Random Access Preamble Transmission for Beam Failure Recovery
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Solution Overview
Problem
Current wireless communication systems face challenges in the random access process, particularly in beam failure recovery, where existing methods suffer from high latency in contention-based processes and insufficient uplink channel information for initial access, leading to inefficiencies in both LTE and NR systems.
Innovation Solution
The proposed solution involves transmitting additional information related to the terminal device, such as a cell radio network temporary identifier (C-RNTI), transmission beam power, and modulation and coding schemes, alongside the random access preamble, to facilitate faster beam recovery and resource allocation, thereby reducing latency and improving access efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If contention-based random access process is used for beam failure recovery, then the process can handle multiple devices, but the time latency increases significantly
Solution Approach 1:
The network pre-allocates dedicated random access preambles to specific devices or device groups before beam failure occurs. When beam failure detection happens, the affected device immediately uses its pre-assigned preamble for recovery, eliminating the contention resolution steps and reducing latency while maintaining multi-device capability through individual preamble assignments
2Loss of time
If non-contention based random access is used, then the time latency is reduced, but the number of available preambles is limited
Solution Approach 1:
The set of random access preambles is segmented and allocated to different devices or device groups based on their specific needs and beam failure scenarios. Each device receives a dedicated subset of preambles, effectively expanding the available preamble resources beyond the traditional limited set while maintaining the low-latency non-contention characteristics
3Productivity
If initial access is performed without uplink channel information, then the access process can start immediately, but the network cannot allocate resources efficiently
Solution Approach 1:
The network performs preliminary channel estimation and uplink quality assessment during the random access preamble transmission phase. By analyzing the received preamble signal characteristics, the network obtains uplink channel information in advance, enabling immediate and efficient resource allocation without delaying the access process
Data Source
AI summary
Embodiments of the present disclosure relate to methods, terminal devices, network nodes and apparatus for random access process in a wireless network. The method at the terminal device may comprise: receiving additional information related to a terminal device together with a random access preamble. With embodiments of the present disclosure, the additional information related to a terminal device can be transmitted to the network node together with a random access preamble; in such a case, further useful information is available for the eNB, which might substantially facilitate the random access process for either initial access or non-initial access.