Most client stations have a fixed power output. However, the transmission power can be configured on some vendors’ client radios. A low-powered client station that is a great distance from the access point could potentially become an unheard client if other highpowered stations are very close to the access point.
The transmissions of the high-powered stations could raise the noise floor to a higher level that would prevent the lower-powered station from being heard. This scenario is referred to as the near/far problem.
The half-duplex nature of the medium usually prevents most near/far occurrences, but you can troubleshoot near/far with a protocol analyzer by looking at the frame transmissions of the suspected far station.
A near/far problem exists if the frame transmissions of the far station are corrupted when listened to with the protocol analyzer near the access point but are not corrupted when listened to with the protocol analyzer near the far station.
If a near/far situation does exist, the following solutions can be used to correct the problem:
- Decrease power to the near stations.
- Increase power to the remote station.
- Move the remote station closer to the access point.
- Add another access point near the far node.
Please understand that the medium access methods employed by Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) usually averts the near/far problem and that it is not as common a problem of, say, hidden node or roaming issues.
