DAB-DMB-DVB Viterbi Decoder IP Core (DAB-DVB-VD01)
The IP core is a customization for combined DAB/DMB & DVB convolutional FEC applications,
sharing the same Add-Compare-Select module, for both coding rates. The Toolbox can generate the Verilog RTL code
and the testbench for the choosen configuration (note: the soft decisions are available only for QPSK modulation; BPSK, M-QAM can used as well).
The simulation can use different channel models: AWGN,
ISI (raised cosine) and flat fading (Rayleigh or Rician pdf).
For decoding the 4-pointers trace-back method is implemented
and the survivor memory length is parameterizable, according with performance required.
A good performance is given by the merge memory length which is half of the total survivor memory.
The decoding latency is four times reduced by using the 4-pointer decoding scheme.
In the Add-Select-Compare Unit the normalization for the accumulated path metrics can be used.
The trace-back process is controlled by Finite State Machines. The packet length (in bits) is an input to the core.
The input soft decisions can be 3,4,5 or 6 bits wide.
Full parameterization is also available.
Below are the test results for AWGN and flat fading Rayleigh channels.
Decoding method: Trace-back
Coding rates: 1/2 (DVB) & 1/4 (DAB/DMB)
4-pointer trace-back decoding method for lower latencies