Calculation the TX OP win chance among different WiFi AC traffics.

ac.py

import random
from collections import defaultdict

SIFS_2G = 10
SIFS_5G = 16
SLOT = 9

LABELS = ['DIFS', 'BE', 'BK', 'VI', 'VO']
AIFS = [2, 3, 7, 2, 2]
CW_min = [15, 15, 15, 7, 3]
CW_max = [1023, 1023, 1023, 15, 7]

SHORT_RETRY_LIMIT = 7

def aifs_2g(ac):
    return AIFS[ac] * SLOT + SIFS_2G

def aifs_5g(ac):
    return AIFS[ac] * SLOT + SIFS_5G

def aifs(ac, band):
    if ac == 0:  # DIFS
        return aifs_5g(ac)
    if band == 0:
        return aifs_2g(ac)
    if band == 1:
        return aifs_5g(ac)

def backoff_cnt(ac, cnt):
    cw = (1 << cnt) * (CW_min[ac] + 1) - 1
    cw = min(cw, CW_max[ac])
    t = random.randint(0, cw + 1)
    return t

stats = []

for cnt in range(SHORT_RETRY_LIMIT):
    stats.append(defaultdict(int))

def run(streams, band):
    for r in range(100000):
        for cnt in range(SHORT_RETRY_LIMIT):
            try_times = [backoff_cnt(ac, cnt) * SLOT + aifs(ac, band) for ac in streams]
            win_i = -1
            win_t = 1000000
            for i, t in enumerate(try_times):
                if t < win_t:
                    win_t = t
                    win_i = i
            stats[cnt][win_i] += 1

    for cnt, v in enumerate(stats):
        print(f'retry={cnt}')
        tot = 0
        for ac, win in v.items():
            tot += win
        for ac, win in v.items():
            print(f'\tac={LABELS[streams[ac]]}, {win=}, win_prob={win/tot:%}')

run([1,2,3,4], 0)
#run([0,1,2], 0)