Arq -

The sender can transmit multiple frames (within a window size

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

The choice of ARQ protocol involves trade-offs between complexity and efficiency: The receiver attempts to correct small errors using

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 Conclusion is a fundamental error-control mechanism used in

is a fundamental error-control mechanism used in telecommunications and data link layers to ensure reliable transmission over unreliable communication links. Unlike Forward Error Correction (FEC) , which allows the receiver to correct errors, ARQ relies on the receiver identifying errors and requesting retransmission of data from the sender. This paper covers the primary types of ARQ protocols, their mechanisms, and performance tradeoffs. 2. Fundamental Mechanisms ARQ protocols operate based on two main principles:

Only the specific lost or corrupted frame is retransmitted, rather than the entire window. Pros: Highly efficient utilization of bandwidth.

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