Operating Manual Vol 1 - ES Documentation

SMIQDigital Standard IS-95 CDMATo generate a reverse link signal, two different operating modes are available. The following figureshows the schematic of reverse link signal generation without channel coding.PN IBasebandFIR FilterListPatternPRBS28800 bps64 fachOrthogonalModulator307200 bps++Delay1/2 ChipIQPN Q1.2288 McpsFig. 2-77Reverse link signal generation without channel codingSimple bit patterns, PRBS and freely programmable data sequences in a data list are available asmodulation data. At a chip rate of 1.2288 MHz, the modulation data rate of the reverse link is28800 bps/s. The modulation type is offset-QPSK. A FIR filter is preset as baseband filter withoutequalizer according to IS-95 (FILTER TYPE IS-95).The second reverse link mode also comprises channel coding. With this reverse link coded mode, bothan access channel (4800 bps) and a traffic channel can be generated with all the data rates between1200 bps and max. 14400 bps complying with IS-95 (Rate Set 1 and 2). The following figure gives anexample of signal generation for the traffic channel with 9600 bps and shows the associated framestructure.ListPRBSAddFQ Indicator,Encoder Tail8600 bps 9600 bpsConvolutionalEncoderPN IBasebandFIR Filter28800 bpsBlockInterleaver64 fachOrthogonalModulator307200 bps++Delay1/2 ChipIQPN Q1.2288 McpsFig. 2-78Traffic channel 9600 in "Reverse Link Coded" mode1125.5555.03 2.131E-9