Multi-Beam Random Access Preamble Power Allocation
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Solution Overview
Problem
In communication systems, terminal devices experience difficulty in reliably accessing a network due to low received power of random access preamble sequences, especially when far from the network device and in unfavorable environments, leading to access failures.
Innovation Solution
The terminal device sends the random access preamble sequence on multiple beams, adjusting transmit powers based on path losses and signal reception strengths to ensure the combined power received by the network device meets a target level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device sends the random access preamble sequence multiple times using the same transmit power, then the terminal device attempts to compensate for path loss, but the combined power at the network device is still less than the expected value
Solution Approach 1:
The patent applies local quality by differentiating transmit powers across different beams based on their individual channel conditions. Each beam's transmit power is calculated considering its specific path loss and signal reception strength, allowing optimal power allocation to each beam rather than using a uniform power level for all beams.
Solution Approach 2:
The patent changes the power parameter dynamically for each beam transmission. The transmit power for each beam is calculated as: P_i = min(P_MAX, P_TARGET + PL_i), where P_MAX is maximum transmit power, P_TARGET is target received power, and PL_i is path loss of beam i. This parameter adaptation ensures each beam achieves adequate received power while respecting device capabilities.
2Reliability
If the terminal device uses a single beam for transmission, then the device complexity is reduced, but the reception success rate is low due to poor signal
Solution Approach 1:
The patent segments the transmission process across multiple beams, where each beam carries a portion of the total required transmit power. The terminal device divides the transmission task into multiple beam-specific transmissions, each optimized for its channel conditions, thereby achieving higher reception success rate through distributed power transmission.
Solution Approach 2:
The patent introduces dynamic power adjustment for each beam based on real-time channel conditions. The transmit power for each beam is calculated dynamically considering path loss and signal reception strength, allowing the system to adapt to varying channel conditions and optimize power distribution across beams.
3Power
If the terminal device transmits on multiple beams with different powers, then the combined received power meets the target level, but the power control complexity increases
Solution Approach 1:
The patent implements self-service power control where the terminal device autonomously calculates and adjusts transmit powers for each beam based on its own channel measurements. The device uses its own path loss estimates and signal reception strength data to determine optimal power levels, eliminating the need for complex network-side power control mechanisms.
Solution Approach 2:
The patent employs feedback mechanisms where the terminal device continuously monitors signal reception strength on each beam and adjusts transmit powers accordingly. The power calculation incorporates feedback about actual channel conditions, allowing iterative optimization of power distribution to meet target received power while managing complexity.
Data Source
AI summary
A terminal device receives random access signaling from a network device, where the random access signaling includes an initial received power at which the network device receives a random access preamble sequence. A total target received power of the network device is determined based on the initial received power, and N transmit powers are determined for N transmissions of the random access preamble sequence on M beams, where a sum of N first powers corresponding to the N transmit powers is not less than the total target received power, the N first powers are powers obtained by subtracting path losses from the N transmit powers, and signal reception strength on the M beams is not exactly the same, where M is an integer greater than or equal to 2, and N is greater than or equal to M.