Comparing the Performances between Adaptive Notch Filter Direct and Lattice Forms Structures for Mitigation Jamming Signals

A jamming signal such as single and multiple Continuous-Wave (CW and MCW) interferences have been shown to have severe effects on the quality of the received signal in wireless communication. This paper presents an approach of a low-complexity algorithm that compares the performances of using Adaptive Notch Filter (ANF) direct and lattice forms structures based on second-order Infinite Impulse Response (IIR) Notch Filter (NF) for the detection and mitigation of CW and MCW interferences in QPSK communication systems. The approach method consists of two ANFs, adaptive IIR NF and adaptive IIR NF . The present algorithm can estimate and mitigate each CWI and computer their power in Time-Domain (TD). In results for performance comparison, the lattice IIR NF structure outperforms the direct IIR NF structure for detection and removal jamming and has a better Bit Error Ratio (BER). Furthermore, compared with the case of full suppression (), both cases (direct and lattice form) work better for low and high-power jammers. Also, compared to the case without an IIR NF, the presented algorithm can detect and mitigate, track hopping frequency interference, and improve BER performance.

On Indecomposable Definite Hermitian Forms

In this paper, for any given natural numbers n and a, we can construct explicitly positive definite indecomposable integral Hermitian forms of rank n over Q(-31/2) with discriminant a, with the following ten exceptions: n=2, a=1,2,4, 10; n=3, a=1,2,5; n=4, a=1; n=5, a=1; and n=7, a=1. In the exceptional cases there are no forms with the desired properties. The method given here can be applied to solving the problem of constructing indecomposable positive definite Hermitian Rm-lattices of any given rank n and discriminant a, where Rm is the ring of algebraic integers in an imaginary quadratic field Q(-m1/2) with class number unity.