PolynomialInterleaver.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

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# *   Copyright (C) 2016 Mobilinkd LLC (rob@mobilinkd.com)                  *
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class PolynomialInterleaver(object):
    """Polynomial bit interleaver.  Default to 80.
    
    Valid LTE polynomials can be found here:
    https://github.com/supermihi/lpdec/blob/master/lpdec/codes/interleaver.py#L264
    """
    
    def __init__(self, f1 = 11, f2 = 20, k = 80):
        
        self.f1 = f1
        self.f2 = f2
        self.K = k
    
    def index(self, i):
        
        return ((self.f1 * i) + (self.f2 * i * i)) % self.K
    
    def interleave(self, data):

        result = np.zeros(self.K, dtype = data.dtype)
        for i in range(len(data)):
            result[self.index(i)] = data[i]
        return result
    
    def deinterleave(self, data):

        result = np.zeros(len(data), dtype = data.dtype)
        for i in range(len(data)):
            if i == self.K: break
            result[i] = data[self.index(i)]
        return result