Vanu Software Radio

What is software radio?

Software Defined Radio, or SDR, allows a single wireless device to support a wide range of capabilities previously available only through multiple products. Taken to the extreme, a single SDR device could provide cellular service, act as an AM/FM receiver, offer GPS position location services, wirelessly access the Internet, or even function as an HDTV receiver or telematics system.

Traditional wireless devices are designed to deliver a single specific communication service using a particular standard. With the steady proliferation of new wireless services and standards, single-purpose devices with dedicated hardware resources can no longer meet user needs, and are overly expensive to upgrade and maintain. SDR offers the flexibility and upgradeability necessary to satisfy these user needs.

Software Radio (SWR) is a type of SDR that maximizes software reuse across platforms and hardware generations. The key design decision that enables this reuse is writing the signal processing software as a portable application-level program running on top of a standard operating system (whether on a general purpose CPU, DSP, or other processing engine). In addition to reducing software development costs, use of application-level software and a standard OS allows the underlying hardware components to be upgraded without incurring the high cost of redeveloping the software. As a result, SWR systems can track the Moore's Law performance curve over time at a much lower cost than other types of SDRs.

How is Vanu Software Radio different?

Vanu Software Radio™ is the first commercially available solution where a single reusable off-the-shelf hardware platform can support multiple wireless services and standards entirely in software.

Vanu, Inc. uses advanced engineering techniques to produce software that can run on a wide range of processing platforms, from a handheld device to a commercial-grade server, allowing customers to choose the best processor for their application. By targeting general purpose processors and developing software in high-level languages, Vanu Software Radio systems become portable, modular and reusable, minimizing the amount of code that has to be re-written to keep pace with advances in the underlying technology.

Design philosophy

Software costs are a significant and growing component of SDR engineering costs. In all but the highest volume applications, the amortized cost of software is a major part of SDR device unit cost. While these facts are widely known, few SDR developers follow through to the logical conclusion: software cost issues must be considered as a primary engineering tradeoff throughout SDR system design. In Vanu Software Radio, this imperative is reflected in a set of design choices that maximize software reuse and minimize development and maintenance effort.

Portability

Vanu Software Radio achieves much better software portability than other SDRs, especially when the high-speed signal processing software is considered. Most of the high-speed software is written in portable high-level code (C and C++). This is supported by selecting processing engines for which there are compilers that can produce highly efficient code. General-purpose CPUs have the best compilers, while some DSPs support acceptably good ones. Other DSPs require hand-tuning of assembly code to achieve good performance, and are thus less desirable. Similarly, current FPGA and reconfigurable hardware tool chains can only produce efficient output if given a tool chain-specific restricted form of source code. The Vanu Software Radio philosophy is to use the latter processing engines to the minimum extent needed to meet customer requirements, while keeping the bulk of the processing on an engine that can efficiently execute the portable version of the code. For the same reasons, Vanu Software Radio systems use off-the-shelf operating systems and rely on standard OS APIs to the greatest extent possible.

Component Reuse

Vanu Software Radio software uses highly standardized internal interfaces and a custom-developed middleware package to ensure that processing components can be reused across families of related waveforms. Component reuse is not a perfect strategy. Some software components are widely used and well-defined, but too slow if implemented with a reusable component. Examples include Fourier transforms and FIR filters, for which the code needs to be specialized both to the platform and to the particular variant of the task being performed. In cases like this, Vanu, Inc. develops and exploits tools that automatically generate the efficient implementation for a given task on a given platform.

Generic Hardware Architecture

Vanu Software Radio systems follow a generic hardware architecture. Many other SDR systems use a different approach, for example having one hardware component specialized for spreading, another for coding, and another for baseband processing. Even if the individual components are software-defined, use of a specialized architecture strongly limits what waveforms can be executed on the platform, even if the available processing cycles are sufficient.