How to Boost Wireless Backhaul Capacity Without Breaking the Bank

Two critical challenges exist in microwave link planning – link capacity (how many gigabytes can be transmitted) and link length (how far the link can span whilst maintaining reliability). The ideal scenario is high capacity over the required link distance, but a variety of factors influence how achievable this is. One of the main factors is the frequency bands involved in the transmissions.

E-band (80 GHz) has emerged from being a niche player to a key frequency in microwave backhaul because of its ability to deliver very high capacity links. The challenge in E-band, though, is link length limitations due to fading in adverse weather conditions. Traditional microwave frequencies such as 18 GHz and 23 GHz can cope with adverse weather, but the amount of spectrum available in these bands limits their capacity. The question, therefore, is how to further increase capacity over existing 18 GHz or 23 GHz links when these are already at maximum capacity.

One potential way of doing this is to couple a traditional microwave band (say, 23GHz) with E-band. The vast majority of the time the E-band provides very high capacity, but in adverse weather conditions, the traditional band still provides some throughput for critical traffic. This is broadly similar in concept to what happens in an adaptive coding and modulation (ACM) radio. As the interference level increases due to a storm, the radio modulation drops, but the link is maintained. Think of a cyclist changing down the gears as headwinds increase – he keeps going forward but slower.

This combined approach would typically require twice the infrastructure – separate antennas for each band, each to be installed and aligned. More significantly, there would be ongoing tower rental costs for both links, too – doubling the operational expenditure. But there is a much more affordable alternative – dual band microwave antennas.

Dual band microwave antennas can carry both E-band and microwave frequencies in the same antenna, without compromising the performance of either. Think of a two-foot antenna able to directly mount E-band and microwave radios in a single compact installation. That capability means only one link to install and align and reduced tower rental costs.

If you have microwave links where you need to seriously increase capacity, think about an E-band overlay with dual-band antennas. And talk to CommScope—we’ve been doing dual band antennas for years.