Technique for generating sets of binary spreading-code sequences for a high data-rate spread-spectrum network

Claim 1

A method for electrically generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said method comprising the steps of simultaneously: a) combining contents of a single stage of a first multi-stage binary shift register with contents of each stage of a plurality of stages of a second multi-stage binary shift register, the contents of each stage of each of said first and second binary shift registers having a period of (2"-1), where n is a fixed integer having the same value for each of said first and second binary shift registers, the contents of said stages of said first and second binary shift registers being combined by modulo-2 addition to produce a first subset of combined spreading-code sequences, and b) combining contents of a single stage of said second binary shift register with contents of each stage of a plurality of stages of said first binary shift register by modulo-2 addition to produce a second subset of combined spreading-code sequences, said first and second subsets of combined spreading-code sequences having cross-correlation properties as follows: (i) a cross-correlation between any two of said combined binary spreading-code sequences over any contiguous (2 n -1) bits has a magnitude ≦(2.sup.[n+1)/2] +1), where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; and (ii) a cross-correlation at zero offset between any two of said combined binary spreading-code sequences in either one of said first and second subsets has a magnitude equal to 1.

Claim 2

A method for electrically generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said method comprising the steps of simultaneously: a) combining contents of a single stage of a first multi-stage binary shift register with contents of each stage of a plurality of stages of a second multi-stage binary shift register, the contents of each stage of each of said first and second binary shift registers having a period of (2"-1), where n is a fixed integer having the same value for each of said first and second binary shift registers, the contents of said stages of said first and second binary shift registers being combined by modulo-2 addition to produce a first subset of combined spreading-code sequences, and b) combining contents of a single stage of said second binary shift register with contents of each stage of a plurality of stages of said first binary shift register by modulo-2 addition to produce a second subset of combined spreading-code sequences, said first and second subsets of combined spreading-code sequences having cross-correlation properties as follows: (i) a cross-correlation between any two of said combined binary spreading-code sequences over any contiguous (2 n -1) bits has a magnitude ≦(2.sup.[n+1)/2] +1), where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; and (ii) a cross-correlation at zero offset between any two of said combined binary spreading-code sequences in either one of said first and second subsets has a magnitude equal to 1.

Claim 3

A method for electrically generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said method comprising: a) specifying a switching interval consisting of a fixed number of steps for each of a first multi-stage binary shift register and a second multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is an integer having the same value for each of said first and second binary shift registers; b) inserting contents into each stage of said first and second multi-stage binary shift registers once per said switching interval; and c) combining the contents of a single stage of said first binary shift register with the contents of a single stage of said second binary shift register by modulo-2 addition at each step of said first and second binary shift registers to produce binary spreading-code sequences such that any two of said binary spreading-code sequences have cross-correlation properties as follows: (i) a cross-correlation between any two of said binary spreading-code sequences over any contiguous (2 n -1) bits has a magnitude ≦(2.sup.[(n+1)/2 +1), where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; (ii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said first binary shift register are identical has a magnitude equal to 1; and (iii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said second binary shift register are identical has a magnitude equal to 1.

Claim 4

A method for electrically generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said method comprising: a) specifying a switching interval consisting of a fixed number of steps for each of a first multi-stage binary shift register and a second multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is an integer having the same value for each of said first and second binary shift registers; b) inserting contents into each stage of said first and second multi-stage binary shift registers once per said switching interval; and c) combining the contents of a single stage of said first binary shift register with the contents of a single stage of said second binary shift register by modulo-2 addition at each step of said first and second binary shift registers to produce binary spreading-code sequences such that any two of said binary spreading-code sequences have cross-correlation properties as follows: (i) a cross-correlation between any two of said binary spreading-code sequences over any contiguous (2 n -1) bits has a magnitude ≦(2.sup.[(n+1)/2 +1), where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; (ii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said first binary shift register are identical has a magnitude equal to 1; and (iii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said second binary shift register are identical has a magnitude equal to 1.

Claim 6

A method for assigning disjoint sets of binary spreading-code sequences to corresponding nodes of a multi-node digital communication network, each of said binary spreading-code sequences being a modulo-2 addition of a first maximal length linear recursive sequence and a second maximal length linear recursive sequence, each of said first and second maximal length linear recursive sequences having a period of (2 n -1), said first maximal length linear recursive sequence being generated by a first primitive polynomial of degree n, said second maximal length linear recursive sequence being generated by a second primitive polynomial also of degree n, said method comprising: a) specifying an initial fill for a first multi-stage binary shift register, contents of each stage of said first binary shift register having a period of (2 n -1), where n is an integer, said first binary shift register being driven by said first primitive polynomial; b) specifying a first plurality of distinct initial fills for a second multi-stage binary shift register, contents of each stage of said second binary shift register also having a period of (2 n -1), where n is an integer that is the same for each of said first and second binary shift registers, said second binary shift register being driven by said second primitive polynomial, said first plurality of initial fills for said second binary shift register being identified with a first node of said network; and c) specifying a second plurality of distinct initial fills for said second binary shift register, each initial fill of said second plurality of initial fills for said second binary shift register being different from any initial fill of said first plurality of initial fills for said second binary shift register, said second plurality of initial fills for said second binary shift register being identified with a second node of said network.

Claim 7

A method for assigning disjoint sets of binary spreading-code sequences to corresponding nodes of a multi-node digital communication network, each of said binary spreading-code sequences being a modulo-2 addition of a first maximal length linear recursive sequence and a second maximal length linear recursive sequence, each of said first and second maximal length linear recursive sequences having a period of (2 n -1), said first maximal length linear recursive sequence being generated by a first primitive polynomial of degree n, said second maximal length linear recursive sequence being generated by a second primitive polynomial also of degree n, said method comprising: a) specifying an initial fill for a first multi-stage binary shift register, contents of each stage of said first binary shift register having a period of (2 n -1), where n is an integer, said first binary shift register being driven by said first primitive polynomial; b) specifying a first plurality of distinct initial fills for a second multi-stage binary shift register, contents of each stage of said second binary shift register also having a period of (2 n -1), where n is an integer that is the same for each of said first and second binary shift registers, said second binary shift register being driven by said second primitive polynomial, said first plurality of initial fills for said second binary shift register being identified with a first node of said network; and c) specifying a second plurality of distinct initial fills for said second binary shift register, each initial fill of said second plurality of initial fills for said second binary shift register being different from any initial fill of said first plurality of initial fills for said second binary shift register, said second plurality of initial fills for said second binary shift register being identified with a second node of said network.

Claim 8

A method for electrically generating a plurality of disjoint sets of binary spreading-code sequences for use in a multi-node communication network, each of said disjoint sets consisting of more than one binary spreading-code sequence, individual binary spreading-code sequences of each set being generated by combining contents of specified stages of a first multi-stage binary shift register with contents of specified stages of a second multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is an integer having the same value for each of said first and second binary shift registers, said method for generating said plurality of disjoint sets comprising: a) selecting a non-zero first initial fill for said second binary shift register, said first initial fill for said second binary shift register being identified with a first node of said network; b) stepping said second binary shift register to produce a second initial fill for said second binary shift register, said second initial fill for said second binary shift register also being identified with said first node of said network; c) selecting a non-zero first initial fill for said second binary shift register that is identified with a second node of said network, said first initial fill that is identified with said second node of said network being different from any initial fill for said second binary shift register that is identified with said first node of said network; and d) stepping said second binary shift register as many times as necessary to a maximum of (2 n -1) times to produce a second initial fill for said second binary shift register that is identified with said second node of said network, said second initial fill for said second binary shift register that is identified with said second node of said network being different from any second initial fill for said second binary shift register that is identified with said first node of said network.

Claim 9

A method for electrically generating a plurality of disjoint sets of binary spreading-code sequences for use in a multi-node communication network, each of said disjoint sets consisting of more than one binary spreading-code sequence, individual binary spreading-code sequences of each set being generated by combining contents of specified stages of a first multi-stage binary shift register with contents of specified stages of a second multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is an integer having the same value for each of said first and second binary shift registers, said method for generating said plurality of disjoint sets comprising: a) selecting a non-zero first initial fill for said second binary shift register, said first initial fill for said second binary shift register being identified with a first node of said network; b) stepping said second binary shift register to produce a second initial fill for said second binary shift register, said second initial fill for said second binary shift register also being identified with said first node of said network; c) selecting a non-zero first initial fill for said second binary shift register that is identified with a second node of said network, said first initial fill that is identified with said second node of said network being different from any initial fill for said second binary shift register that is identified with said first node of said network; and d) stepping said second binary shift register as many times as necessary to a maximum of (2 n -1) times to produce a second initial fill for said second binary shift register that is identified with said second node of said network, said second initial fill for said second binary shift register that is identified with said second node of said network being different from any second initial fill for said second binary shift register that is identified with said first node of said network.

Claim 11

An apparatus for generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said apparatus comprising: a) a first multi-stage binary shift register; b) a second multi-stage binary shift register; and c) means for simultaneously: (i) combining contents of a single stage of said first binary shift register with contents of each stage of a plurality of stages of said second binary shift register by modulo-2 addition, the contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is a fixed integer having the same value for each of said first and second binary shift registers, so as to produce a first subset of combined spreading-code sequences; and (ii) combining contents of a single stage of said second binary shift register with contents of each stage of a plurality of stages of said first binary shift register by modulo-2 addition to produce a second subset of combined spreading-code sequences; said first and second subsets of combined spreading-code sequences having cross-correlation properties as follows: (A) a cross-correlation between any two of said binary spreading-code sequences over any contiguous (2 n- 1) bits has a magnitude ≦(2.sup.[(n+1/2] +1) where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; and (B) a cross-correlation at zero offset between any two of said binary spreading-code sequences in either one of said first and second subsets has a magnitude equal to 1.

Claim 12

An apparatus for generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said apparatus comprising: a) a first multi-stage binary shift register; b) a second multi-stage binary shift register; and c) means for simultaneously: (i) combining contents of a single stage of said first binary shift register with contents of each stage of a plurality of stages of said second binary shift register by modulo-2 addition, the contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is a fixed integer having the same value for each of said first and second binary shift registers, so as to produce a first subset of combined spreading-code sequences; and (ii) combining contents of a single stage of said second binary shift register with contents of each stage of a plurality of stages of said first binary shift register by modulo-2 addition to produce a second subset of combined spreading-code sequences; said first and second subsets of combined spreading-code sequences having cross-correlation properties as follows: (A) a cross-correlation between any two of said binary spreading-code sequences over any contiguous (2 n- 1) bits has a magnitude ≦(2.sup.[(n+1/2] +1) where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; and (B) a cross-correlation at zero offset between any two of said binary spreading-code sequences in either one of said first and second subsets has a magnitude equal to 1.

Claim 13

An apparatus for electrically generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said apparatus comprising: a) means for specifying a switching interval consisting of fixed number of steps for each of a first multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is an integer having the same value for each of said first and second binary shift registers; b) means for inserting contents into each stage of said first and second binary shift registers once per said switching interval; and (c) means for combining the contents of a single stage of said first binary shift register with the contents of a single stage of said second binary shift register by modulo-2 addition at each step of said first and second binary shift registers to produce binary spreading-code sequences such that any two of said binary spreading-code sequences have cross-correlation properties as follows: (i) a cross-correlation between any two of said binary spreading-code sequences over any contiguous (2 n -1) bits has a magnitude ≦(2.sup.[(n+1)/2] +1). where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; (ii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said first binary shift register are identical has a magnitude equal to 1; and (iii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said second binary shift register are identical has a magnitude equal to 1.

Claim 14

An apparatus for electrically generating a set of binary spreading-code sequences for use in transmitting information in a multi-node communication network, said set of binary spreading-code sequences consisting of more than one binary spreading-code sequence, said apparatus comprising: a) means for specifying a switching interval consisting of fixed number of steps for each of a first multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is an integer having the same value for each of said first and second binary shift registers; b) means for inserting contents into each stage of said first and second binary shift registers once per said switching interval; and (c) means for combining the contents of a single stage of said first binary shift register with the contents of a single stage of said second binary shift register by modulo-2 addition at each step of said first and second binary shift registers to produce binary spreading-code sequences such that any two of said binary spreading-code sequences have cross-correlation properties as follows: (i) a cross-correlation between any two of said binary spreading-code sequences over any contiguous (2 n -1) bits has a magnitude ≦(2.sup.[(n+1)/2] +1). where [(n+1)/2] denotes the greatest integer ≦(n+1)/2; (ii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said first binary shift register are identical has a magnitude equal to 1; and (iii) a cross-correlation at zero offset over any contiguous (2 n -1) bits between any two of said binary spreading-code sequences for which the initial contents of said second binary shift register are identical has a magnitude equal to 1.

Claim 15

An apparatus for electrically generating a plurality of disjoint sets of binary .spreading-code sequences for use in transmitting information in a multi-node communication network, each of said disjoint sets consisting of more than one binary spreading-code sequence, individual binary spreading-code sequences of each set being generated by combining contents of specified stages of a first multi-stage binary shift register with contents of specified stages of a second multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is a fixed integer having the same value for each of said first and second binary shift registers, said apparatus comprising: a) means for inserting a non-zero first initial fill into said second binary shift register corresponding to a first node of said network; b) means for stepping said second binary shift register to produce a second initial fill for said second binary shift register corresponding to said first node of said network; d) means for inserting a non-zero first initial fill into said second binary shift register corresponding to said second node of said network, said first initial fill corresponding to said second node of said network being different from any initial fill corresponding to said first node of said network; and e) means for stepping said second binary shift register as many times as necessary to a maximum of (2 n -1) times to produce a second initial fill for said second binary shift register corresponding to said second node of said network that is different from said second initial fill for said second binary shift register corresponding to said first node of said network.

Claim 16

An apparatus for electrically generating a plurality of disjoint sets of binary .spreading-code sequences for use in transmitting information in a multi-node communication network, each of said disjoint sets consisting of more than one binary spreading-code sequence, individual binary spreading-code sequences of each set being generated by combining contents of specified stages of a first multi-stage binary shift register with contents of specified stages of a second multi-stage binary shift register, contents of each stage of each of said first and second binary shift registers having a period of (2 n -1), where n is a fixed integer having the same value for each of said first and second binary shift registers, said apparatus comprising: a) means for inserting a non-zero first initial fill into said second binary shift register corresponding to a first node of said network; b) means for stepping said second binary shift register to produce a second initial fill for said second binary shift register corresponding to said first node of said network; d) means for inserting a non-zero first initial fill into said second binary shift register corresponding to said second node of said network, said first initial fill corresponding to said second node of said network being different from any initial fill corresponding to said first node of said network; and e) means for stepping said second binary shift register as many times as necessary to a maximum of (2 n -1) times to produce a second initial fill for said second binary shift register corresponding to said second node of said network that is different from said second initial fill for said second binary shift register corresponding to said first node of said network.