Channel-dependent MC-CDMA utilizing adaptive spreading codes aided physical layer security

A method of operating Channel-Dependent multi-carrier code-division multiple access (Mc-CDMA) with Adaptive Spreading Codes Aided Physical Layer Security, the method comprising:

• distinguishing legitimate receivers (UEs') channel gains with different quantization levels, the step of distinguishing being in a first window:
• defining the UEs' channel gains in the first window as H={HUE1, HUE2, . . . , HUEK};
• sorting the UEs' channel gains in a descending manner as HUE1≤HUE2≤ . . . HUEK;
• initiating channel gain range as
• [
• min
• ⁡
• (
• H
• )
• ,
• H
• UE
• 1
• +
• H
• UE
• 2
• 2
• ,
• …
• ,
• H
• UE
• K
• -
• 1
• +
• H
• UE
• K
• 2
• ,
• max
• ⁡
• (
• H
• )
• ]
• where the min (H) and the max (H) denote a minimum channel gain and a maximum channel gain in the first window;
• moving to a next window to increase quantization so as to keep the UEs' channel gains distinguishable in the next window;
• defining a code length as M=2┌log2(AQL)┐ in which an acceptable quality limit (AQL) is a total number of quantization levels with respective adaptive intervals;
• generating a codebook (CM×M) in which codes therein are orthogonal;
• generating a shared map of quantization levels versus orthogonal codes in which a spreading code sequence is assigned to an quantization level;
• passing a signal process for decoding after generating the shared map;
• completing the passed signal process for decoding.