PUCCH Power Control for CBG-Based HARQ-ACK in 5G NR
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Solution Overview
Problem
Current communication systems, particularly in the context of New Radio (NR) for next-generation mobile communication, face inefficiencies in uplink and downlink communication due to complexities in power control and HARQ-ACK transmission, especially when dealing with Code Block Groups (CBGs) and varying numbers of bits in UCI.
Innovation Solution
A terminal and base station apparatus configuration that determines PUCCH transmit power based on the number of CBGs and UCI bits, adjusting power settings dynamically to optimize transmission efficiency by using RRC information to manage HARQ-ACK transmission effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PUCCH transmit power is determined based on the maximum number of CBGs (X) configured by RRC, then the power control is simple and consistent with TB-level HARQ-ACK, but the power allocation becomes inefficient when the actual number of CBGs is less than X
Solution Approach 1:
The patent changes the parameter basis for PUCCH power control from the static RRC-configured maximum CBG number (X) to the dynamic actual CBG number (Y). The terminal determines the actual number of CBGs based on the received PDSCH and adjusts the PUCCH transmit power accordingly using the formula: P_PUCCH = min{P_CMAX, P0_PUCCH + 10log10(2^μ * M_RB * min(Y, X)) + Δ_F_PUCCH(F) + Δ_TDS + f_PUCCH(n)}. This allows the power allocation to adapt to the actual data transmission needs while maintaining consistency with the configured maximum.
2Loss of energy
If PUCCH transmit power is determined based on the actual number of CBGs, then power allocation efficiency is improved, but the complexity of power control increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the maximum number of CBGs (X) through RRC signaling before actual data transmission. This allows the terminal to have a reference value ready in advance, simplifying the real-time power control calculation. During actual transmission, the terminal only needs to determine the actual CBG number (Y) and compare it with the pre-configured X, rather than calculating everything from scratch.
Solution Approach 2:
The patent introduces a hybrid parameter approach where the power control uses min(Y, X) - the minimum of the actual CBG number and the configured maximum. This parameter transformation simplifies the complexity by providing a bounded calculation that leverages both the actual transmission needs and the pre-configured limits, avoiding the need for complex dynamic adjustments.
3Measurement precision
If the number of HARQ-ACK bits is dynamically adjusted based on actual CBG transmission, then transmission accuracy is improved, but the determination complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the terminal determines the actual number of CBGs (Y) based on the received PDSCH and feeds this information into the PUCCH power control calculation. The base station configures the maximum number of CBGs (X) through RRC signaling, and the terminal uses both X and Y to determine the appropriate number of HARQ-ACK bits and corresponding transmit power. This feedback loop ensures accurate matching between the number of ACK bits and the actual transmission requirements.
4Reliability
If the PUCCH power is increased to ensure reliable transmission of HARQ-ACK for multiple CBGs, then transmission reliability is improved, but the energy consumption increases
Solution Approach 1:
The patent applies partial action by allocating PUCCH transmit power based on the minimum of the actual and configured CBG numbers (min(Y, X)). This means the terminal transmits power proportional to the actual number of HARQ-ACK bits needed rather than always using the maximum configured value. When the actual CBG number is less than the configured maximum, the terminal uses less power, avoiding excessive energy consumption while maintaining sufficient reliability for the actual transmission requirements.
Data Source
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AI summary
A terminal apparatus receives one transport block by using a PDSCH, receives RRC information indicating a maximum number X of CBGs, determines transmit power of a PUCCH, and transmits UCI at least including a HARQ-ACK corresponding to the one transport block on the PUCCH. The one transport block includes NCB code blocks. The HARQ-ACK includes the X HARQ-ACKs bits. In a case that a number of bits of the UCI does not exceed a prescribed number of bits, the transmit power of the PUCCH including the UCI is determined at least based on a smaller value of the X and the NCB. In a case that the number of bits of the UCI exceeds the prescribed number of bits, the transmit power of the PUCCH is determined at least based on the number of bits of the UCI.