论高速接入网技术

On high-speed access network technology

光纤通信技术的发展使单根光纤的数据传输能力提高了6个数量级,为高速骨干网络的发展奠定了通信技术基础。但是,接入网技术的发展却相对滞后,而长期被人们视为“最后一英里”(LastM ile)或“第一英里”(FirstM ile)问题。接入网是指从骨干网的边界节点(接入节点)到用户计算机之间的网络部分,它是OSI/RM中由中继系统(Relay System)或中间系统(Intermed iate System)组成的通信子网的重要组成部分。因此,它可能涉及OSI的物理层到网络层的三层技术。对高速接入网技术的讨论中,部分地涉及了数据链路层技术,但主要是讨论物理层通信技术;重点介绍了有线接入技术,而对无线接入技术的讨论,仅限于目前使用较少但却极具应用前景几种高速无线通信技术(自由空间光通信、制导灵敏激光束通信和超宽带通信)。最后总结了未来高速接入网通信技术发展的特点将表现为:多样化、高传输速率、远传输距离和低综合成本。

It is the development of optical communications that has raised transmission capability of a single fiber up to 6 orders of magnitude, and provided a solid communication basis for high-specd backbone networks. However, the access network technology develops comparatively slowly and has been regarded to as the ＂Last Mile＂ or ＂First Mile＂ communication problem. Access network refers to that from the edge of backbone networks to individual costomer computer, and playsan important part in the communication subnet composed if Relay System or Intermediate System in OSI/RM. Therefore, access network may get the three lower layers in OSI/RM involved. The access network communication techniques with an emphasis on wire-based high-spoed communication techniques were addressed, although a few new wireless techniques with potentials were also discussed. Finally, it concludes that high-speed access network communication techniques in the future will be characterized by diversity, higher speed, long transmission distance, and lower cost.