Operating Manual Vol 1 - ES Documentation

SMIQDigital Standard 3GPP W-CDMA (FDD)UplinkIn the "DPCCH+DPDCH" mode, the signal consists of a DPCCH and one or several (max. 6) DPDCHs.To derive the constellation of this signal, the constellation of a single channel (DPDCH or DPCCH) isconsidered first. Its data are exclusively supplied to the I or Q path. The second path is not used(second path is: C q = 0).withS i = C i SC i – C q SC q 'S q = C i SC q ' + C q SC ithe following equation is obtained:S i = C i SC iS q = C i SC q 'This corresponds to a QPSK constellation diagram. Compared to the DPCH constellation diagram, thisdiagram is shifted and the constellation points only have half the amplitude:Fig. 2-142 Constellation of a DPDCH/DPCCH channelNote: A suitable modification of the PN sequences ("HPSK") in the uplink eliminates 50 % of all zerocrossings,which, in contrast to the downlink, causes a deformation of the constellation ranges.If DPCCH and DPDCH are combined, the constellation considerably depends on the ratio of the channelpowers. If the two powers are equal, a constellation as with the P-CCPCH will be obtained. Thefollowing illustration shows the constellation with DPCCH power 0dB and DPDCH power –6 dB:Fig. 2-143Constellation of an uplink signal consisting of a DPDCH and a DPCCH1125.5555.03 2.223E-9