Demand for bandwidth, small-cell densification and operators’ 5G plans are regularly cited as driving increased investment in fibre optical distribution networks (ODN) for RAN (radio access network) mobile backhaul. However, Ericsson has highlighted the benefits of microwave-based transport too.
A blog post from Shane McClelland, Head of Transport in Market Area North America, Ericsson, notes the benefits of fibre optic distribution networks but also points out some potential downsides, such as availability, cost, complexity and time to implement.
McClelland says that advances in microwave technology, including software and hardware, mean speed has moved from ‘megabit-per-second to gigabit-per-second'. He added that microwave hops can offer lower latency than fibre links because “the refractive index of air is lower than fibre optic cable”.
McClelland argues that microwave technology can cope with the demands of a 5G RAN, as long as service providers choose the right products.
For example, he says, 5G-ready microwave systems need to support 4096 QAM (quadrature amplitude modulation) with a light-coding mechanism. He explains that this, in combination with wide channels, uses spectrum most efficiently and increases link capacity.
According to McClelland, 5G-capable microwave systems also need a radio link bonding capability to enable them to use both licensed and unlicensed spectrum. A MIMO (multiple input/multiple output)-ready capability is also required, as is a range of traffic interfaces up to 10G. Further essentials, according to Ericsson, are functionality for integrated Ethernet switching and IP routing (to save costs on external equipment and cut complexity); hierarchical QoS (Quality of Service) for network slicing; and advanced automation and intelligence.
Ericsson Microwave Outlook
McClelland writes: “Ericsson saw the need for all these enhanced capabilities, and more, in microwave so we’ve continued to invest in microwave technology, adding 5G-ready microwave products to the market-leading MINI-LINK portfolio.”
Ericsson also recently published a new Microwave Outlook, concluding that: “High-capacity microwave is a key enabler for 5G.” It explores how demand for high-quality mobile broadband can be met with advanced microwave technology and spectrum, coupled with fibre and machine intelligence.