Re: about CDMA
CDMA stands for code division multiple access
I think that you should learn Spread Spectrum first, since it is the basic theory for CDMA. You should say CDMA is only a kind of Communication protocol, like GSM which ultilizing TDMA method, also AMPS.
In Spread Spectrum, there are so many method to spread your carrier into wide bandwidth carrier, which almost embedded under noise floor.
1. Psuedo Code Spreading, e.g. BW of Carrier = 1/ T data rate, then if multiply very high data rate orthgonal code with data rate tc, then BW is spread
2. Frequency Hopping, which means your carrier is randomly appearing in particular Wide BW, making it like Spreading
3. Time Hopping, just randomly appears and disappears in time domain.