HARQ-ACK Codebook Generation for Dynamic TDD Feedback Overhead
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently generating HARQ-ACK codebooks, particularly in 5G networks, due to resource shortages and high-speed service demands, which affect the reception and transmission of control channels.
Innovation Solution
A method for generating dynamic and semi-static HARQ-ACK codebooks in a wireless communication system, where the number of bits is determined based on PDCCH signaling, and the codebook is transmitted via a physical uplink control channel, with specific rules for determining the last PDCCH in case of ambiguity, and handling SPS PDSCH release scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic TDD is used to vary the number of OFDM symbols according to data traffic directions, then spectral efficiency is improved, but the complexity of HARQ-ACK codebook generation increases
Solution Approach 1:
The patent applies dynamics by making the HARQ-ACK codebook size adaptive rather than fixed. The codebook dynamically adjusts its length based on the actual number of downlink OFDM symbols received in a slot, which varies according to dynamic TDD configuration. This allows the system to maintain high spectral efficiency while managing codebook generation complexity through runtime adaptation.
Solution Approach 2:
The patent changes the parameter of codebook size from a static value to a dynamic value that depends on the number of received downlink OFDM symbols. By making the codebook length variable based on actual reception conditions, the system optimizes the balance between spectral efficiency and codebook generation complexity.
2Reliability
If the number of HARQ-ACK bits is increased to cover all possible downlink channels, then reliability of feedback is improved, but the overhead of control channel transmission increases
Solution Approach 1:
The patent applies partial action by including only the necessary number of HARQ-ACK bits corresponding to the actual number of downlink OFDM symbols received. Instead of always preparing a fixed maximum number of bits, the system generates only the required number of bits based on actual reception, reducing overhead while maintaining reliability for the received channels.
Solution Approach 2:
The patent changes the parameter of HARQ-ACK codebook size from a fixed maximum to a variable size that matches the actual number of received downlink channels. This dynamic parameter adjustment ensures reliability is maintained for received channels while minimizing overhead by excluding bits for channels that were not actually received.
3Ease of operation
If semi-static codebook is used to simplify codebook generation, then ease of operation is improved, but adaptability to dynamic TDD configuration deteriorates
Solution Approach 1:
The patent bridges the gap between semi-static simplicity and dynamic adaptability by making the codebook size dynamically determined based on the number of received downlink OFDM symbols. This maintains the simplicity of semi-static codebook generation while enabling adaptability to dynamic TDD configurations through runtime adjustment of codebook length.
Solution Approach 2:
The patent creates a universal codebook generation method that works for both semi-static and dynamic TDD configurations. By using a unified approach where the codebook size is determined by the actual number of received downlink OFDM symbols, the system achieves multi-functionality across different TDD modes without requiring separate handling for each case.
Data Source
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AI summary
Disclosed is a base station in a wireless communication system. Each base station in wireless communication comprises: a communication module; and a processor. The processor generates a hybrid automatic repeat request (HARQ)-ACK codebook comprising one or more bits and indicating whether or not reception of a channel or signal is successful, and transmits the HARQ-ACK codebook to the base station.