# Copyright (c) IMToolkit Development Team
# This toolkit is released under the MIT License, see LICENSE.txt
import numpy as np
from .Modulator import Modulator
[docs]class ADSMCode(object):
"""Algebraic differential spatial modulation (ADSM), which was firstly proposed in [1] and was later extended in [2].
- [1] R. Rajashekar, N. Ishikawa, S. Sugiura, K. V. S. Hari, and L. Hanzo, ``Full-diversity dispersion matrices from algebraic field extensions for differential spatial modulation,'' IEEE Trans. Veh. Technol., vol. 66, no. 1, pp. 385--394, 2017.
- [2] R. Rajashekar, C. Xu, N. Ishikawa, S. Sugiura, K. V. S. Hari, and L. Hanzo, ``Algebraic differential spatial modulation is capable of approaching the performance of its coherent counterpart,'' IEEE Trans. Commun., vol. 65, no. 10, pp. 4260--4273, 2017.
"""
def __init__(self, M, modtype, L):
"""
Args:
M (int): the number of transmit antennas.
modtype (string): the constellation type.
L (int): the constellation size.
"""
self.M = M
self.Nc = M * L
self.B = np.log2(self.Nc)
symbols = Modulator(modtype, L).symbols
u_phase = 2.0 * np.pi / L
A = np.zeros((M, M), dtype=np.complex)
A[0, M-1] = np.exp(1j * u_phase)
for m in range(M-1):
A[(m+1)%M, m] = 1
As = np.zeros((M, M, M), dtype=np.complex) # M \times M \times M
for m in range(M):
As[m] = np.linalg.matrix_power(A, m)
#print(As)
codestensor = np.kron(symbols, As) # M \times M \times M * L (=Nc)
self.codes = np.array(np.hsplit(np.hstack(codestensor), self.Nc)) # Nc \times M \times M
[docs] def putRate(self):
print("B / M = %d / %d = %d [bit/symbol]" % (self.B, self.M, self.B / self.M))
