Patent ID: 7586995

Claim:
A method of processing a data signal in a Code Division Multiple Access wireless communications system, to achieve crest factor reduction, the method comprising: upconverting the data signal to an intermediate frequency; and applying a triangular windowing function to said upconverted data signal wherein the triangular windowing function can be expressed as: y ( n )= b ( n )· x ( n ) where x(n) is the input signal, y(n) is the output signal and b(n) is the triangular windowing function, wherein an intermediate signal m(n) is given by: m ⁢ ⁢ ( n ) = max ⁢ ⁢ ( 0 , 1 - c ⁢ ⁢ ( n ) - ∑ i = 1 ⌈ k / 2 ⌉ ⁢ ⁢ m ⁢ ⁢ ( n - i ) · w ⁢ ⁢ ( ⌈ k / 2 ⌉ - i ) ) , and b(n) is given by: b ⁢ ⁢ ( n ) = 1 - ∑ i = 1 k ⁢ ⁢ m ⁢ ⁢ ( n - i ) · w ⁢ ⁢ ( i - 1 ) , where w(n) is a regular triangular window, and c(n) is a clipping function: c ⁢ ⁢ ( n ) = { 1 , if ⁢ ⁢  x ⁢ ⁢ ( n )  ≤ A A  x ⁢ ⁢ ( n )  , if ⁢ ⁢  x ⁢ ⁢ ( n )  > A } where A is a clipping threshold.