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Talk:Binary symmetric channel

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The converse can be shown by a sphere packing argument. Given a codeword, there are roughly 2n H(p) typical output sequences. There are 2n total possible outputs, and the input chooses from a codebook of size 2nR. Therefore, the receiver would choose to partition the space into "spheres" with 2n /
373:-- What is the definition of the variable R? How do we deduce it has size 2nR, or is this a hypothesis? What is a codebook? A list of possible encodings of one desired message? That sounds like only one entry, a tiny fraction of the whole codebook. 357:-- What is a codeword in this context? A binary sequence of length n? What does a "typical output sequence" mean? A possible damaged version of the original sequence? Then why not 2^n? 265: 556: 140: 130: 284: 216: 197: 418:
I've attempted to clarify the (previously incoherent) statement of this theorem to something plausible, but it still has the following defect: δ is not quantified.
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1 − H(p), then the spheres will be packed too tightly asymptotically and the receiver will not be able to identify the correct codeword with vanishing probability.
489: 485: 471: 178: 106: 551: 97: 58: 419: 382: 289: 365:-- What is the difference between an "output" and an "output sequence"? I suppose they can't be the same since there's a factor of H(p). 457: 467:
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I rewrote the capacity section and used a proof which is as far as a know well known. Further improvements or feedback is welcome.
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the receiver will not be able to identify the correct codeword with vanishing probability
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The capacity of the channel is 1 − H(p), where H(p) is the binary entropy function.
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Given a codeword, there are roughly 2n H(p) typical output sequences.
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for additional information. I made the following changes:
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445: 272: 223: 204: 185: 166: 101:, a collaborative effort to improve the coverage of 484:using the archive tool instructions below. Editors 323:2nR = 2n(1 − R) potential outputs each. If R : --> 278: 259: 210: 191: 172: 470:This message was posted before February 2018. 370:the input chooses from a codebook of size 2nR 8: 273: 205: 381:-- I think there's a double negative here. 557:Mid-importance Telecommunications articles 440:I have just modified one external link on 47: 271: 222: 203: 184: 165: 115:Knowledge:WikiProject Telecommunications 118:Template:WikiProject Telecommunications 49: 19: 414:Statement of Theorem 1 was incoherent 7: 95:This article is within the scope of 552:C-Class Telecommunications articles 362:There are 2n total possible outputs 260:{\displaystyle (1-H(p+\epsilon )n)} 38:It is of interest to the following 14: 444:. Please take a moment to review 303:Unclear proof in "Capacity of BSC 82: 72: 51: 20: 135:This article has been rated as 408:13:21, 22 September 2017 (UTC) 254: 248: 236: 224: 98:WikiProject Telecommunications 1: 428:14:40, 20 November 2014 (UTC) 391:14:43, 20 November 2014 (UTC) 345:-packing argument, since the 109:and see a list of open tasks. 349:of the pieces is not used. 288:Is that last ')' misplaced? 298:15:08, 2 January 2010 (UTC) 121:Telecommunications articles 573: 501:(last update: 5 June 2024) 437:Hello fellow Wikipedians, 141:project's importance scale 538:15:44, 20 July 2017 (UTC) 134: 67: 46: 442:Binary symmetric channel 279:{\displaystyle \rfloor } 211:{\displaystyle \lfloor } 90:Telecommunication portal 433:External links modified 338:sphere packing argument 280: 261: 212: 193: 174: 28:This article is rated 281: 262: 213: 194: 192:{\displaystyle \leq } 175: 482:regular verification 270: 221: 202: 183: 164: 472:After February 2018 526:InternetArchiveBot 477:InternetArchiveBot 276: 257: 208: 189: 170: 112:Telecommunications 103:Telecommunications 59:Telecommunications 34:content assessment 502: 173:{\displaystyle k} 155: 154: 151: 150: 147: 146: 564: 536: 527: 500: 499: 478: 285: 283: 282: 277: 266: 264: 263: 258: 217: 215: 214: 209: 198: 196: 195: 190: 179: 177: 176: 171: 123: 122: 119: 116: 113: 92: 87: 86: 85: 76: 69: 68: 63: 55: 48: 31: 25: 24: 16: 572: 571: 567: 566: 565: 563: 562: 561: 542: 541: 530: 525: 493: 486:have permission 476: 450:this simple FaQ 435: 416: 341:-- It is not a 312:Capacity of BSC 309: 306: 268: 267: 219: 218: 200: 199: 181: 180: 162: 161: 159: 120: 117: 114: 111: 110: 88: 83: 81: 61: 32:on Knowledge's 29: 12: 11: 5: 570: 568: 560: 559: 554: 544: 543: 520: 519: 512: 465: 464: 456:Added archive 434: 431: 420:178.38.132.253 415: 412: 411: 410: 397: 383:178.38.132.253 308: 304: 301: 290:68.239.116.212 275: 256: 253: 250: 247: 244: 241: 238: 235: 232: 229: 226: 207: 188: 169: 158: 156: 153: 152: 149: 148: 145: 144: 137:Mid-importance 133: 127: 126: 124: 107:the discussion 94: 93: 77: 65: 64: 62:Mid‑importance 56: 44: 43: 37: 26: 13: 10: 9: 6: 4: 3: 2: 569: 558: 555: 553: 550: 549: 547: 540: 539: 534: 529: 528: 517: 513: 510: 506: 505: 504: 497: 491: 487: 483: 479: 473: 468: 463: 459: 455: 454: 453: 451: 447: 443: 438: 432: 430: 429: 425: 421: 413: 409: 405: 401: 398: 395: 394: 393: 392: 388: 384: 380: 379: 374: 372: 371: 366: 364: 363: 358: 356: 355: 350: 348: 344: 340: 339: 334: 332: 331: 326: 325: 319: 318: 314: 313: 302: 300: 299: 295: 291: 286: 251: 245: 242: 239: 233: 230: 227: 186: 167: 157: 142: 138: 132: 129: 128: 125: 108: 104: 100: 99: 91: 80: 78: 75: 71: 70: 66: 60: 57: 54: 50: 45: 41: 35: 27: 23: 18: 17: 524: 521: 496:source check 475: 469: 466: 439: 436: 417: 377: 376: 375: 369: 368: 367: 361: 360: 359: 353: 352: 351: 346: 342: 337: 336: 335: 329: 328: 327: 321: 320: 316: 315: 311: 310: 287: 160: 136: 96: 40:WikiProjects 546:Categories 533:Report bug 516:this tool 509:this tool 307:" section 522:Cheers.— 347:geometry 330:Converse 446:my edit 139:on the 30:C-class 343:sphere 36:scale. 400:BBC89 424:talk 404:talk 387:talk 294:talk 490:RfC 460:to 131:Mid 548:: 503:. 498:}} 494:{{ 426:) 406:) 389:) 296:) 274:⌋ 246:ϵ 231:− 206:⌊ 187:≤ 535:) 531:( 518:. 511:. 422:( 402:( 385:( 305:p 292:( 255:) 252:n 249:) 243:+ 240:p 237:( 234:H 228:1 225:( 168:k 143:. 42::

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178.38.132.253
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14:40, 20 November 2014 (UTC)
Binary symmetric channel
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this simple FaQ
https://web.archive.org/web/20160217105359/http://www.inference.phy.cam.ac.uk/mackay/itila/book.html
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After February 2018

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