Patent ID: 7561613

Claim:
A method comprising: generating, in a transmitter device, a set of two or more digital frequencies, wherein each digital frequency corresponds to a subcarrier within an ultra-wideband (UWB) system; processing, in the transmitter device, the digital frequencies with a digital transform function to generate a plurality of digital carriers, wherein each of the digital carriers occupies multiple frequency bands; and assigning, in the transmitter device, different combinations of the digital carriers to the users within the UWB system to generate digital carrier multi-band user codes substantially according to the following equations: [ g _ n ] k = { cos ⁡ ( 2 ⁢ π ⁢ ⁢ f n ⁢ k ) , if ⁢ ⁢ n = 0 ⁢ ⁢ ⁢ or ⁢ ⁢ n = N f 2 ⁢ 2 ⁢ cos ⁡ ( 2 ⁢ π ⁢ ⁢ f n ⁢ k ) , if ⁢ ⁢ n ∈ [ 1 , N f 2 - 1 ] 2 ⁢ sin ⁡ ( 2 ⁢ π ⁢ ⁢ f n ⁢ k ) , if ⁢ ⁢ ⁢ n ∈ [ N f 2 + 1 , N f - 1 ] ⁢ ∀ k ∈ [ 0 , N f - 1 ] , ⁢ f n = n N f , where g n comprises digital carriers generated based on a digital frequency f n for N f frames of a nth subcarrier's UWB signal, and [ g n ] k represents a digital carrier of g n corresponding to the kth frame, and c u =G mc c (o) u ∀u ε[0, N f −1], where c u comprises the digital carrier multi-band user codes for a uth user in the UWB system, G mc is a digital carrier matrix defined as G mc =[ g 0 . . . g N f −1 ], and c (o) u =a set of real orthonormal sequences.