There has been a lot of ink spilled on the fact that LTE is an OFDM based technology. That is a fact, but that doesn’t really help in understanding the way that 3GPP has developed the technology to do all of the magic that LTE is supposed to do. In my opinion, the heart of LTE is its Physical Downlink Control Channel (PDCCH). You don’t believe me? Let me show you what I mean.
In the downlink of LTE there are only a handful of channels. For all practical purposes we can narrow the number of channels in the downlink down to five channels. Three of the channels are supporting channels that provide broadcast information, acks & nacks, or information on the size of the control channel. That leaves us with two key channels. They are the PDCCH and the Physical Downlink Shared Channel (PDSCH).
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