Flexibility is a must to support all the standards listed above, some of which are still under development and will require updates and remote upgrades in the field.
PLC for example, has been standardized by multiple standardization bodies such as IEEE P1901.2, PRIME (PoweRline Intelligent Metering Evolution) and G3 all of which offer multiple variants for data rates and frequency bandwidth. Countries have also derived variants of PLC to optimize them to the specifics of their electrical power networks.
To date there are still no universally agreed interoperability standards governing smart grid communications and there will probably never be one!
Multi-mode is also mandatory as most use-cases require multiple functions to run concurrently. The mesh NAN topology deployed in European and Asian cities calls for concurrent PLC and 802.15.4g as a node may be connected to one node via PLC and to another node via 802.15.4g at the same time.
Extreme low power
While electric smart meters have mains power, non-electric meters must run 5 to 10 years on two AA batteries which requires very careful optimization of both idle and peak power consumption.
Very low cost
To enable fast and widespread deployment of electric smart meters, the complete HAN/NAN communication module bill of material (BOM) should be in the $15 to $20 range.
Existing communication solutions use hardware centric modems which cannot be upgraded to track standards evolution and country variants and cannot support field updates.
Therefore Multimode systems are heterogeneous because they consist of a piecemeal collection of independent hardware-based modems. Such heterogeneous solutions are sub-optimal from a power, performance, cost and area standpoint. They also require longer time to market.
Software Defined Modems (SDM) are required to address these challenges with low cost and low power solutions. These modems should run on a unified high performance processor that can run multiple PHYs & Protocols with a true RTOS to support concurrency while minimizing task switching and MAC to PHY latencies.
And at the heart of these flexible communications engines are programmable DSP architectures, such as CEVA-XC5 and CEVA-XC8 that, by supporting a variety of communication standards, allow the developer to implement software-defined modems with no extra hardware requirement. Not only do such architectures reduce time to market but they also minimize risk by offering future-proof solutions that can evolve over the product lifetime by upgrading firmware in the field as standards evolve. Software only country to country customizations allow economies of scale which reduce further the system solution BOM.