单项选择题
A.抗快衰落 B.抗慢衰落 C.调制
A.1200bit/s，20ms B.2400bit/s，26.666ms C.2400bit/s，20ms D.1200bit/s，26.666ms
A.power budget evaluation B.high interference on uplink C.uplink level too low D.uplink quality too low