The hop is not long enough! Multi-band booster: “Hold my beer, I’ve got this”

With ever mounting pressure on the spectrum available to them, service providers need a surefire way to boost their assets so they can deliver the microwave backhaul performance required. Here’s a look at the multi-band booster method: a radically different way of using spectrum efficiently.

Hong Kong city, night view
Dec 17, 2019
Magnus Berggren 

Strategic Product Manager

Category, topic & hashtags

Struggling with figuring out how to backhaul your 5G equipment?

“Fiber is OK, but not always an option for multiple reasons.”
“Microwave used to cut it, but now the capacity requirements are so much higher.”
There is however another solution which has been around for a few years now: the multi-band booster microwave/mmW hop, your new best friend.

A winning combination for high-capacity backhaul

So, what exactly is a multi-band booster hop? It’s when you combine two different frequencies over one hop. This means combining an E-band radio (70/80GHz) with a microwave radio (18GHz), for example.

Assume that you can transmit 300Mbps over the 18GHz radio and 5Gbps over the E-band radio… When combined, that would give you a total capacity of 5.3Gbps – which is good enough for many 5G sites.

The trick is to play with the availability figures for the combined hop. Let’s say that you set up the hop so that the 18GHz radio has an availability of 99.999 percent and the E-band say 99.9 percent… That would give you 300Mbps with five minutes of downtime per year and you would have 5.3Gbps with 8.7 hours’ downtime per year. And of course, you can prioritize the traffic so that the high-priority traffic for those mere 8.7 hours gets access to the 300Mbps available. Now how does that sound?

How far did you say?

You have the capacity. Now you have to reach that hill 6km away. Is that possible? As mentioned above, given that you allow a lower availability for the E-band hop, this can be done perfectly well by applying the multi-band booster concept. The best thing is that this method has already been proven in the field on a large scale.

Multi-band booster is widely used by all the service providers in Poland, and the distances they reach are impressive. An astonishing 11 percent of all mobile broadband hops are actually greater than 6km, as illustrated in the graphs below. The hop length that can be reached is of course dependent on which rain zone a particular network is located in, but rest assured that the E-band radios in a multi-band booster combination can be used for much longer distances than the typical 0-2km commonly associated with products in the 70/80GHz spectrum.

Need an even longer distance?

What to do if the hop distance required is greater, but you still need 10Gbps of capacity? Well, then you can combine a long-haul hop with a short-haul hop: the same principle as with the E-band multi-band booster, but now between 18GHz and 7GHz, for example.

Combining a long-haul hop (7GHz, 56MHz channel, 8+0 configuration) with a short-haul hop (18GHz, 112MHz channel, 4+0 configuration) will give 10Gbps with 99.9 percent availability: in other words, 8.7 hours’ downtime per year. And you have 2.5Gbps with 99.99 percent availability too! So, during the 8.7 hours’ downtime of 10Gbps, you still have 2.5Gbps. All this over a whopping distance of 20km!

Can multi-band booster even save me money?

OK, so you benefit from greater distances and more capacity using multi-band booster solutions. But could it even be that you can save yourself a cent or two? Well, yes, actually you can.

Comparing three different 10Gbps solutions in the German market shows that the lowest total cost of ownership is reached by using microwave (0-3km, standalone E-band / 3-5km, multi-band booster configurations) compared with dark fiber and self-built fiber. This is because the cost of leasing fiber or building your own is higher than the cost of investing in your own microwave hop – and the greater the distance, the greater the savings, as seen in the graph below.

Hop length x capacity = success

The combination of lower and higher frequencies – in other words, a multi-band booster configuration – offers you the best of two worlds: the long reach and high availability of the lower frequency, and the boost injected via the higher frequency significantly multiplying the capacity. The best thing is that the multi-band booster is readily available, and is starting to be deployed all around the world – both in existing 4G networks but above all, in preparation for the 5G rollouts to come.

Interested to learn more about this topic? Visit our Microwave multi-band booster page, and don’t forget to try out the virtual tool yourself!

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