Patent ID: 7558346
Filing Date: 2009-07-07
Classification: H04B,H04L

Abstract:
1. A symbol detector based on frequency offset compensation in ZigBee system, wherein the symbol detector detects symbols of a signal which is expanded in its band by a PN sequence to be received in an Offset Quaternary Phase Shift Keying (OQPSK) short-range wireless communication system, comprising: a frequency offset estimator for acquiring frequency offset in the received signal using a particular symbol contained in a preamble of a packet of the signal; a multi-delay-differential filter for multi-delay-differentiating the signal by a plurality of predetermined delay times; a multi-frequency offset compensator for complex-conjugating the multi-delay-differentiated signal by the multi-delay differential filter and the frequency offset acquired by the frequency offset estimator to eliminate the frequency offset; a plurality of multi-correlators for correlating an output value from the multi-frequency offset compensator and a PN sequence delay-differentiated through the same process as conducted by the multi-delay-differential filter, where the PN sequence corresponds one-to-one to the particular symbol; a plurality of summers for summing individual output values from the multi-correlators; and a maximum value selector for selecting a maximum value out of the summed values of the plurality of summers.