Minimum tolerable signal to noise ratio in modern communication systems
What your professor is almost certainly referring to is SSDS (Spread Spectrum Direct Sequence) encoding technicals (yes they are convolutional) and they trade off data rate for a given bandwidth for the ability to recover signal in deep noise.  CDMA systems from Qualcomm use CDMA but not so much for signal in noise recovery but for code diversity in band, meaning multiple independent transmissions overlapped in band.

CDMA uses the concept of process gain to reflect the ability to recover from noise and it counts on the fact that the "pseudo noise" (aka PN) has a distinct matched filter.  When the matched filter is applied any noise in band will be mapped out of band and any PN will be mapped to a modulated signal.  the process gain (measured in dB) tells you how much excess that you can have in S/N.

However, 60dB is trivial in context to the the NASA PN codes that are used in it's deep space network.  These codes can have repeat lengths of 1000's of chips.  A chip is s sub-unit of modulation, it is the ratio of chips to bits that determines the process gain.

An excellent book on this subject is "spread spectrum systems" by Dixon.

GPS is also based upon CDMA.

This work was first developed by Claude shannon and was top secret for many years post war.