From 1eeb46db05ce7734f77796cf0a3d99ccca21ca04 Mon Sep 17 00:00:00 2001
From: Chance <tarver.chance@gmail.com>
Date: Thu, 26 Sep 2019 09:37:44 -0500
Subject: [PATCH] Working on a MIMO simulator

---
 phypy/mimo/__init__.py  |  6 +++
 phypy/mimo/channels.py  |  0
 phypy/mimo/mimo.py      | 95 +++++++++++++++++++++++++++++++++++++++++
 phypy/mimo/precoders.py |  0
 requirements.txt        |  4 +-
 5 files changed, 104 insertions(+), 1 deletion(-)
 create mode 100644 phypy/mimo/__init__.py
 create mode 100644 phypy/mimo/channels.py
 create mode 100644 phypy/mimo/mimo.py
 create mode 100644 phypy/mimo/precoders.py

diff --git a/phypy/mimo/__init__.py b/phypy/mimo/__init__.py
new file mode 100644
index 0000000..5cad29c
--- /dev/null
+++ b/phypy/mimo/__init__.py
@@ -0,0 +1,6 @@
+# -*- coding: utf-8 -*-
+
+"""MIMO Module for PhyPy"""
+
+__author__ = """Chance Tarver"""
+__email__ = 'tarver.chance@gmail.com'
diff --git a/phypy/mimo/channels.py b/phypy/mimo/channels.py
new file mode 100644
index 0000000..e69de29
diff --git a/phypy/mimo/mimo.py b/phypy/mimo/mimo.py
new file mode 100644
index 0000000..a99d47d
--- /dev/null
+++ b/phypy/mimo/mimo.py
@@ -0,0 +1,95 @@
+import numpy as np
+import simpy
+
+
+class MimoTransmitter:
+    """ Class that represents an entire MIMO Transmitter Array. Includes channel and precoder."""
+
+    def __init__(self,
+                 n_antennas: int = 64,
+                 n_users: int = 4,
+                 precoder: str = 'zero_forcing',
+                 update_precoder_frequency: int = 7):
+        self.n_antennas = n_antennas
+        self.n_users = n_users
+        self.channel_matrix = None  # Will store the channel matrix when we get it.
+        self.precoder = ZeroForcing(self.channel_matrix, update_precoder_frequency)
+
+    def update_channel(self, channel):
+        """ The channel object exists in its own object. Periodically, our transmitter will get new CSI/channel.
+        This method updates the classes copy of the channel"""
+
+    def transmit(self, symbols):
+        pass
+
+
+class LinearPrecoder:
+    def __init__(self):
+        pass
+
+    def precode(self, symbols):
+        out = np.dot(self.precoding_matrix, symbols)
+        return out
+
+    def precode_update_process(self, env):
+        env.timeout(
+            0.001
+        )  # Small delay so that we always update based on a new channel
+        while True:
+            print(f'Current Symbol = {env.now}. Updating precoder')
+            self.create_precoder_matrix(self.precoding_matrix)
+            yield env.timeout(self.update_rate)
+
+
+class ZeroForcing(LinearPrecoder):
+    def __init__(self, channel_matrix, update_rate):
+        self.precoding_matrix = None  # Will be set by create_precoder_matrix method
+        self.create_precoder_matrix(channel_matrix)
+        self.update_rate = update_rate
+
+    def create_precoder_matrix(self, channel_matrix):
+        self.precoding_matrix = channel_matrix
+
+
+class MIMO_Channel:
+    def channel_update_process(self, env):
+        while True:
+            print(f'Current Symbol = {env.now}. Updating channel')
+            self.update_channel()
+            yield env.timeout(self.update_rate)
+
+
+class MimoAwgn(MIMO_Channel):
+    def __init__(self, n_users: int = 8, n_antennas: int = 64, n_subcarriers=1200, update_rate: int = 7):
+        self.n_users = n_users
+        self.n_antennas = n_antennas
+        self.n_subcarriers = n_subcarriers
+        self.update_rate = update_rate
+        self.matrix = 1
+
+    def update_channel(self):
+        new_channel = 0.9*old_channel + guassian
+        pass
+
+
+if __name__ == "__main__":
+    env = simpy.Environment()
+    update_channel_frequency = 1  # Every 2 symbols, make new  MIMO channel
+    update_precoder_frequency = 7
+    n_users = 4
+    n_antennas = 64
+    n_subcarriers = 1200
+    n_symbols = 64
+
+    channel = MimoAwgn(n_users=n_users, n_antennas=n_antennas, n_subcarriers=n_subcarriers)
+    tx = MimoTransmitter(n_users=n_users, n_antennas=n_antennas,
+                         update_precoder_frequency=update_precoder_frequency)
+    env.process(channel.channel_update_process(env))
+    env.process(tx.precoder.precode_update_process(env))
+    env.run(until=n_symbols)
+
+    print(tx.n_antennas)
+    print(tx.n_users)
+    print(tx.precoder)
+
+
diff --git a/phypy/mimo/precoders.py b/phypy/mimo/precoders.py
new file mode 100644
index 0000000..e69de29
diff --git a/requirements.txt b/requirements.txt
index 283f5d5..19b9d6f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,4 +9,6 @@ Sphinx==1.8.5
 twine==1.14.0
 Click==7.0
 pytest==4.6.5
-pytest-runner==5.1
\ No newline at end of file
+pytest-runner==5.1
+numpy
+simpy