Spread spectrum communications system for networks
AssigneeIntellon Corporation
InventorsJames E. Vander Mey, Timothy J. Vander Mey
Life of this patent
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Abstract
Spread spectrum chirps (i.e., wideband frequency packets) are propagated on a local area network in a hostile communications environment, such as a powerline or a crowded radio frequency band. Chirps are self-synchronizing, data bit (or subdata bit) in length and detectable by all network nodes, to allow the contention resolution and collision detection needed to support carrier-sense based network protcols. A matched filter of the same time length and encoding sequence as the transmitted chirp provides the self-synchronized chirp reception at each receiver.
Claims37
A communication system comprising:
- a plurality of transmitters each generating a plurality of signals, each signal being a chirp and being generated at a plurality of frequencies over a time interval;
- a communications channel for carrying the signals;
- each said transmitter including means for sensing a presence on the communications channel of a carrier signal prior to initiating a generation of signals, said carrier signal including a sequence of at least one chirp, and having timing which is asynchronous relative to that of at least one other of the plurality of transmitters;
- and
- means for receiving the signals from the communications channel, wherein the means for receiving includes means for self synchronizing on each signal of the plurality of signals.
A method of transmitting data on a communications channel to a receiver comprising the steps of:
- generating a plurality of signals at a transmitter, each signal being a chirp and being generated at a plurality of frequencies over a time interval;
- providing the signals to a carrier-sense based communications channel;
- sensing a presence on the communications channel of a carrier signal prior to initiating a generation of signals, said carrier signal including a sequence of at least one chirp, and having a timing which is asynchronous relative to that of at least one other transmitter associated with communications channel;
- receiving the signals at the receiver from the communications channel;
- and
- determining a synchronization for each signal solely from the signal.
A receiver for a network comprising:
- means connected to the network for receiving an analog signal including a stream of chirps including a plurality of frequencies from the communications channel and converting the analog signal to a digital signal;
- means for receiving the digital signal and storing the digital signal;
- means for comparing the stored digital signal to a predetermined value and providing an output signal in response thereto;
- and
- means for self synchronizing and locking into the stream of chirps at a predetermined rate, wherein the receiver synchronizes itself independent of a transmitter of the analog signal.
A communication system comprising:
- a plurality of transmitters each generating a plurality of signals, each signal being a chirp and being generated at a plurality of frequencies over a time interval, wherein the chirps are transmitted at a predetermined rate for emulation of a carrier signal;
- a communications channel for carrying the signals;
- means for sensing a presence of the carrier signal on the communications channel and thereby inhibiting a generation of signals by at least one transmitter, wherein each transmitter generates signals asynchronously to signals generated by at least one other transmitter;
- and
- means for receiving the signals from the communications channel, wherein the means for receiving includes means for self synchronizing on each signal of the plurality of signals.
A method of transmitting data on a communications channel to a receiver comprising the steps of:
- generating a plurality of signals, each signal being a chirp and being generated at a plurality of frequencies over a time interval, wherein chirps are transmitted at a predetermined rate for carrier emulation;
- providing the signals to a carrier-sense based communications channel;
- receiving the signals at the receiver from the communications channel;
- and
- determining a synchronization for each signal solely from the signal thereby synchronizing independently of a source of the plurality of signals.
Dependencies are inferred from the claim text.