Wireless Device Random Access Beam Fallback for Reliable NR Handovers
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Solution Overview
Problem
The existing random access procedures in New Radio (NR) wireless communication networks face challenges in efficiently handling handovers due to the use of narrow beams, which can lead to increased overhead, latency, and reduced performance, especially when beam refinement is required after handover, resulting in gaps in data rates and service quality.
Innovation Solution
A mechanism where wireless devices transmit preambles associated with both narrow and wide beams, monitoring for random access responses in multiple reception windows, allowing fallback to wide beams if narrow beam selection fails, thereby ensuring continuous communication during handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrow beams are used for random access in handover, then beam precision and data rate are improved, but overhead and latency increase, and reliability decreases when beam refinement is required
Solution Approach 1:
The random access procedure is segmented into two distinct phases: initial access using wide beams for reliable connection establishment, and subsequent refinement using narrow beams for optimized data transmission. This segmentation allows the system to benefit from both wide beam reliability and narrow beam precision without compromising handover success.
Solution Approach 2:
Wide beams are used in advance during the initial random access phase to establish a reliable connection before narrow beam refinement is attempted. This preliminary action ensures that the device has a stable connection in place before transitioning to more precise but riskier narrow beam operations.
2Productivity
If narrow beams are used for random access, then data rate is improved, but latency increases due to beam refinement requirements
Solution Approach 1:
The system performs preliminary wide beam access to establish connection quickly before attempting narrow beam refinement. This preliminary action reduces overall handover latency by ensuring initial connectivity is achieved rapidly, even if narrow beam optimization takes additional time.
Solution Approach 2:
The beam width is dynamically adjusted based on connection stage: wide beams during initial access for speed, transitioning to narrow beams during refinement for data rate optimization. This dynamic adaptation allows the system to balance latency and throughput requirements at different phases of the handover process.
3Measurement precision
If narrow beams are used for random access, then beam accuracy is improved, but overhead increases due to multiple access attempts
Solution Approach 1:
The access procedure segments beam usage by function: wide beams handle initial access and synchronization with minimal overhead, while narrow beams are reserved for subsequent data transmission where their precision provides value. This segmentation prevents unnecessary narrow beam overhead during critical access phases.
Solution Approach 2:
The system applies wide beams partially - only during the initial access phase rather than continuously. This partial application of wide beams reduces overall overhead while maintaining their benefits where most needed (initial connection establishment), allowing narrow beams to be used more efficiently in later stages.
Data Source
AI summary
Embodiments herein relate, e.g., to a method performed by a wireless device for handling communication in a wireless communication network. The wireless device transmits to a radio network node, a first preamble associated with a selected downlink beam. The wireless device further monitors for a random access response, RAR, in a first RAR reception window and when the RAR is not received in the first RAR reception window, monitors for the RAR in a second RAR reception window of a different beam or to transmit, to the radio network node, a second preamble associated with a second beam wherein the first preamble is associated with a channel state information reference signal and the second preamble is associated with a synchronization signal block.