LTE TDD Feedback Coding for Precise ACK/NACK Reporting
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Solution Overview
Problem
In time division duplex telecommunication systems, particularly in LTE networks, the asymmetric ratio of downlink to uplink traffic poses challenges in efficiently scheduling feedback reports, leading to inefficiencies in ACK/NACK bundling, which results in unnecessary downlink re-transmissions and reduced throughput.
Innovation Solution
Assigning multiple unique codes to each mobile terminal allows for more granular feedback reporting by using code combinations to convey additional information, enabling the transmission of multiple feedback messages within a single bit without increasing bandwidth, thereby improving the accuracy of data retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ACK/NACK bundling is used to schedule feedback reports in asymmetric TDD systems, then the feedback reporting mechanism can be implemented, but the downlink transmission burden increases and throughput decreases due to inefficient retransmissions
Solution Approach 1:
The patent segments the feedback reporting mechanism by assigning multiple unique codes to each mobile terminal instead of using a single bundled ACK/NACK. This allows granular feedback reporting where each code represents a specific feedback state, eliminating the need for bundling and enabling precise identification of which data packets need retransmission, thereby reducing unnecessary downlink retransmissions and improving throughput
Solution Approach 2:
The patent changes the parameter of code assignment from one code per terminal to multiple codes per terminal. By allocating a set of unique codes to each mobile terminal and using different codes to represent different feedback states (ACK, NACK, DTX), the system achieves more efficient feedback reporting that reduces downlink retransmission overhead while maintaining reliability
2Measurement precision
If multiple unique codes are assigned to each mobile terminal to enable granular feedback reporting, then feedback accuracy improves and unnecessary retransmissions are reduced, but the code allocation complexity increases
Solution Approach 1:
The patent applies universality by using the same set of unique codes for multiple purposes: terminal identification and feedback state indication. The codes serve dual functions as both terminal identifiers and feedback carriers, where different codes from the allocated set represent different feedback states (ACK, NACK, DTX), thereby achieving granular feedback reporting without requiring separate signaling mechanisms
Data Source
AI summary
Methods of transmitting and receiving information in a telecommunications network are described. A method of transmitting, for example, includes identifying a message for transmission, the message selected from a plurality of predetermined messages, and selecting a code combination from a set of codes combinations, each code combination corresponding to a predetermined message. Data is encoded with the selected code combination, and the encoded data is transmitted. A method of receiving may include receiving the signal including data encoded for transmission with the selected code combination, and decoding the signal to retrieve unencoded data, the decoding including determining with which code combination selected from the set of code combinations the data is encoded. The data is decoded, and the message for transmission is selected from the plurality of predetermined messages, wherein the message is selected based on the code combination with which the data was encoded.