Spread spectrum modulator and demodulator
AssigneeAlcatel Lucent
InventorsHassan El Nahas El Homsi, Moussa Abdi, Alexandre Jard
Life of this patent
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Abstract
A spread spectrum modulator converts input sequences composed of digital symbols into n≧2 spread-spectrum sequences. The spread spectrum modulator can generate spreading code and can combine the spreading code with the input sequences to produce the n spread spectrum sequences for transmission from n respective antennas of a radio transmitter. Each spread spectrum sequence corresponds to a sum of at least two contributions mutually shifted by a time substantially less than the duration of a symbol, each contribution being the product of a version of one of the n input sequences times the spreading code.
Claims11
A spread spectrum modulator for converting input sequences composed of digital symbols into n spread spectrum sequences in a radio transmitter, n being a positive integer number at least equal to 2, comprising:
- a spreading code generator for generating a spreading code, and
- means for combining the spreading code with the input sequences to produce n spread spectrum sequences for transmission from n respective antennas of the radio transmitter,
- wherein the combining means is arranged so that each spread spectrum sequence corresponds to a sum of at least two contributions mutually shifted by a time substantially less than the duration of a symbol, each contribution being the product of a version of one of the n input sequences times the spreading code.
A radio transmitter comprising:
- n transmission antennas, n being a positive integer number at least equal to 2;
- means for obtaining input sequences of digital symbols;
- a spread spectrum modulator for converting input sequences into n spread spectrum sequences;
- circuits operative to produce producing n respective radio frequency signals on the basis of the n spread spectrum sequences;
- and
- means for providing respectively the n radio frequency signals to the n transmission antennas,
- wherein the spread spectrum modulator comprises a spreading code generator for generating a spreading code and means for combining the spreading code with the input sequences to produce the n spread spectrum sequences for transmission from n respective antennas of the radio transmitter, and wherein the combining means is arranged so that each spread spectrum sequence corresponds to a sum of at least two contributions mutually shifted by a time substantially less than the duration of a symbol, each contribution being the product of a version of one of the n input sequences times the spreading code.
A cellular radio communication base station comprising a radio transmitter, wherein the radio transmitter comprises:
- n transmission antennas, n being a positive integer number at least equal to 2;
- means for obtaining input sequences composed of digital symbols;
- a spread spectrum modulator operative to convert input sequences into n spread spectrum sequences;
- circuits operative to produce n respective radio frequency signals on the basis of the n spread spectrum sequences;
- and
- means for providing respectively the n radio frequency signals to the n transmission antennas, wherein the spread spectrum modulator comprises:
- a spreading code generator for generating a spreading code;
- and
- means for combining the spreading code with the input sequences to produce the n spread spectrum sequences for transmission from n respective antennas of the radio transmitter, and wherein the means for combining is arranged so that each spread spectrum sequence corresponds to a sum of at least two contributions mutually shifted by a time substantially less than the duration of a symbol, each contribution being the product of a version of one of the n input sequences times the spreading code.
A cellular telecommunication terminal, comprising a radio transmitter, wherein the radio transmitter comprises:
- n transmission antennas, n being a positive integer number at least equal to 2;
- means for obtaining input sequences composed of digital symbols;
- a spread spectrum modulator operative to convert input sequences into n spread spectrum sequences;
- and,
- circuits operative to produce n respective radio frequency signals on the basis of the n spread spectrum sequences and means for providing respectively the n radio frequency signals to the n transmission antennas,
- wherein the spread spectrum modulator comprises:
- a spreading code generator for generating a spreading code;
- and
- means for combining the spreading code with the input sequences to produce the n spread spectrum sequences for transmission from n respective antennas of the radio transmitter, and wherein the means for combining is arranged so that each spread spectrum sequence corresponds to a sum of at least two contributions mutually shifted by a time substantially less than the duration of a symbol, each contribution being the product of a version of one of the n input sequences times the spreading code.
Dependencies are inferred from the claim text.