300328疑问

请问划线里面提到的CCA和LBT分别是什么，有什么用呢？划线部分又怎么解析呢？
For Adaptive FHSS equipment using LBT, if a signal isdetected during the CCA. the equipment may jump immediately to the next hopping frequency in the HoppingSeauence (see clause 4 3.1.7.2 2, point 2) provided the limit for Accumulated Transmit Time on the new hoppingfrequency is respected.

Listen Before Talk (LBT): mechanism by which an equipment first applies CCA before using the channel
先听后说（LBT）：设备在使用信道前首先应用CCA的机制

Clear Channel Assessment (CCA): mechanism used by an equipment to identify other transmissions in the channel
清除信道评估（CCA）：设备用于识别信道中其他传输的机制

Example of timing for Frame Based Equipment