Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 5 Articles
The application of device-to-device (D2D) communication in cellular networks can significantly improve the\nefficiency of spectrum utilization, which benefits local area cooperative services. On the other hand, network coding\ncan realize more efficient cooperation among cellular users. Thus, it is natural to combine network coding with D2D\ncommunication in order to further increase the system sum rate. In this paper, a coalitional graph game framework is\nproposed to jointly accomplish resource allocation and relay selection, two challenging problems in network\ncoding-aided D2D communication networks. It is shown that this framework can model D2D communication\ncombined with various network coding schemes. Based on the coalitional graph game framework, a distributed\nalgorithm with low computational complexity is proposed to solve the formulated problem for physical layer network\ncoding-aided D2D communication. Finally, the performance of the proposed transmission scheme is evaluated\nthrough extensive simulations....
In the presence of the direction of arrival (DOA) mismatch, the performance of generalized sidelobe canceller (GSC)\nmay suffer severe degradation due to the gain loss of the desired signal in the main array and cancellation. In this\npaper, one effective GSC algorithm is proposed to improve the robustness against the DOA mismatch of the desired\nsignal. Firstly, two subspaces, which contain the desired signal�s actual steering vectors of the main and auxiliary arrays,\ncan be obtained by using the range information of the angle which the desired signal may come from. By rotating\nthese two subspaces, the desired signal�s actual steering vectors of the main and auxiliary arrays can be estimated\nbased on the maximum output power criterion. Then, with the estimates of the steering vectors in the former step, the\ngain loss of the desired signal in the main array can be alleviated. Moreover, one adaptive weight vector with the\nability to block the desired signal in the auxiliary array can be obtained simultaneously, which effectively avoids the\nsignal of interest cancellation consequently. Cycle iterative approach is also applied to guarantee the estimation\naccuracy of a wide range of angle deviation. Numerical simulations demonstrate the effectiveness and applicability of\nthe proposed method....
Conventional range-Doppler (RD) inverse synthetic aperture radar (ISAR) imaging method utilizes coherent\nintegration of consecutive pulses to achieve high cross-range resolution. It requires the radar to keep track of the\ntarget during coherent processing intervals (CPI). This restricts the radar�s multi-target imaging ability, especially\nwhen the targets appear simultaneously in different observing scenes. To solve this problem, this paper proposes a\nmulti-target ISAR imaging method for phased-array radar (PAR) based on compressed sensing (CS). This method\nexplores and exploits the agility of PAR without changing its structure. Firstly, the transmitted pulses are allocated\nrandomly to different targets, and the ISAR image of each target can be then reconstructed from limited echoes\nusing CS algorithm. A pulse allocation scheme is proposed based on the analysis of the target�s size and rotation\nvelocity, which can guarantee that every target gets enough pulses for effective CS imaging. Self-adaptive\nmechanism is utilized to improve the robustness of the pulse allocation method. Simulation results are presented\nto demonstrate the validity and feasibility of the proposed approach....
Active noise control (ANC) systems employing adaptive filters suffer from stability issues in the presence of\nimpulsive noise. To overcome this limitation, new methods must be investigated. In this paper, we propose the\nfiltered-x state-space recursive least square (FxSSRLS), an SSRLS-based practical and adaptive algorithm for ANC.\nComputer simulations are executed to verify the enhanced performance of the FxSSRLS algorithm. Symmetric\n�±-stable (S�±S) distributions are used to model impulsive noise. The results show that the proposed FxSSRLS algorithm is\nmore robust in eliminating high-peaked impulses than the recently reported algorithms for ANC applications. Moreover,\nthe suggested solution exhibits better stability and faster convergence, without jeopardizing the performance of the\nproposed solution in terms of residual noise suppression in the presence of impulses....
Optimal finite impulse response (FIR) error feedback filters for noise shaping in Ã?â?Ã?£ modulators are designed by using\nweighting functions based on the system norms. We minimize the weighted norms of the quantization error in the\noutput of a Ã?â?Ã?£ modulator, which corresponds to the minimization of the system norm. Three norms, the H2 system\nnorm, the HâË?ž system norm, and the l1 norm of the impulse response of the system, are adopted. The optimization\nproblem for three types of FIR filters are evaluated by using linear matrix inequalities (LMIs) and then solved\nnumerically via semi-definite programming. Design examples are provided to demonstrate the effectiveness of our\nproposed methods....
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