Chapter 7 – Jamming with Noise and Fading Channels
This chapter investigates a sub-optimal method to improve the SESS under the jamming
conditions. The method makes a soft decision on the chip values rather than the bit values
like the systems in the pervious chapters. The only problem with this system is that in
previous simulations, the noise of the channel was assumed to be irrelivate. By adding the
noise and fading into the jamming channel the flaws in the new sub-optimal method are
By looking at the way the PNJ works, we can develop methods to defeat the jammer.
The method that proposed in this section makes decisions on each chip rather than each bit.
Looking at the jammer at the lower jamming duty cycles, it is effective because it is jamming
one chip a large amount, which then gets factored into the decision of the bit. If a decision is
made at the chip level, then each chip is weighed evenly at the bit level. This means that when
the jammer heavily jams one chip, the chip decision will be made and it will only effect the bit
decision by the change on that one chip. In other words, only 1 of the N chips is going to be
wrong. The final bit decision has a better chance of correcting the jammed chip since the
jammed chip contributes a value of 1/N to the final bit decision, rather than the actual jammed
amount. So, the chip values get changed from the receiver voltage to either -1 or 1. Normally