CSI request procedure in LTE / LTE-A for unlicensed spectrum

摘要

A channel state information (CSI) request procedure is disclosed for use in a long term evolution (LTE) / LTE advanced (LTE-A) network with unlicensed spectrum. An aperiodic reference that provides an on-demand reference signal and CSI request for user equipment (UE) instead of relying on a periodic reference signal that is not transmitted due to a failed clear channel assessment (CCA) operation A signal is defined. The serving base station transmits an identifier that signals when an aperiodic reference signal is to be transmitted, either in the same subframe or in a future subframe, and then the designated subframe. A non-periodic reference signal is transmitted in the frame. The UE served by the base station receives the identifier and identifies the CSI request either implicitly through the identifier signal received from the base station or explicitly through the UE specific CSI request, and then A CSI report will be generated based on the aperiodic reference signal for transmission back to the serving base station. [Selection] Figure 5