Is there any Spread Spectrum system that uses Rake with cyclic Prefix? My question is that could the use of cyclic prefix can enhance the performance of Rake receiver ?

I find this proposal here CP for DSSS Rake Receiver that seems correct.

Without CP, ISI emerges and stays as interference in Rake finger.


With CP, no ISI.


The cost could be an overhead of transmission. But if I take a typical value of delay spread 5µs (ETU channel model) with UMTS SF = 256, the symbol duration is roughly SF/3.84Mcps = 256 / 3.84e6 = 66,66 µs. The cost 5/66.66 = 7.5% is acceptable ?

If the reason is not the overhead cost, is there any reason ? Or Rake receiver performance is not impacted by adding CP thanks to its pilots ?
you can read the following paper, they are using almost the same idea, the title of the paper: Symbol Cyclic Shift Equalization PAM-OFDM - A Low complexity CP-free OFDM Scheme ..  Good luck