2-Step Random Access for Low-Latency Buffer Status Reporting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing wireless communication networks face significant latency issues in transmitting Buffer Status Reports (BSR) due to the need for multiple Listen-Before-Talk (LBT) procedures and Random Access (RA) processes, especially in unlicensed spectrum and non-terrestrial networks, which hinder efficient uplink data transmission.
Innovation Solution
Implementing a 2-step Random Access (RA) procedure specifically tailored for BSR transmissions, including dedicated resource configurations, conditions for triggering BSR, and simplified response procedures to reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional 4-step Random Access procedure is used for BSR transmission, then reliability of random access is improved, but latency is increased due to multiple LBT procedures and longer access time
Solution Approach 1:
The patent segments the traditional 4-step RA procedure into a simplified 2-step procedure by combining Message 1 (preamble) and Message 3 (BSR) into a single MsgA transmission, and combining Message 2 (RAR) and Message 4 (contention resolution) into a single MsgB transmission. This segmentation reduces the number of LBT procedures from 4 to 2, directly addressing the latency issue while maintaining reliability through preserved contention resolution mechanisms.
Solution Approach 2:
The patent merges multiple message exchanges into fewer transmissions. Specifically, MsgA combines the random access preamble and BSR report into a single uplink transmission, while MsgB combines the random access response and contention resolution into a single downlink transmission. This merging reduces procedural steps and LBT requirements, solving the latency contradiction.
2Reliability
If multiple LBT procedures are performed before BSR transmission, then channel access reliability is improved, but communication efficiency deteriorates due to increased access delay
Solution Approach 1:
The patent performs preliminary channel access by incorporating LBT procedures into the simplified 2-step RA framework. The gNB configures specific RA resources that include LBT requirements, allowing the UE to perform channel access as part of the MsgA transmission. This preliminary action maintains reliability while reducing overall access delay compared to traditional multi-step procedures.
Solution Approach 2:
The patent changes the parameters of the RA procedure by reducing the number of steps from 4 to 2, and consequently reducing the number of LBT procedures. The gNB configures specific parameters for the 2-step RA including preamble formats, time resources, and LBT requirements, optimizing the balance between reliability and efficiency for BSR transmissions.
3Productivity
If 2-step RA procedure is implemented for BSR, then latency is reduced and productivity is improved, but device complexity increases due to new configuration requirements
Solution Approach 1:
The patent creates a universal 2-step RA procedure that can be used for multiple purposes including BSR transmission, initial access, and other uplink data transmissions. The gNB configures 2-step RA resources that can serve different functions, reducing the need for separate configuration mechanisms and thereby managing complexity while improving productivity.
Solution Approach 2:
The gNB acts as an intermediary that manages the complexity of 2-step RA configuration. It provides detailed configuration information including preamble formats, time resources, frequency resources, and LBT parameters through system information or dedicated signaling. This intermediary role shields the UE from excessive complexity while enabling efficient BSR transmission.
4Productivity
If dedicated 2-step RA resources are allocated for BSR, then resource utilization is optimized and productivity improved, but device complexity increases due to resource management overhead
Solution Approach 1:
The patent implements dynamic resource allocation for 2-step RA where the gNB can configure and adjust RA resources based on traffic conditions, UE capabilities, and network state. The configuration includes dynamic parameters such as preamble formats, time resource assignments, and frequency resource allocations that can be adapted to optimize resource utilization while managing complexity through standardized configuration mechanisms.
Data Source
AI summary
Buffer Status Reports (BSR), by which the network is made aware of uplink transmission needs of wirless devices, are specifically enabled to be transmitted using 2-step Random Access (RA), to reduce latency and network resource use. In one embodiment, 2-step RA configurations tailored to BSR-transmissions are introduced. These may, for example, use a subset of the configured resources in the configured 2-step RA resources for BSR. In another embodiment, conditions for triggering BSR over 2-step RA, depending on the traffic, are introduced. For example, the priority or the the delay budget of the traffic may be used to determine whether a BSR over 2-step RA should be triggered. In another embodiment, simplified procedures when receiving the response to MsgA are introduced. These may include, for example, not transmitting a full MsgB, but rather having the UE receive an UL grant.