Arq Today

Automatic Repeat Request (ARQ): Reliable Data Transmission 1. Introduction

ARQ is an indispensable tool for achieving reliable digital communication. While Stop-and-Wait is efficient for simple, low-delay networks, Go-Back-N and Selective Repeat are essential for modern high-speed networks. The hybrid approach (HARQ) offers the best balance of efficiency and reliability in modern wireless scenarios. Automatic Repeat Request (ARQ): Reliable Data Transmission 1

If the sender does not receive an ACK within a designated time (timeout) or receives a NAK, it retransmits the packet. 3. Types of ARQ Protocols 3.1. Stop-and-Wait ARQ The hybrid approach (HARQ) offers the best balance

) before needing an ACK. If a frame is lost, the receiver discards all subsequent frames, and the sender must retransmit all frames starting from the lost one. Better utilization than Stop-and-Wait. Cons: High retransmission overhead in poor channels. 3.3. Selective Repeat ARQ (SR) Types of ARQ Protocols 3

The receiver sends an ACK to confirm the successful receipt of a packet.

ARQ increases latency due to retransmissions, making it less suitable for real-time applications like VoIP.