Winning the 5G race with SDN in microwave backhaul
12 MINS READ
And communications service providers (CSPs) the world over are striving to roll out premium 5G technology to increase their average revenue per user (ARPU). But late spectrum allocation and its high cost, issues surrounding the right of way (ROW) rules in fiber laying, are some of the challenges telcos must face. Applications of 5G technology in niche business areas like self-driving cars, healthcare, and artificial intelligence (AI) are expected to inflate telcos’ revenue, but high spectrum charges, fuel costs, and low user charges pose hurdles.
To increase profitability and deliver compelling, differentiated customer experience, CSPs must roll out 5G services quickly – the trusted microwave technology can be of immense help here. The limitations and challenges of microwave technology from a telco standpoint can be addressed using a software-defined network (SDN). We discuss how a combination of microwave and SDN technology can help telcos get the maximum return on 5G.
Speed is of essence
SDN is an approach to networking that uses software-based controllers or application programming interfaces (APIs) to communicate with underlying hardware infrastructure and direct traffic on a network. SDN is already in advanced usage in modern networking but its use in microwave backhaul is still nascent. However, SDN and microwave can together help address the challenges of spectrum scarcity, cost of spectrum, interference, and compliance.
SDN helps telcos reduce the total cost of ownership (TCO) and drive faster 5G network rollout.
SDN and microwave – a smart combo
As leading telecom operators mull over ways to streamline 5G roll-out and reduce TCO, SDN and microwave technology usage offer four compelling benefits. They are:
Interference assessment and correction: As per standard practice, the planning team analyses microwave link performance reports and suggests corrective measures to remove interference issues. Link performance remains poor if analysis, suggestion, and implementation are not performed in real time.
On the other hand, SDN-enabled networks can analyze interference issues on any microwave link and make intelligent decisions to reduce the same. SDN can perform the below activities in real time:
Let us take an example to understand this better. Consider a service affecting interference on 1+0 MW link @64 QAM ,112 MHz, and the airlink capacity of this link as 501MBPS. 112 MHz frequency channel is a combination of two 56MHz frequency channels. SDN will first analyze the channel which is affected by interference. SDN controller will then automatically reduce the channel’s bandwidth to 56 MHz and allocate the frequency spot of 56 MHz (the channel not affected by interference) to the link. By doing this, interference will reduce, and with it, the capacity too will decrease to 321 MBPS. SDN will now step up the modulation to increase the link’s ability based on its performance. SDN can increase to 2048 QAM to get the desired capacity of 500 MBPS. Figure 1 illustrates this radio data sheet for granular clarity.
Figure 1: Illustrative radio data sheet
Automated software updates: Microwave original equipment manufacturers (OEMs) regularly release new software patches. Presently, these are run manually in each link through EMS, which is time-consuming.
The controller can automate software upgrades by efficiently running software patches on the microwave link based on the utilization of the link and its traffic priority. The controller can route traffic to the best possible redundant microwave path in the eventuality of a failure.
Energy saving: Links are usually less utilized during the night or non-peak hours. Network elements (NEs) can be kept in sleep mode during underutilization periods to save energy. Modem and outdoor units are transmitting round the clock. Centralized control can access the link’s utilization and close few channels or ODUs based on the current and past utilization patterns. For example, if the 2+2 HSB link has less than 50% utilization during non-peak hours, then out of eight, four outdoor units can be muted (see Figure 2). This will result in significant energy saving for the telco.
Similarly, in a mesh topology, some links can be deactivated entirely for fewer non-peak hours and dynamically re-activated when the demand increases.
Figure 2: An example of energy saving with link utilization
Adaptative coding and modulation (ACM)-triggered SDN rerouting: In the case of bad weather or rain, modulation of the ACM-enabled microwave link decreases. In such situations, SDN can intelligently route traffic on less utilized and stable redundant paths. For instance, when there is bad weather, the ACM reduces the modulation of the link between sites A and B (see Figure 3). Here, SDN is triggered and a more stable path between locations B and D compensates for the compromised capacity.
Figure 3: An example of ACM-triggered SDN rerouting
The role of automation in the microwave lifecycle
A LOS survey is the initial requirement after the desktop survey to establish a microwave link. It requires a physical visit to the site and the collecting of critical information, including type, height, and coordinates of obstruction along the LOS. This information is then shared with the backend planning team.
We believe, a LOS survey app can play a significant role in allocating the survey to the field team, uploading site information (pictures and coordinates), and LOS obstruction with the planning team on a real-time basis. It can also aid site selection for a green field project and reduce rework.
We foresee such an automation to yield a range of benefits such as real-time monitoring of field survey, an increase in throughput and efficiency, up to 25% reduction in manual effort, and significant reduction in rework and mobilization. It will also drive down the cycle time of finalizing field data by up to 30% and result in more than 95% accuracy in network design data and reporting dashboard.
The TCO associated with antennas is a crucial criterion for network designs. For customers who lease tower space, the recurring charge (opex) is calculated on the leased vertical space on the tower based on the antenna size.
Thanks to technological advancements, we can now use a single antenna for two different bands. An antenna that supports two traditional frequency bands, for example 6GHz and 11 GHz, in a single standard reflector, with multiple RF ports, is now available. With such an antenna, 6 GHz plus 11 GHz multi-band links can now be implemented as quickly and cost-effectively as a 2+0, 6 GHz link. Also, we can use a single antenna for transmitting traditional frequency bands and E-bands.
Lowering the spectrum cost is another focus area for telcos in the race to 5G, as microwave spectrum cost is one of the most prominent TCO component worldwide. And as capacity demands grow, more spectrum is required. By combining microwave and e-band in the same product, like with multiband radio, customers can achieve significant savings on spectrum costs as e-band is available at lower spectrum fees. Exciting times lie ahead for telcos and customers alike, and early adopters of innovative new technologies stand to reap significant rewards.