Operating Manual Vol 1 - ES Documentation

Digital Standard 3GPP W-CDMA (FDD)SMIQ2.14.3.3.1 Two DPCHs with Uncorrelated DataIf the two channels are uncorrelated (data source PRBS with active option ),the resulting constellation diagram is obtained from the superposition of the constellations of twoseparate signals (see Fig. 2-102).Fig. 2-149Constellation of a signal with two DPCHs (uncorrelated data)The resulting crest factor is 8.07 dB.2.14.3.3.2 Two DPCHs with Same DataIf the two channels contain exactly the same data (PRBS data source with equal initial values), the individualcomponents only differ in the channelization codes. Comparing any two lines of the channelization code matrixshows that 50% of the bits are identical and 50% are different (orthogonal matrix)). Where the bits areidentical, the two channels furnish the same components; where the bits are different, the components canceleach other. The I/Q signal of this sum signal would then have the following characteristic:Fig. 2-150Signal with two DPCHs (same data) in time domainNote:The bursts occurring at regular intervals are due to the use of the channelization code numbers0 and 1. The two lines of the matrix are identical in the first half and different in the second half.Therefore, each of the 40 source symbols causes one of these bursts, the period of which isequivalent to half the symbol length. Other combinations of channelization code numbers oftencause erratic results.1125.5555.03 2.226E-9