METHOD FOR TRANSMITTING INFORMATION

Abstract

In the repeated transmission of information in the form of a coded packet from a transmitter via a radio link to a receiver, an interference-free receive packet is quickly available if interference-free subpackets are assembled from the packet as subpackets of the interference-free receive packet. For this purpose, subpackets of successively received and temporarily stored packets assigned to one another can be compared with one another and, in the event of a match, can be inserted in a gap-filling manner into the received packet. Alternatively, the successive packets are already divided in each case at the transmitting end into subpackets provided with error detection codes, the subpackets being incorporated into the received packet as soon as they have been correctly received in a packet.

Claims

1. A method for transmitting information in a form of a coded packet, which comprises the steps of: transmitting repeatedly the coded packet from a transmitter via a radio link to a receiver; and assembling interference-free subpackets derived from received coded packets into an interference-free received packet.

2. The method according to claim 1, which further comprises dividing the coded packet transmitted multiple times in succession at a receiving end into the subpackets.

3. The method according to claim 1, which further comprises dividing the coded packet transmitted multiple times in succession at a receiving end into the subpackets provided with error detection codes.

4. The method according to claim 1, wherein lengths of the subpackets are statically or dynamically variable.

5. The method according to claim 2, which further comprises: comparing the subpackets of successively received coded packets assigned to one another at the receiving end on a basis of an arrangement in the coded packet with one another; and assembling the subpackets into the interference-free received packet in an event of a match.

6. The method according to claim 1, wherein at least x=3 successively received coded packets are in each case divided into a sequence of at least y=3 said subpackets.

7. The method according to claim 2, which further comprises dividing the subpackets into secondary subpackets which are to be compared with one another.

8. The method according to claim 3, which further comprises comparing the subpackets successively received correctly according to an error detection code with one another for matching.

9. The method according to claim 3, which further comprises dividing the subpackets received into secondary subpackets which are to be compared with one another.

10. The method according to claim 3, which further comprises providing the subpackets at a transmitting end with cyclic redundancy check (CRC) checksums, with 3-from-6 codings or with different or with a plurality of error detection codes.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0023] FIG. 1 is an illustration showing an information transmission with subpacket formations on repeatedly received packets only at a receiving end; and

[0024] FIG. 2 is an illustration showing an information transmission with subpacket formation already at a transmitting end.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a normally battery-operated transmitter 11 that is, for example, a control unit of a radio remote control for domestic appliances, but, in particular, a consumption metering point (smart meter) which sporadically or more or less continuously transmits current or accumulated measured values.

[0026] A receiver 12 may correspondingly be a switching device for a drive device in situ, or a concentrator for the temporary storage and, if necessary, processing of measured values which, correspondingly source-coded, can also be received from a plurality of different metering points. It may equally also be a radio link 13 from a concentrator equipped with a transmitter to a receiver at an addressed metering point, for example to transmit tariff change information. In practice, it predominantly involves two-way radio links of this type between a concentrator and a number of metering points.

[0027] The information transmission, drawn by way of example as a one-way transmission, from the transmitter 11 to the receiver 12 is performed successively in packets via a radio link 13 in one of the ISM bands freely available for this purpose, but correspondingly under a heavy load and severely affected by interference. The repeatedly transmitted information is in each case coded, for example as a binary sequence to form a packet 14.i which is 64 bytes long.

[0028] Even if only one bit of the received packet 14.i is affected by interference, the information will be lost. Each packet 14.i is therefore transmitted i=x times. For the communication to be successful at least two successive repetitions of the x repetitions must conventionally be totally free from interference, i.e. they must have been received as exact matches. The resulting transmission outlay is therefore considerable, since successively received complete packets 14 must in each case be compared with one another and, if necessary, rejected.

[0029] Conversely, as already mentioned above, the invention is based on the notion that only a part of the received packet 14 is in fact normally affected by interference, whereas the interference-free part corresponds exactly to the transmitted bit sequence.

[0030] In the variant according to the invention shown in FIG. 1, each received packet 14.i is therefore divided into subpackets 15.j=y and is temporarily stored in the receiver 12. Packets 14.i are received successively for this purpose. Subpackets 15.j allocated to one another therein are compared with one another and are deemed to be correct, i.e. to be received without interference, if at least two of them match one another. If all received subpackets 15.j=y) are therefore detected as valid, they are assembled into the interference-free receive packet 14.

[0031] The subpackets 15.j within the packets 14.i can essentially be of different lengths, and their length may also vary. In order to simplify the presentation, the drawing shows subpackets 15 of equal length, for example (typically at least) j=y=4 subpackets 15.j, each comprising 16 bytes, of a packet 14.i which is 64 bytes long. The probability of transmitting a long subpacket 15 without interference is generally lower than in the case of a shorter subpacket 15 due to the longer-lasting potential effects of interference. Shorter (but not too short) subpackets 15.j therefore offer increased probabilities in terms of the existence of interference-free subpackets 15.j.

[0032] In the example embodiment shown in FIG. 1, x=i=4 successive complete packets 14.i having identical content are received and temporarily stored in the receiver 12. Those of the at least two subpackets 15.j which are assigned to one another on the basis of their respective position in the packet 14,i and which specifically have at least two instances of matching content (here 15.1 in 14.1 and 14.3; 15.2 in 14.1 and 14.3; 15.3 in 14.2 and 14.4; 15.4 in 14.2 and 14.4) are deemed to be received without interference and are therefore assembled in a gap-filling manner into the valid, since interference-free, receive packet 14. A packet 14 is therefore available at the receiver 12 more quickly than in the case of waiting until at least one entire packet repetition matches.

[0033] A valid, since interference-free, receive packet 14 is even more quickly available if the respective subpacket 14.i is already divided into subpackets 15.j (j=1 . . . y) at the transmitting end according to the development shown in FIG. 2. In order to establish whether these received subpackets 15.j are in each case valid, their bit sequence is checked for correctness at the receiving end. To do this, an error detection code 16, e.g. a CRC checksum, is already attached at the transmitting end in a manner known per se to each of these subpackets 15.i.

[0034] For the example drawing, the subdivision into subpackets 15.j is in turn assumed to be identical in all packets 14.i without them having to be intrinsically identical; i.e. again as a subdivision of the 64-byte-long packet 14.i in each case into four equal-length subpackets 15.y=4, each containing 16 bytes.

[0035] Each received subpacket 15.j of a packet 14.i just received can be rejected immediately in the receiver 12 if the error detection code 16 detects a transmission error in this subpacket 15.j; here in the packet 14.i=1 in the case of the subpackets 15.j=1 and 15.3 and also in the following packet 14.2 in the case of the subpackets 15.2 and 15.4. The gaps still remaining in the packet 14 at the receiving end when the first packet 14.1 is received are filled from the next (or, if necessary, the next-but-one, etc.) received packet 14.i in which precisely this still missing packet 15.j is not affected by interference; as a result of which the interference-free packet 14 is then already available in assembled form.

[0036] Instead of or in addition to the error detection 16, it can also be demanded, comparable to the method according to FIG. 1, that, in the case of more than two transmissions, the subpackets 15.j received in succession and compared with one another match one another in order to classify them as valid. This results in an increased reliability of the received data.

[0037] In another advantageous combination of both described measures, the subpackets 15.j detected as usable via error detection codes 16 according to FIG. 2 are in turn divided into secondary subpackets at the receiving end and are selected in the reciprocal comparison according to FIG. 1. This improves the residual error probability.

[0038] In one development according to the invention, it is also possible to combine the two measures outlined in relation to FIG. 1 or FIG. 2 in the sense that not only the subpackets 15.j proven to be usable via error detection codes 16 according to FIG. 2, but also the unusable subpackets are stored. Usable subpackets can then be extracted from the latter through the subdivision in the reciprocal comparison according to FIG. 1.

[0039] If different error detection methods are combined in such a way, for example, a CRC checksum investigation can first be carried out. Subpackets 15.j thus detected as an error, divided into secondary subpackets, can be investigated by means of a different checksum, for example a 3-from-6 coding, and can be reconstructed.

[0040] In the repeated transmission of information in the form of a coded packet 14.i from a transmitter 11 via a potentially interference-affected radio link 13 to a receiver 12 which is operated, in particular, in the concentrator of a recording system for consumption measured values, the interference-free receive packet 14 is therefore available comparatively quickly if interference-free received subpackets 15.j are assembled according to the invention into the interference-free receive packet 14. For this purpose, successively received packets 14,i can be temporarily stored in the receiver 12 in order to compare subpackets 15.j assigned to one another therein and, in the event of a match, to assemble them in a gap-filling manner into the interference-free receive packet 14, Alternatively, the successive packets 14.i are already divided in each case at the transmitting end into subpackets 15.j provided with error detection codes 16, the subpackets being assembled in a gap-filling manner into the interference-free receive packet 14 if they have been correctly received.