Re: [Discuss-gnuradio] Best Resample Method For Resampling LTE Data

[Tom Tsou]

Hi Paul,

On Sun, Nov 30, 2014 at 6:52 PM, Paul Creaser <address@hidden> wrote:
> I'm currently using the Rational Resampler in GUNURADIO to resample LTE
> data, for example from 30.72MHz to 15.36MHz and 50MHz to 15.36MHz. I`m able
> to decode the data, so every thing seems to be well.
>
> I chose the Rational Resampler, simply because it is easy to use. However I
> noticed, GNURADIO has a number of resample modules, Fractional Resampler,
> Polyphase Arbitrary Resampler etc... I'm guessing each resampler has it`s
> strengths and weaknesses. Perhaps one is better for audio, another is better
> for LTE data etc..

In your specific use case, rational/fractional and arbitrary
resamplers are mathematically equivalent since the 'arbitrary' portion
doesn't apply. For example, rather than rational 2-to-1 downsampling
in your example, an arbitrary rate conversion would handle something
like 2-to-Pi. A more realistic use case for arbitrary resampling is
symbol timing loops where the output sample rate is not fixed, but
continuously drifting over time.

That said, despite similarities in math, there may be implementation
differences between the blocks that you mention. So one or another
might be newer, better optimized, or just easier to use. Tom Rondeau
can more easily explain those differences if they exist.

  -TT