Virtual machines and stochastic scheduling simplify wireless design

摘要

System designers sometimes refer to the traditional stack-development approach for user-equipment handsets as "silo-based" because of its extreme vertical integration between software and hardware and the lack of horizontal integration with other stacks (Figure 1). This silo approach breaks down when implementing multiple packet-based standards, because it assumes that the stack developer "owns" the underlying hardware resource and can therefore make assumptions about resources, such as scratch- and persistent-memory-buffer allocation. These availability assumptions are meaningless in a multimode environment, in which stacks that may "beat" against one another in their underlying timing are competitively acquiring resources, such as memory. The silo approach assumes that you can configure the worst-case system loading at design time, allowing you to assign resources during system design rather than at runtime. However, the approach is essentially unworkable for multichannel, packet-based systems with a high peak-to-mean resource-loading profile. In addition, it assumes that one design group will code the system and that the standard will not change significantly during development. Both assumptions are likely wrong for modern communications systems.