Patent ID: 7826559

Claim:
A method executed in a hardware module for creating a training sequence of symbols, of chosen length N t , for estimating L unknowns of a wireless channel, comprising the steps of: (a) if N and k exist such that N<N t is a power of 2, k is a positive integer, and kN+(L−1)=N t , concatenating k instances a perfect roots-of-unity sequence of alphabet N (N PRUS sequence), and adding an L−1 portion of the concatenated k instances of said N PRUS sequence; (b) if N and k do not exist such that N<N t is a power of 2, k is a positive integer, and kN+(L−1)=N t (i) selecting k that minimizes M in kN+(L−1)+M=N t where M is a positive integer, concatenating k instances a perfect roots-of-unity sequence of alphabet N (N PRUS sequence), adding an L−1 portion of the concatenated k instances of said N PRUS sequence; and adding M additional symbols; or (ii) selecting k that minimizes M in kN+(L−1)−M=N t where M is a positive integer, concatenating k-1 instances a perfect roots-of-unity sequence of alphabet N (N PRUS sequence), adding an N+L−1−M portion of the concatenated k instances of said N PRUS sequence; and (c) transmitting said training sequence over said channel.