RF for Data Transmit and Receicve for Beginners
A possible combination is a copy of Digital Communications by Proakis &amp; Salehi along with GNU Radio.

With SDR, you actually create / process the signals that carry your data over the RF medium.

Therefore, to an extent, "freshman level theory" is all you are stuck with if you have to write an end-to-end SDR system.

But, you could keep the book (or, a book) as a reference for points you don't understand when going through something like GNU Radio's PSK Demodulation resources for example.

I am not sure what your expectation is from SDR, but taking the comment (about SS7) as a starting point, it's not like the SDR has an API which you use to simply "send data". Although, I am sure that you could add that layer too once you have your basic DSP dataflow set up.

The beauty of SDR is that you take full control of every building block from transmission to reception. So, there is nothing stopping you from writing a Phase Locked Loop (which you are going to need) from first principles or use one of the existing ones (or here). 

But you still have to have some awareness of what is the "loop bandwidth" for example, in the case of the PLL.

Hope this helps