摘要
软件无线电（Software Radio）是通信系统中极具发展前途的技术。随着高速数字信号处理器的发展以及大规模可编程门阵（FPGA）的普及，软件无线电把诸多与具体信号类型紧密相关的处理任务软件化，从而使通信中的硬件设备更为通用。但是待传输的数据或已被接收的数据都需要通过局域网或其他类型的骨干网络与数据中心交换数据。多协议传输平台（MSTP）是一种融合数据业务与实时业务在SDH网络中传输的规范，是目前流行宽带数据接入形式，它为软件无线电提供了多种灵活的接入形式。作为MSTP，其关键技术之一是虚级联。与传统的连续级联相比，虚级联减小了带宽分配的颗粒度，使SDH传输管理更为灵活，提高了整体网络的资源利用率。本文介绍我们在MSTP芯片中VC-12虚级联模块的设计和理论分析过程。经过软件仿真和FPGA验证，这部分电路设计正确合理，可以稳定工作在预定工作速率。应用该设计的MSTP芯片目前已经完成加工，并被成功应用于MSTP网络设备中。相信我们的工作对软件无线电技术的未来发展有着积极的作用。
Software Radio is a kind of promising technology in today and future＇s communication systems. To share the resources of software radio systems to a large extent, we need to connect the instruments through backbone networks, such as the Multi-Service Transport Platform （MSTP）, which is a dominating network technology that adopts both telecom and datacom traffic into existing transport infrastructures -- Synchronous Digital Hierarchy （SDH）. Virtual concatenation （VCAT） is one of the key technologies in MSTP. Compared with traditional contiguous concatenation, VCAT reduces transmission granularities, provides more flexibility to Network Management System （NMS） and as a result, improves the network efficiency greatly. In this paper, we introduce our design and implementation of VCAT module for a MSTP ASIC. The procedure of theoretical analysis to determine several important performance related parameters is also discussed in detail. The overall design has been thoroughly simulated and verified through our self-made FPGA board, and has been successfuUy applied in our MSTP ASICs. We believe our work is significant for future development of software radio technology.
