Multi-Hop IAB Power Control for Uplink Interference
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Solution Overview
Problem
In multi-hop integrated access and backhaul networks, the varying power levels of uplink transmissions from relay nodes and user equipment devices cause interference, impacting automatic gain control and overall throughput, as relay nodes receive backhaul and access link communications simultaneously with differing signal strengths and power spectral densities.
Innovation Solution
A power control system manages power levels by scheduling relay nodes to transmit alongside UE devices with high signal strength, performing closed-loop power control through outer-loop and inner-loop mechanisms, and adjusting power levels to reduce differences, using reference signals for feedback and adjustments via Physical Downlink Control Channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If relay nodes transmit uplink communications with high power levels, then backhaul link coverage is improved, but interference with access link communications increases and automatic gain control performance deteriorates
Solution Approach 1:
The patent implements dynamic power control by adjusting the transmit power parameter of relay nodes based on channel conditions, traffic load, and interference levels. The network controller modifies power levels in real-time to optimize backhaul coverage while preventing excessive interference to access links, thereby resolving the contradiction between coverage extension and interference control.
Solution Approach 2:
The system transitions from static power levels to dynamic power adjustment mechanisms. Relay nodes continuously adapt their transmit power based on feedback from the network controller, which monitors channel quality indicators, interference measurements, and traffic demands. This dynamic behavior allows the system to maintain optimal performance across varying network conditions.
2Productivity
If relay nodes and user equipment transmit simultaneously, then spectral efficiency is improved, but power level differences cause automatic gain control degradation
Solution Approach 1:
The patent implements closed-loop power control where relay nodes transmit reference signals and receive feedback from the network controller regarding received power levels. Based on this feedback, the controller adjusts the relay node's transmit power to match desired power levels, ensuring that simultaneous transmissions from relay nodes and user equipment maintain consistent power levels and do not degrade automatic gain control performance.
Solution Approach 2:
The system aims to equalize the received power levels from different transmission sources (relay nodes and user equipment) at the receiver. By adjusting relay node transmit power to compensate for path loss differences and ensure comparable received signal strengths, the system creates an equipotential condition that prevents automatic gain control degradation while allowing simultaneous transmissions.
3Reliability
If power control adjustments are made to reduce power level differences, then automatic gain control performance is improved, but system complexity increases
Solution Approach 1:
The patent divides the power control functionality into separate modules: a network controller that performs centralized power level management and relay nodes that execute local power adjustments. This segmentation allows complex control algorithms to be implemented in the network controller while keeping relay node complexity manageable, as they only need to implement power adjustment based on received control messages.
Solution Approach 2:
The network controller acts as an intermediary between the relay nodes and the power control algorithm. Instead of implementing complex distributed power control algorithms at each relay node, the network controller receives channel state information, calculates optimal power levels, and sends control commands to relay nodes. This intermediary approach centralizes the computational complexity while simplifying individual node operations.
Data Source
AI summary
Various embodiments disclosed herein provide for power control system in a multi-hop integrated access and backhaul network. In a multi-hop integrated access and backhaul network a donor node can communicate with user equipment devices and relay nodes that have varying power levels, and to avoid receiving uplink transmissions with varying power levels which can impact automatic gain control systems and lower overall throughput, the power control system disclosed herein can manage the power levels of the relay node in order to reduce the difference in power levels. In one embodiment, the power control system can schedule relay node devices to transmit uplink transmissions alongside UE devices that have a high signal strength. In another embodiment, the power control system can schedule relay nodes and UE devices to separate symbols within a time slot. In another embodiment, the power control system can perform closed loop power control management at the relay node to reduce the power level for the uplink transmission.