Research On Design Technology And SI Simulation Of The PCI Express Link Path In Backplane System

Owing to its superexcellent capability in the data exchange and the system stability,the cabinet’s backplane system has been widely used in many complex electronicsystems, especially in telecom equipments and high performance computer systems.The bus standard of PCI Express, as a result of the typical third-generation I/Otechnology, has been proverbially applied to and supported by the electronic industry.The bus standard of PCI Express provides the performance with higher data rate andbandwidth than the former bus standard, the PCI Express3.0transfer rate, as we known,having been reached at8Gbps in reality, so the puzzle how to design backplane systemis also bring up to electronic designers. How to effectively reduce or avoid the signalintegrity (SI) problems on long-distance transmission line, such as the signal reflecton,medium loss, data jitter and code, and so on, cannot help but being confronted bysystem designers and SI engineers.Combined with practical engineering requirement, the experimental backplanesystem has been established in this paper. According to the PCI Express link path in theexperimental backplane system, we extract every models, design transmission path andsimulate signal integrity in time region and frequency region by EDA tools. Thesimulation results are analyzed in detail. The contents and results of our research aremainly in the following:Considering the technological development of the third-generation I/O bus, theanalysis of the PCI Express bus architecture and protocol have been presentedconcretely. We mainly discuss and focus on the features of every protocol layer,encoding way of the PCI Express, which is foundation works for following PCI Expresstransmission path design and SI simulation.We research and analyze design technologies of the high speed PCB. The keyelements are designed and SI simulated, including the PCB laminates, board materials,vias and connectors, in the high-speed transmission design. Based on the analysis ofthe various key elements on the high speed signal transmission path, we have designand optimize those elements’ parameters, which is a beneficial attempt for engineeringdesign.On the basis of the topic design target, we have analysed a variety of backplanesystem structures and characteristics, designed and established a experiment system bythe parallel backplane structure. Aslo, we have constructed cross-backplane link modelfor the PCI Express high-speed signal transmission according to the interconnectionpattern of the experimental system.According to the actual demand of engineering design, we extracted the link modelof the high speed signal transmission from the experimental backplane system, and carried out a lot of SI simulations and analyses with different rates (5Gbps and8Gbps),different materials (FR4and N4000-13SI), and different transmission lengthes (55cm,80cm and100cm). After the comprehensive simulation and analysis of PCI Express2.0and PCI Express3.0with two different signal rates on the link model, we can concludethe useful layout distance for the PCB transmission line during the engineering design.Additionally, in order to further improve the backplane signal transmission quality, wehave put forward a new design method of repeat chip that the repeat chip is added in thetransmission link to increase the transmission distance in backplane system. Aftercontaining repeat chip in link path, we have also analysed the stimulation results.Finally, we have discussed and stimulated the14Gbps backplane design which we mayface in the future.