The hierarchical multi-function matrix operation (MFMO) circuit modules are designed using coordinate rotations digital computer (CORDIC) algorithm for realizing the intensive computation of matrix operations. The paper emphasizes that the designed hierarchical MFMO circuit modules can be used to develop a power-efficient software-defined radio (SDR) digital beamformer (DBF). The formulas of the processing time for the scalable MFMO circuit modules implemented in field programmable gate array (FPGA) are derived to allocate the proper logic resources for the hardware reconfiguration. The hierarchical MFMO circuit modules are scalable to the changing number of array branches employed for the SDR DBF to achieve the purpose of power saving. The efficient reuse of the common MFMO circuit modules in the SDR DBF can also lead to energy reduction. Finally, the power dissipation and reconfiguration function in the different modes of the SDR DBF are observed from the experiment results.

In this paper, we propose an error resilience scheme for wireless video coding based on adaptive flexible macroblock ordering (FMO) and intra refresh. An FMO explicit map is generated frame-by-frame by using prior information. This information involves estimated locations of guard and burst sections in the channel and estimated effect of error propagation (EEP) from the previous frame to the current frame. In addition, the role of the current frame in propagating an error to the next frame is also considered. A suitable intra refresh rate which is adaptive to the channel state is used to reduce the dependence between frames and thus can stop the EEP. The results in experiments show that the proposed method gains some improvements in terms of peak signal-to-noise rate (PSNR) as compared with some other methods that have not considered the channel condition and the error propagation in generating an FMO map.

Various optical fiber connectors have been developed during the 20 years since optical fiber communications systems were first put into practical use. As the domain of optical fiber communication systems expanded from trunk lines to subscriber lines and customer premises the main focus changed from performance improvement to miniaturization and cost reduction. This paper describes the technical background, recent trends in standard optical connectors, and recent issues related to photonic connection technologies.