- 2071 Chaitra · 2+4 marks
Dataword vs codeword; error coding techniques
Short answer
A dataword is the k-bit original message; a codeword is the n-bit encoded block with n−k redundant bits, e.g., 1011 → 1011100 in (7,4) Hamming code. Key error techniques: parity (UART), checksum (IP), CRC (Ethernet), Hamming (ECC RAM), Reed-Solomon (CD/DVD), convolutional (GSM), Turbo/LDPC (4G/5G).
Define Dataword and Codeword with suitable example. List the error detection and correction coding techniques with their application case.
Dataword and codeword
- Dataword: the original block of k message bits before encoding.
- Codeword: the n-bit block (n > k) produced by the encoder, containing the dataword plus n − k redundant bits.
Example: in a (7,4) Hamming code, the dataword 1011 becomes the codeword 1011100. In a simple even-parity code, dataword 1011 becomes codeword 10111 (parity bit 1).
Error detection and correction techniques and applications
| Technique | Capability | Application |
|---|---|---|
| Parity check (simple, 2D) | Detects odd errors (2D can correct one) | UART serial links, memory |
| Checksum | Detects errors | IP, TCP, UDP headers |
| CRC | Detects burst errors | Ethernet, HDLC, USB, Wi-Fi |
| Hamming code | Corrects 1 bit | ECC memory (RAM) |
| Reed-Solomon | Corrects burst errors | CD/DVD, QR codes, satellite |
| Convolutional code (Viterbi) | Corrects random errors | GSM, deep-space, Wi-Fi |
| Turbo / LDPC | Near Shannon limit | 3G/4G/5G, DVB-S2 |
| ARQ (retransmission) | Detect + resend | TCP, data link layer |
✓ Answer checked by Claude Sonnet 5.5
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