BER vs. Eb/No N=32 Tx=100000 in AWGN
BER vs. Eb/No N=32 Tx=100000 Rayleigh Fading
Bit Decisions AWGN Chip Decision
Bit Decision AWGN Rayleigh Fading Chip Decision
6 Eb/No (dB)
15 Eb/No (dB)
Figure 18 - SESS Chip Decision Vs Bit Decision (AWGN on right, Rayleigh fading on Left)
This performance hit in chip decision can be described by the model being fundamentally
suboptimal and goes against the of correlation detection. However, it does offer a potential
solution to improve the worst-case jamming.
If bit decision works better in noise channels and chip decisions work better in the worst-
case jamming scenario, then what if there is a noise channel with jamming? Figure 19 and
Figure 20 on the next page show the effects of jamming in AWGN and Rayleigh fading channels
with bit decisions and chip decision respectively.
From these figures it can be seen that there are a few things about the differences between
chip and bit decisions. The first is that the ρ in an AWGN channel doesn‟t affect the chip
decision. It suffers from the 2.5 db worse performance than the bit decision when the ρ is one.
The second is that it becomes advantageous to use the chip decision when ρ is less than 0.08.