Common reference signal design based on semi-uniform pilot spacing and orthogonal cover code

A wireless communications device, comprising:

• a processor configured to:
• apply a first cover code to a first pilot sequence to produce a first set of pilot symbols comprising a pair of pilot symbols in a time domain, and a second cover code to a second pilot sequence to produce a second set of pilot symbols, wherein the first cover code and the second cover code are orthogonal to each other in time and frequency domains;
• deliver the first set of pilot symbols using a first number of resource elements and the second set of pilot symbols using a second number of resource elements for transmission;
• and
• a transceiver comprising a first transmit port and a second transmit port, the first transmit port being configured to:
• transmit the pair of pilot symbols within a first time interval of each other in the time domain;
• and
• transmit a third set of pilot symbols within a second time interval of the pair of pilot symbols, the first time interval being less than the second time interval;
• and
• the second transmit port being configured to transmit the second set of pilot symbols, the first and second transmitted sets of pilot symbols comprising a common reference signal.

A method for wireless communication, comprising:

• receiving, at a wireless communications device, a first set of pilot symbols comprising a pair of pilot symbols within a first time interval from each other in a time domain, using a first number of resource elements and spread with a first cover code;
• receiving, at the wireless communications device, a second set of pilot symbols using a second number of resource elements and spread with a second cover code, the first and second cover codes being orthogonal to each other in time and frequency domains, the first and second sets of pilot symbols comprising a common reference signal;
• de-spreading the first and second sets of pilot symbols in the frequency domain to recover at least two pilot observations in the time domain;
• and
• receiving, at the wireless communication device, a third set of pilot symbols within a second time interval of the first set of pilot symbols in the time domain, the second time interval being greater than the first time interval.