NR UE Power Saving via L1 Cross-Slot Scheduling Switching
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Solution Overview
Problem
Existing communication systems face challenges in efficiently transitioning between cross-slot and same-slot scheduling in New Radio (NR) standards, leading to increased power consumption and delays, particularly in scenarios requiring low latency and high reliability.
Innovation Solution
A method is introduced to enable fast and robust physical-layer based switching between cross-slot and same-slot scheduling by utilizing a Cross-Slot Indicator field (CSIF) in the downlink control information (DCI) format, allowing User Equipment (UE) to dynamically adjust its scheduling state based on specific conditions, such as DCI reception patterns and HARQ feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cross-slot scheduling is used to reduce power consumption, then UE power consumption is reduced, but transmission latency increases
Solution Approach 1:
The patent implements dynamic switching between cross-slot and same-slot scheduling modes based on traffic conditions and QoS requirements. The network can configure the UE to operate in cross-slot mode for power saving during low-activity periods, while enabling same-slot mode for low-latency applications when needed. This dynamic adaptability resolves the contradiction by allowing the system to optimize for power consumption or latency depending on current operational requirements.
Solution Approach 2:
The patent changes the scheduling parameter (slot offset) dynamically based on service type and traffic conditions. For eMBB services with relaxed latency requirements, larger slot offsets are used to enable power saving. For URLLC services requiring low latency, smaller or zero slot offsets are applied. This parameter adjustment resolves the contradiction by tailoring the scheduling behavior to specific service requirements.
2Loss of time
If same-slot scheduling is used to reduce latency, then transmission latency is reduced, but UE power consumption increases
Solution Approach 1:
The system dynamically selects between same-slot and cross-slot scheduling based on real-time traffic conditions and QoS parameters. When low-latency performance is critical (e.g., URLLC traffic), same-slot scheduling is activated. When power saving is more important (e.g., eMBB during idle periods), cross-slot scheduling is used. This dynamic selection resolves the contradiction by adapting to instantaneous requirements.
Solution Approach 2:
The slot offset parameter is adjusted based on service requirements. For latency-sensitive services, the slot offset is minimized or set to zero, enabling same-slot scheduling. For power-sensitive scenarios, the slot offset is increased to enable cross-slot scheduling and micro-sleep opportunities. This parameter control mechanism resolves the contradiction by optimizing the trade-off based on current priorities.
3Use of energy by moving object
If cross-slot scheduling is configured for power saving, then UE can enter micro-sleep states, but switching flexibility between scheduling modes is limited
Solution Approach 1:
The patent implements a dynamic state machine that allows the UE to switch between cross-slot state and same-slot state based on received DCI indications. The UE can be configured with both modes and switch between them rapidly based on traffic conditions, maintaining both power-saving capability and scheduling flexibility. This resolves the contradiction by enabling the system to adapt to different operational requirements in real-time.
Solution Approach 2:
The patent creates a universal scheduling framework that supports both cross-slot and same-slot scheduling within the same UE configuration. The UE maintains capability for both operating modes and can transition between them based on network indications and traffic conditions. This multi-functionality resolves the contradiction by allowing the system to access both power-saving benefits and low-latency capabilities as needed.
4Adaptability or versatility
If fast switching between scheduling states is enabled, then system adaptability is improved, but control complexity increases
Solution Approach 1:
The patent uses DCI (Downlink Control Information) as an intermediary mechanism to control the switching between scheduling states. Instead of complex higher-layer signaling or frequent RRC reconfiguration, the network can rapidly switch UE scheduling modes by setting specific bits in DCI messages. This intermediary control mechanism resolves the contradiction by providing fast, flexible state switching through a simple and efficient signaling interface.
Solution Approach 2:
The system implements feedback mechanisms where the UE monitors DCI indications and adjusts its scheduling behavior accordingly. The UE provides HARQ feedback and maintains state information that allows the network to optimize switching decisions. This feedback loop resolves the contradiction by enabling adaptive switching based on actual system state and traffic conditions, avoiding unnecessary state transitions.
Data Source
AI summary
A user equipment (UE), method and computer program product are provided. A configuration is received to detect a first field within a first DCI, the UE operating in a first state upon reception of the configuration. While operating in the first state where a minimum slot offset is applicable for at least one of receiving data or transmitting data, the UE switches from operating in the first state to a second state responsive to detecting a first state value for the first field in a first control message using the first DCI format in a first slot of a first set of slots. While operating in the second state where the minimum slot offset is not applicable for at least one of receiving the data and transmitting the data, the UE switches from operating in the second state to the first state responsive to detecting a second state value.