5.给下列各种功控类型按从高到低的优化级排序

1.        给下列各种功控类型按从高到低的优化级排序             

a. PC due to Upper level thresholds (UL and DL)

b. PC due to Lower level thresholds (UL and DL)

c. PC due to Lower quality thresholds (UL and DL)

d. PC due to Upper quality thresholds (UL and DL)

请问那些英文都是什么意思啊？谢谢

英文意为功率控制根据：

a.电平上门限

b.电平下门限

c.质量下门限

d.质量上门限