Wireless communication method
View Patent ↗A wireless communication method between a plurality of end-points by a plurality of base stations, based on frames that have a CSS-modulated preamble followed by a data body modulated at a narrower bandwidth, either by CSS or by a UNB modulation. The system permit to avoid or mitigate collision between packets and to increase the network capacity, maintaining the simplicity of detection inherent of CSS modulation.
1. A wireless communication method between a plurality of end-points by a plurality of base stations, comprising:
sending a message by a transmitter including a preamble modulated according to a chirp spread spectrum format, and a body comprising data modulated with a narrower bandwidth than the preamble,
receiving said message in a receiver,
detecting said chirp spread-spectrum preamble,
aligning a local time reference of the receiver to the time reference of the transmitter by means of said chirp spread-spectrum preamble,
finding the narrower bandwidth body, based on a data rate of the preamble, and
demodulating said body.
2. The method of claim 1 , wherein said body is modulated by chirp spread spectrum modulation with a spreading factor lower than the preamble.
3. The method of claim 2 , wherein said body occupies a plurality of frequency sub-channels according to a frequency hopping scheme.
4. The method of claim 3 , in a network comprising a plurality of nodes, the frequency hopping scheme being common to all nodes.
5. The method of claim 2 , in a network with a plurality of nodes, comprising a step of assigning different sub-channels to different nodes.
6. The method of claim 3 , in a network comprising a plurality of base stations, with time-synchronized transmissions, preambles being transmitted simultaneously, comprising a step assigning different sub-channels to different base stations.
7. The method of claim 1 wherein said body is modulated in narrow-band modulation.
8. The method of claim 6 , wherein said body 312 consists of one narrow-band signal in one narrow-band sub-channel, if it be a uplink message, or of a plurality of narrow-band signals in separate frequency sub-channels if it be a downlink and/or multicast message.
9. The method of claim 6 , comprising adapting a data rate for the narrow-band modulated body 312 .
10. A wireless communication method between a plurality of end-points by a plurality of base stations, comprising:
sending a message by a transmitter including a preamble and a body modulated according to a chirp spread spectrum format
receiving said message in a receiver,
detecting said chirp spread-spectrum preamble,
aligning a local time reference of the receiver to the time reference of the transmitter by means of said chirp spread-spectrum preamble,
demodulating said body,
selecting a narrow-band channel having a narrower bandwidth than the preamble, and
replying to the transmitter with an uplink message in said narrow-band channel.