Automatic modulation identification for non-linear digital modulation (based on software radio techniques)

We implemented indoor and outdoor evaluation tests on the developed modulation mode identification algorithm using a experiment system with software radio techniques. In the indoor evaluation test, identification probability test was executed on S/N and fading conditions. As the result, it was confirmed that modulation mode identification probability of 90% or better was achievable at S/N ≥ 1 dB for FSK, S/N ≥ 13 dB for MSK, and S/N ≥ 9 dB for GMSK (BbT=0.3 dB). Additionally, it was confirmed from identification test results on GMSK that identification probability deteriorates as BbT product decreases. Furthermore, it was confirmed that modulation mode can be identified under the fading environment with Rayleigh fading 50 Hz. In the outdoor evaluation test, the test source was mounted on a vehicle and identification probability test was executed. Its result showed that identification probability of 94% or better was possible with the proposed algorithm under the dynamic environment where it was influenced of fading and multipath.