mcbts: Add multi-ARFCN channelizing filters
Introduce polyphase channelizer (Rx) and synthesis (Tx) filterbanks,
which serve as the signal processing backend for multi-carrier GSM.
Fast Fourier Transform (FFT) is used internally. FFTW is added as
a new build dependency.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
diff --git a/Transceiver52M/ChannelizerBase.h b/Transceiver52M/ChannelizerBase.h
new file mode 100644
index 0000000..7da506b
--- /dev/null
+++ b/Transceiver52M/ChannelizerBase.h
@@ -0,0 +1,39 @@
+#ifndef _CHANNELIZER_BASE_H_
+#define _CHANNELIZER_BASE_H_
+
+class ChannelizerBase {
+protected:
+ ChannelizerBase(size_t m, size_t blockLen, size_t hLen);
+ ~ChannelizerBase();
+
+ /* Channelizer parameters */
+ size_t m;
+ size_t hLen;
+ size_t blockLen;
+
+ /* Channelizer filterbank sub-filters */
+ float **subFilters;
+
+ /* Input/Output buffers */
+ float **hInputs, **hOutputs, **hist;
+ float *fftInput, *fftOutput;
+
+ /* Pointer to opaque FFT instance */
+ struct fft_hdl *fftHandle;
+
+ /* Initializer internals */
+ bool initFilters();
+ bool initFFT();
+ void releaseFilters();
+
+ /* Map overlapped FFT and filter I/O buffers */
+ bool mapBuffers();
+
+ /* Buffer length validity checking */
+ bool checkLen(size_t innerLen, size_t outerLen);
+public:
+ /* Initilize channelizer/synthesis filter internals */
+ bool init();
+};
+
+#endif /* _CHANNELIZER_BASE_H_ */