System and method for constructing unique word sets for efficient detection using orthogonal functions
View Patent ↗A system and method of construction of unique word sets together with an efficient method of implementing correlation with the members of the set is presented. The set of UWs is constructed by breaking a UW sequence in to equal length segments, and then multiplying this vector by an orthogonal matrix. First an arbitrary vector U is chosen of length K for a set of N UWs. Then a matrix H of size N×N is chosen. The columns of H are then repeated L times to form a matrix H′. The set of N UW consists of the rows of H′U T . N sub-correlations of the N segments of the vector U with the segments of the (suitably delayed) received signal is performed at the receiver. Then the N different outputs are obtained as Z=HC T , where C=[C 0 . . . C N-1 ] is the vector of correlated outputs. The receiver only requires N correlators, each of length L, instead of length K, which provides a less complex and more efficient solution for detection of UW sets.
1. A device comprising:
a signal generator processor configured to generate an initial unique word vector signal comprising a symbol sequence of length K symbols;
a divider module configured to receive the initial unique word vector and to divide the initial unique word vector into N equal segments (each of length L);
a matrix generator module configured: to receive the initial unique word vector divided into the N equal segments; to generate an orthogonal N×N first matrix H N×N ; to generate a second matrix H′ N×N , wherein each column comprises a repetition of the N segments of the initial unique word vector (each segment being placed in a respective row of the column); and to generate a third matrix UW N×K , resulting from an entrywise multiplication of each element of the first matrix by the respective element (unique word segment) of the second matrix; and
wherein each column of the third matrix reflects a distinct unique word vector, wherein one column reflects the initial unique word vector, and the distinct unique word vectors of the third matrix are orthogonal to each other.
2. The device of claim 1 , wherein the second matrix comprises a square matrix having entries of either +1 or −1, and wherein its rows or columns are mutually orthogonal (a Hadamard matrix).
3. The device of claim 1 , wherein the second matrix comprises a square matrix with dimensions of a power of 2 and entries of either +1 or −1, and wherein the dot product of any two rows or columns of the matrix equals zero (a Walsh matrix).
4. The device of claim 1 , wherein the second matrix comprises a matrix H(q, N) of size N, with all entries being q th roots of unity, ([H] j,k ) q =1, j, k=1, 2, . . . , N (a Butson-type Hadamard matrix).
5. A method comprising:
generating, via a signal generator processor, an initial unique word vector signal comprising a symbol sequence of length K symbols;
dividing the initial unique word vector into N equal segments (each of length L);
generating an orthogonal N×N first matrix H N×N ;
generating a second matrix H′ N×N , wherein each column comprises a repetition of the N segments of the initial unique word vector (each segment being placed in a respective row of the column);
generating a third matrix UW N×K by entrywise multiplication of each element of the first matrix by the respective element (unique word segment) of the second matrix; and
wherein each column of the third matrix reflects a distinct unique word vector, wherein one column reflects the initial unique word vector, and the distinct unique word vectors of the third matrix are orthogonal to each other.
6. The method of claim 5 , wherein the second matrix comprises a square matrix having entries of either +1 or −1, and wherein its rows or columns are mutually orthogonal (a Hadamard matrix).
7. The method of claim 5 , wherein the second matrix comprises a square matrix with dimensions of a power of 2 and entries of either +1 or −1, and wherein the dot product of any two rows or columns of the matrix equals zero (a Walsh matrix).
8. The method of claim 5 , wherein the second matrix comprises a matrix H(q,N) of size N, with all entries being q th roots of unity, ([H] j,k ) q =1, j, k=1, 2, . . . , N (a Butson-type Hadamard matrix).