A package for polar codes in Python.
Project description
Polar Codes in Python
A library written in Python3 for Polar Codes, a capacity-achieving channel coding technique used in 5G. The library includes functions for construction, encoding, decoding, and simulation of polar codes. In addition, it supports puncturing and shortening.
It provides:
- non-systemic encoder and Successive Cancellation Decoder (SCD) for polar codes.
- mothercode construction of polar codes using Bhattacharyya Bounds or Gaussian Approximation
- support for puncturing and shortening.
- Bit-Reversal Shortening (BRS), Wang-Liu Shortening (WLS), and Bioglio-Gabry-Land (BGL) shortening constructions.
- an AWGN channel with BPSK modulation.
Documentation:
A YouTube video with an introduction to polar codes, shortening, and the library:
Getting Started
- Install the package with
pip install py-polar-codes
. - Install matplotlib from https://mipatplotlib.org/users/installing.html.
- Install numpy from https://docs.scipy.org/doc/numpy/user/install.html.
- Run test.py using a Python3 compiler. If the program runs successfully, the library is ready to use. Make sure the compiler has writing access to directory "root/data", where simulation data will be saved by default.
- Run main.py to start the GUI.
Examples
Mothercode Encoding & Decoding
An example of encoding and decoding over an AWGN channel for a (256,100) mothercode, using Bhattacharyya Bounds and SCD.
import numpy as np
from polarcodes import *
# initialise polar code
myPC = PolarCode(256, 100)
myPC.construction_type = 'bb'
# mothercode construction
design_SNR = 5.0
Construct(myPC, design_SNR)
print(myPC, "\n\n")
# set message
my_message = np.random.randint(2, size=myPC.K)
myPC.set_message(my_message)
print("The message is:", my_message)
# encode message
Encode(myPC)
print("The coded message is:", myPC.x)
# transmit the codeword
AWGN(myPC, design_SNR)
print("The log-likelihoods are:", myPC.likelihoods)
# decode the received codeword
Decode(myPC)
print("The decoded message is:", myPC.message_received)
Shortened Code Construction
An example of constructing a shortened polar code with Bit-Reversal Shortening (BRS) algorithm.
import numpy as np
from polarcodes import *
# initialise shortened polar code
shorten_params = ('shorten', 'brs', None, None, False)
myPC = PolarCode(200, 100)
# construction
design_SNR = 5.0
Shorten(myPC, design_SNR)
print(myPC, "\n\n")
Simulation & Plotting
A script to simulate a defined polar code, save the data to a JSON file in directory "/data", and then display the result in a matplotlib figure.
# simulate polar code
myPC.simulate('data/pc_sim')
myPC.simulate(save_to='data/pc_sim', Eb_No_vec=np.arange(1,5), design_SNR=5.0, manual_const_flag=True)
# plot the frame error rate
myPC.plot(['pc_sim'], 'data/')
The simulation will save your Polar Code object in a JSON file, for example:
{
"N": 64,
"n": 6,
"K": 32,
"frozen": [
22,
38,
49,
26,
42,
3,
28,
50,
5,
44,
9,
52,
6,
17,
10,
33,
56,
18,
12,
34,
20,
36,
1,
24,
40,
48,
2,
4,
8,
16,
32,
0
],
"construction_type": "bb",
"punct_flag": false,
"punct_type": "",
"punct_set": [],
"source_set": [],
"punct_algorithm": "",
"update_frozen_flag": [],
"BER": [
0.09709375,
0.03740625,
0.00815625,
0.0010184612211221122
],
"FER": [
0.313,
0.126,
0.03,
0.004125412541254125
],
"SNR": [
1,
2,
3,
4
]
}
This is a final year project created by Brendon McBain under the supervision of Harish Vangala at Monash University.
Project details
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