Rake Receiver..
Rake receiver, as the name suggests, try to get multiple copies of the transmitted signal. These multiple copies then to be combined to produced better estimate compared if you just have one copy. The philosophy behind it is that if you have multiple copies then you can expect that at least one of it is in good condition, so you get better chance to decode the transmitted signal perfectly.
Rake receiver is conventional receiver and you can find the detail how it works from many standard textbook like digital communication by proakis, etc.
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