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802.11g Kernel Identification. Saba Zia Bilal Saqib 3 rd September, 2008. Barker Code Despreading - Kernel Identification. Received chip sequence for data bit ‘1’ and ‘0’ 10110111000 01001000111 In bipolar format 1-111-1111-1-1-1 -11-1-11-1-1-1111
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802.11g Kernel Identification Saba Zia BilalSaqib 3rd September, 2008
Barker Code Despreading - Kernel Identification • Received chip sequence for data bit ‘1’ and ‘0’ • 10110111000 01001000111 • In bipolar format • 1-111-1111-1-1-1 -11-1-11-1-1-1111 • Correlation with Barker sequence determines actual data bit
CCK Decoding Process - Kernel Identification 8 chip code 8 chip code correlation By FWB Find Largest Modulus by Comparators Data bits estimated Decode Phase 2 bits estimated
Demodulation Fast Walsh Block Specifications
Fast Walsh Transform • ------ represents -1 • ____ represents 1 • -.-.-.- represents j • ……..represents -j
Maximum Power Selection Extract Magnitude of each branch by CORDIC Compare the magnitudes Highest magnitude branch correspond to the code word index Index is used to decode the data with the help of LUT