Microwave will ease '4G' backhaul strain — RFS

The relentless march of next-generation wireless data services is beginning to strain backhaul infrastructure, as high data throughputs — and subscriber demand — consume network capacity.

According to Radio Frequency Systems (RFS), high-capacity microwave links could provide the global backhaul panacea, as operators rush to meet subscriber uptake.

“Regardless of how the battle for technical supremacy in third- and fourth-generation mobile data pans out, backhaul capacity will fast become a bottleneck unless the network is quickly upgraded,” said RFS's global product manager radio link networks, Daniel Wojtkowiak.

“Market studies predict network operators will need 100 Mbps for full mobility and 1 Gbps at wireless hotspots. Current backhaul capacities are clearly insufficient for the new data-rich services.”

Traditionally, network operators have chosen between copper E1/T1 lines, optical fibre and microwave radio technologies to support the backhaul network.

According to Wojtkowiak, the copper option is no longer viable in this new era — it simply cannot handle the higher capacities.

Above 2 Gbps, fibre is often selected, provided there are no impediments to installation. Where such capacities are not required, however, microwave has a number of advantages.

In the first place, said Wojtkowiak, microwave networks are less costly and far quicker to install. This will be a prime consideration for operators as they move fast to overcome the backhaul strain and protect their 4G investments.

“Whether in urban or regional areas, access for optical cable trenches or ducts can be difficult to obtain and interruptions due to accidental cable cuts are a constant threat,” he said.

“In contrast, microwave links are quickly installed and less prone to accidental disturbance. For network operators, the prospect of owning the infrastructure, rather than leasing from competitors, adds to the attraction of a quickly installed, secure solution.”

Accommodating the higher-capacity services opens the way for innovative system architectures in microwave backhaul networks.

Dual-polarised antennas double the capacity of the antenna system. Moreover, the superior interference characteristics of ultra-high performance antennas allow the installation of additional antennas on existing sites as new microwave backhaul systems are deployed.

Recent technological advances provide further backhaul options.

Wojtkowiak expects two sections of the E-band spectrum, which are available between 71 and 86 GHz, to come into frequent use this year. Trial systems have already been deployed. Using 250 or 500 mm antennas, E-band microwave systems provide 200 to 600 Mbps capacity over distances up to 3 km.

According to Wojtkowiak, the growing demand for enhanced wireless data services to be available ‘anytime and anywhere’ is increasing pressure on operators to reassess their backhaul infrastructure — with higher capacity the key.

“For the network operators, the expression ‘time is money’ rings true,” he said. “Quick-to-install, high-capacity microwave systems offer a flexible and reliable solution to the backhaul dilemma as we embark on the next steps of wireless evolution.”