ARQ for point to point links
AssigneeCisco Technology, Inc.
InventorsVincent K. Jones, Gregory G. Raleigh, David P. Bokaie, Joseph Middleton, Ali Raissinia
Life of this patent
Estimating the term…
Abstract
An automatic retransmission system offering good latency and overhead characteristics combined with programmable tradeoffs among overhead, latency, and error performance. ARQ (Automatic Repeat reQuest) blocks present at both ends of a link coordinate to automatically attempt to re-send data if that data was not received properly the first time it was sent. Re-transmission from the transmitter (transmitter) is requested by the receiver (Receiver) via a highly reliable “Repeat Request” (RR) mechanism. This RR scheme carries sufficient information back to the transmitter for it to determine which previous transmissions need to be re-sent.
Claims15
In a digital communication system, a method for requesting retransmission of received data comprising:
- detecting errors in received data words;
- in response to said errors, creating entries identifying each of said received data words on a highest priority one of a plurality of lists, each of said lists representing a priority level for requesting retransmission;
- upon an opportunity to send a request for retransmission, selecting an entry from a highest priority list that is not empty;
- requesting retransmission of a received data word identified by said selected entry;
- and thereafter
- removing said selected entry from said highest priority list that is not empty;
- and
- storing received data words along with information indicating ages of said received data words within a transmitter memory;
- wherein requesting retransmission comprises:
- requesting retransmission of said received data word identified by said selected entry only if said received data word has an age below an age limit for requests.
In a digital communication system, apparatus for requesting retransmission of received data comprising:
- a receiver system that detects errors in received data words;
- a repeat request control system that, in response to said errors, creates entries identifying each of said received data words on a highest priority one of a plurality of lists, each of said lists representing a priority level for requesting retransmission, and upon an opportunity to send a request for retransmission, selects an entry from a highest priority list that is not empty;
- and
- a transmitter system that requests retransmission of a received data word identified by said selected entry;
- and
- a receiver memory that stores received data words along with information indicating ages of said received data words within a transmitter memory;
- and
- wherein said repeat request control system removes said selected entry from said highest priority list that is not empty and said transmitter system requests retransmission of said received data word identified by said selected entry only if said received data word has an age below an age limit for retransmission requests.
In a digital communication system, an apparatus for requesting retransmission of received data comprising:
- means for detecting errors in received data words;
- means for creating entries identifying each of said received data words on a highest priority one of a plurality of lists, in response to said errors, each of said lists representing a priority level for requesting retransmission;
- means for selecting an entry from a highest priority list that is not empty, upon an opportunity to send a request for retransmission;
- means for requesting retransmission of a received data word identified by said selected entry;
- means for removing said selected entry from said highest priority list that is not empty;
- and
- means for storing received data words along with information indicating ages of said received data words within a transmitter memory;
- wherein means for requesting retransmission comprises:
- means for requesting retransmission of said received data word identified by said selected entry only if said received data word has an age below an age limit for requests.
Dependencies are inferred from the claim text.