Opportunistic signal transmission for inter-rat co-existence

At least one non-transitory computer-readable storage medium comprising a set of wireless communication instructions that, in response to being executed at an evolved node B (eNB) cause the eNB to:

• determine a search window for transmission of one or more reference signals over an unlicensed frequency band, the search window comprising multiple subframes;
• generate the one or more reference signals;
• transmit configuration information regarding positioning of the one or more reference signals in one or more selected subframes of the search window;
• determine whether a frequency band is free during the selected subframes of the search window;
• and
• in response to a determination that the frequency band is not free during the selected subframes of the search window, transmit the one or more reference signals in the frequency band in one or more subframes of the search window different from the selected subframes.

User equipment (UE), comprising:

• logic, at least a portion of which is in hardware;
• and
• a radio frequency (RF) transceiver;
• the logic to determine a configuration of a window for receiving one or more reference signals over an unlicensed carrier, the logic to determine the configuration of the window based on configuration information received by the RF transceiver, the window comprising multiple subframes, the configuration information comprising information regarding positioning of the one or more reference signals in one or more selected subframes of the window, the logic to determine a serving cell of the UE is configured to perform opportunistic transmission of the one or more reference signals within the window;
• the radio frequency (RF) transceiver to monitor the unlicensed carrier for the one or more reference signals during the window;
• the logic to perform a detection operation on transmissions received on the unlicensed carrier within the window to recover the one or more reference signals transmitted in one or more subframes of the window different from the selected subframes when the unlicensed carrier is not available during the selected subframes of the window.