Underwater acoustic channels are recognized for being one of the most difficult propagation media due to considerable difficulties such as： multipath, ambient noise, time-frequency selective fading. The exploitation ...Underwater acoustic channels are recognized for being one of the most difficult propagation media due to considerable difficulties such as： multipath, ambient noise, time-frequency selective fading. The exploitation of sparsity contained in underwater acoustic channels provides a potential solution to improve the performance of underwater acoustic channel estimation. Compared with the classic 10 and 11 norm constraint LMS algorithms, the p-norm-like （Ip） constraint LMS algorithm proposed in our previous investigation exhibits better sparsity exploitation performance at the presence of channel variations, as it enables the adaptability to the sparseness by tuning of p parameter. However, the decimal exponential calculation associated with the p-norm-like constraint LMS algorithm poses considerable limitations in practical application. In this paper, a simplified variant of the p-norm-like constraint LMS was proposed with the employment of Newton iteration m to approximate the decimal exponential calculation. Num simulations and the experimental results obtained in physical shallow water channels demonstrate the effectiveness of the proposed method compared to traditional norm constraint LMS algorithms.展开更多
We describe briefly here the recent R&D activities in the optical subassembly packaging technologies at the Hong Kong Applied Science and Technology Research Institute (ASTRI). We have designed, developed and prot...We describe briefly here the recent R&D activities in the optical subassembly packaging technologies at the Hong Kong Applied Science and Technology Research Institute (ASTRI). We have designed, developed and prototyped multiple of low-cost high performance packages for serial and parallel transmitters and receivers, in particular, the novel chip-in-plastic (CiP) package designed for 10G serial transmission for data communications.展开更多
基金Supported by the National Natural Science Foundation of China （No.11274259） and the Specialized Research Foundation for the Doctoral Program of Higher Education of China （No.20120121110030）.
文摘Underwater acoustic channels are recognized for being one of the most difficult propagation media due to considerable difficulties such as： multipath, ambient noise, time-frequency selective fading. The exploitation of sparsity contained in underwater acoustic channels provides a potential solution to improve the performance of underwater acoustic channel estimation. Compared with the classic 10 and 11 norm constraint LMS algorithms, the p-norm-like （Ip） constraint LMS algorithm proposed in our previous investigation exhibits better sparsity exploitation performance at the presence of channel variations, as it enables the adaptability to the sparseness by tuning of p parameter. However, the decimal exponential calculation associated with the p-norm-like constraint LMS algorithm poses considerable limitations in practical application. In this paper, a simplified variant of the p-norm-like constraint LMS was proposed with the employment of Newton iteration m to approximate the decimal exponential calculation. Num simulations and the experimental results obtained in physical shallow water channels demonstrate the effectiveness of the proposed method compared to traditional norm constraint LMS algorithms.
文摘We describe briefly here the recent R&D activities in the optical subassembly packaging technologies at the Hong Kong Applied Science and Technology Research Institute (ASTRI). We have designed, developed and prototyped multiple of low-cost high performance packages for serial and parallel transmitters and receivers, in particular, the novel chip-in-plastic (CiP) package designed for 10G serial transmission for data communications.
