A wireless link is composed of  a wireless transmitter, wireless receiver and a transmission medium termed channel. To answer the question it is required to What do you mean active and passive?

In general the link quality is  measured by the bit error rate for a given,

transmit power, antenna gain,

transmission distance and transmission obstacles, the channel specification,

the receiver sensitivity in terms of of the minimum received power.

Best wishes 

A wireless link is composed of  a wireless transmitter, wireless receiver and a transmission medium termed channel. To answer the question it is required to What do you mean active and passive?

In general the link quality is  measured by the bit error rate for a given,

transmit power, antenna gain,

transmission distance and transmission obstacles, the channel specification,

the receiver sensitivity in terms of of the minimum received power.

Best wishes 

The wireless channel is comprises of    a wireless transmitter,  receiver and a transmission medium .

The link quality is  measured by the bit error rate for a given channel specification.

WLAN link quality usually measured by RSSI (Received signal strength indicator). Also Bit Error Rate is a good candidate for detecting link quality. Because It represent different environmental impairments like Noise, Interference, Path loss, Multi path fading and so on. My recent paper can help you to study more.

http://www.sciencedirect.com/science/article/pii/S0045790616000070

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