Merge pull request #18 from YairMZ/bp_decoder

Refactored WiFi spec out of encoder package. Added a WiFi decoder based on spec.

Author: YairMZ

README.md

@@ -37,7 +37,8 @@ simulations.
 import numpy as np
 from bitstring import BitArray, Bits
 from ldpc.decoder import LogSpaDecoder, bsc_llr
-from ldpc.encoder import EncoderWiFi, WiFiSpecCode
+from ldpc.encoder import EncoderWiFi
+from ldpc.wifi_spec_codes import WiFiSpecCode
 from ldpc.utils import QCFile
 
 # create information bearing bits

examples/ieee802_11_example.py

@@ -1,7 +1,8 @@
 import numpy as np
 from bitstring import BitArray, Bits
-from ldpc.decoder import LogSpaDecoder, bsc_llr
-from ldpc.encoder import EncoderWiFi, WiFiSpecCode
+from ldpc.decoder import DecoderWiFi, bsc_llr
+from ldpc.encoder import EncoderWiFi
+from ldpc.wifi_spec_codes import WiFiSpecCode
 from ldpc.utils import QCFile
 
 # create information bearing bits
@@ -19,7 +20,7 @@
 # create a decoder which assumes a probability of p=0.05 for bit flips by the channel
 # allow up to 20 iterations for the bp decoder.
 p = 0.05
-decoder = LogSpaDecoder(bsc_llr(p=p), h=h, max_iter=20, info_idx=np.array([True]*324 + [False]*324))
+decoder = DecoderWiFi(bsc_llr(p=p), spec=WiFiSpecCode.N648_R12, max_iter=20, info_idx=np.array([True]*324 + [False]*324))
 
 # create a corrupted version of encoded codeword with error rate p
 corrupted = BitArray(encoded)

ldpc/__init__.py

@@ -1,2 +1,3 @@
 from ldpc.base_code import CodeStructure
-__all__: list[str] = ["CodeStructure"]
+from ldpc.wifi_spec_codes import WiFiSpecCode
+__all__: list[str] = ["CodeStructure", "WiFiSpecCode"]

ldpc/decoder/__init__.py

@@ -1,4 +1,5 @@
 from ldpc.decoder.log_spa_decoder import LogSpaDecoder, InfoBitsNotSpecified
 from ldpc.decoder.channel_models import bsc_llr
+from ldpc.decoder.ieee802_11_decoder import DecoderWiFi
 
-__all__: list[str] = ["LogSpaDecoder", "bsc_llr", "InfoBitsNotSpecified"]
+__all__: list[str] = ["LogSpaDecoder", "bsc_llr", "InfoBitsNotSpecified", "DecoderWiFi"]

ldpc/decoder/ieee802_11_decoder.py

@@ -0,0 +1,27 @@
+from ldpc.decoder.log_spa_decoder import *
+from numpy.typing import NDArray
+import numpy as np
+from ldpc.decoder.channel_models import ChannelModel
+from typing import Optional
+from ldpc.wifi_spec_codes import WiFiSpecCode
+import os
+from ldpc.utils.qc_format import QCFile
+
+
+class DecoderWiFi(LogSpaDecoder):
+    """Decode messages according to the codes in the IEEE802.11n standard using Log SPA decoder"""
+    _spec_base_path: str = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'code_specs', 'ieee802.11')
+
+    def __init__(self, channel_model: ChannelModel, spec: WiFiSpecCode, max_iter: int,
+                 info_idx: Optional[NDArray[np.bool_]] = None):
+        """
+
+        :param channel_model: a callable which receives a channel input, and returns the channel llr
+        :param spec: specify which code from the spec we use
+        :param max_iter: The maximal number of iterations for belief propagation algorithm
+        :param info_idx: a boolean array representing the indices of information bits in the code
+        """
+        self.spec = spec
+        qc_file = QCFile.from_file(os.path.join(self._spec_base_path, spec.name + ".qc"))
+        h = qc_file.to_array()
+        super().__init__(channel_model, h, max_iter, info_idx)

ldpc/encoder/__init__.py

@@ -1,4 +1,4 @@
 from ldpc.encoder.base_encoder import Encoder
 from ldpc.encoder.generator_based_encoder import EncoderG
-from ldpc.encoder.ieee802_11_encoder import WiFiSpecCode, EncoderWiFi
-__all__: list[str] = ["Encoder", "EncoderG", "WiFiSpecCode", "EncoderWiFi"]
+from ldpc.encoder.ieee802_11_encoder import EncoderWiFi
+__all__: list[str] = ["Encoder", "EncoderG", "EncoderWiFi"]

ldpc/encoder/ieee802_11_encoder.py

@@ -1,39 +1,23 @@
-from enum import Enum, auto
 from ldpc.encoder.base_encoder import Encoder
 import numpy as np
 from bitstring import Bits
 from ldpc.utils.custom_exceptions import IncorrectLength
 from ldpc.utils.qc_format import QCFile
 import os
 from numpy.typing import NDArray
-
-
-class WiFiSpecCode(Enum):
-    """Enumerate models"""
-    N648_R12 = auto()
-    N648_R23 = auto()
-    N648_R34 = auto()
-    N648_R56 = auto()
-    N1296_R12 = auto()
-    N1296_R23 = auto()
-    N1296_R34 = auto()
-    N1296_R56 = auto()
-    N1944_R12 = auto()
-    N1944_R23 = auto()
-    N1944_R34 = auto()
-    N1944_R56 = auto()
+from ldpc.wifi_spec_codes import WiFiSpecCode
 
 
 class EncoderWiFi(Encoder):
     """Encode messages according to the codes in the IEEE802.11n standard"""
-    spec_base_path: str = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'code_specs', 'ieee802.11')
+    _spec_base_path: str = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'code_specs', 'ieee802.11')
 
     def __init__(self, spec: WiFiSpecCode) -> None:
         """
         :param spec: specify which code from the spec we use
         """
         self.spec = spec
-        qc_file = QCFile.from_file(os.path.join(self.spec_base_path, spec.name + ".qc"))
+        qc_file = QCFile.from_file(os.path.join(self._spec_base_path, spec.name + ".qc"))
         self.h = qc_file.to_array()
         self.m, n = self.h.shape
         k = n - self.m

ldpc/wifi_spec_codes.py

@@ -0,0 +1,17 @@
+from enum import Enum, auto
+
+
+class WiFiSpecCode(Enum):
+    """Enumerate codes"""
+    N648_R12 = auto()
+    N648_R23 = auto()
+    N648_R34 = auto()
+    N648_R56 = auto()
+    N1296_R12 = auto()
+    N1296_R23 = auto()
+    N1296_R34 = auto()
+    N1296_R56 = auto()
+    N1944_R12 = auto()
+    N1944_R23 = auto()
+    N1944_R34 = auto()
+    N1944_R56 = auto()

tests/test_ieee802_11.py

@@ -1,6 +1,7 @@
 import numpy as np
 from bitstring import Bits, BitArray
-from ldpc.encoder import WiFiSpecCode, EncoderWiFi
+from ldpc.encoder import EncoderWiFi
+from ldpc.wifi_spec_codes import WiFiSpecCode
 import pytest
 from ldpc.utils import IncorrectLength, QCFile
 from ldpc.decoder import LogSpaDecoder, bsc_llr, InfoBitsNotSpecified