Long-TermEvolution(LTE)isarguablyoneofthemostimportantstepsinthecurrentphaseof
the development of modern mobile communications. It provides a suitable base for enhanced
services due to increased data throughput and lower latency figures, and also gives extra
impetus to the modernization of telecom architectures. The decision to leave the circuit-
switched domainoutofthescope ofLTE/SAEsystem standardization might soundradical but
itindicatesthatthetelecomworldisgoingstronglyfortheall-IPconcept----andthedeployment
of LTE/SAE is concrete evidence of this global trend.
SAE J1939協議是由汽車工程協會(SAE)定義的,SAE J1939協議在商用車輛、艦船、軌道機車、農業機械和大型發動機中是應用最廣泛的應用層協議,基于傳輸可靠性能優越的CAN-bus總線,可達到250Kbps的通訊速率。在協議中,不僅指定了傳輸類型、報文結構及其分段、流量檢查等,而且報文內容本身也做了精確的定義,SAE J1939協議由美國SAE( Society of Automotive Engineer)組織維護和推廣