‫Now we come to the problem of multi party effect in the wireless channels.
‫Now, in the case of wireless channels, for example, consider this example.
‫Here we have our transmitter and here we have a receiver.
‫And very often we have more than one parts that are dear between the transmitter and the receiver.
‫What example here in this case, this is the direct part.
‫Between the transmitter and the receiver and this is the.
‫In Darick, but in this case, the signal would be reflected from the building and then it would be
‫received by the receiver.
‫And here we have another part in which the signal would be deflected from this building and then it
‫would be received by these receiver.
‫So as a result, what happens is that, for example, this transmitter transmits assemble to the receiver.
‫This is the symbol that is transmitted by the transmitter.
‫It will breach the receiver by the direct part.
‫But also we would get echoes of December, for example.
‫Dissemble would also be reflected from this building and it will reach the receiver.
‫But with a certain time delay and another echo of this symbol would be reached would be received by
‫the receiver after being reflected by this building.
‫So we have the actual symbol that is being received from the direct path.
‫And we have it two copies now.
‫When this transmitter would transmit the second symbol.
‫It will be received.
‫At the receiver from the direct part, and we would also have to Aquos, similarly, when the third
‫symbol is transmitted, we would receive it at the receiver from the direct part and we would have its
‫copies.
‫Now we can see that the echoes of the first symbol are interfering with the second and the third symbol.
‫Similarly, the echoes of the second symbol are also interfering with the third symbol and the symbols
‫that we transmitted afterwards.
‫So as a result, there is a.
‫Enter symbol interference.
‫And as a result of this inter symbol interference, there would be frequency distortion in the signal.
‫Ah, in other words, we can see that or channel has frequency, selective nature.
‫If we blocked this channel in the frequency domain.
‫And this is the frequency axis.
‫And this is the attenuation that is there in the channel, we can see that some frequencies are being
‫attenuated more as compared to the other frequencies.
‫So as a result of these frequencies selectivity which is caused by the inter symbol interference, there
‫would be distortion in the signal that is being received at the receiver.
‫And as a result, wou we would have bit errors at the receiver.