Orthogonal frequency division multiplexing is special case of frequency division multiplexing where a ling serial data streams are divided into parallel data streams and each data stream is multiplied either by orthogonal frequency or code. when multiplied by code known as frequency code division multiplexing and when multiplied by orthogonal frequency then know as orthogonal frequency division multiplexing

Orthogonal frequency-division multiplexing

Frequency-division multiplexing, wavelength-division multiplexing, and time-division multiplexing.

Split up among several closely spaced subcarriers.

Multiplexing techniques vary widely based on what is being multiplexed. Modern telecommunications use a very wide array of techniques including:

TDM - examples: TDMA, T-carrier

FDM - examples: DWDM

Spatial - example: MIMO

Code division - examples: CDMA

Phase or polarization division - cable/satellite TV

Statistcal - examples: packet mode (STS), FHSS etc etc.

This is far from a complete list. I think the question needs to be more specific.