Operating Manual Vol 1 - ES Documentation

Digital Standard 3GPP W-CDMA (FDD)SMIQPRACH and PCPCH consist of preambles and the message part. Similar to a P-CCPCH, the preambleuses the 4 constellation points (2, 0), (0,2), (-2, 0) and (0, -2). In the case of the message part, separatepowers can set for Data (on the I path) and Control (on the Q path) so that a component is obtained asdescribed above for the DPCCH+DPDCH signal. As the third part of the constellation, points can be seenat the origin, which can be assigned to the interval between preamble and message part:Fig. 2-144 Constellation of a PRACHEnvelopesTo eliminate smearing of the amplitude due to the root-cosine filter, all envelopes are calculated using asquare-wave filter. The DPCCH and the DPDCHs are continuous channels that feature a constantenvelope during the complete sequence.Note: Section 2.14.2.6 "Misuse TPC for output power control", describes how to vary also theenvelope of DPCCH and DPDCHs.PRACH and PCPCH consist of one or several preambles and the message part.Example of a PRACH with a preamble and reduced power in the message part:Fig. 2-145 Envelope of a PRACHExample of a PCPCH with the parameters• Access Slot # = 0• Preamble Repetition = 4• Preamble Power Step = 1 dB• Message Part Length = 1 frame• Preamble Power = 0 dB• Control Part Power = 0 dB• Data Part Power = 0 dBFig. 2-146Envelope of a PCPCH1125.5555.03 2.224E-9