Patent ID: 8295327
Filing Date: 2012-10-23
Classification: H04B,H04L

Abstract:
1. An apparatus for estimating a noise variance in a receiver of a code multiplex telecommunications system with orthogonal spreading codes, said apparatus comprising: a processing unit for processing two successive despread QPSK estimated symbols having substantially same amplitudes of the estimated descrambled total chip level signal and received at successive non-coincident instants; an adding unit for adding said successive QPSK symbols and for outputting real and imaginary parts; a subtracting unit for subtracting said successive QPSK symbols at successive non-coincident instants and for outputting real and imaginary parts; a first set of squaring units for determining the energy values of said real and imaginary parts outputted by said adding unit; a second set of squaring units for determining the energy values of said real and imaginary parts outputted by said subtracting unit; a first comparator for comparing the energy value of the imaginary part of said adding and subtracting units; a second comparator for comparing the energy value of the real part of said adding and subtracting units; an adder unit for adding a minimum energy value associated with the imaginary parts with a minimum value associated with the real parts; and a multiplying or dividing unit coupled to the adder unit for generating an estimation of the noise variance.