Demodulation reference signals (e.g., DM-RSs) are transmitted for a 5G, or other next generation network using an adaptive DM-RS structure. Demodulation reference signal data representative of demodulation reference signals employable to perform channel estimation of data channels is generated the demodulation reference signal data is transmitted, via a channel other than the data channels, to be used for the channel estimation. The adaptive DM-RS structure can be based on a modulation scheme used for data transmission. An orthogonal variable spreading factor code tree can be used when choosing an orthogonal cover code, and resource mapping for DM-RSs can be made unequal based on analysis of antenna ports. Further, a DM-RS with high resource density can be used to compensate for phase noise.