In the early days of 5G, industry discussions on backhaul network planning mainly focused on fiber, and it was expected that fiber alone could meet 5G's high backhaul capacity requirements. As technology developed, however, these early assumptions were found to be wrong. Today, microwave technology is a competitor to optical fiber.
In order to understand how the transmission network will develop to support 5G services, the "Operator Strategy Survey for 5G Transmission Market Leadership Research" was launched in May 2020. The survey drew 86 qualified network operator respondents from around the world who Shared their views on transmission deployment issues and schedules, prequel network and wireless Access network (RAN) centralization, routing and synchronization, and testing 5G networks.
Feasible prequel technique
With the data rate jumping to 10Gbps, microwave backtracking is quickly returning to the market as a viable 5G backtracking solution. In the survey, 35 percent of carrier respondents said 10Gbps microwaves were "very important" for 5G transmission.
In general, in 5G xHaul, the prequel has been the biggest challenge and area of industry concern due to its high bandwidth requirements and strict delay limits, relative to the middle haul. Early assumptions were that optical fiber could solve this emerging problem. But survey data suggests that wireless connectivity will also be a viable option for a prequel network, especially in millimeter-wave frequencies above 30GHz, which can increase data rates to 25Gbps or higher. According to the 2020 5G transmission survey, microwave/millimeter-wave transmission will account for 18 percent of 5G pre-transmission connections.
To be clear, operators are looking to fiber as their preferred prequel technology, but microwave/millimeter wave will be an option in cases where fiber is not available or banned. This trend can vary greatly geographically, as the resources of optical fiber infrastructure, economic viability and so on vary widely between countries.
Microwave application cases
An interesting conclusion from the data is that the operators believe that microwave will solve the 5G problem in all possible use cases. As expected, macro return is the number one microwave priority. Of the respondents, 49% chose a macro return use case with a speed of 10Gbps or higher, while 40% chose a macro return less than 10Gbps. But other use cases also score highly. Many operators see Street Macro and Small Cell return trips as viable microwave use cases, with one-third or more respondents prioritizing these two use cases. Even at 10Gbps data rates, microwave precursors came into play, with 23% of respondents choosing them as the preferred option.
All in all, the data show strong momentum for microwave transmission, even in use cases that have traditionally been limited to fiber optics.
