Two-Step RACH Power and Timing for NTN Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-terrestrial networks face challenges with high latency and low reliability in random access procedures due to large propagation delays and varying pathloss, especially in communications involving high-altitude vehicles like non-geostationary satellites.
Innovation Solution
Configuring communication devices with specific transport block sizes, power ramping values, timing configurations, and adjusted response windows to enhance reliability and reduce latency in random access procedures, particularly for two-step RACH procedures in non-terrestrial networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional random access procedures are used in non-terrestrial networks, then the basic connectivity is established, but the reliability is low and latency is high due to large propagation delays and varying pathloss
Solution Approach 1:
The network pre-configures the UE with multiple parameters including transport block sizes, power ramping values, timing configurations, and response window adjustments before the random access procedure begins. This preliminary configuration allows the UE to adapt to NTN-specific conditions (large propagation delays, varying pathloss) without real-time negotiation, reducing latency while maintaining reliability
Solution Approach 2:
The patent modifies multiple parameters simultaneously: transport block size for message A, power ramping values for preamble transmission, timing advance configurations, and response window durations. These parameter changes are specifically tailored for NTN conditions, allowing the system to overcome the contradiction between reliability and latency by optimizing each parameter for the high-latency environment
2Reliability
If power ramping is increased to improve reliability in varying pathloss conditions, then connection reliability improves, but power consumption increases
Solution Approach 1:
The patent implements dynamic power ramping where the UE adjusts transmit power based on predefined ramping values configured for NTN conditions. The power adjustment is dynamic and adaptive, increasing power only when necessary (e.g., after failed attempts or in high pathloss conditions) rather than maintaining high power continuously, thus balancing reliability with power consumption
Solution Approach 2:
The network provides preliminary power configuration including multiple power ramping values and thresholds before the random access procedure. The UE uses these pre-configured values to make informed power decisions, avoiding unnecessary power consumption while ensuring sufficient power is available when reliability is at risk
3Productivity
If transport block size is increased to carry more control information and uplink data, then communication efficiency improves, but the complexity of random access procedure increases
Solution Approach 1:
The patent merges control information (buffer status report, timing advance, other uplink data) into a single transport block carried in message A of the two-step random access procedure. This consolidation improves communication efficiency by reducing the number of separate transmissions needed, while the complexity is managed through pre-configuration of the transport block structure and size
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods, systems, and devices for wireless communication are described. A communication device, such as a user equipment (UE) may transmit, to a base station of a non-terrestrial network, a random access request message associated with a random access procedure using a transport block size (TBS) and a power control specified for the random access request message (e.g., a payload of the random access request message) for the random access procedure. The random access request message including a random access preamble and a random access payload carrying a buffer status report (BSR) or uplink data, or both. The UE may then monitor a response window based at least in part on transmitting the random access request message. The UE may receive, from the base station of the non-terrestrial network, a response message of the random access procedure during the response window.