Patent ID: 7512185

Claim:
A dual carrier modulator (DCM) for a multiband orthogonal frequency division multiplexing (OFDM) transceiver of an ultra wide band (UWB) wireless network transmitting OFDM modulated symbols, wherein each OFDM symbol is modulated by a first predetermined number (N CBPS ) of encoded bits, said dual carrier modulator comprising: (a) a grouping unit configured to group the N CBPS encoded bits of a serial bit stream into bit groups each having a second predetermined number (m) of bits; (b) a mapping unit configured to map each bit group received from said grouping unit to complex symbols (y); and (c) a reordering unit configured to reorder the complex symbols (y) mapped by said mapping unit, wherein each complex symbol (y) is provided to modulate a corresponding data tone of an OFDM symbol; wherein the first predetermined number is two hundred (N CBPS =200) and the second predetermined number is four (m =4), such that the grouping unit groups two hundred encoded bits to bit groups each having four bits; wherein the mapping unit maps bit groups each having four bits respectively to two complex symbols (y n ; y n+NCBPS/4 ) to generate N CBPS /2 complex symbols (y 0 . . . y NCBPS /2) for modulating one N CBPS /2 data tones of an OFDM symbol; wherein the mapping unit ( 1 - 2 ) comprises: a first mapping stage for mapping unipolar bit values of the encoded bits within each bit group to bipolar bit values, and a second mapping stage which provides an orthogonal 2Ã—2 mapping of two complex numbers composed of the 4 bipolar bits into two complex symbols; and wherein the orthogonal 2Ã—2 mapping is defined by the equation: ( y n y n + 50 ) = 1 b 2 + 1 â¢ ( 1 b b - 1 ) â¢ ( x a â¡ ( n ) j â¢ â¢ x a â¡ ( n ) + 50 x a â¡ ( n ) + 1 j â¢ â¢ x a â¡ ( n ) + 51 ) wherein â¢ â¢ n = 0 , 1 â¢ â¢ â€¦ â¢ â¢ 49 a â¡ ( n ) = { 2 â¢ n n = 0 , 1 , 2 , â¢ â€¦ â¢ â¢ 24 2 â¢ n + 50 n = 25 , 26 , â¢ â€¦ â¢ â¢ 49 wherein b is a constant.