Dynamic PDCCH Search Space Group Switching for Power and Latency
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Solution Overview
Problem
In wireless communication networks, especially in unlicensed frequency bands, the unpredictable completion time of listen-before-talk procedures can lead to idle periods during transmission slots, causing collisions and interference, particularly when downlink control channel search spaces are limited, and frequent monitoring for DL control information is power-consuming and not always necessary.
Innovation Solution
Configuring user equipment (UE) with multiple groups of search spaces for dynamic DL control channel monitoring, allowing switching between different monitoring patterns based on physical layer signaling, detection of COT start/end, scheduling grants, or timers, to minimize idle periods and conserve power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If frequent monitoring for DL control information is performed, then scheduling delay is reduced, but power consumption increases
Solution Approach 1:
The patent implements dynamic switching between two search space groups (first and second groups) with different monitoring characteristics. The UE can switch between these groups based on scheduling conditions, allowing the monitoring frequency to be adjusted dynamically rather than using a fixed pattern. This resolves the contradiction by enabling the system to use frequent monitoring (first search space group) when scheduling delay needs to be minimized, and less frequent monitoring (second search space group) when power conservation is prioritized.
Solution Approach 2:
The patent changes the monitoring parameters by configuring two distinct search space groups with different monitoring periodicities and offsets. The first search space group has parameters optimized for low latency (more frequent monitoring), while the second group has parameters optimized for power efficiency (less frequent monitoring). By switching between these parameter sets based on scheduling needs, the system resolves the trade-off between scheduling delay and power consumption.
2Device complexity
If downlink control channel search spaces are limited, then device complexity is reduced, but collision and interference increase
Solution Approach 1:
The patent divides the search space into two separate groups (first search space group and second search space group) with distinct time-frequency resources and monitoring patterns. This segmentation allows downlink control information to be distributed across different search space groups, reducing the probability of collisions and interference within any single search space while maintaining manageable complexity through organized group structures.
Solution Approach 2:
The patent introduces an additional dimension to the search space structure by creating multiple search space groups that can be switched between. This adds a time-varying dimension to the search space configuration, where the UE monitors different search space groups at different times. This dimensional expansion provides more resource opportunities for downlink control information transmission, reducing collisions and interference without significantly increasing device complexity.
3Productivity
If idle periods are minimized, then spectrum utilization is optimized, but monitoring frequency must increase
Solution Approach 1:
The patent implements dynamic switching between search space groups based on scheduling conditions and idle period detection. When idle periods are detected, the system can switch to the first search space group with more frequent monitoring to minimize future idle periods and optimize spectrum utilization. When active scheduling is occurring, the system can use the second search space group with less frequent monitoring to conserve power. This dynamic adaptation resolves the contradiction between spectrum utilization and power consumption.
Solution Approach 2:
The patent uses feedback mechanisms where the UE monitors for scheduling grants and detects idle periods, then adjusts its monitoring behavior accordingly. The base station can also provide feedback through scheduling decisions that indicate which search space group the UE should monitor. This feedback loop enables the system to optimize spectrum utilization by increasing monitoring frequency when idle periods occur, while conserving power during active scheduling periods.
Data Source
AI summary
Wireless communications systems and methods related to downlink control channel communications in a wireless communication network are provided. A first wireless communication device communicates, with a second wireless communication device, a configuration indicating a first group of one or more search spaces and a second group of one or more search spaces, where at least one of the first group or the second group includes at least one search space not included in an other of the first group or the second group. The first wireless communication device communicates, with the second wireless communication device, a first downlink control information (DCI) message in a first search space of the first group of one or more search spaces. The first wireless communication device communicates, with the second wireless communication device, a second DCI message in a second search space of the second group of one or more search spaces.