D2D Transmit Power Control for Uplink Interference Mitigation
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Solution Overview
Problem
In D2D communication, the use of maximum transmit power for D2D signals causes inter-carrier interference with uplink signals, reducing the accuracy of uplink signal reception by network devices due to differences in subframe formats and cyclic prefixes.
Innovation Solution
A transmit power control method that dynamically adjusts power for D2D signals in D2D communication by determining and delivering control information for user equipment to use different power control manners in different subframes, based on path loss compensation factors and target receive powers, to minimize interference with uplink signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If maximum transmit power is used for D2D signals, then D2D communication coverage is improved, but inter-carrier interference with uplink signals increases
Solution Approach 1:
The patent implements dynamic transmit power adjustment for D2D signals based on subframe type. The network device configures different power control parameters (P0, alpha, path loss compensation) for first subframes (with uplink signals) and second subframes (without uplink signals). This allows the D2D transmit power to be dynamically adapted - reduced in first subframes to minimize interference to uplink signals, and increased in second subframes to maximize coverage - thereby resolving the contradiction between coverage and interference
Solution Approach 2:
The patent changes key power control parameters (P0, alpha, path loss compensation factor) based on subframe characteristics. By configuring different parameter sets for different subframe types, the system optimizes the balance between D2D coverage and uplink interference protection. Specifically, P0 is adjusted to control baseline power, alpha modifies path loss compensation, and these parameter changes enable flexible power management to resolve the coverage-interference tradeoff
2Device complexity
If maximum transmit power is used for D2D signals, then transmit power control simplicity is improved, but uplink signal reception accuracy deteriorates
Solution Approach 1:
The patent segments the radio frame into different subframe types (first subframes with uplink signals, second subframes without uplink signals) and applies different power control configurations to each segment. The network device provides separate power control parameters for each subframe type, allowing differentiated power management. This segmentation approach maintains relatively simple power control procedures while significantly improving uplink reception accuracy by reducing interference in appropriate subframes
3Measurement precision
If different power control manners are used in different subframes, then uplink signal reception accuracy is improved, but control information complexity increases
Solution Approach 1:
The patent implements periodic power control adjustment synchronized with the subframe structure. Power control parameters are configured periodically for different subframe types, creating a regular pattern of power adjustment. The network device provides power control information that repeats according to the subframe configuration, allowing user equipment to efficiently process and apply power control without handling overly complex aperiodic control information, while still achieving improved uplink reception accuracy
Data Source
AI summary
In the present invention, a network device determines and delivers control information, where the control information includes first subframe information and a first power control manner in which power control is performed in a first subframe corresponding to the first subframe information, and second subframe information and a second power control manner in which power control is performed in a second subframe corresponding to the second subframe information. A user equipment in D2D communication acquires the control information delivered by the network device; transmits, by using the transmit power determined according to the first power control manner, a D2D signal in the first subframe corresponding to the first subframe information; and transmits, by using the transmit power determined according to the second power control manner, a D2D signal in the second subframe corresponding to the second subframe information.