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Self-Encoded Spread Spectrum is very similar to BPSK spread spectrum in that it uses a

sequence of bits to encode the data before it is sent over the channel. The initial encoding and

decoding sequences are the same as in BPSK, but there is one key difference, which impacts the

design, reliability, and performance of the system. The encoding sequence is updated after the

transmission of each bit to include the transmitted bit. Each time a bit is transmitted the

encoding sequence is shifted and the previously sent bit is added to the sequence. So, in SSES

the randomness of the current spreading sequence comes from previous bits transmitted. If the

appropriate data compression methods are used to remove any redundant data, the binary data

can be modeled as independent and identically distributed Bernoulli random variables. This

smoothes out the spectrum of the signals and eliminates the spectral lines associated with PN

sequences. As a result of not using PN codes, the detection of the digital data by an unintended

receiver is practically impossible, resulting in ideally secure transmissions. The SESS provides a

real world implementation of random-coded spread spectrum systems that previously have been

thought to be impractical [11].

Figure 4 - How Pseudorandom Code is Used

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