2-Step RACH Message A Power Control for 5G Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems, particularly in 5G networks, face challenges in efficiently performing the random access channel (RACH) procedure due to high latency and complexity, especially in scenarios requiring low latency and high reliability like ultra-reliable and low-latency communication (URLLC).
Innovation Solution
A 2-step RACH procedure is introduced, where a user equipment (UE) transmits a combined message including a physical random access channel (PRACH) and a physical uplink shared channel (PUSCH), with adaptive transmission power configuration based on a counter value and spatial filter changes, and receives contention resolution from the base station, optimizing power ramping and reducing the number of retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a 4-step RACH procedure is used, then compatibility with legacy systems is maintained, but latency and signaling overhead increase
Solution Approach 1:
The patent combines Message 1 (PRACH with preamble) and Message 3 (PUSCH with uplink data) into a single transmission called Message A. This merging reduces the number of RACH steps from 4 to 2, directly decreasing latency and signaling overhead while maintaining random access functionality in 5G NR systems.
Solution Approach 2:
The patent segments the RACH procedure into two distinct messages: Message A (combining PRACH and PUSCH) and Message B (containing random access response and contention resolution). This segmentation simplifies the overall procedure by eliminating redundant steps while preserving essential functions through adaptive power control and spatial filter management.
2Reliability
If transmission power is increased for retransmissions, then reliability improves, but energy consumption increases
Solution Approach 1:
The patent implements dynamic transmission power control for Message A retransmissions based on the counter value. The power level adapts according to the number of retransmission attempts, using higher power only when necessary to improve reliability while minimizing unnecessary energy consumption. The counter value dynamically adjusts power ramping behavior.
Solution Approach 2:
The patent changes the transmission power parameter adaptively based on the counter value and spatial filter status. When the spatial filter changes or the counter increments, the transmission power is adjusted accordingly. This parameter change ensures reliable delivery while optimizing energy usage by avoiding excessive power transmission.
3Reliability
If the number of retransmissions is increased, then delivery reliability improves, but latency increases
Solution Approach 1:
The patent uses feedback mechanisms where the UE monitors for Message B containing random access response and contention resolution. The counter value provides feedback on retransmission attempts, and the system adjusts power levels based on this feedback. This closed-loop feedback ensures reliable delivery while minimizing unnecessary retransmissions and associated latency.
4Productivity
If adaptive power control is implemented, then transmission efficiency improves, but system complexity increases
Solution Approach 1:
The patent implements self-service power control where the UE autonomously manages its own transmission power based on the counter value and spatial filter status. The UE independently determines when to increment the counter, when to maintain power levels, and how to adjust for retransmissions without requiring complex network coordination. This self-service approach improves efficiency while keeping the control mechanism relatively simple.
Data Source
AI summary
A method of transmitting and receiving a signal for a random access channel (RACH) procedure by a user equipment (UE) in a wireless communication system is disclosed. The method includes transmitting a message A including a physical random access channel (PRACH) and a physical uplink shared channel (PUSCH), and receiving a message B related to contention resolution in response to the message A. Transmission power for a retransmission of the message A is configured based on that a counter value related to the transmission power is incremented or maintained, the counter value is maintained based on that a transmission spatial filter related to the PRACH is changed for the retransmission of the message A, and the counter value is used for configuring the transmission power based on that the PRACH and the PUSCH are transmitted via the message A.