Small Data Transmission in RRC Inactive State
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems, particularly 5G NR, face challenges in efficiently performing small data transmission (SDT) while a user equipment (UE) is in an RRC_INACTIVE state, leading to increased power consumption due to the need for RRC state transitions for infrequent small UL data transmissions.
Innovation Solution
The method involves initiating a Random Access (RA) procedure with a Base Station (BS) while in an RRC_INACTIVE state, transmitting a preamble, receiving a Random Access Response (RAR), and subsequently transmitting UL data without switching to an RRC_CONNECTED state by using specific search spaces and RNTIs for data transmission and reception, allowing SDT to occur without state transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transitions to RRC_CONNECTED state for small data transmission, then data transmission capability is improved, but power consumption increases
Solution Approach 1:
The patent segments the data transmission process into two parts: small data transmission occurs in RRC_INACTIVE state using simplified procedures, while only larger or more complex data transmissions require transition to RRC_CONNECTED state. This segmentation allows the UE to maintain low power consumption for routine small data exchanges while preserving full capability when needed.
Solution Approach 2:
The patent extracts the small data transmission functionality from the traditional RRC state transition requirement, allowing it to occur independently in the RRC_INACTIVE state. This extraction eliminates the need for full state transitions for small data, thereby reducing power consumption while maintaining transmission capability.
2Use of energy by moving object
If the UE remains in RRC_INACTIVE state for small data transmission, then power consumption is reduced, but data transmission efficiency deteriorates
Solution Approach 1:
The patent introduces dynamic resource allocation and adaptive procedure selection for small data transmission in RRC_INACTIVE state. The network can dynamically allocate uplink resources and adjust transmission parameters based on traffic conditions, while the UE can adaptively choose between different transmission modes (e.g., configured grant vs. random access), thereby maintaining efficiency without requiring state transition.
Solution Approach 2:
The patent changes key transmission parameters such as allocating specific uplink resources, adjusting grant configurations, and modifying random access procedures to optimize small data transmission in RRC_INACTIVE state. These parameter adjustments enable efficient data transmission while the UE remains in the lower-power inactive state.
3Reliability
If traditional RRC state transition procedure is used for small data, then connection reliability is improved, but latency increases
Solution Approach 1:
The patent performs preliminary actions by pre-configuring uplink resources and transmission parameters while the UE is in RRC_INACTIVE state. This allows small data transmission to begin immediately without waiting for state transition, thereby eliminating transition latency while maintaining connection reliability through pre-established configurations.
Solution Approach 2:
The patent skips the traditional RRC state transition step for small data transmission by enabling direct transmission in RRC_INACTIVE state. This skipping of the intermediate state transition phase eliminates the associated latency while maintaining sufficient reliability through adapted transmission procedures.
Data Source
AI summary
A UE and a method for SDT are provided. The method includes initiating a RA procedure with a BS while the UE is in an RRC_INACTIVE state; transmitting a preamble; receiving a RAR scheduled by first DCI with CRC bits scrambled by a RA-RNTI on a first search space; transmitting first UL data on a first UL resource, being not from a CCCH, scheduled by the RAR; monitoring the first search space for receiving first DL data scheduled by second DCI with CRC bits scrambled by a TC-RNTI indicated by the RAR; applying the TC-RNTI as a C-RNTI while receiving the first DL data; monitoring the second search space for a second UL resource scheduled by third DCI with first CRC bits scrambled by the C-RNTI if the first DL data indicates the search space configuration; otherwise, monitoring the first search space for the second UL resource.