Method for generating and encoding signals for spread spectrum communication
First Claim
1. A method of communication using a plurality of spread spectrum codes comprising the steps of:
- generating a plurality of spreading codes, at least one of said spreading codes being non-maximal,defining a code length,selecting from said spreading codes a plurality of code portions of said code length, one of said code portions being selected from each of said spreading codes,receiving a data stream, andtransmitting said code portions in response to said data stream.
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Accused Products
Abstract
A method for communicating using a plurality of spread spectrum codes. A plurality of spreading codes are generated by use of one or more linear feedback shift registers configured with feedback taps. The spreading codes may be maximal or non-maximal. A plurality of code portions are selected, one from each of the spreading codes. The code portions each have the same length and are selected for low cross-correlation and favorable auto-correlation and spectral properties. Each of the code portions is associated with a data symbol representing a unique group of data bits. An input data stream is divided into groups of data bits and, in response thereto, the code portion associated with each group of data bits is transmitted. At the receiver, the transmitted signal is captured in one or more receive shift registers. The receive shift register or registers have tap locations matching the tap locations of the transmitter, and simultaneously detect for each code portion by combining the incoming signal with each of the taps for a given code portion. When a code portion is recognized, a sequence of consecutive ones is output. More than one code portion may be sent and received using offset quadrature phase shift keyed modulation.
213 Citations
31 Claims
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1. A method of communication using a plurality of spread spectrum codes comprising the steps of:
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generating a plurality of spreading codes, at least one of said spreading codes being non-maximal, defining a code length, selecting from said spreading codes a plurality of code portions of said code length, one of said code portions being selected from each of said spreading codes, receiving a data stream, and transmitting said code portions in response to said data stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of communication using a plurality of spread spectrum codes comprising the steps of:
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generating a plurality of spreading codes, at least one of said spreading codes being non-maximal, defining a code length, selecting from said spreading codes a plurality of code portions of said code length, one of said code portions being selected from each of said spreading codes, defining a plurality of data symbols, each of said data symbols comprising a predefined number of data bits, associating one of said data symbols with each one of said code portions, receiving a data stream, dividing said data stream into groups of bits, each one of said groups of bits corresponding to one of said data symbols, and transmitting, for each one of said groups of bits, the code portion associated with said data symbol. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of communication using a plurality of spread spectrum codes comprising the steps of:
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generating a plurality of spreading codes, at least one of said spreading codes being non-maximal, from a shift register having a plurality of feedback taps, selecting a code length, selecting from said spreading codes a plurality of code portions each having said code length, one of said code portions being selected from each of said spreading codes, receiving a data stream, and transmitting said code portions in response to a data stream. - View Dependent Claims (20)
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21. A method of communication using a plurality of spread spectrum codes comprising the steps of:
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generating a plurality of spreading codes from a single shift register having a plurality of feedback taps, each one of said spreading codes defined by a unique pair of said feedback taps, selecting a code length less than or equal to the length of the shortest of said spreading codes, selecting from each of said spreading codes a code portion having said code length, receiving a data stream, dividing said data stream into groups of data bits, and transmitting one of said code portions in response to one of said groups of data bits. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification