Haolin Li

ATTO: Wireless Networking at Fiber Speed

To provide a tremendous wireless capacity (100Gbps/m2) and latencies <10μs, ultra-small floor-integrated cells are proposed. RF-over-fiber, coherent communication and a dedicated 2D PON structure support the interconnection and selection of the cells and allow to minimize the required transceiver electronics.

Personal exposimeter for radiation assessment in real environments in the 60-GHz band

For the first time, a personal exposimeter (PEX) for 60 GHz radiation measurements is presented. The PEX is designed based on numerical simulations and both on-body and on-phantom calibration measurements to determine the antenna aperture and measurement uncertainty of the PEX. The measurement uncertainty of the PEX is quantified in terms of 50 and 95% prediction intervals of its response. A PEX consisting of three nodes (antennas) with VHH (vertical-horizontal-horizontal) polarization results in a 95% prediction interval of 6.6 dB. A 50% prediction interval of 1.3 dB (factor of 1.3) is obtained for measured power densities which is 3.1 dB lower than a single antenna experiment. The uncertainty is 19.7 dB smaller than that of existing commercial exposimeters at lower frequencies (≤6GHz).

Efficient Parallelization of Polyphase Arbitrary Resampling FIR Filters for High-Speed Applications

This article describes a method for increasing the sampling rate of efficient polyphase arbitrary resampling FIR filters. An FPGA proof of concept prototype of this architecture has been implemented in a Xilinx Kintex-7 FPGA which is able to convert the sampling rate of a signal from 500 MHz to 600 MHz. This article compares this new architecture with other best known efficient resampling architectures implemented on the same FPGA. The area usage on the FPGA shows that our proposed implementation is very proficient in high bandwidth applications without requiring significantly more resources on the FPGA. A theoretical calculation of the resampling error introduced on a modulated data stream is provided to evaluate the new architecture against other existing resampling architectures.

Maximally Flat and Least-Square Co-Design of Variable Fractional Delay Filters for Wideband Software-Defined Radio

This paper describes improvements in a Farrow-structured variable fractional delay (FD) Lagrange filter for all-pass FD interpolation. The main idea is to integrate the truncated sinc into the Farrow structure of a Lagrange filter, in order that a superior FD approximation in the least-square sense can be achieved. Its primary advantages are the lower level of mean-square-error (MSE) over the whole FD range and the reduced implementation cost. Extra design parameters are introduced for making the trade-off between MSE and maximal flatness under different design requirements. Design examples are included, illustrating an MSE reduction of 50% compared to a classical Farrow-structured Lagrange interpolator while the implementation cost is reduced. This improved variable FD interpolation system is suitable for many applications, such as sample rate conversion, digital beamforming and timing synchronization in wideband software-defined radio (SDR) communications.

Farrow structured variable fractional delay lagrange filters with improved midpoint response

This paper describes improvements in the Farrow structured variable fractional delay (FD) Lagrange interpolation. The main idea is to replace the first sub-filter of the Farrow structure by a sinc-interpolation filter of half a sample period to achieve a superior FD approximation in the vicinity of half a sample period. Its primary advantages over classical Farrow structured FD Lagrange interpolators are the lower level of mean-square-error (MSE) over the whole FD range and the reduced implementation cost. Design examples are included, illustrating an MSE reduction of 50% compared to a classical Farrow structured interpolator while the implementation cost is halved.