If there are two signals, one having OFDM modulation and other one having DSSS modulation occupying the same bandwidth and over the same part of spectrum, will i be able to demodulate both signals correctly? Asking this question because it is said that DSSS is immune to narrow-band interference and OFDM basically consists of many narrow band sub-carriers.
The simple answer is that one transmission will be degraded in receptivity by the presence of the other and there will be points in time where neither signal can be adequately demodulated because of the way they become so tangled together.
Signals that are orthogonal are be totally separated. With no Bit Errors.
There is no reason to expect DSSS to be orthogonal to OFDM.