Patent ID: 8223888
Filing Date: 2012-07-17
Classification: H04B

Abstract:
1. A method comprising: receiving a radio signal comprising at least one data symbol, the at least one data symbol allocated at a transmit side with one or more pseudo-noise (PN) sequences, the one or more PN sequences being offset quadrature phase shift keying (QPSK) modulated; converting the received radio signal into a complex baseband signal sampled in a chip clock; generating a demodulated signal by differential demodulation of the complex baseband signal sampled in the chip clock; providing one or more derived sequences, each derived sequence assigned to a particular PN sequence of the one or more PN sequences and including at least one derived chip with a first positive index, the at least one derived chip with the first positive index having a value derived by exclusive ORing (XORing) a PN chip with the first positive index and an index-wise preceding PN chip; calculating correlation results measuring conformity of the demodulated signal to each of the one or more derived sequences by correlating the demodulated signal with each of the one or more derived sequences; and deriving the values of the at least one data symbol using a selected one of the one or more derived sequences with a highest degree of conformity to the demodulated signal determined by evaluating the correlation results.