Based on the assumptions of zero-mean white noise and independent sources, we can find the estimate SZ of Q from the minima of(l/N)C,N=, E,Z(0, w) (with respect to 0) which lie below a chosen threshold. Sources whose powers cause the corresponding minima to lie above the threshold (i.e. weak sources) will not be detected. Simulation results: Simulations have been run on the computer for L = 24, N = 100 (i.e. a ULA of 24 sensors using 100 snapshots) for both a single source and two independent equipower sources, corrupted by additive white noise of mean zero when dih = 0.5. The results are shown in Tables 1 and 2. The accuracy of the estimates and the resolution is not as high as those of MUSIC and associated subspace methods [I, 21. However, the method has two advantages over subspace methods: (i) the processing is simpler because on-line eigendecomposition of the data correlation matrix is not needed, and (ii) the number of sources present need not be known a priori.

The Cauchy-Schwarz bounding technique is used to derive useful bounds on the generalized Marcum Q-function and its complement. Three new exponential-type bounds on Q M (˛,ˇ) are derived, and these are found to be tight and useful for a number of applications of interest. One such example is the derivation of an upper bound on the average symbol error rate probability for noncoherent and differentially coherent communication systems over generalized fading channels. It is shown that these exponential-type bounds are considerably tighter than the Chernoff bound (Rappaport SS. IEEE Trans. on Information Theory 1971; 17: 497-498) counterpart. Numerical results also reveal that the tightness of one of the exponential-type bounds is comparable to the bound obtained in Simon and Alouini (IEEE Trans. on Communications 2000: 359-366), while another is found to be superior than that obtained in Simon and Alouini over a wide range of arguments.

No abstract

No abstract