Heavy Integration Approach to SDR
Although the baseband processing may be implemented in software with SDR, the software still needs to run on some hardware platform. One implementation, outlined in Figure 2, places two baseband signal processing cores on the same chip, each with its own front-end, to handle AM and FM. This architecture does not fully lend itself to the SDR strategy, since more standards exist. The demodulation algorithm is also hard wired inside the baseband signal processing section, hence there is no possibility for adapting to a variety of techniques and evolving standards as desired for an ideal SDR.
World Band Radio
In order to fully achieve the flexibility envisioned by SDR, a more flexible architecture is needed. A stand-alone front-end tuner (Figure 3) capable of implementing all primary analog and digital radio standards (Table 1), dubbed World Band Radio (WBR), has been proposed by Maxim Integrated. This flexible tuner, paired with an SDR backend, enables a single radio platform to receive all global radio standards.
The advent of powerful multicore processors has enabled this approach to SDR. With a multicore processor, the software flexibility required by SDR can be pushed inside the main application processor, where one core can be dedicated to each standard. This simplifies the radio design and reduces cost by more efficiently utilizing the multicore application processor already present in the system.