RACH Preamble Count Determination for Wireless Access
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Solution Overview
Problem
In wireless communication systems, User Equipment (UE) faces challenges in determining the optimal number of Random Access Channel (RACH) preamble messages to transmit, balancing reception likelihood at the base station with the ability to receive further RACH messages in response.
Innovation Solution
The UE determines the number of RACH preamble messages to transmit based on its capability to simultaneously monitor for Random Access Responses (RARs), using reference signals received from the base station, and by indicating its capabilities to the base station for resource configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE increases the number of RACH preamble messages transmitted, then the likelihood of reception at the base station improves, but the ability of the UE to receive further RACH messages in response deteriorates
Solution Approach 1:
The UE dynamically adjusts the number of RACH preamble messages transmitted based on its current operational state, including its ability to simultaneously monitor for RAR messages. The system transitions between different transmission strategies depending on real-time conditions, optimizing the balance between reception reliability and response monitoring capability.
Solution Approach 2:
The patent changes the parameter of transmission number by adjusting it according to the UE's monitoring capability. The UE determines an appropriate number of preamble messages to transmit based on parameters such as the number of simultaneous RAR messages it can monitor, thereby adapting the transmission parameter to system constraints.
2Productivity
If the UE transmits multiple RACH preamble messages within a short time frame, then the speed of RACH procedure initiation improves, but the complexity of determining the optimal number of transmissions worsens
Solution Approach 1:
The UE autonomously determines the optimal number of RACH preamble messages to transmit by evaluating its own capability to simultaneously monitor for RAR messages. The system uses self-assessment of monitoring capacity to make transmission decisions, eliminating the need for complex external coordination or trial-and-error approaches.
3Productivity
If the base station sends multiple RACH transmission opportunities within a short time frame, then the productivity of RACH procedure improves, but the difficulty of UE monitoring for responses worsens
Solution Approach 1:
The UE performs preliminary assessment of its monitoring capability before initiating RACH transmissions. By determining in advance how many RAR messages it can simultaneously monitor, the UE prepares an appropriate transmission strategy that aligns with its monitoring capacity, avoiding situations where transmission opportunities exceed monitoring ability.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. In some systems, base stations and user equipment (UEs) may use beamforming for transmitting random access channel (RACH) messages. A UE may transmit multiple RACH preamble messages (e.g., within a random access response (RAR) window) to initiate a RACH procedure. The UE may transmit the RACH preamble messages in transmission opportunities corresponding to reference signals received from the base station. In some cases, the UE may determine the number of RACH preamble messages to transmit within the RAR window based on an ability of the UE to simultaneously monitor for a RAR message in response to each of the transmitted messages. In other cases, the UE may transmit an indication of UE capabilities to the base station. The base station may determine a RACH resource configuration for the UE based on the capabilities and may indicate the configuration to the UE.