Sounds as if they are mixing the PN code into the equation.
All spread spectrum systems make use of pseudoranandom code generators. This code is referred to as pseudorandom noise code (PN code). This code is used to determine the frequency spectrum that the output signal will occupy. It determines and controls the spreading pattern of the system.
Perhaps it is a hybrid approach to both DSSS and FHSS
Hybrid (FH/DS) Systems
Last part of this link elaborates on it.
My guess, it is mostly used by the military.
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