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.  DragonWave’s Harmony Enhanced, Enhanced^MC, and Eband products are all software upgradeable to SDN, to enable future network intelligence.  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:

1. 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.
2. Link transmit power and modulation – A network-wide view of each link’s 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. When combined with knowledge of traffic requirements, the orchestrator can choose between keeping transmit powers low to avoid interference or reducing modulations to improve link budget, albeit with the resulting reduced capacity.
3. 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.
4. 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.
5. 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.  Although SDN capabilities are still in the very early stages, it is important to prepare for an SDN infrastructure today.  DragonWave’s Harmony Enhanced, Enhanced^MC, and Eband products are all SW upgradeable to SDN.  This allows operators to prepare for the future benefits of SDN with today’s network investment.