Method for transmitting data packets on carrier frequency with linear variation and transmitter implementing this method

Abstract

A method for transmitting data packets having a heading followed by a data field. The data of the field is transmitted by groups of symbols. According to the OFDM technique, subcarriers modulated by the groups are generated. A frequency modulation of a carrier signal delivered by a linear ramp generator is produced with a set of modulated subcarriers. When the signal is received, mixing with a linear ramp results in subcarriers which are separated and then demodulated for supplying data. This is useful for transmitting data packets particularly in wide band networks.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to the transmission, in particular in broadband networks, of data in packets, these packets comprising a header at a first carrier frequency, followed by an information field at a second carrier frequency, the start of transmission of the field being tied to the start of transmission of the header of the corresponding packet.[0003]2. Discussion of the Background[0004]It is known practice to transmit data in packets each comprising a header followed by an information field, the information afforded by the header making it possible, among other things, for the packet to be recognized and taken into account by the parties for whom it is intended.[0005]It is known practice, utilizing a given frequency band for transmitting packets in a network, to define various transmission channels within the band and to allocate them to the transmitters of the network, either in a predetermined manner or on ...

AI Technical Summary

Benefits of technology

"The invention is about improving the transmission of data on a carrier frequency that changes. It aims to enhance the spreading of the spectrum, increase the bit rate, and make the transmission easier to exploit. The invention uses a technique called OFDM, which splits the data into groups and assigns them to subcarriers. A ramp generator is used to create a signal that changes over time, which is then combined with the data to be transmitted. This results in a modulated signal that can be easily detected and extracted. The invention can be implemented in both the transmitter and receiver."

Problems solved by technology

It is known practice, utilizing a given frequency band for transmitting packets in a network, to define various transmission channels within the band and to allocate them to the transmitters of the network, either in a predetermined manner or on the basis of the transmission requirements; it turns out that such a method does not allow optimal use of the frequency band and is scarcely practical especially when a receiver is liable to receive packets on any of the channels and must therefore monitor the transmission of packets on all the channels.

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