Hybrid ARQ Packet Scheduling for Low-Latency Multimedia Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication technologies over packet channels face challenges in ensuring error-free transmission due to noise and interference, particularly in multimedia data transmission, where FEC adds overhead and ARQ introduces significant delays, limiting their effectiveness in multimedia communications.
Innovation Solution
A hybrid approach combining Forward Error Correction (FEC) and Automatic Repeat Request (ARQ), referred to as Hybrid ARQ, which schedules the transmission of interdependent data packets using systematic Reed-Solomon or Tornado codes, generating parity packets to replace lost data with reduced overhead, and optimizing packet sizes and transmission order to minimize delays and errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Forward Error Correction (FEC) is used to combat data losses, then error resilience is improved, but data overhead increases
Solution Approach 1:
The patent applies partial FEC by generating parity packets only for selected groups of data packets rather than all packets. The system selectively applies FEC to groups where error protection is most needed, thereby reducing overall overhead while maintaining error resilience for critical data
Solution Approach 2:
The patent segments data into multiple groups and applies FEC selectively to different groups. By dividing the data stream into segments and applying error correction only to specific segments, the system reduces total parity overhead while maintaining reliability where needed
2Reliability
If Automatic Repeat Request (ARQ) is used for robust data communications, then error-free transmission is improved, but transmission delay increases
Solution Approach 1:
The patent generates and transmits parity packets in advance with the data packets, before any errors are detected. This preliminary provision of error correction capability eliminates the need for retransmission delays, as errors can be corrected using the pre-sent parity information
Solution Approach 2:
The patent skips the retransmission step by providing forward error correction capability. Instead of detecting errors and requesting retransmission (which causes delays), the system rushes through the error correction process by having parity packets ready in advance, allowing immediate correction without waiting for round-trip acknowledgment
3Reliability
If ARQ is used for error detection and retransmission, then transmission reliability is improved, but communication channel requirements increase
Solution Approach 1:
The patent extracts the error correction function from the interactive ARQ process and implements it as a one-way forward correction mechanism. By taking out the need for return channel communication and incorporating error correction directly into the forward data stream via parity packets, the system reduces communication channel requirements
Data Source
AI summary
A method and apparatus to provide communications over a packet channel, including applying a forward error correction (FEC) code to a first group of data packets to create a coded group of packets by supplementing a set of parity packets to the first group of data packets; and transmitting the first group of data packets, and transmitting the set of corresponding parity packets after the first group of data packets have been transmitted. In response to receiving a positive acknowledgement corresponding to the first group of packets, ceasing to send parity packets corresponding to the first group of packets and sending a second group of data packets dependent on the first group of data packets. In response to not receiving the acknowledgment, not sending the second group of data packets and continuing to transmit the parity packets corresponding to the first group of data packets.