Size, Weight, and Power (SWaP) vs. Performance Trade-offs in Software-Defined Radio (SDR)
The advent of Software-Defined Radio (SDR) has revolutionized the radio frequency (RF) world. These devices have shifted the primary technical paradigm of the RF industry from fixed, bulky analog electronics to flexible, compact software-based signal processing, significantly expanding the applicability of Commercial Off-The-Shelf (COTS) radio systems. As a result, SDRs now dominate the RF market and are used in a wide range of applications. However, each application has its own requirements, including Size, Weight, and Power (SWaP), performance, and cost. Therefore, developers must carefully design SDRs to meet market demands. A key bottleneck in the design process is the trade-off between SWaP and performance: each SDR consists of many different components, and optimizing these components is critical to achieving the desired balance.
A well-optimized SDR can meet the needs of multiple markets with varying performance requirements, channel counts, and digital signal processor (DSP) capabilities, while also adhering to SWaP and budget constraints. In fact, compared to traditional analog counterparts, SDRs alone can reduce the overall size and weight of an RF system by 80% or more, making them highly suitable for applications such as MRI, radar, spectrum monitoring, point-to-point links, and testing and measurement.
However, key markets demand further reductions in SWaP and cost. This is achieved by compromising on the performance or total features of certain components, such as:
Reducing the tuning range
Decreasing the number of receive (Rx) and transmit (Tx) channels
Lowering DSP capabilities
Limiting total bandwidth
These trade-offs enable SDRs to cater to specialized applications where minimal SWaP and cost are prioritized without sacrificing core functionality.