Fronthaul 101- What is Fronthaul?

By Dudy Cohen 5 min read

So now that we understand backhaul, let’s talk about fronthaul.

What is fronthaul? Why do we need it? What role does it play in 5G networks? And why on earth does it require so much capacity?

Watch this video to learn.

Full Video Transcript:

Welcome back. So remember fronthaul? People asking me what is fronthaul? I tell them, “What is backhaul?” They tell me, I don't know etc., etc.

So now we all know what is backhaul. Now let's talk about fronthaul.

Basically, fronthaul is the same thing. Fronthaul is another connectivity between two points. In the mobile network, we have a base station, we have the core network; the connection between them is a backhaul and we have some new elements like a radio unit and the centralized unit and distributed unit. And the connection between the radio unit and the distributed unit is fronthaul.

We talked about it when you talk about open networks. We talk about disaggregation, horizontal disaggregation in the RAN, etc., etc. And the whole idea behind this disaggregation is having an extremely low cost radio unit.There are lots of them in the network. And in order to make the networks scalable and cost efficient, vendors are making those very cheap. You want them cheap. And in order to make them cheap, you make them, well, stupid. So what happens when you try to talk to someone who is not as intelligent as you? You call him, again, with the antenna gain and with the transmit power and with the receiver sensitivity. You are sure that he hears you and you tell him a sentence like "If two witches were watching two watches, which witch would watch which watch?" And all he has to say is,

- Huh?

Huh. Because he's remote unit. He's a radio and he's dumb. He does not understand. So you go again, "If two witches were watching two watches, which witch would watch which watch." And you get again,

- "Say what."

So in fronthaul, you need to explain very slowly. In fronthaul, you actually need to tell him, Do like this with your mouth - “eee” and then exhale and then do “fff” and then exhale etc, etc. And then you have “if”, and then “two”, and then witches, etc., etc. So you see, you put in a lot of effort in order to convey a very simple message. And this is what causes fronthaul to be capacity extensive. This is what causes fronthaul to be, to demand about six times the capacity, the same amount of information require in the backhaul.

This is why in fronthaul you need either fiber or millimeter wave connectivity; 10, 20Gbps, to convey all this information, even though the amount of real information is not greater than you have in backhaul. So this is fronthaul. By the way, this is also the reason that you need shorter latency or reduced latency in fronthaul links. So the entire process of back and forth will move on much quicker and would not exhaust you.

So now we know what backhaul is and what fronthaul is, all we have left to do is understand what's midhaul. But midhaul is easy, you don't need a video for that. Just look at our blogs and you'll understand it right away. Thank you very much for watching, again. And I will see you next time. Bye bye.

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