The sender can transmit multiple frames (within a window size
Only the specific lost or corrupted frame is retransmitted, rather than the entire window. Pros: Highly efficient utilization of bandwidth.
Low throughput on links with high propagation delay, as the channel remains idle while waiting for ACKs. 3.2. Go-Back-N ARQ (GBN) The sender can transmit multiple frames (within a
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.
combines traditional ARQ with Forward Error Correction (FEC) . The receiver attempts to correct small errors using error-correcting codes; if the error is too great, a retransmission is requested. This approach, specifically Type-II Hybrid ARQ , provides a more efficient approach in poor radio conditions, optimizing throughput. 6. Conclusion The hybrid approach (HARQ) offers the best balance
SR provides the best throughput in high-error rate scenarios.
Requires complex buffering and ordering at the receiver. 4. Performance Considerations it retransmits the packet.
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