RACH Procedure Configuration for Flexible Access in Unlicensed Spectrum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current random access channel (RACH) procedures in cellular networks are inflexible and inefficient, particularly in unlicensed spectrum bands, where multiple bandwidth parts (BWPs) are used, leading to suboptimal performance and increased interference due to fixed message flows and limited early data transmission capabilities.
Innovation Solution
A coordinated approach to configure RACH procedures between user equipment (UE) and base stations, allowing for selection among multiple configurations and using different BWPs for message transmission and early data transmission, enabling more flexible and efficient access methods, including two-step procedures and simultaneous use of multiple BWPs for enhanced payload capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed RACH procedure configuration is used in legacy systems, then the procedure is simple to implement, but it lacks flexibility and results in suboptimal performance in unlicensed spectrum bands
Solution Approach 1:
The patent implements dynamic RACH configuration by allowing the network to select and indicate different RACH procedure configurations (e.g., 2-step or 4-step procedures) based on current network conditions and UE capabilities. The configuration is no longer fixed but can be changed through RRC signaling, enabling the system to adapt between different RACH types dynamically.
Solution Approach 2:
The patent changes key parameters of the RACH procedure including the number of steps (2-step vs 4-step), the bandwidth parts used for different messages, and the timing relationships. These parameter changes are signaled to the UE through RRC configuration, allowing the system to optimize performance by adjusting parameters based on network conditions.
2Quantity of substance
If multiple bandwidth parts are used for RACH messages, then data transmission capacity increases, but interference between messages and increased complexity occur
Solution Approach 1:
The patent segments the RACH procedure messages across different bandwidth parts (BWPs). Specifically, message 1 (PRACH preamble) is transmitted in one BWP while message 2 (RAR) and subsequent messages are transmitted in another BWP. This segmentation allows simultaneous transmission of different messages in frequency-divided resources, increasing overall capacity while reducing interference between messages.
Solution Approach 2:
The patent introduces an additional frequency dimension by using multiple bandwidth parts for different RACH messages. Instead of transmitting all messages in a single BWP, the system utilizes the frequency domain resource division, allowing parallel transmissions in different frequency ranges, thereby increasing transmission capacity and reducing mutual interference.
3Productivity
If early data transmission is enabled during RACH procedure, then network access efficiency improves, but message handling complexity increases
Solution Approach 1:
The patent merges the early data transmission function with the existing RACH procedure message structure. Data can be transmitted alongside RACH messages (particularly in message 3 or message 4) without requiring a separate transmission procedure. This integration allows efficient data transmission during the access procedure while utilizing existing message handling mechanisms.
4Productivity
If RACH procedure messages are transmitted in one BWP and network responses in another BWP, then resource utilization improves, but synchronization complexity increases
Solution Approach 1:
The patent applies preliminary action by configuring the UE with multiple bandwidth parts and their associated parameters before the RACH procedure begins. The network provides BWP configuration information including frequency locations, bandwidths, and timing relationships in advance through RRC signaling. This preliminary configuration enables the UE to properly synchronize and transmit/receive messages in different BWPs without requiring complex real-time synchronization decisions.
Data Source
AI summary
Configuring a random access channel (RACH) procedure in a wireless communication network may include selecting one of plural RACH procedure configurations for a radio communication device to employ to initiate access with the wireless communication network and communicating the selected RACH procedure configuration to the radio communication device.