EMANE  1.2.1
collisiontable.cc
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33 
34 
35 #include "collisiontable.h"
36 
37 namespace {
38  const int NUM_NBRS{60};
39 
40  const float v1024[NUM_NBRS] = { 0.0, 0.0, 0.4, 0.9, 0.6, 0.9, 2.0, 3.1, 3.5, 3.9, \
41  5.1, 5.4, 8.6, 8.1, 9.8, 10.7, 11.4, 12.9, 14.5, 17.6, \
42  18.4, 20.0, 23.5, 26.0, 27.2, 28.3, 29.3, 30.9, 31.2, 34.9, \
43  38.9, 39.2, 41.1, 42.2, 43.8, 46.2, 48.0, 49.6, 51.4, 53.8, \
44  56.4, 58.0, 59.9, 60.3, 63.0, 64.0, 65.5, 66.0, 70.2, 72.0, \
45  72.5, 75.0, 77.5, 80.0, 85.0, 87.5, 90.0, 92.5, 95.0, 100.0 };
46 
47 
48  const float v512[NUM_NBRS] = { 0.0, 0.0, 0.6, 0.9, 1.9, 3.8, 4.2, 5.6, 7.2, 7.5, \
49  9.6, 12.0, 16.0, 18.6, 20.6, 22.4, 23.4, 27.5, 28.2, 30.1, \
50  33.9, 36.9, 40.8, 41.2, 44.6, 51.1, 49.6, 54.5, 56.4, 57.9, \
51  59.6, 62.7, 64.0, 68.0, 69.0, 71.3, 72.8, 74.2, 75.0, 79.6, \
52  82.1, 83.0, 83.4, 85.1, 86.7, 87.9, 89.1, 89.7, 91.5, 92.0, \
53  98.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
54 
55 
56  const float v256[NUM_NBRS] = { 0.0, 0.2, 0.8, 3.1, 4.4, 5.1, 6.7, 9.7, 12.7, 15.4, \
57  20.2, 21.6, 26.3, 31.7, 33.2, 39.3, 40.8, 44.5, 47.6, 54.1, \
58  56.6, 59.9, 63.7, 67.5, 68.3, 74.2, 76.2, 76.8, 81.1, 83.1, \
59  86.3, 86.3, 86.4, 89.7, 91.4, 91.8, 93.3, 94.2, 96.2, 97.1, \
60  98.0, 99.3, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
61  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
62 
63 
64  const float v128[NUM_NBRS] = { 0.0, 0.8, 2.8, 4.3, 8.2, 10.6, 16.6, 19.6, 22.9, 28.2, \
65  38.4, 39.8, 48.0, 51.0, 57.2, 64.3, 67.1, 71.4, 76.3, 77.8, \
66  84.2, 85.6, 89.2, 89.5, 90.9, 94.2, 94.5, 95.7, 96.2, 97.6, \
67  98.9, 99.3, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
68  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
69  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
70 
71 
72  const float v64[NUM_NBRS] = { 0.0, 0.9, 5.5, 9.5, 15.2, 21.5, 28.5, 34.9, 44.7, 49.4, \
73  60.6, 69.9, 72.1, 80.3, 83.3, 87.7, 90.0, 93.1, 94.6, 95.7, \
74  97.5, 98.4, 98.7, 99.0, 99.3, 99.6, 99.7, 100.0, 100.0, 100.0, \
75  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
76  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
77  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
78 
79 
80  const float v32[NUM_NBRS] = { 0.0, 3.5, 9.5, 18.2, 27.5, 39.3, 50.6, 61.2, 71.8, 76.2, \
81  84.3, 88.9, 94.3, 96.6, 97.7, 99.0, 100.0, 100.0, 100.0, 100.0, \
82  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
83  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
84  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
85  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
86 
87 
88  const float v16[NUM_NBRS] = { 0.0, 5.8, 18.2, 32.6, 49.8, 64.8, 76.9, 86.8, 93.2, 96.1, \
89  99.0, 99.6, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
90  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
91  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
92  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
93  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
94 
95 
96  const float v8[NUM_NBRS] = { 0.0, 14.0, 32.0, 59.5, 78.5, 88.8, 95.8, 98.0, 100.0, 100.0, \
97  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
98  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
99  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
100  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
101  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
102 
103 
104  const float v4[NUM_NBRS] = { 0.0, 25.0, 62.5, 90.6, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
105  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
106  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
107  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
108  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
109  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
110 
111 
112  const float v2[NUM_NBRS] = { 0.0, 50.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0,
113  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
114  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
115  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
116  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
117  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
118 
119 
120  const float v1[NUM_NBRS] = { 0.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0,
121  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
122  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
123  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
124  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, \
125  100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0, 100.0 };
126 
127 
128  const int NUM_CW {11};
129 
130  const float *TABLE[NUM_CW] = { v1, v2, v4, v8, v16, v32, v64, v128, v256, v512, v1024 };
131 }
132 
133 
134 EMANE::Models::IEEE80211ABG::CollisionTable::CollisionTable()
135 { }
136 
137 
138 
139 float
140 EMANE::Models::IEEE80211ABG::CollisionTable::getCollisionFactor(int num, int cw)
141 {
142  // check num nbrs
143  if(num == 0)
144  {
145  // no nbrs return 0
146  return 0.0f;
147  }
148  else if(num > NUM_NBRS)
149  {
150  // too many nbrs return 100
151  return 100.0f;
152  }
153 
154 
155  // cap min contention window
156  if(cw < 1)
157  {
158  cw = 1;
159  }
160 
161  // cap max contention window
162  if(cw > 1024)
163  {
164  cw = 1024;
165  }
166 
167  // start at table 1
168  int tbl{1};
169 
170  // check table from lowest to highest
171  for(int i = 0; i < NUM_CW; ++i, tbl *= 2)
172  {
173  // cw is at or below this tbl
174  if(cw <= tbl)
175  {
176  // exact match, always true for cw 1 and 2
177  if(cw == tbl)
178  {
179  // use this tbl
180  return TABLE[i][num - 1];
181  }
182  // possbile for cw > 2
183  else
184  {
185  // interpolate from previous tbl to this tbl, where i always >= 1
186  return interpolate(tbl / 2, tbl, TABLE[i - 1][num - 1], TABLE[i][num - 1], cw);
187  }
188  }
189  }
190 
191  // default
192  return 0.0;
193 }
194 
195 
196 
197 float
198 EMANE::Models::IEEE80211ABG::CollisionTable::interpolate(float x0, float x1, float y0, float y1, float x)
199 {
200  const float deltaX{x1 - x0};
201 
202  const float deltaY{y1 - y0};
203 
204  const float m{deltaX == 0.0f ? 0.0f : deltaY / deltaX};
205 
206  return y0 + (x - x0) * m;
207 }