Evaluation of High-Speed Link Parameters for Highly Reliable Reconfigurable Systems Based on S-Parameters and BER
Authors: Orda-Zhigulina M. V. 
Published: February 2023

Purpose of research. is to improve signal transmission parameters in high-speed signal transmission lines, including between programmable logic integrated circuits (PLIC). This improvement in signal transmission parameters is necessary to increase throughput of modern highly reliable reconfigurable systems to ensure data transfer rate of up to tens of Gbit/s. It can be done considering the influence of electrical and structural parameters of multi-layer printed circuit boards (MPCB) on them. It is possible to provide such high data rates by using a wider frequency band of transmitted signals. One of the existing approaches to this problem is to increase "physical" frequency of transmitted information signals to 25-300 GHz, which is sufficient to achieve desired rates.Methods. A method for estimating quality of high-speed signal transmission lines based on the definition of standardized methods for analyzing signal transmission parameters, such as JCOM, S-parameters and BER is proposed in the article. This method allows evaluating high-speed communication lines. Thus, the Channel Operating Margin (COM)/JCOM parameter can be used to estimate the quality of a digital communication channel - a standardized method for determining the overall channel quality indicator. Known methods are used to estimate such signal transmission parameters as S11 reflection coefficient and S21 attenuation coefficient (S-Parameters). These methods are used to estimate attenuation and loss of the information signal in the path, when copies of the signal reflected from inhomogeneities affect the original and lead to its distortion. Simulation of such parameter as Bit Error Rate (BER) is carried out according to G.821/G.826/M2100 rationing and quality control methodology.Results. The main metrics were selected to evaluate the quality of high-speed signal transmission lines. It is based on the evaluation of such signal transmission parameters as Channel Operating Margin (COM), S-parameters and Bit Error Rate (BER). Numerical evaluations of signal transmission parameters were obtained and their effect on the design parameters of high-speed signal transmission lines was estimated. It is recommended to use at least 1 transition hole between screening polygons in GND separation layers every 0.5 cm or 0.25 cm2 of WFP area. It is for a data rate of less than 25 Gbit/s, It is recommended to use at least 2 transition holes between screening polygons in GND separation layers every 0.5 cm or 0.25 cm² of PV area, if high-speed signal transmission line passes at a distance of closer than 2.5 cm from the power supply circuits in a projection on the layer where the power supply circuits are located.Conclusion. A method for calculating signal transmission parameters on high-speed signaling lines based on the calculation of Channel Operating Margin (COM), S-parameters and Bit Error Rate (BER) parameters is introduced. As part of introduced method, an analysis of signal transmission parameters was carried out. This analysis shows that when the "reference" values of electrical parameters of the line are met, the transfer holes contribute most to the signal distortion; then the layers in which the signal line is located, the number of screening polygons between the signal layers and the layers; in which the power supply circuits, the design parameters of the transition holes, as well as the length and number of segments of the high-speed line pass. Numerical evaluations of minimum number of transition holes and their diameter, the length of segments of differential pairs are given. These results can be used in pre-layout analysis step of high-speed signal transmission lines for computational modules of highly reliable reconfigurable systems.