Packet Retransmission Control for Burst-Error Optical Communication
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Solution Overview
Problem
Optical free space communication is susceptible to burst errors due to atmospheric fluctuations, leading to inefficiencies in packet retransmission when redundant codes are used, and existing technologies fail to address these issues effectively.
Innovation Solution
A communication apparatus and system that employs encoding means to generate encoded data using multiple data packets, with redundant transmission and reception of packets, and control means to manage retransmission based on decoded and received data numbers, optimizing retransmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is encoded over a long time in a dispersed manner to cope with burst errors, then reliability against burst errors is improved, but delay until decoding is completed increases
Solution Approach 1:
The patent divides the encoded data into multiple packets and transmits them in parallel through different paths or at different times. This segmentation allows the receiver to reconstruct the original data as soon as enough packets are received, without waiting for all packets to arrive, thereby reducing decoding delay while maintaining reliability against burst errors
Solution Approach 2:
The patent performs preliminary encoding of data into multiple packets with redundant information before transmission. This preliminary action ensures that even if some packets are lost due to burst errors, the receiver can still reconstruct the original data from the remaining packets, reducing the need for retransmission and thereby reducing overall delay
2Reliability
If packet coding method with redundant codes is used to improve reliability, then reliability is improved, but coding efficiency deteriorates when transmission speed changes or some packets are confirmed received
Solution Approach 1:
The patent implements dynamic adaptation of the coding scheme based on channel conditions and packet reception status. When transmission speed changes or packet loss patterns are observed, the system adjusts the number of redundant codes and encoding parameters accordingly, maintaining reliability while optimizing coding efficiency for current conditions
Solution Approach 2:
The patent incorporates feedback mechanisms where the receiver informs the transmitter about successfully received packets. Based on this feedback, the transmitter can adjust subsequent encoding strategies, reducing redundant coding for already successfully transmitted data and improving overall coding efficiency while maintaining reliability
3Reliability
If retransmission is performed for all packets to ensure reliability, then reliability is improved, but loss of time increases due to redundant retransmission of successfully decoded data
Solution Approach 1:
The patent uses feedback from the receiver about which packets have been successfully decoded to enable selective retransmission. The transmitter only retransmits packets that were not successfully received or decoded, avoiding redundant retransmission of already successfully decoded data, thereby reducing retransmission time while maintaining reliability
Solution Approach 2:
The patent extracts and identifies specifically which packets require retransmission based on feedback information, separating the retransmission task from blanket retransmission of all packets. This extraction approach focuses retransmission resources only on necessary packets, reducing overall retransmission time while ensuring reliability
Data Source
AI summary
A communication apparatus includes a receiving unit that receives, from the communication apparatus on the other side, an acknowledgement including at least one of a decoded-data number corresponding to successfully-decoded data, and a received-data number corresponding to data included in the successfully received first and second packets, and a control unit that controls retransmission of the first and second packets based on at least one of the decoded-data number and the received-data number.