为减小单个根节点的负载，选择多个能感知到相同空闲信道数量的次要用户作为根节点。

To reduce the loading of root in a spectrum-tree, some users, which sense the same number of idle channels, are selected as roots.

youdao

根据频谱树以及基于最小时延的路由度量标准，建立路由以完成次要用户间的通信，同时提供了高效的路由维护机制。

By using the spectrum-trees and a new route metric about delay, the route, with an efficient route recovery method, can be established for the secondary users.

youdao