来源：http://blog.chinaunix.net/uid-21389973-id-1827277.html
RXThresh_ is the reception threshold. If the received signal strength is greater than this threshold, the packet can be successfully received.
CSThresh_ is the carrier sensing threshold. If received signal strength is greater than this threshold, the packet transmission can be sensed. However, the packet cannot be decoded unless signal strength is greater than RXThresh_.
CPThresh_ refers to the capture phenomenon. If two packets are received simultaneously, i.e. they collide, it is still possible to receive the 'stronger' packet if its signal strength is CPThresh_ times the other packet. For example, if CPThresh_ is 10.0, the stronger packet in a collision can be decoded if its signal strength is at least 10.0 times that of the other packet; otherwise, both packets are lost in the collision.