Interference studies in the 2.3 GHz band

MOD had been considering the implications of clearing spectrum for release in the 2.3 GHz bands.  This involved not only re-planning the frequency use of existing and future MOD systems but also consideration of the potential for interference to and from these systems with respect to anticipated use of the released spectrum, namely LTE.  These studies provided input into this process. Some of the analysis considered co-channel interference in relation to a few sites that might continue to operate in the band but most analysis was based on adjacent-channel operations concentrating on the various interference mechanisms that can occur and mitigation measures that can be put in place.

Specifically modelling activities were undertaken to examine the impact of LTE base station and user terminal transmitters on WLAN and Wireless Video Link (WVL) receivers operating in 2.3 GHz band.

The first study investigated the impact of adjacent band interference from LTE base stations and user terminals operating in the band 2340 – 2390 MHz into WLAN receivers operating in the band 2400 – 2483.5 MHz.  The results of protection ratio measurements at different guard bands were incorporated into the modelling which included simple static and detailed statistical scenarios simulated using CEPT SEAMCAT interference analysis tool.

The second study analysed the implications of co-channel and adjacent channel interference from LTE (operating in 2350 -2390 MHz band) into actual set of example WVL receivers (operating below 2360 MHz band).  The analysis made use of LTE base station and user terminal emission masks as well as WVL receiver adjacent band selectivity figures.  A range of ‘what if’ scenarios were considered to examine the impact of variations in transmitter antenna pointing, guard band, path loss models and receiver interference thresholds.