Prior understanding orthogonality feature, we must clear out the meaning of the orthogonal , which means more than one object is acting independently.
Therefore, in OFDM the neighbour signals do not interfere with each other. So, how does orthogonality works?
Similarly, with the other two signals, the peak of one signal occurs at the null of the other two signals. In the receiver end, the multiplexer strengthens the signal according to the orthogonal characteristics of the signal. OFDM is a prevalent multiplexing technique mostly implemented in the latest wireless methods and telecommunication standards, like Wi-Fi The OFDM technique is advantageous over FDM because it is more spectrally efficient by placing the subchannels closely until they generate an overlapping effect.
Your email address will not be published. Media New media New comments Search media. Blogs New entries New comments Blog list Search blogs. Groups Search groups. Log in Register. Search only containers. Search titles only. Search Advanced search…. New posts. Search forums. Both are orthogonal in your example, in different ways. The FDM example provides orthogonality by properly spacing the signals in the frequency domain their dot product is 0. OFDM is far more spectrally efficient where you have overlapping carriers that are orthogonal.
Each of the carriers is a much lower bit rate that turns a frequency selective fading channel into flat fading. This is not true for your FDM example. There are many other differences but these are a few. You can have the channel of kHz split into orthogonal sub-carriers. If you lose orthogonality, the data in one sub-carrier will be affected by data in another sub-carrier hence inter-carrier interference.
In order to achieve orthogonality here, your total BW is kHz, so you can split them into sub-carriers of 1kHz each. Or you can split into 20 sub-carriers of 10kHz each. You can choose any combination like this to achieve orthogonality. But you can vary it depending on your channel and transmission requirement. Orthogonality in the time domain means you can separate the signals even if their spectrum crosses into each other.
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