RX path loss 为何有正负值？

guody2007

请哪位大侠帮解答一下  RX   loss  为何有正负值？如下实例。

Temperature 0 Max UARFCN=10562,10631,10700,10769,10838,0,0,0,0,0,0,0,0,0,0
Temperature 0 RX loss high mode=1.00000,0.75000,2.00000,2.50000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.000000
Temperature 0 RX loss mid mode=0.75000,1.50000,1.25000,2.00000,0.50000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.000000
Temperature 0 RX loss low mode=1.00000,-1.50000,1.25000,2.25000,-0.50000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.00000,0.000000

谢谢。