5 Areas for SDN Innovation in the Microwave Network
An industry buzzword often heard today is SDN (Software Defined Networking), and it’s starting to appear as a key requirement in most tenders. Having SDN capabilities is only the first step in addressing a very broad term that involves a lot of variables. For microwave systems, the value of SDN will be found in the network orchestrator, and it will be based on what reconfigurability is developed. In the microwave layer, which is comprised primarily of fixed point-to-point links, there are fewer areas for dynamic reconfigurability than in an IP core. However, there are still five key areas where an intelligent SDN orchestrator will be able to add value in the future, including:
- Traffic queuing and prioritization settings – Having network wide awareness of individual link status, including failures and capacity changes due to modulation changes, as well as end-to-end knowledge of traffic requirements, network orchestration can adjust prioritization settings on each link to meet current network demands.
- Link transmit power and modulation – A network-wide view of each links’ performance can pinpoint where interference may be occurring. This can allow the orchestrator to reduce output powers on links causing interference in the network. It can also be used to monitor path fade events and adjust transmit power upwards on affected links, in a more network optimized manner than current link based ATPC (Automatic transmit power control) systems can do. When combined with a knowledge of traffic requirements, the orchestrator can choose between keeping transmit powers low to avoid interference, or instead reduce modulations to improve link budget, albeit with the resulting reduced capacity.
- Link Channel Size and assignment – With a combined network-wide view of interference, as well as capacity requirements, the orchestrator can make intelligent decisions on channel assignment. For example, as greater capacity is required on a particular link, the channel size could increase from 14 to 56 MHz, while channel size on links requiring less capacity can be reduced. The network could also reassign a link from channel 1 to channel 3 in order to improve interference performance.
- Antenna Array Steering – In the unlicensed 60 GHz bands (also commonly known as V-Band), phased array antennas are emerging that will enable the radio to steer the antenna to create a new link dynamically with another radio. A network orchestrator will be required to trigger this reconfiguration based on capacity requirements, interference or network failures and knowledge of the radio’s positions and bearing. This combination of capabilities would enable a very fast wireless mesh architecture.
- System type reconfiguration – The network orchestrator can also be used to change system configuration types. For example, when a link requires less capacity, it could be dynamically reconfigured from a 2:0 configuration to a 1+1 Hot Standby configuration. Or, in another case, if there is a rain fade, and less capacity is required, a MIMO configuration would be adjusted to provide system gain instead of a doubling of capacity
Although microwave links are fixed point-to-point systems, and therefore have some reconfigurability limitations, certain key areas exist where an intelligent SDN orchestrator will allow the microwave network to better react to network events and traffic requirements. Addressing these opportunities for advancing microwave networks will bring added value, but it requires more than just having an “SDN enabled microwave system”, as the key element for improvements will be realized by a microwave aware intelligent orchestrator.
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Mr. Greg, I´m developing a concept called SRN (Smart Radio Network) which I´m trying to apply it to an existing Radio Network and I think is a first step approach to more complex solutions such as SD-WAN or full stack SDN, I found you'r post very accurate and reachable (as Tamas said, in some countries the ETSI regulations could result in an issue which will not allow some concepts to be fully automated), nevertheless if I achieve to publish an article in a local professional magazine or scientific journal I would like to quote your post if you allow me. Kind Regards.
Hey Karel, I see it is exciting times for all transmission technology with sdn
Interesting Post! What we are doing today is link planning, and we define the capacity for fixed topology and some basic figures. This is far from a SDN-TRM network, so the links are often overdimensioned and the network is unbalanced. Sometimes it is not possible to find a channel for the proper capacity/path lenght. Even if the equipment is capable to handle SDN features, the areas 2-5 you mentioned are regulatory issues. In some countries even the usage of ACM, has restrictions. Why operators cannot use more flexible systems, and light licensing in trad bands? The answer is interference, and the regulatory handle the spectrum management in a same way like tens of years ago, when there were much less links in the air, with much less bandwidth. I met several hard interference cases occured by error, and surprisingly the effect was much much less than calculated. So I think a flexible self tuning network would serve significantly more capacity, than a network defined by conservative objectives. It is not a problem if all the links are "SDN-mw", and the links can spot the interference source, and the orchestrator command them to reduce bw, tx power, modulation and change frequency or mode. Even the SDN and non-SDN mw's can work together if the SDN-mw link has the same licensed default settings, and retreat from high capacity mode in conflicts. And probably in the future all the links will be SDN-mw and the network orchestrator would manage all the operators links, who would also share each others resources if needed.
Hi Luke, I agree completely. This is absolutely an area of network rerouting for SDN. An orchestrator in the future will be able to select between multiple technologies, including NLOS, microwave, V-Band/E-Band, and potentially even fiber. We have not done or seen studies on this yet, but as we start to understand the capabilities, we will certainly publish our findings.