Terminal Device Transmit Power Scaling for Heterogeneous Network Backhaul Delays
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Solution Overview
Problem
In heterogeneous networks, the delay in backhaul communication between macro and small cells hinders efficient transmit power control and control information exchange, making conventional methods ineffective.
Innovation Solution
A terminal device and base station device configuration that scales the transmit power of the physical uplink control channel to prevent exceeding a set limit, ensuring efficient power management and control by transmitting hybrid auto repeat request-acknowledgement (HARQ-ACK) information, and transmitting guaranteed power parameters through higher-layer signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transmit power control method is used in heterogeneous networks, then transmit power can be controlled in ideal backhaul conditions, but transmit power control becomes ineffective when backhaul delay occurs
Solution Approach 1:
The base station device determines guaranteed power for each cell group in advance, before backhaul delay occurs. This preliminary determination of power allocation allows the system to maintain effective transmit power control even when backhaul communication experiences delays, as the power allocation decisions are made locally without requiring real-time backhaul coordination.
2Loss of information
If information sharing between cells is restricted due to backhaul delay, then control information exchange is hindered, but conventional methods can no longer be directly used
Solution Approach 1:
The system segments the network into multiple cell groups (first CG and second CG) with independent guaranteed power allocations. This segmentation allows each cell group to operate with its own power control parameters determined by the respective base station device, reducing dependency on real-time information sharing across the entire network and mitigating the impact of backhaul delays on control information exchange.
3Reliability
If transmit power of PUCCH exceeds upper limit, then transmission quality may improve, but power management becomes inefficient and may cause interference
Solution Approach 1:
The system introduces guaranteed power as a new parameter that defines an upper limit for PUCCH transmit power in each cell group. By changing the power management approach from unlimited power allocation to constrained power allocation with guaranteed power parameters, the system maintains transmission quality within acceptable limits while improving overall power management efficiency and reducing potential interference.
Data Source
AI summary
Provided is a transmission unit that, if transmission of a PUCCH of a first CG overlaps transmission of a PUSCH and/or a PUCCH of a second CG in a certain subframe and UCI including HARQ-ACK is transmitted on the PUCCH of the first CG, upon transmit power of the PUCCH of the first CG exceeding a first upper limit value, performs scaling on the transmit power of the PUCCH of the first CG such that the transmit power of the PUCCH does not exceed the first upper limit value, and upon the transmit power of the PUCCH of the first CG not exceeding the first upper limit value, sets the transmit power of the PUCCH of the first CG to power required for the PUCCH of the first CG.