Dynamic Transmit Power Control for D2D Uplink Interference
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Solution Overview
Problem
Existing device-to-device (D2D) communication systems face challenges in managing power control to minimize interference with uplink transmissions in wireless communication networks, often restricting D2D performance unnecessarily by constraining transmit power levels even when no uplink transmissions are scheduled.
Innovation Solution
A transmit power control (TPC) command system that instructs D2D user equipment (UE) to operate at a pre-defined maximum power level when no uplink transmissions are scheduled, and switch to a power control rule-based power level when uplink transmissions are received, allowing for optimized D2D performance and range without excessive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If D2D transmissions use uplink resources to enable direct communication between UEs, then system capacity and spectral efficiency are improved, but interference with uplink signals received at nearby eNBs increases
Solution Approach 1:
The patent implements dynamic power control for D2D transmissions by adjusting transmit power based on real-time conditions. The eNB sends power control commands to D2D UEs to dynamically adjust their transmit power levels, enabling the system to adapt between maximizing D2D performance when interference is acceptable and minimizing interference when uplink signals are present, thus resolving the contradiction between system capacity and interference generation.
Solution Approach 2:
The patent changes the power parameter of D2D transmissions based on scheduling conditions. When uplink transmissions are scheduled, the eNB reduces D2D transmit power to mitigate interference; when no uplink transmissions are scheduled, the eNB allows higher D2D transmit power to improve system capacity. This parameter adjustment resolves the technical contradiction by making D2D power adaptive to network conditions.
2Object-generated harmful factors
If power control commands are sent to D2D UEs to mitigate interference during uplink transmissions, then interference to nearby eNBs is reduced, but D2D communication performance and range deteriorate when no uplink transmissions are scheduled
Solution Approach 1:
The patent implements periodic power control where the eNB sends power control commands to D2D UEs based on the periodic scheduling of uplink transmissions. During periods when uplink transmissions are scheduled, power control commands reduce D2D power to mitigate interference. During periods when no uplink transmissions are scheduled, the eNB suspends or relaxes power control commands, allowing D2D UEs to transmit at higher power levels, thus improving D2D performance during these periods while still protecting against interference during uplink periods.
3Object-generated harmful factors
If maximum D2D transmit power is set to a predetermined value, then interference to nearby eNBs is controlled, but D2D communication range and performance are unnecessarily constrained when no uplink transmissions are scheduled
Solution Approach 1:
The patent replaces static predetermined maximum power settings with dynamic power control. Instead of fixing D2D maximum transmit power to a predetermined value that limits range, the eNB dynamically adjusts the effective maximum power through power control commands based on whether uplink transmissions are scheduled. This allows D2D communication range to expand when no uplink transmissions occur while still being constrained when uplink transmissions are present, resolving the contradiction between interference control and communication range.
Data Source
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AI summary
A transmit power control rule for device-to-device (D2D) transmissions may not be necessary during periods in which no uplink transmissions are scheduled to be received by an enhanced Node B base station (eNB) (900, 1000). When uplink transmissions are not scheduled to be received by the eNB (900, 1000), the eNB (900, 1000) may send a transmit power control (TPC) command to a D2D capable user equipment (D2D UE) that instructs the D2D UE to perform a D2D transmission at a pre-defined transmit power level (e.g., maximum transmit power level). When uplink transmissions are scheduled to be received by the eNB (900, 1000), the eNB (900, 1000) may send a TPC command to the D2D UE that instructs the D2D UE to perform a D2D transmission at a transmit power level defined by a power control rule.