Signal-in-Space Coexistence with LTE Networks


Federal users of AWS band in the United States are prone to causing interference with commercial LTE systems, particularly as more of this band will be allocated to commercial wireless networks. The question was how destructive, if at all, is the potential interference from signal-in-space (SiS) waveforms on LTE service.

Problem & Approach

The interference applies to the uplink communication path in the 1700 MHz band. Signals from SiS waveforms would collide with LTE signals from mobiles subscribers communicating with their respective base stations leading to degraded performance. To assess the impact of interference, we began with the characteristics of the SiS waveform to determine the power spectral density and concentration of energy. We then mapped the results onto the LTE waveform to determine the potential of interference taking into consideration the three-dimensional aspect of signal propagation in space. We estimated the noise rise and assessed the impact of interference on the performance of LTE uplink signals using statistical analysis that takes multiple scenarios into consideration.


The model weconstructed provided estimates of interference on uplink LTE signals from SiS waveforms and allowed our client to gain insightful knowledge on the potential degradation of LTE service, which will factor into their tactical and strategic approach to coexistence with commercial LTE operations during the process of spectrum reallocation.

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