Fig. 3

CRLB for RSS-based DOA estimation. Apparently, DOA estimation variance depends on the direction of the received signal. For a received signal direction of \(\phi \approx k\frac {\pi }{2}\), the variance approaches infinity. This is quite obvious, as the gain difference function ΔG(ϕ) is close to zero in that range. Therefore, network topologies, especially node orientation, matters