Mobility reference signal allocation

A network node for allocating and transmitting Mobility Reference Signals (MRS) for a wireless communication device to measure beam signal quality in a wireless communication network, the network node is configured to:

• obtain information on one or more of frequency diversity, a time diversity of a channel between the network node and the wireless communication device, an antenna spatial diversity of the wireless communication device;
• select an MRS pattern out of a set of candidate patterns based on the obtained information, wherein the candidate patterns are characterized by one or more of their density in time and density in frequency, and by one or more of their temporal duration and frequency range, and wherein each of the candidate patterns differs from each other one of the candidate patterns by at least their densities in time;
• signal the selected MRS pattern to the wireless communication device;
• and transmit the MRS according to the selected MRS pattern, wherein the network node is further configured to:
• evaluate a number of independent measurement symbols M for different sets of candidate patterns which comprise different numbers of subcarriers Nf with different spacing Df in frequency dimension and different numbers of symbols Nt with different spacing Dt in time dimension;
• and select an MRS pattern which has a minimum number of resource elements in frequency and time dimension, wherein the MRS pattern is selected based on one or more of a maximum frequency span limit Fmax, a maximum mobility measurement session length limit Tmax, and a minimum number of measurement symbols Lmin.

A nontransitory computer readable storage medium comprising instructions which, when executed on at least one processor in a network node, cause the network node to carry out a method in a network node for allocating and transmitting Mobility Reference Signals (MRS) for a wireless communication device to measure beam signal quality in a wireless communication network, the method comprising:

• obtaining information on one or more of a frequency diversity, a time diversity of a channel between the network node and the wireless communication device, an antenna spatial diversity of the wireless communication device;
• selecting an MRS pattern out of a set of candidate patterns based on the obtained information, wherein the candidate patterns are characterized by one or more of their density in time and density in frequency, and by one or more of their temporal duration and frequency range, and wherein each of the candidate patterns differs from each other one of the candidate patterns by at least their densities in time;
• signalling the selected MRS pattern to the wireless communication device;
• and transmitting the MRS according to the selected MRS pattern, wherein selecting an MRS pattern out of a set of candidate patterns based on the received information comprises:
• evaluating a number of independent measurement symbols M for different sets of candidate patterns which comprise different numbers of subcarriers Nf with different spacing Df in frequency dimension and different numbers of symbols Nt with different spacing Dt in time dimension;
• selecting an MRS pattern which has a minimum number of resource elements in frequency and time dimension, wherein selecting the MRS pattern is based on one or more of a maximum frequency span limit (Fmax), a maximum mobility measurement session length limit (Tmax), and a minimum number of measurement symbols (Lmin).