Uplink Transmission Parameter Selection During Random Access
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Solution Overview
Problem
In wireless communication systems, particularly in mmW and NR systems, user equipment (UE) faces challenges in successfully transmitting random access messages due to changing communication conditions, leading to inefficiencies in uplink transmission parameter selection during random access message transmission and retransmission.
Innovation Solution
The method involves identifying a first uplink transmission beam and power for a random access preamble, receiving a response, and then selecting a second uplink transmission beam and power based on path loss differences to optimize the transmission of a connection request message, allowing for adaptive parameter adjustment during retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the UE uses the same transmission parameters (beam, power, resource) for the second directional transmission as for the initial transmission, then the transmission process is simple, but the transmission reliability decreases when communication conditions change
Solution Approach 1:
The patent implements dynamic transmission parameter selection where the UE adapts its transmission beam, power, and resource based on current communication conditions. The UE determines whether to reuse initial transmission parameters or select new parameters by evaluating channel quality indicators and path loss changes, making the system flexible rather than static.
Solution Approach 2:
The patent employs feedback mechanisms where the UE monitors the reception status of its transmissions and adjusts subsequent transmission parameters accordingly. When the UE does not receive an acknowledgment for its second transmission, it uses feedback from channel measurements to determine whether to retransmit with the same or different parameters, improving reliability through iterative adaptation.
2Reliability
If the UE dynamically adjusts transmission parameters based on changing conditions, then the message reception reliability improves, but the device complexity and computational overhead increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing criteria and thresholds for parameter adjustment before actual transmission occurs. The UE is configured with reference values for path loss, channel quality indicators, and power adjustment thresholds that guide its real-time decision-making, reducing computational complexity during active communication.
Solution Approach 2:
The patent systematically changes transmission parameters (beam direction, transmission power, time-frequency resources) based on measured communication conditions. The UE compares current channel measurements against reference values and adjusts parameters in a controlled manner, balancing reliability improvement with manageable complexity through structured parameter adaptation.
3Reliability
If the UE retransmits the second RACH message multiple times with parameter adjustments, then the probability of successful reception increases, but the transmission time and energy consumption increase
Solution Approach 1:
The patent implements dynamic retransmission strategies where the UE adapts its retransmission behavior based on channel conditions. Rather than fixed retransmission schedules, the UE dynamically determines whether to retransmit and with what parameters based on real-time channel quality assessments, optimizing the balance between success probability and time consumption.
Solution Approach 2:
The patent changes transmission parameters during retransmissions to improve success probability. The UE adjusts beam direction, power level, and resource selection based on measured path loss and channel conditions, allowing fewer retransmission attempts by making each transmission more likely to succeed through parameter optimization.
4Reliability
If the UE increases transmission power for retransmissions, then the message reception reliability improves, but the energy consumption increases
Solution Approach 1:
The patent adjusts transmission power as a variable parameter based on measured communication conditions. The UE compares current path loss against reference values and dynamically sets transmission power levels, using higher power only when channel conditions warrant it, thereby optimizing the trade-off between reception reliability and energy consumption.
Solution Approach 2:
The patent employs feedback-based power control where transmission power adjustments are driven by measured channel conditions and reception outcomes. The UE uses feedback from channel quality indicators and path loss measurements to determine appropriate power levels, avoiding unnecessary energy expenditure while maintaining reliable communication.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described for selecting different uplink transmission parameters for transmission or retransmission of a random access message. A user equipment (UE) may transmit or retransmit a random access message such as a layer 2 or layer 3 (L2/L3) message to a base station during a random access procedure. The UE may select a transmission beam, uplink resource or transmission power for the transmission of the L2/L3 message that differ from those used for transmission of a previous random access message. The selection may be based on path loss associated with synchronization signals or previous transmissions. The selection may also be based on a maximum number of retransmissions.