Random Access Selection for 2-Step and 4-Step NTN Procedures
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Solution Overview
Problem
In non-terrestrial networks, existing methods for selecting between 2-step and 4-step random access procedures in 3GPP 5G New Radio (NR) are inadequate, leading to load imbalance, congestion, and increased access delay due to reliance on reference signal received power (RSRP) thresholds, which are insufficient for networks with varying propagation delays and network slice priorities.
Innovation Solution
Introduce additional conditions such as network slice identification, quality of service indicators, propagation delay, location, and distance thresholds to determine the appropriate random access procedure, allowing UEs to selectively perform 2-step or 4-step random access based on these criteria, and include timers and threshold numbers for switching between procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RSRP threshold is used to select random access procedure type, then device complexity is reduced, but network efficiency deteriorates due to load imbalance and congestion in non-terrestrial networks
Solution Approach 1:
The patent changes the selection parameter from a single RSRP threshold to multiple parameters including RSRP threshold, propagation delay threshold, and network slice identification. This allows the system to adapt to different network conditions (terrestrial vs non-terrestrial) and different service requirements, thereby improving network efficiency while maintaining reasonable device complexity through standardized measurement procedures.
Solution Approach 2:
The patent introduces dynamic conditions for random access procedure selection that can change based on network type, propagation delay, and service requirements. The UE and gNB can dynamically adjust which procedure (2-step or 4-step) to use based on current network conditions, making the system adaptable to varying scenarios in non-terrestrial networks and improving overall network efficiency.
2Loss of time
If 2-step random access procedure is used, then access delay is reduced, but reliability deteriorates in networks with varying propagation delays
Solution Approach 1:
The patent makes the random access procedure selection dynamic based on propagation delay conditions. When propagation delay is within an acceptable threshold, the system uses the faster 2-step procedure to minimize access delay. When propagation delay exceeds the threshold, the system switches to the more reliable 4-step procedure, ensuring reliable operation in networks with varying propagation delays while still achieving low latency when conditions permit.
3Ease of operation
If single RSRP threshold is used for procedure selection, then ease of operation is improved, but adaptability deteriorates for different network slices and services
Solution Approach 1:
The patent extends the selection criteria from a single RSRP threshold to multiple parameters including network slice identification and service requirements. This allows different network slices and services to have customized thresholds and conditions, enabling the system to adapt to diverse service requirements (e.g., enhanced mobile broadband, ultra-reliable low-latency communication, massive machine type communication) while maintaining ease of operation through automated measurements and comparisons.
Data Source
AI summary
The present application relates to a method and an apparatus for performing random access. The method includes: receiving a random access type condition message from a base station; and selectively performing a 2-step random access procedure or a 4-step random access procedure with the base station according to the random access type condition message.