What is the actual use of scrambling in telecom and how it is being used for lte ?

Question

I came to know total six subframes of a radio frame can be used for MBSFN transmission. How UE come to know about exact number of sub frames that are being used in a radio frame ? Does the eNodeB send this information to UE or UE itself figure out ?

Answer 1

Scrambling or scrambling code is used to distinguish different transmitters
In WCDMA
For downlink, scrambling code is used to separate different cells in one carrier
For uplink, scrambling code is used to separate different UEs in one carrier

In LTE we use PCI which is a set of 504 IDs (derived from 3 primary synch sequences and 168 secondary sequences) used to scramble certain downlink transmissions so the UE can distinguish signals from different cells.