In this paper, a novel adaptive interference suppression algorithm is proposed for high dynamic GPS (global positioning system) receiver. The new method incorporates derivative constraints on the interference DOA (direction of arrival) into power minimization approach, which could broaden the width of nulls in the interferences directions and adapt to the rapid change of the interference directions. Compared with the traditional wide nulling algorithm based on the derivative constraints, the new method does not have to know or estimate the DOAs of the desired signal and the interference. The new method is firstly discussed in the context of spatial processing, and then extended to space-time adaptive processing to mitigate wideband diffusive multipath interference. Effectiveness of the new method is verified via simulation examples.

In this article, we propose a method to estimate the synthetic aperture radar interferometry (InSAR) interferometric phase based on the model of correlation weight joint pixel by using the joint subspace projection technique. In the method, the correlation weight joint data vector is constructed and the data vector can make the noise subspace dimension of the corresponding weight covariance matrix which is not affected by the coregistration error, thus avoiding the trouble of calculating the noise subspace dimension before estimating the InSAR interferometric phase. The method takes advantage of the coherence information of neighboring pixel pairs to auto-coregister the SAR images and employs the projection of the joint signal subspace onto the corresponding joint noise subspace to estimate the terrain interferometric phase. The method can auto-coregister the SAR images and reduce the interferometric phase noise simultaneously. Theoretical analysis and computer simulation results show that the method can provide accurate estimate of the interferometric phase (interferogram) even when the coregistration error reaches one pixel. The effectiveness of the method is verified via simulated data and real data.

We present an adaptive detection (AD) for broadband communication in the presence of co-channel interference (CCI). In the case of imperfect channel estimation, a robust AD (RAD) is proposed to maintain the good performance. We also show that both AD and RAD can be further improved by using an iterative scheme, referred to as iterative AD (IAD) and iterative RAD (IRAD), respectively. Numerical examples show that all the proposed methods outperform the conventional maximum likelihood sequence estimator (MLSE) significantly, and that they are also computationally more efficient.

The combination of a multihop relay system and orthogonal frequency-division multiplexing (OFDM) modulation is a promising way to increase the capacity and coverage area. For the OFDM two-hop relay system with separate power constraints, joint subcarrier matching and power allocation is considered in this paper, which uses the “decode-and-forward” relay strategy. The aforementioned problem can be formulated as a mixed binary integer programming problem, which is prohibitive when trying to find the global optimum. By separating the subcarrier matching and the power allocation, the optimal scheme, i.e., the optimal joint subcarrier matching and power allocation, is presented in this paper. After that, a suboptimal scheme with less complexity is also proposed, which can also be used to better understand the effects of power allocation. Simulation results show that the capacity of the optimal scheme is almost equivalent to the upper bound of thesystem capacity, and the capacity of the suboptimal scheme is close to that of the optimal scheme. In addition, simulation results also show that the one-to-one subcarrier matching is almost optimal, although it simplifies the system architecture.

Synthetic aperture radar has found wide applications in many areas, e.g., battlefield awareness.However, SAR is vulnerable to various kinds of interference, among which narrow-band interference is commonly used.In this letter, an eigensubspace-based filtering approach is proposed for NBI suppression in SAR without using passive-sniff data as the reference signal.