Patent ID: 8767699

Claim:
An apparatus for transmitting packet data in a wireless sensor network (WSN), comprising: a serial-to-parallel converter configured to parallel-convert information to be transmitted, and output the converted information as first channel data and second channel data, respectively; a first mixer and a second mixer configured to mix the first channel data and the second channel data with a pseudo noise (PN) code and a Walsh code pair; a first filter and a second filter configured to filter the mixed first channel data and the mixed second channel data; a delay configured to delay the filtered second channel data; a third mixer and a fourth mixer configured to mix the filtered first channel data and the delayed second channel data with respective corresponding quadrature phase signals, wherein the Walsh code pair is determined by cross correlations in order to have a small cross correlation among the plurality of all Walsh code pairs, wherein index of the Walsh code pair corresponds to index {j=0, 2, 8, 16, 18}.