Noise and interference estimation for colliding neighbor reference signals

A wireless user equipment (UE) device, comprising:

• an antenna;
• a radio operably coupled to the antenna;
• and
• a processing element operably coupled to the radio;
• wherein the antenna, radio and processing element are configured to:
• establish a cellular communication link with a base station, wherein the base station provides a serving cell to the wireless UE device, wherein the serving cell provides cell-specific reference signals (CRS);
• determine CRS provided by a neighbor cell, wherein the neighbor cell is a colliding CRS neighbor to the serving cell such that all CRS resource elements for the serving cell collide with CRS resource elements for the neighbor cell;
• determine a channel quality index (CQI) value and a rank indicator (RI) value for the serving cell based at least in part on the CRS provided by the serving cell;
• estimate an expected spectral efficiency using the CQI value and the RI value;
• receive a modulation and coding scheme (MCS) assignment from the base station;
• estimate an actual spectral efficiency using the MCS assignment;
• perform a comparison using the estimated expected spectral efficiency and the estimated actual spectral efficiency;
• determine that load conditions for the neighbor cell are light if the estimated actual spectral efficiency is greater than the estimated expected spectral efficiency by at least a first threshold and if interference cancellation on the CRS provided by the serving cell to cancel interference from the CRS provided by the neighbor cell is not currently enabled;
• and
• enable interference cancellation on the CRS provided by the serving cell to cancel interference from the CRS provided by the neighbor cell when load conditions for the neighbor cell are determined to be light.

A method for a wireless user equipment (UE) device, the method comprising:

• establishing a wireless communication link with a base station, wherein the base station provides a serving cell to the wireless UE device;
• receiving reference signals from the base station;
• determining that at least one neighboring cell has colliding reference signals with the reference signals received from the base station;
• determining a channel quality index (CQI) value and a rank indicator (RI) value for the serving cell based at least in part on cell-specific reference signals (CRS) provided by the serving cell;
• estimating an expected spectral efficiency using the CQI value and the RI value;
• receiving a modulation and coding scheme (MCS) assignment from the base station;
• estimating an actual spectral efficiency using the MCS assignment;
• performing a comparison using the estimated expected spectral efficiency and the estimated actual spectral efficiency;
• determining that load conditions for the neighboring cell are not light if the estimated actual spectral efficiency is not greater than the estimated expected spectral efficiency by at least the first threshold and if interference cancellation on the CRS provided by the serving cell to cancel interference from the CRS provided by the neighboring cell is not currently enabled;
• and
• determining whether to modify the reference signals received from the base station to reduce interference effects from the colliding reference signals based at least in part on the determined load conditions for the neighboring cell.