Methods for transmitting and receiving data in a digital telecommunications system

Abstract

A method for transmitting data via a terminal to a station of a digital telecommunications system. A first stream of data is encoded in data packets and a second stream of data is encoded in a frequency-hopping pattern. The data packets, in which the first stream of data is encoded, is consecutively transmitted in respective frequency bands of a frequency resource. The frequency bands are determined based on the frequency-hopping pattern in which the second stream of data is encoded.

The invention claimed is:  
     
       1. A method for transmitting data by a terminal to a station of a digital telecommunications system, comprising the steps of:
 simultaneously transmitting a first data stream and a second data stream to the station; 
 encoding the first data stream in data packets; 
 encoding the second data stream in a frequency-hopping pattern; and 
 consecutively transmitting the data packets, in which the first data stream is encoded, in respective frequency bands of a frequency resource, the frequency bands are determined according to the frequency-hopping pattern in which the second data stream is encoded. 
 
     
     
       2. The transmission method as claimed in  claim 1 , further comprising the steps of associating a theoretical frequency-hopping pattern with the terminal; and encoding the second data stream in a modification of the theoretical frequency-hopping pattern. 
     
     
       3. The transmission method as claimed in  claim 2 , further comprising the step of modifying or removing at least one theoretical frequency hop from the theoretical frequency-hopping pattern to encode the second data stream. 
     
     
       4. The transmission method as claimed in  claim 3 , further comprising the step of modifying or removing only theoretical frequency hops corresponding to predefined indices of the theoretical frequency-hopping pattern to encode the second data stream. 
     
     
       5. A method for receiving, by the station of a digital telecommunications system, data transmitted by the terminal in accordance with the transmission method as claimed in  claim 1 , comprising the steps of:
 searching, in a frequency resource, for data packets transmitted by the terminal; 
 extracting the first data stream from the detected data packets; 
 measuring the frequency bands in which the data packets have been detected; 
 extracting the second data stream according to measurements of the frequency bands in which the data packets have been detected. 
 
     
     
       6. The reception method as claimed in claimed  5 , further comprising the step of comparing the measurements of the frequency bands in which the data packets have been detected to a theoretical frequency-hopping pattern associated with the terminal. 
     
     
       7. The reception method as claimed in  claim 5 , wherein the data packets incorporate a counter incremented by the terminal on each new transmission; and
 further comprising the step of extracting the second data stream according to the counter of the data packets. 
 
     
     
       8. The reception method as claimed in  claim 5 , further comprising the steps of encrypting a part of the data packets with a rolling key incremented by the terminal at each new transmission; and extracting the second data stream according to the rolling keys used for encrypting the data packets. 
     
     
       9. A terminal of a digital telecommunications system comprises a transmitter configured to transmit data to a station, the transmitter:
 simultaneously transmits a first data stream and a second data stream to the station; 
 encodes the first data stream in data packets; 
 encodes the second data stream in a frequency-hopping pattern; and 
 consecutively transmits the data packets, in which the first data stream is encoded, in respective frequency bands of a frequency resource, the frequency bands are determined according to the frequency-hopping pattern in which the second data stream is encoded. 
 
     
     
       10. A station of a digital telecommunications system comprises a receiver configured to receive data from the terminal of  claim 9 , the receiver:
 searches, in a frequency resource, for the data packets transmitted by the terminal; 
 extracts the first data stream from the detected data packets; 
 measures frequency bands in which the data packets have been detected; 
 extracts the second data stream according to measurements of the frequency bands in which the data packets have been detected.