Radio Data Packet Transmission Using New Data Indicator
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Solution Overview
Problem
In radio mobile communication systems, the misinterpretation of negative confirmation messages as positive confirmation messages can lead to data loss and gaps in the receiver's buffer, as the transmitter continues to send new data packets instead of retransmitting errored packets.
Innovation Solution
A method where an indicator is sent with each data packet to distinguish between new and re-sent packets, allowing the receiver to request retransmissions and ensuring that errored packets are retransmitted correctly, even if the transmitter misinterprets negative confirmation messages, using a 1-bit New Data Indicator (NDI) via the High Speed Shared Control Channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmitter uses simple confirmation messages without indicators, then the communication protocol is simpler, but data loss occurs when negative confirmation messages are misinterpreted as positive ones
Solution Approach 1:
The confirmation message is segmented into two distinct types: positive confirmation messages (ACK) and negative confirmation messages (NACK), each with unique identification. This segmentation allows the receiver to clearly indicate whether a packet was successfully received or needs retransmission, preventing misinterpretation even when using simple message formats.
Solution Approach 2:
Different confirmation messages are distinguished by their semantic 'color' or identity - ACK messages indicate successful reception while NACK messages indicate errors. This clear differentiation ensures that even if messages are briefly viewed or processed, their meaning is correctly understood, preventing the type of misinterpretation that causes data loss.
2Reliability
If the transmitter re-sends data packets upon receiving negative confirmation, then data reliability is improved, but transmission time increases due to repeated transmissions
Solution Approach 1:
The receiver performs preliminary action by sending a negative confirmation message immediately when an error is detected, before the transmitter sends the next packet. This allows the transmitter to prepare for retransmission in advance, minimizing the time loss by overlapping the retransmission preparation with the next transmission cycle.
Solution Approach 2:
The transmission system maintains continuity by ensuring that every packet sent has a corresponding confirmation response. The retransmission mechanism ensures that useful action (successful data delivery) continues without interruption, as failed packets are promptly retransmitted and acknowledged, keeping the data stream continuous and reliable.
3Manufacturing precision
If the receiver sends confirmation messages for every packet, then transmission accuracy is improved, but the number of messages increases communication overhead
Solution Approach 1:
Instead of sending confirmation messages for every single packet (excessive action), the system uses selective confirmation where NACK messages are sent only when errors occur, while ACK messages are implied or bundled. This partial action approach reduces the total number of messages while maintaining transmission accuracy through targeted error correction.
Data Source
AI summary
Due to NACK-to-ACK misinterpretations in base stations, packets are lost, and there may be gaps in a re-ordering buffer of a base station. According to the present invention, when the receiver decodes—possibly after some retransmissions—a first data packet without an error, which first data packet is sent along with an indicator indicating that the first data packet is a new data packet, after the receiver has sent a negative confirmation message (NACK) with respect to a second data packet, the receiver sends a Revert (REV) message to the transmitter. The REV message informs the base station that the first data packet was decoded error-free, and that the second data packet is still missing on the receiving side so that the base station may re-send this second data packet.