Patent ID: 9609647
Date: 2017-03-28
CPC Classifications: H04L,H04W

Claim:
1. A method for receiving a downlink signal by a user equipment, the method comprising: obtaining, by the user equipment, first indication information indicating a first demodulation reference signal (DMRS) configuration from among a plurality of DMRS configurations defined for DMRS transmission; receiving, by the user equipment, a DMRS for the user equipment in a time-frequency resource region, to which the downlink signal for the user equipment is mapped, according to the first DMRS configuration indicated by the first indication information; demodulating, by the user equipment, the downlink signal using the DMRS; obtaining, by the user equipment, second indication information indicating that the first DMRS configuration is to be switched with a second DMRS configuration; and using, by the user equipment, a default DMRS configuration during a time interval when it is unclear whether to use the first DMRS configuration or the second DMRS configuration, wherein the plurality of DMRS configurations differ in a density of the DMRS, wherein the plurality of DMRS configurations include the default DMRS configuration, and at least a DMRS configuration of a lower density than a density of the default DMRS configuration or a DMRS configuration of a higher density than the density of the default DMRS configuration, and wherein the DMRS configuration of the lower density is defined to include only some resource elements (REs) for the DMRS among DMRS REs of the default DMRS configuration and the DMRS configuration of the higher density is defined to include predetermined DMRS REs in addition to the DMRS REs of the default DMRS configuration.