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JPL's Wireless Communication Reference WebsiteChapter: Analog and Digital Transmission Section: Spread Spectrum |
In this section the relation between the data detection input SNR and the BER was made for both an Additive Gaussian Noise Channel and a Multi-Path Channel in a DS/FH system like WISSCE . This was done in two steps: we started with discussing the SNR degradation due to non-ideal despreading and MA-interference. Secondly the relation between the SNR and the BER was explained. A difference with a usual BER-analysis is the usage of the data-detection input SNR as a reference value. In WISSCE the bandwidth at this stage in the receiver is about 1.3 MHz. As a consequence, proper SNR values are below 0 dB.
It appeared that WISSCE has to operate in a slowly fading channel . It is however difficult to catch the channel properties in a typical description. This is illustrated in figure 5, the different curves show the relation between SNR and BER for various values of the strength of the line-of-sight path.
