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23

1 = 1 0 , 1 1 , , 1

, 1(+1)

21 20 2 =   ,   , , 2(+1)

, 2(+2)

31 32 3 =   ,   , , 3(+2)

, 3(+3)

= 1 , 2

, , 1 , 0

  • 

    +1

=

+ 1 ,

+ 1 1

, , +12,

  • +11)

Figure 9 - Iterative Detector Signals in SESS

From Figure 9 above, it is easy to see that 1 is not only related to the previous N+1 bits,

but also related to N future transmitted bits. This means that N future bits contain information

about 1 , that can be used to help make the final decision on Bit1 should there be excessive

channel noise or jamming on Bit1 that would normally cause an error. So by incorporating

future transmitted signals together with previous detected bits, we expect to improve the

performance over the feedback detector, which only estimates the current bits by correlating with

N previous detected bits. How these future transmitted signals are incorporated into the final

decision can be seen in Figure 10 on the next page. Also, for a step by step run through of the

iterative detector see Appendix A on page 54. It should be noted that additional iterations are

able to be run through this detector. Each additional iteration requires N more chips, so if there

are M iterations then the storage of roughly N*M transmissions is required. The effect of the

number of iterations can be seen in Figure 11 on page 25. Despite the number of iterations, the

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