first time-out cut (20.1) for receiving and a second time period (20.2) for sending.

16. Transceiver according to claim 14 or 15, characterized by means (28) for detecting faults by a transceiver not integrated in the same communication network and by means (27) for switching to a restricted mode, in which a fixed predetermined first time period (31.1) for sending and a fixed predetermined second time period (31.2) for receiving.

17. Transceiver according to one of claims 14 to 16, characterized in that the means for receiving a time signal independent of the communication network (8; 23) receive and decode one of the following time signals:

a) a phase of the 50 or 60 Hz power supply network;

b) a publicly broadcast radio signal for time reference;

c) a navigation signal broadcast by radio, in particular from GPS or GLONASS;

d) a time reference signal of a mobile radio network, in particular a GSM, CDMA or UMTS network;