Millimeter wave radio with phase modulation
AssigneeTrex Enterprises Corp.
InventorsEric Korevaar, Richard Chedester, Paul Johnson
Life of this patent
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Abstract
Millimeter wave radio with phase modulation. In preferred embodiments each of the two radios in a link uses a single aperture to transmit radiation in one of the two bands, and receive radiation in the other of the bands. The counterpart radio used to form a link preferably is almost identical, except for the interchange of the transmit and receive frequencies. Preferred embodiments utilize a modulation scheme in which the radios each receive on-off keyed data and transmit the on-off keyed data encoded in a millimeter wave carrier wave with binary phase shift keying.
Claims19
A variable data rate binary phase shift keying (BPSK) millimeter wave radio communications system comprising:
- A) a transmitter adapted to receive on-off keyed (OOK) data at a data rate and to transmit BPSK encoded data at a baud rate using a millimeter wave carrier at a millimeter wave frequency, said transmitter comprising:
- 1) a frequency stabilized millimeter wave source operating at said millimeter wave frequency;
- 2) an encoder having an output clocked at said baud rate and adapted to encode said data such that the output is equal to the Exclusive Or (XOR) of said OOK data and said output;
- and
- 3) a modulator adapted to apply the output of the encoder to the millimeter wave carrier as a BPSK signal;
- wherein said data rate is approximately equal to the baud rate divided by an integer n, where n=1, 2, 3 . . . and
- B) a receiver adapted to receive a millimeter wave signal transmitted from the transmitter comprising:
- 1) a millimeter wave amplifier adapted to amplify said received millimeter wave signal;
- 2) a splitter adapted to split said amplified signal;
- 3) a mixer defining two mixer inputs and a mixer output;
- and
- 4) a circuit defining two propagation paths from said splitter to each of said two mixer inputs with different path lengths defining a signal time delay;
- wherein said signal time delay is approximately equal to the reciprocal of said baud rate, and equal to a half integer multiple of the reciprocal of said millimeter wave frequency to within 25% of the reciprocal of said millimeter wave frequency;
- and
- wherein said output reproduces said OOK data provided to said transmitter.
A method for communicating at a millimeter wave frequency using binary phase shift keying (BPS K) comprising the steps of:
- A) presenting to a radio transmitter at a first location raw data of a certain data rate to be transmitted;
- B) encoding said raw data at a baud rate which is an integer multiple of said data rate such that a bit of said encoded data is equal to the Exclusive Or (XOR) of said raw data and the previous bit of said encoded data;
- C) binary phase shift key (BPSK) modulating a millimeter wave carrier with said encoded data;
- D) amplifying said modulated carrier;
- E) transmitting said amplified modulated carrier through free space to a millimeter wave receiver at a second location;
- F) amplifying the millimeter wave signal received by said millimeter wave receiver;
- G) splitting said amplified received signal onto two paths with propagation lengths causing a relative time delay;
- and
- H) multiplying together the millimeter wave signals propagating on said two paths in a mixer to recover said raw data originally presented to the transmitter;
- wherein said time delay is approximately equal to the reciprocal of said baud rate and wherein said time delay is equal to a half integer multiple of the reciprocal of said millimeter wave frequency to within 25% of the reciprocal of said millimeter wave frequency.
A system for communicating a data stream at a millimeter wave frequency using binary phase shift keying (BPSK) comprising:
- a. an encoder and modulator for applying a 180 degree phase shift on a millimeter wave signal to be transmitted if an incoming bit from said data stream is a “1”, while leaving the phase of said millimeter wave signal to be transmitted unchanged if an incoming bit from said data stream is a “0”;
- b. a power amplifier for amplifying said millimeter wave signal to be transmitted;
- c. an antenna system for transmitting said amplified millimeter wave signal through free space;
- d. an antenna system for receiving said transmitted millimeter wave signal;
- e. a low noise amplifier for amplifying said received millimeter wave signal;
- f. a two way splitter, two propagation paths of different length, and a mixer for comparing said received millimeter wave signal at two different times separated by a time delay to regenerate said data stream;
- wherein said two different times are separated by approximately one bit period of said data stream, and wherein said two different times are approximately separated by a half integer multiple of the period of the transmitted millimeter wave signal.
Dependencies are inferred from the claim text.