In the earliest days of 5G, backhaul network planning discussions centered largely on fiber, with the expectation that fiber alone will meet the high backhaul capacity demands of 5G. But with a combination of technology advances and general industry education, those early assumptions have proven wrong. Today, microwave is asserting itself as a legitimate 5G transport contender.

In order to understand how transport networks will evolve to support 5G services, Heavy Reading launched the Operator Strategies for 5G Transport Market Leadership Study with collaboration partners Anritsu, Ericsson, Fujitsu and Infinera in May 2020. The survey attracted 86 qualified network operator respondents from around the world that shared their views on transport deployment issues and timelines, fronthaul networks and radio access network (RAN) centralization, routing and synchronization and testing 5G networks.

This blog, the last in a four-part series highlighting the key findings from the 2020 study, focuses on trends in microwave transport.

Viable for fronthaul
With a jump to 10Gbps data rates, microwave backhaul quickly came back into play as a viable 5G backhaul option. In Heavy Reading's 2019 Operator Strategies for 5G Transport survey, 35% of operator respondents selected 10Gbps microwave as "highly important" for 5G transport, a respectable showing for the former dark horse technology candidate.

For 5G xHaul generally, fronthaul has been the area of greatest challenges and industry attention due to its high bandwidth requirements and stringent latency restrictions relative to midhaul and backhaul. Again, the earliest assumption was that fiber alone can address this emerging segment. But current (2020) Heavy Reading survey data suggests that wireless connectivity will be a viable option for fronthaul networks too, particularly in the millimeter wave (mmWave) frequencies above 30GHz that can boost data rates to 25Gbps and higher. Microwave/mmWave transport is expected to account for 18% of the 5G fronthaul connectivity mix, according to Heavy Reading's 2020 5G transport survey — another respectable showing.

Figure 1: 5G fronthaul connectivity by type n=71
(Source: Heavy Reading)

To be clear, operators will select fiber to be their first choice for fronthaul, but microwave/mmWave will be an option in cases where fiber is not possible or is economically prohibitive. This trend may vary significantly by geographic region, as fiber richness — and thus physical and economic viability — varies greatly from country to country.

Microwave use cases
Digging into microwave connectivity a bit deeper, Heavy Reading asked operators to identify their top use cases for microwave connectivity during the next three years across all transport segments. Survey respondents were able to select up to three options.

Figure 2: Microwave use case priorities n=84
(Source: Heavy Reading)

The interesting takeaway from the data is that operators see microwave as suitable to address 5G across all possible use cases. As expected, macro backhaul tops the list among the microwave priorities. Among the respondents, 49% selected 10Gbps or greater macro backhaul use cases and 40% selected less than 10Gbps macro backhaul. But other use cases scored highly as well. Street macro and small cell backhaul are viewed as viable microwave options by many operators, with each of these use cases selected as a priority by one-third or more respondents. Even microwave fronthaul is in play, particularly at 10Gbps data rates, which was prioritized by 23% of the survey group. In summary, the data shows solid momentum in microwave transport, even for use cases that have been traditionally restricted to fiber.

The lesson from Heavy Reading's survey data is: Don't underestimate the strength of microwave transport.

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This blog is sponsored by Ericsson.

— Sterling Perrin, Principal Analyst, Heavy Reading