Figure shows a 240-QAM signal constellation, which may be viewed as an extended form of QAM cross constellation.

(a) Identify the portion of Figure that is a QAM square constellation,.

(b) Build on part (a) to identify the portion of Figure that is a QAM cross cons te11ato n.

(c) Hence, identify the portion of Figure that is an extension to QAM crossconstellation.

-3 1 5 13 17 21 25 29 33 -39 -35 -31 -27 -23 -19 -15 -11 -7 37 (Im) 236 224 216 212 218 228 37 37 33E 33 234 205 185 173 164 162 170 181 197 220 29 - 29 179 207 226 193 165 146 133 123 121 125 137 154 25E 25 92 100 117 140 172 208 229 189 156 131 110 96 87 33 21 21 112 141 180 221 90 54 62 71 201 160 126 98 79 64 58 17 17 118 155 198 91 41 31 37 48 65 222 177 135 102 77 55 35 13 13 72 101 138 182 230 49 17 15 20 30 203 158 119 84 50 39 24 93 127 171 219 21 38 63 28 13 4 194 148 108 75 50 56 85 122 163 213 16 32 22 43 238 186 142 103 69 124 166 217 (Re) 36 59 88 25 11 18 73 45 190 144 106 -3 -3 66 97 134 174 225 14 26 42 52 33 19 12 10 199 152 113 80 H-7 -7 111 147 187 237 81 23 40 57 67 47 34 27 29 210 167 128 94 -11 -11 78 99 132 168 209 51 61 232 183 149 115 89 68 53 46 44 -15 -15 E 129 157 195 235 74 70 76 86 104 214 175 139 116 95 82 -19 -19 161 191 227 114 107 105 109 120 136 205 176 150 130 -23 -23 202 231 159 178 215 184 169 153 145 |143 151 -27 -27 233 211 200 192 188 196 204 223 -31 -31 239 -35 -35 33 37 13 17 21 25 29 -3 -39 -35 -31 -27 -23 -19 -15 -1l -7