aether-primitives - a rusty software-defined radio toolbox

What is aether?

Aether is designed to ease development of SDR applications by providing convenient (low-level) building blocks for common SDR signal processing operations.

Design Decisions

• Should come with batteries included, but should not get in the way
• Modular
  • Convenience Traits should be implementable for your own objects
  • Feature gating of non-essential components (i.e. swap out the FFT impl by implementing a trait)
• The base versions will be written in idiomatic rust
• Optimisations and unsafe speedups will be hidden behind feature flags

Examples

Core operations are implemented in the form of the VecOps trait implemented for Vecs/Slices of the C compatible num::Complex (cf32 for short).

// #[macro_use] // includes the assert_evm macro
// extern crate aether_primitives;
// use aether_primitives::{cf32, vecops::VecOps};
// The main sample type is cf32 which is a type alias for num::Complex<f32>
let mut v = vec![cf32::new(2.0, 2.0); 100];
let twos = v.clone();
let ones = vec![cf32::new(1.0, 1.0); 100];

let correct = vec![cf32::new(1.0, -1.0); 100];

v.vec_div(&twos)
    .vec_mul(&twos)
    .vec_zero() // zero the vector
    .vec_add(&ones)
    .vec_sub(&twos)
    .vec_clone(&ones)
    .vec_mutate(|c| c.im = -1.0) 
    .vec_conj()
    .vec_mirror(); // mirror swaps elements around the midpoint of the array

/// ensure each element's error vector magnitude vs the correct vector is below -80dB
assert_evm!(&v, &correct, -80.0); 

Implemented functionality

• Macros:

  • assert_evm!: check if elements of both vectors have a certain error vector magnitude relative to each other (given in dBm)

• Vecops: Helpers for operations of vectors/slices of cf32

  • Element wise operations: add, subtract, divide, multiply, complex conjugate, mutate . Mirror: Swap elements around mid of vector (for even length vectros)
  • Zero entire vector, copy elements over from another vector
  • FEATURE: Perform (i)FFTs using new or existing fourier transform instance (enabled via fft_chfft)

• Sequence: Helpers for binary pseudo-random sequence generation (esp. M-Sequences)

  • expand: Expand a seed value into an initialisation vector for a Pseudo-random sequence
  • generate: Generate a pseudo random sequence

• Sampling

  • linear interpolation
  • even downsampling

• Modulation

  • Generic BPSK and QPSK modulation
  • Hard Demodulator

• Pool

  • Generic, thread-safe object pool

• FFT: DEFAULT FEATURE fft_rustfft

  • perform fast fourier transforms (forward/backward) on slices/vecs of cf32 with different scaling factors
  • Supported fft implementations: chfft

• File

  • binary file writing and reading for arbitrary structs
  • csv file writing and reading for arbitrary structs

• Noise

  • AWGN generator

• Pipeline

  • Multithreaded processing pipelines

• Plot: FEATURE plot; requires an installed version of gnuplot

  • Constellation diagram
  • Time sequence plot
  • Comparison plot of two sequences
  • Waterfall plot with a given fft size (requires fft_chfft)

• Utils

  • Conversion from and to dB

• Benches: benchmarks for most operations in aether using criterion.rs framework

  • downsampling, interpolation, fft

TODO

• Add vec_align! macro to create vecs aligned for SIMD instructions
• Ungrowable Vecs
  • maybe derefs to slice for convenience
• Add VecStats (f32,cf32)
  • Min(index),Max(index),Mean(index),Power
• Add VecOps Features
  • Feature: use faster once it works on stable again
  • Add tests to ensure generated code is correctly aligned - should be ensured since cf32 (2x4 bytes) is 8 bytes. VOLK prefers 32byte alignment /libfftw prefers 16 byte alignment
• Add Correlation by Freq. Domain Convolution
• Add FIR

License

Mozilla Public License 2.0