Feasibility evaluations for secondary LTE usage in 2.7–2.9GHz radar bands

In this paper, we have studied the potential for secondary usage of radar bands by 3GPP LTE eNB devices in different scenarios, such as HeNB transmitters located at street level, HeNB transmitters located at high-rise buildings, macro LTE transmitter, etc. Different pathloss models are used to best suite the scenarios. By using different types of radar characteristics (e.g. radio navigations radars, meteorological radars, etc) and a protection requirement of -10dB Interference-to-Noise Ratio (INR), we have shown that in some scenarios, the required distances for adjacent channel radar usage in 2.7-2.9GHz band are quite reasonable. This means, in those scenarios, it could be possible to utilize the radar bands for secondary LTE systems. A protection margin of 18 to 20dB can be added for capturing the aggregate interference effects from multiple secondary interferers for downlink direction. More detailed system level investigations are required in this direction for further understanding the secondary usage in this band.