Communication method for transmitting useful data and corresponding communication system

1. A communication method for transmitting useful data between a first traffic participant, at least one second traffic participant, and a central communication device, comprising:

generating, by the first traffic participant, a data packet;

assigning, by the first traffic participant, the data packet to a changing key;

transmitting, by the first traffic participant, the key together with the assigned data packet to the central communication device;

transmitting, by the first traffic participant, an identifier together with the key to the second traffic participant, the identifier being associated with the first traffic participant;

requesting, from the central communication device by the second traffic participant, using the key, the data packet assigned to the key;

receiving, from the central communication device by the second traffic participant, the data packet assigned to the key; and

assigning, by the second traffic participant, the received data packet to the first traffic participant, and creating, by the second traffic participant, a movement profile of the first participant, using the assigned received data packet.

2. The communication method as recited in claim 1 , wherein the key changes randomly or at particular time intervals.

3. The communication method as recited in claim 1 , wherein the data packet has at least one data set.

4. The communication method as recited in claim 3 , wherein the at least one data set includes a timestamp and at least one of at least one operating variable and a position of the first traffic participant.

5. The communication method as recited in claim 4 , further comprising:

evaluating, by the central communication device, the data set; and

transmitting, by the central communication device, an evaluation result thus obtained to the at least one second traffic participant.

6. The communication method as recited in claim 5 , wherein the evaluation result is transmitted with the data packet, and the central communication device evaluates at least one of the operating variable and the position.

7. The communication method as recited in claim 5 , wherein the evaluating includes a map matching.

8. The communication method as recited in claim 1 , wherein the identifier is transmitted from the first traffic participant to the second traffic participant one of immediately and via a further central communication device.

9. The communication method as recited in claim 1 , wherein the transmission from the first traffic participant to the second traffic participant takes place via a first communication path, and the transmission to the central communication device takes place via a second communication path different from the first communication path.

10. The communication method as recited in claim 9 , wherein the first communication path is produced via a short-range communication device, and the second communication path is produced via a long-range communication device.

11. A communication system for transmitting useful data, comprising:

a first traffic participant;

at least one second traffic participant; and

a central communication device, wherein:

the first traffic participant generates a data packet,

the data packet is assigned, by the first traffic participate, to a changing key;

the first traffic participant transmits the key together with the assigned data packet to the central communication device,

the first traffic participant transmits an identifier together with the key to the second traffic participant, the identifier being associated with the first traffic participant, and

the second traffic participant (i) requests, using the key, the data packet assigned to the key from the central communication device, (ii) receives the data packet assigned to the key from the central communication device, (iii) assigns the received data packet to the first traffic participant, and (iv) creates a movement profile of the first participant, using the assigned received data packet.