High capacity DMRS sequences for a communication system

A second communication device, comprising:

• a processor;
• and
• a memory coupled to the processor and storing instructions, which when executed by the processor, cause the second communication device to:
• receive a demodulation reference signal (DMRS) and associated data signal on one or more PRBs from a first communication device,
• determine a DMRS sequence based on a cover code in a set of cover codes, wherein the cover code is dependent on a DMRS antenna port index, the cover codes in the set of cover codes are orthogonal to each other in each PRB, and a maximum correlation power between two cover codes in the set of cover codes is larger than 0 in each half PRB, and
• demodulate the associated data signal based on the received DMRS and the DMRS sequence.

A method performed by a first communication device, comprising:

• determining a demodulation reference signal (DMRS) sequence based on a cover code in a set of cover codes;
• determining a DMRS by mapping the DMRS sequence onto one or more physical resource blocks (PRBs), wherein the cover code is dependent on a DMRS antenna port index, cover codes in the set of cover codes are orthogonal to each other in each PRB, and a maximum correlation power between two cover codes in the set of cover codes is larger than 0 in each half PRB;
• and
• transmitting the DMRS via a DMRS antenna port having DMRS antenna port index to a second communication device.