摘要 |
A method of allocating resource elements in an orthogonal frequency division multiplexing (OFDM) system for transmission of a channel state information reference signal (CSI-RS) is disclosed. The method includes converting resource elements to a two-dimensional frequency-time domain. The converted resource elements can then be partitioned to units of a physical resource block (PRB), which can be one subframe, for example. It can be determined whether a portion of a PRB is being used by another signal; and if the portion of the PRB is not being used, it can be allocated for transmission of the CSI-RS. The CSI-RS can be transmitted at resource element locations determined by the resource elements available to the CSI-RS in a regular or a frequency-division duplexing (FDD) downlink subframe, for example. The CSI-RS can be transmitted in a downlink subframe configured as a Multi-Media Broadcast over a Single Frequency Network (MBSFN) or a non-MBSFN subframe. |