What are hidden station problem and exposed station problem in WLAN? How are the problems solved?
Hidden station problem: B is sending data to A, and after some time C also wants to send data to B. but C is not in the range of B and so it will be unaware of the transmission between B and A, and so C will send data to A and therefore there will be a collision.
Exposed station problem: station A is sending data to B and C also wants to send data to D, but since C is in the transmission range of A, C will not send data to D. But the transmission between C and D will not affect the transmission between A and B.
The hidden node can solve be solved by the use of handshaking. B before sending data to A, will first send request to send (RTS) to A. after that if A is ready to receive data from B then it will respond by sending Clear to send(CTS) to B, which will also be received by C since it will also in the transmission range of A. as a result of which C will stop transmission for the time period that is been specified in the CTS.
The use of handshaking is unable to prevent handshaking. C stops transmission for the time period specified in the RTS as it is in the range of A, but does not receive the CTS send by B. as a result of which it send RTS to D, and if D sent CTS to C then it collides with the data sent by A to B(also received by C).
USE OF HANDSHAKING TO PREVENT HIDDEN NODE PROBLEM
USE OF HANDSHAKING TO PREVENT EXPOSED NODE PROBLEM
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