CA2073912A1 - Data exchange process - Google Patents
Data exchange processInfo
- Publication number
- CA2073912A1 CA2073912A1 CA002073912A CA2073912A CA2073912A1 CA 2073912 A1 CA2073912 A1 CA 2073912A1 CA 002073912 A CA002073912 A CA 002073912A CA 2073912 A CA2073912 A CA 2073912A CA 2073912 A1 CA2073912 A1 CA 2073912A1
- Authority
- CA
- Canada
- Prior art keywords
- data
- station
- repetition number
- data telegram
- external
- 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.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 14
- 230000005540 biological transmission Effects 0.000 claims abstract description 43
- 230000000977 initiatory effect Effects 0.000 claims 1
- 238000009826 distribution Methods 0.000 description 5
- 230000006978 adaptation Effects 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000006854 communication Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/20—Hop count for routing purposes, e.g. TTL
Abstract
ABSTRACT
In a process for the exchange of data between a master station (M) and at least one external station (A1 to A4) via a common data channel (1) and a plurality of interposed relay stations (R1 to R3), in which process the master station (M) directs a request to the external station and receives from the latter an answer and during transmission into the interposed relay stations (R1 to R3), the data are repeated by reception and retransmission, said data being transmitted in the form of data telegrams between the master station (M) and the external station.
Thus, with each data telegram is linked a positive integer in the form of a repetition number, being transmitted with the data telegram and determining how often the data telegram must be successively repeated by the relay stations (R1 to R3). Each relay station (R1 to R3), which receives a data telegram with a repetition number higher than zero, repeats said data tele-gram, provided that the reception quality has a minimum acceptable quality level. Each relay station (R1 to R3), which repeats a data telegram, derives from the old repetition number linked with the received data telegram by reducing by one a new repetition number and transmits the thus derived, new repetition number, in place of the old repetition number, together with the data telegram.
In a process for the exchange of data between a master station (M) and at least one external station (A1 to A4) via a common data channel (1) and a plurality of interposed relay stations (R1 to R3), in which process the master station (M) directs a request to the external station and receives from the latter an answer and during transmission into the interposed relay stations (R1 to R3), the data are repeated by reception and retransmission, said data being transmitted in the form of data telegrams between the master station (M) and the external station.
Thus, with each data telegram is linked a positive integer in the form of a repetition number, being transmitted with the data telegram and determining how often the data telegram must be successively repeated by the relay stations (R1 to R3). Each relay station (R1 to R3), which receives a data telegram with a repetition number higher than zero, repeats said data tele-gram, provided that the reception quality has a minimum acceptable quality level. Each relay station (R1 to R3), which repeats a data telegram, derives from the old repetition number linked with the received data telegram by reducing by one a new repetition number and transmits the thus derived, new repetition number, in place of the old repetition number, together with the data telegram.
Description
DESCRIPTION
DATA EXC*~NGE PROCESS
TECHNICAL FIELD
The present invention relates to the data transmission field and more spec-ifically to a process for the exchange of data between a master station and at least one e~ternal station via a ccmmon data channel and a plurality of interconnected relay stations, in which (a) the master station to which at least one external station directs a request and frcm which the at least one external station receives an answer and (b) during transmission into the interconnected relay stations, the data are repeated by reception and retransmission.
Such a process is e.g. known fron EP-A1-395 495.
PRIOR ART
During data transmission, e.g. in radio systems or specifically in communi-cations systens, which use the electrical medium and low voltage distribution network as the data channel (DLC = distribution line carriers or power line carriers), in certain cases the transnission conditions are so poor, that between remote stations it is not possible to build up a direct connection.
It is therefore necessary to prcduce a corresponding connection via relay stations.
Experience has shown that there are major differences in the transmission quality in two transmission directions (frcm the transmitting to the receiving station and back again) and therefore also in the nunber of relay stations which are required. Therefore for optimum transmission in both directions, it is highly likely that different stations will be used as relay stations.
The presently ccmmercially available DLC systems are inapprc~riate for the concept of relay stations. They operate with high transmitting power levels for bridging the distances between remote stations. Other existing systems 2~73~12 use specific relay stations whicll, as reqlir~d, are only used for this pur-pose. This involves high engineering effort and correspondingly high costs, because the sites for these relay stations must be predete~mined for all possible network topologies, such a system also suffering frcm inflexibility.
The aforementioned document proposes an algorithm for the determination of relay stations in such a DLC network. The proposal is based on a specific interrogation cycle with w~lich the master station firstly determines the best way to all its slave stations. Hcwever, this solution is also much too ccmplicated and inflexible. The interrogation cycle re~uires expensive transmission time and, particularly in the case of large networks, will take a correspondingly long time. In the case of changes in the transmission conditions it is always firstly necessary with such an interrogation cycle to determine the best transmission paths, which is the same as delaying the actual data transmission. Admittedly over a period of time it is possible to produce a data bank of alternative transmission paths fc;r each station, but such a bank is very ccmplex in its implementation.
As prior art reference is also made to EP-A1-388 672 and EP-Al-388 687.
DESCRIPTION OF THE INVENTION
The problem of the invention is to improve a process of the aforementioned type in such a way that there can be a rapid, flexible adaptation to modified network conditions and the implementation of such a system only involves ccmparatively limited engineering effort and expenditure.
In the case of a process of the aforementioned type, this problem is solved in that (c) the data are transmitted in the form of data telegrams between the master station and the at least one external station, (d) with each data telegram is linked a positive integer as a repetition number, which is transmitted with the data telegram and determines how often the data telegram must be successively repeated by relay stations, (e) each relay station, which receives a data telegram with a repetition number higher than zero repeats said data telegran, provided that the reception quality has a mini~num acceptable quality level, (f) each relay station which repeats a data telegram derives fran the old repetition nunber linked with the received data telegram a new repeti-tion nunber by reducing by one and retransmits the thus derived, new repetition nunber in place of the old repetition nunber together with the data telegran, (g) at the start of a transmission the maxi~n number of necessary repeti-tions for the particular transmission is linked with each data telegran as the initial repetition number and (h) a data telegran is not repeated again if the repetition number linked with it has been reduced by the preceding repetitions to zero.
Due to the fact that each relay station hearing a data telegram to be repeated autcmatically repeats said telegran, there is no need for the ca~-plicated determination and indication of individual relay stations for all the external stations in the network. Therefore the engineering effort and expenditure prior to the installation of such a ca~municat_on syste~ can be drastically reduced. Canpared with networks in which the master station autanatically seeks the best relay stations, the inventive solution has the advantage that it requires virtually no connunications overheads.
A first, preferred enbcdiment of the invention is characterized in that(a) each data telegran has a heading in which the repetition number is written in fixed form, (b) frcm a data telegram received by it, each external station derives a provision, first initial repetition number for an optimum transmission of data frcm the master station to said external station and passes on said prc~isional, initial repetition number on an ackncwledgement to the master station, (c) on the basis of the data telegrams received fr~m each external station,, the master station derives a provisional, second, initial repetition nunber necessary for an optinum transmission of data fran said external station to the master station and (d) frcm the provisional, first and second, initial repetition numbers, the master station determines the final first and second, initial repetition numbers and writes the~ in fixed form in the heading of each data tele-gram for the particular transmission directions.
In this enbodiment the connunication of an external station to the master station takes place out-bound via the necessary number of repetitions by a few bits in the heading of the normal answer telegram. These bits are trans-mitted whenever the external station transmits an information package to the master station. The simultaneous consequence of this is that there can be a maximum speed updating of the corresponding initial repetition numbers in the master station. Therefore a network, according to this solution, can adapt within the shortest possible time to modify topologies or transmission con-ditions. The independent treatment of two transmission directions leads to the advantage of a mininum transmission time with a sinultaneous, high trans-mission reliability.
Further embodiments of the invention can be gathered frcm the subclaims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail hereinafter relative to non-limitative embodiments and with reference to the attached drawings, wherein sha~:
Fig. 1 In detail an example fo,r the topology of a ccmmNnications system based on an electrical distribution network.
Fig. 2 Different possible transmission paths in a system according to fig. 1.
WAYS TO IMPLEMENT THE INVENTICN
Fig. 1 shows the fundamental topology for a ccmmunications system based c,n an electrical distribution network. The individual line paths of the network are fcnmed by data channels 1, by means of which the master station M can exchange line-bound data with a plurality of external stations Al to A4 dis-tributed within the network.
Due to possible interference on the network and the possibly considerable distances between master station M and external stations Al to A4, the data exchange takes place by means of interposed relay stations Rl to R3, which :
receive and retransnit, i.e. repeat (arrcws in fig. 2) the data transmitted by the master station M or the answer supplied by an interrogated external station. In both transmission directions master station -~ external station (continuous line arrows in fig. 2) and external station-- ~ master station (broken line arrows in fig. 2), as a result of the large number of interposed relay stations R1 to R3, different trangmission paths are possible, which include different relay stations which generally differ frcm one another in the transmission quality. Such transmission paths are selected and fixed in the aforementioned prior art, so that transmissions between the master station M and a particular external station always take place via the same selected relay stations.
m e present invention takes a different ccurse and firstly the data are exchanged between the stations in the form of data telegrams. Each data telegram contains an information indicating whether it d oe s or d oe s not haveto be repeated on reception by a relay station. Each station receiving a data telegram which has to be repeated, repeats the said data telegram if the reception quality has a minimum acceptable quality level. m us, not only are the relay stations of a particular transmission path, but also numerous other relay stations take part in the passing on of data.
The repetition-related information in the data telegram is a positive integer, i.e. the repetition number. m is repetition number indicates how often the data telegram must be successively repeated by relay stations. For each repetition by a relay station the old repetition number of the received data telegram is reduced by one. The thus obtained new repetition number is transmitted again with the data telegram in place of the old repetition num-ber, so that with advancing transmission the repetition number of a data telegram beccmes increasingly smaller. A data telegram will no longer be repeated if the repetition number linked with it has been reduced to zero by the preceding repetitions.
What is important is the way in which the necessary output values for the repetition number, i.e. the initial repetition numbers, are determined for a particular transmission and which on transmitting a data telegram are assoc-iated with the latter. As the transmission frcm the master static~n M to an 2073~12 external station A1 to A4 and the response fron the external station to the master station M can take place by different ways or channels, for both transmission directions there are varying initial repetition nunbers, nanely the first and second initial repetition n~mbers.
According to a preferred enbcdilnent of the invention each external station initially determines on the basis of the received data telegrams (e.g. by an estimate) a prcvisional, first, initial repetition nunber necessary for an c~timum data transmission and supplies said number on retransmitting to the master station M.
In the same way, by means of the data telegrams received fron each external station, the master station determines a provisional, second, initial repe-t-ition number necessary for an optimum data transmission between the external station and the master station M. Fr~n the thus obtained provisional values for the first and second initial repetition numbers, the master station M
nc~ derives the final first and second initial repetition nunbers, which are then written in fixed form in a data telegram heading in both transmission directions by the master station M. This ensures a reliable data transmis-sion under stationary network conditions.
If a particular external station fails to reply (because the transmission conditions in the network have changed in the meantime), the master station M increases a~ least the associated first and possibly also the associated second initial repetition nunbers by in each case one and then makes a further request to the same external station until either said station replies or a predetermined maximum value of the numbers has been reached.
On receiving a reply the hitherto first (possibly also the hitherto second) initial repetition number is replaced by the newly fo~med, increased repeti-tion number. The initial repetition numbers are filed in the master station, preferably in a data bank.
As has been stated hereinbefore as a result of the autcmatic repetition of the data telegrams in all the receiving relay stations, there is no need for a ccmplicated determination and indication of individual relay stations for all the external stations in the network. The automatic cammunications of the repetition numbers only caver a few bits in the heading of a data tele-gram, so that the additional communication expenditure is low. The contin-ual transmission of the repetition numbers means that the data bank is always brought to the updating state for these numbers in a minimum amount of time, so that adaptations to changes in the network take place rapidly.
Due to the fact that each station which hears a data telegram to be repeated autcmatically repeats said telegram, it is ensured that the target station always has the best possible signal quality. This is due to the fact that it is highly probable that the most appropriate neighbouring station for the target station is autamatically used as the relay station. Fr~m the statis-tical standpoint it is virtually impossible fa,r there to be a signal cancel-lation or deletion by the superimposing of two or more signals f mm different relay stations, because the high signal attenuation an the electrical distri-bution network makes such a superimposing effect virtually impossible. Thus, in all the receivers in a real network one of the many transmitted signals will always have a much higher signal amplitude than the others. This signal then doninates all the others and in most such standard mcdulatian modes is highly preferred in the demodulata~r (so-called capture effect).
Although in figs. 1 and 2 and the previaus description a distinction has been made between the external stations A1 to A4 and the relay stations Rl to R3, according to a preferred embadiment of the invention for both station types the sane network stations are used, i.e. the normal external stations can, if necessary, operate as relay stations and vice versa.
~ ~ , , ' . .
' ',, ~ ' ~ ~ ,, ::
DATA EXC*~NGE PROCESS
TECHNICAL FIELD
The present invention relates to the data transmission field and more spec-ifically to a process for the exchange of data between a master station and at least one e~ternal station via a ccmmon data channel and a plurality of interconnected relay stations, in which (a) the master station to which at least one external station directs a request and frcm which the at least one external station receives an answer and (b) during transmission into the interconnected relay stations, the data are repeated by reception and retransmission.
Such a process is e.g. known fron EP-A1-395 495.
PRIOR ART
During data transmission, e.g. in radio systems or specifically in communi-cations systens, which use the electrical medium and low voltage distribution network as the data channel (DLC = distribution line carriers or power line carriers), in certain cases the transnission conditions are so poor, that between remote stations it is not possible to build up a direct connection.
It is therefore necessary to prcduce a corresponding connection via relay stations.
Experience has shown that there are major differences in the transmission quality in two transmission directions (frcm the transmitting to the receiving station and back again) and therefore also in the nunber of relay stations which are required. Therefore for optimum transmission in both directions, it is highly likely that different stations will be used as relay stations.
The presently ccmmercially available DLC systems are inapprc~riate for the concept of relay stations. They operate with high transmitting power levels for bridging the distances between remote stations. Other existing systems 2~73~12 use specific relay stations whicll, as reqlir~d, are only used for this pur-pose. This involves high engineering effort and correspondingly high costs, because the sites for these relay stations must be predete~mined for all possible network topologies, such a system also suffering frcm inflexibility.
The aforementioned document proposes an algorithm for the determination of relay stations in such a DLC network. The proposal is based on a specific interrogation cycle with w~lich the master station firstly determines the best way to all its slave stations. Hcwever, this solution is also much too ccmplicated and inflexible. The interrogation cycle re~uires expensive transmission time and, particularly in the case of large networks, will take a correspondingly long time. In the case of changes in the transmission conditions it is always firstly necessary with such an interrogation cycle to determine the best transmission paths, which is the same as delaying the actual data transmission. Admittedly over a period of time it is possible to produce a data bank of alternative transmission paths fc;r each station, but such a bank is very ccmplex in its implementation.
As prior art reference is also made to EP-A1-388 672 and EP-Al-388 687.
DESCRIPTION OF THE INVENTION
The problem of the invention is to improve a process of the aforementioned type in such a way that there can be a rapid, flexible adaptation to modified network conditions and the implementation of such a system only involves ccmparatively limited engineering effort and expenditure.
In the case of a process of the aforementioned type, this problem is solved in that (c) the data are transmitted in the form of data telegrams between the master station and the at least one external station, (d) with each data telegram is linked a positive integer as a repetition number, which is transmitted with the data telegram and determines how often the data telegram must be successively repeated by relay stations, (e) each relay station, which receives a data telegram with a repetition number higher than zero repeats said data telegran, provided that the reception quality has a mini~num acceptable quality level, (f) each relay station which repeats a data telegram derives fran the old repetition nunber linked with the received data telegram a new repeti-tion nunber by reducing by one and retransmits the thus derived, new repetition nunber in place of the old repetition nunber together with the data telegran, (g) at the start of a transmission the maxi~n number of necessary repeti-tions for the particular transmission is linked with each data telegran as the initial repetition number and (h) a data telegran is not repeated again if the repetition number linked with it has been reduced by the preceding repetitions to zero.
Due to the fact that each relay station hearing a data telegram to be repeated autcmatically repeats said telegran, there is no need for the ca~-plicated determination and indication of individual relay stations for all the external stations in the network. Therefore the engineering effort and expenditure prior to the installation of such a ca~municat_on syste~ can be drastically reduced. Canpared with networks in which the master station autanatically seeks the best relay stations, the inventive solution has the advantage that it requires virtually no connunications overheads.
A first, preferred enbcdiment of the invention is characterized in that(a) each data telegran has a heading in which the repetition number is written in fixed form, (b) frcm a data telegram received by it, each external station derives a provision, first initial repetition number for an optimum transmission of data frcm the master station to said external station and passes on said prc~isional, initial repetition number on an ackncwledgement to the master station, (c) on the basis of the data telegrams received fr~m each external station,, the master station derives a provisional, second, initial repetition nunber necessary for an optinum transmission of data fran said external station to the master station and (d) frcm the provisional, first and second, initial repetition numbers, the master station determines the final first and second, initial repetition numbers and writes the~ in fixed form in the heading of each data tele-gram for the particular transmission directions.
In this enbodiment the connunication of an external station to the master station takes place out-bound via the necessary number of repetitions by a few bits in the heading of the normal answer telegram. These bits are trans-mitted whenever the external station transmits an information package to the master station. The simultaneous consequence of this is that there can be a maximum speed updating of the corresponding initial repetition numbers in the master station. Therefore a network, according to this solution, can adapt within the shortest possible time to modify topologies or transmission con-ditions. The independent treatment of two transmission directions leads to the advantage of a mininum transmission time with a sinultaneous, high trans-mission reliability.
Further embodiments of the invention can be gathered frcm the subclaims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail hereinafter relative to non-limitative embodiments and with reference to the attached drawings, wherein sha~:
Fig. 1 In detail an example fo,r the topology of a ccmmNnications system based on an electrical distribution network.
Fig. 2 Different possible transmission paths in a system according to fig. 1.
WAYS TO IMPLEMENT THE INVENTICN
Fig. 1 shows the fundamental topology for a ccmmunications system based c,n an electrical distribution network. The individual line paths of the network are fcnmed by data channels 1, by means of which the master station M can exchange line-bound data with a plurality of external stations Al to A4 dis-tributed within the network.
Due to possible interference on the network and the possibly considerable distances between master station M and external stations Al to A4, the data exchange takes place by means of interposed relay stations Rl to R3, which :
receive and retransnit, i.e. repeat (arrcws in fig. 2) the data transmitted by the master station M or the answer supplied by an interrogated external station. In both transmission directions master station -~ external station (continuous line arrows in fig. 2) and external station-- ~ master station (broken line arrows in fig. 2), as a result of the large number of interposed relay stations R1 to R3, different trangmission paths are possible, which include different relay stations which generally differ frcm one another in the transmission quality. Such transmission paths are selected and fixed in the aforementioned prior art, so that transmissions between the master station M and a particular external station always take place via the same selected relay stations.
m e present invention takes a different ccurse and firstly the data are exchanged between the stations in the form of data telegrams. Each data telegram contains an information indicating whether it d oe s or d oe s not haveto be repeated on reception by a relay station. Each station receiving a data telegram which has to be repeated, repeats the said data telegram if the reception quality has a minimum acceptable quality level. m us, not only are the relay stations of a particular transmission path, but also numerous other relay stations take part in the passing on of data.
The repetition-related information in the data telegram is a positive integer, i.e. the repetition number. m is repetition number indicates how often the data telegram must be successively repeated by relay stations. For each repetition by a relay station the old repetition number of the received data telegram is reduced by one. The thus obtained new repetition number is transmitted again with the data telegram in place of the old repetition num-ber, so that with advancing transmission the repetition number of a data telegram beccmes increasingly smaller. A data telegram will no longer be repeated if the repetition number linked with it has been reduced to zero by the preceding repetitions.
What is important is the way in which the necessary output values for the repetition number, i.e. the initial repetition numbers, are determined for a particular transmission and which on transmitting a data telegram are assoc-iated with the latter. As the transmission frcm the master static~n M to an 2073~12 external station A1 to A4 and the response fron the external station to the master station M can take place by different ways or channels, for both transmission directions there are varying initial repetition nunbers, nanely the first and second initial repetition n~mbers.
According to a preferred enbcdilnent of the invention each external station initially determines on the basis of the received data telegrams (e.g. by an estimate) a prcvisional, first, initial repetition nunber necessary for an c~timum data transmission and supplies said number on retransmitting to the master station M.
In the same way, by means of the data telegrams received fron each external station, the master station determines a provisional, second, initial repe-t-ition number necessary for an optimum data transmission between the external station and the master station M. Fr~n the thus obtained provisional values for the first and second initial repetition numbers, the master station M
nc~ derives the final first and second initial repetition nunbers, which are then written in fixed form in a data telegram heading in both transmission directions by the master station M. This ensures a reliable data transmis-sion under stationary network conditions.
If a particular external station fails to reply (because the transmission conditions in the network have changed in the meantime), the master station M increases a~ least the associated first and possibly also the associated second initial repetition nunbers by in each case one and then makes a further request to the same external station until either said station replies or a predetermined maximum value of the numbers has been reached.
On receiving a reply the hitherto first (possibly also the hitherto second) initial repetition number is replaced by the newly fo~med, increased repeti-tion number. The initial repetition numbers are filed in the master station, preferably in a data bank.
As has been stated hereinbefore as a result of the autcmatic repetition of the data telegrams in all the receiving relay stations, there is no need for a ccmplicated determination and indication of individual relay stations for all the external stations in the network. The automatic cammunications of the repetition numbers only caver a few bits in the heading of a data tele-gram, so that the additional communication expenditure is low. The contin-ual transmission of the repetition numbers means that the data bank is always brought to the updating state for these numbers in a minimum amount of time, so that adaptations to changes in the network take place rapidly.
Due to the fact that each station which hears a data telegram to be repeated autcmatically repeats said telegram, it is ensured that the target station always has the best possible signal quality. This is due to the fact that it is highly probable that the most appropriate neighbouring station for the target station is autamatically used as the relay station. Fr~m the statis-tical standpoint it is virtually impossible fa,r there to be a signal cancel-lation or deletion by the superimposing of two or more signals f mm different relay stations, because the high signal attenuation an the electrical distri-bution network makes such a superimposing effect virtually impossible. Thus, in all the receivers in a real network one of the many transmitted signals will always have a much higher signal amplitude than the others. This signal then doninates all the others and in most such standard mcdulatian modes is highly preferred in the demodulata~r (so-called capture effect).
Although in figs. 1 and 2 and the previaus description a distinction has been made between the external stations A1 to A4 and the relay stations Rl to R3, according to a preferred embadiment of the invention for both station types the sane network stations are used, i.e. the normal external stations can, if necessary, operate as relay stations and vice versa.
~ ~ , , ' . .
' ',, ~ ' ~ ~ ,, ::
Claims (6)
1. Process for the exchange of data between a master station (M) and at least one external station (A1 to A4) via a common data channel (1) and a plurality of interconnected relay stations (R1 to R3), in which (a) the master station (M) to which at least one external station (A1 to A4) directs a request and from the at least one external station (A1 to A4) receives an answer and (b) during transmission into the interconnected relay stations (R1 to R3), the data are repeated by reception and retransmission, characterized in that (c) the data are transmitted in the form of data telegrams between the master station (M) and the at least one external station (A1 to A4), (d) with each data telegram is linked a positive integer as a repetition number, which is transmitted with the data telegram and determines how often the data telegram must be successively repeated by relay stations (R1 to R3), (e) each relay station (R1 to R3) which receives a data telegram with a repetition number higher than zero repeats said data telegram, provided that the reception quality has a minimum acceptable quality level, (f) each relay station (R1 to R3) which repeats a data telegram derives from the old repetition number linked with the received data telegram a new repetition number by reducing by one and retransmits the thus derived, new repetition number in place of the old repetition number together with the data telegram, (g) at the start of a transmission the maximum number of necessary repeti-tions for the particular transmission is linked with each data telegram as the initial repetition number and (h) a data telegram is not repeated again if the repetition number linked with it has been reduced by the preceding repetitions to zero.
2. Process according to claim 1, characterized in that each data telegram has a heading in which the repetition number is written in fixed form.
3. Process according to claim 2, characterized in that (a) from a data telegram received by it, each external station (A1 to A4) derives a provisional, first, initial repetition number for an optimum transmission of data f m n the master station (M) to said external station and passes on said provisional, first, initial repetition number during acknowledgement to the master station (M), (b) on the basis of the data telegrams received from each external station (A1 to A4), the master station (M) derives a provisional, second, ini-tial repetition number for an optimum transmission of data from said external station to the master station (M) and (c) from the provisional first and second, initial repetition numbers, the master station (M) determines the final first and second, initial repet-ition numbers and writes sane in fixed form in the heading of each data telegram for the particular transmission directions.
4. Process according to claim 3, characterized in that when there is no reply from an interrogated external station (A1 to A4) (a) the master station (M) increases by in each case one at least the associated first, initial repetition number and then directs a further request to the external station until either the interrogated external station replies or a predetermined maximum value has been reached and (b) on receiving a reply, at least the previous, first, initial repetition number is replaced by the newly obtained, increased, first, initial repetition numbers.
5. Process according to claim 4, characterized in that the valid first and second, initial repetition numbers are filed in a data bank in the master station (M).
6. Process according to one of the claims 1 to 5, characterized in that the external stations are used as relay stations (R1 to R3).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4124227.0 | 1991-07-22 | ||
| DE4124227A DE4124227A1 (en) | 1991-07-22 | 1991-07-22 | METHOD FOR EXCHANGING DATA |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2073912A1 true CA2073912A1 (en) | 1993-01-23 |
Family
ID=6436719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002073912A Abandoned CA2073912A1 (en) | 1991-07-22 | 1992-07-15 | Data exchange process |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0524909A1 (en) |
| JP (1) | JPH05211522A (en) |
| CA (1) | CA2073912A1 (en) |
| DE (1) | DE4124227A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3821847B2 (en) * | 1995-06-30 | 2006-09-13 | コーニンクレッカ、フィリップス、エレクトロニクス、エヌ．ヴィ． | Method and apparatus for routing messages in a network of nodes |
| JPH10505732A (en) * | 1995-07-03 | 1998-06-02 | フィリップス、エレクトロニクス、ネムローゼ、フェンノートシャップ | Building management device by packet hopping communication |
| DE19904358B4 (en) * | 1999-02-04 | 2005-07-07 | Abb Research Ltd. | Method for data exchange via a decentralized network |
| FI112307B (en) | 2000-08-02 | 2003-11-14 | Nokia Corp | communication Server |
| CN115070746A (en) * | 2022-08-22 | 2022-09-20 | 深圳时代能创能源科技有限公司 | Device for solving double-active signal switching |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4099024A (en) * | 1977-02-16 | 1978-07-04 | Xerox Corporation | Communications network repeater |
| US5032833A (en) * | 1989-04-27 | 1991-07-16 | Schlumberger Industries, Inc. | Adaptive network routing for power line communications |
| EP0426911A1 (en) * | 1989-11-06 | 1991-05-15 | Hewlett-Packard Company | Routing management in computer networks |
-
1991
- 1991-07-22 DE DE4124227A patent/DE4124227A1/en not_active Withdrawn
-
1992
- 1992-07-15 CA CA002073912A patent/CA2073912A1/en not_active Abandoned
- 1992-07-22 EP EP92810562A patent/EP0524909A1/en not_active Withdrawn
- 1992-07-22 JP JP4195303A patent/JPH05211522A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05211522A (en) | 1993-08-20 |
| DE4124227A1 (en) | 1993-01-28 |
| EP0524909A1 (en) | 1993-01-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |