Multirate, constant envelope, constant bandwidth, modulation, channelization and detection system based on orthogonal bipolar spreading vectors
First Claim
1. A multirate communication system comprising:
- a set of orthogonal spreading modulation vectors, each vector 2v chips in length, where v is any positive integer, each modulation vector supporting transfer of information at a first information rate;
each modulation vector additionally supporting the transfer of information at an information rate 2n times the first information rate, where n is any positive integer, with the exclusion of (2n−
1) vectors in said set not orthogonal to the first 2(v−
n) chips of said modulation vectors;
a transmitter for modulating and transmitting information over said set of modulation vectors; and
a receiver for receiving and demodulating information over said modulation vectors.
3 Assignments
0 Petitions
Accused Products
Abstract
A modulation channelization and demodulation system based on orthogonal bipolar spreading vectors is provided that permits a variable information rate to be transmitted without inducing envelope fluctuations and permits multiple access without requiring the transmitter amplifiers to support the combined information rate of all users. The modulation system uses the vectors of a Hadamard matrix to form communication channels. The information rate on any channel may be doubled by using half the vector length to transmit information. The vector that is not non-orthogonal-in-the-half to the rate-doubled vector is preferably deactivated. In the same fashion, higher information rates may be provided through truncation of the transmission vector and the elimination of the resultant non-orthogonal vectors. A multi-channel receiver including a Fast Hadamard Transform structure comprised of controllable modified logic cells for performing the multi-rate communication of the present invention is illustrated. A multi-channel transmitter for performing the present invention is also shown.
9 Citations
7 Claims
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1. A multirate communication system comprising:
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a set of orthogonal spreading modulation vectors, each vector 2v chips in length, where v is any positive integer, each modulation vector supporting transfer of information at a first information rate; each modulation vector additionally supporting the transfer of information at an information rate 2n times the first information rate, where n is any positive integer, with the exclusion of (2n−
1) vectors in said set not orthogonal to the first 2(v−
n) chips of said modulation vectors;a transmitter for modulating and transmitting information over said set of modulation vectors; and a receiver for receiving and demodulating information over said modulation vectors.
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2. A multirate communication system comprising:
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a set of orthogonal spreading modulation vectors, each vector being 2v chips in length, where v is any positive integer, each modulation vector supporting the simultaneous transfer of information at variable rates of 2n times a first information rate, where the total information transfer rate for the set of orthogonal spreading modulation vectors is less than or equal to 2v bits per vector epoch; each modulation vector additionally supporting the transfer of information at an information rate 2n times the first information rate, where n is any positive integer, with the exclusion of (2n−
1) vectors in said set not orthogonal to the first 2(v−
n) chips of said modulation vectors;a transmitter for modulating and transmitting information over said set of modulation vectors; and a receiver for receiving and demodulating information over said modulation vectors.
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3. A multirate communication system comprising:
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a set of orthogonal spreading modulation vectors comprising a Hadamard matrix, each vector being 2v chips in length, where v is any positive integer, each modulation vector supporting transfer of information at a first information rate; each modulation vector additionally supporting the transfer of information at an information rate 2n times the first information rate, where n is any positive integer, with the exclusion of (2n−
1) vectors in said set not orthogonal to the first 2(v−
n) chips of said modulation vectors;a transmitter for modulating and transmitting information over said set of modulation vectors; and a receiver for receiving and demodulating information over said modulation vectors.
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4. A method for transmitting information comprising:
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forming a set of orthogonal spreading modulation vectors having a first length; transmitting information at a first information rate using a first vector of said set of vectors having said first length; transmitting information at a second information rate using a portion of a second vector of said set of vectors, said portion of said second vector being orthogonal to said first vector so that the information is transmitted at the first and second information rates using the same length orthogonal vectors; refraining from transmitting using any vector in said set not orthogonal to said portion of said second vector; and receiving and demodulating said information transmitted at said first and second information rates.
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5. A method for transmitting information comprising:
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forming a set of orthogonal spreading modulation vectors having a first length into a Hadamard matrix; transmitting information at a first information rate using a first vector of said set of vectors having said first length; transmitting information at a second information rate using a portion of a second vector of said set of vectors, said portion of said second vector being orthogonal to said first vector so that the information is transmitted at the first and second information rates using the same length orthogonal vectors; refraining from transmitting using any vector in said set not orthogonal to said portion of said second vector; and receiving and demodulating said information transmitted at said first and second information rates.
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6. A multirate communication system comprising:
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a set of orthogonal spreading modulation vectors, each vector being 2v chips in length, where v is any positive integer, each modulation vector supporting transfer of information at a first information rate, wherein at least one of said set of orthogonal spreading modulation vectors is variably truncated to support the transfer of information at any of v different rates over said at least one of said set of orthogonal spreading modulating vectors using orthogonal vectors having the same length; a transmitter for modulating and transmitting information over said set of modulation vectors; and a receiver for receiving and demodulating information over said modulation vectors.
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7. A multirate communication system comprising:
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a set of orthogonal spreading modulation vectors, each vector being 2v chips in length, where v is any positive integer, each modulation vector supporting transfer of information at a first information rate; each modulation vector additionally supporting the transfer of information at an information rate 2n times the first information rate, where n is any positive integer, by truncating the modulation vector to a length of 2v−
n) chips;a transmitter for modulating and transmitting information over said set of modulation vectors; and a receiver for receiving and demodulating information over said modulation vectors.
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Specification