IAB Relay Node Backhaul Beam Failure Recovery Signaling
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Solution Overview
Problem
In multi-hop Integrated Access and Backhaul (IAB) networks, legacy systems lack signaling mechanisms for an IAB Relay Node (RN) to inform its child nodes about backhaul beam failure, leading to lengthy connection disruptions and delayed route switches when beam failure recovery fails.
Innovation Solution
New signaling mechanisms are defined between an IAB RN and its child nodes for backhaul beam failure recovery, involving periodic reference signal decoding, beam failure detection, and preparation for link switchovers, with the RN encoding and transmitting BFR requests to the Donor Node (DN) based on candidate beam signal thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy systems are used without signaling mechanisms for backhaul beam failure notification, then device complexity is reduced, but connection reliability deteriorates due to lengthy disruptions and delayed route switches
Solution Approach 1:
The patent implements preliminary action by having the IAB RN proactively notify child nodes about backhaul beam failure conditions before complete link disruption occurs. The notification mechanism allows child nodes to prepare alternative routes in advance, preventing service interruption and enabling seamless handover to backup paths, thus resolving the contradiction between maintaining connection reliability and avoiding complex signaling.
2Loss of time
If new signaling mechanisms are implemented for backhaul beam failure recovery, then connection reliability improves through faster recovery, but device complexity increases due to additional signaling processes
Solution Approach 1:
The patent applies the extraction principle by isolating the backhaul beam failure notification function as a separate, dedicated signaling mechanism independent of existing beam failure recovery procedures. This extracted notification mechanism operates autonomously to alert child nodes about backhaul issues, enabling fast recovery without entangling the complexity of multiple intertwined protocols, thus reducing overall device complexity while maintaining fast recovery times.
Solution Approach 2:
The patent segments the failure management process into distinct functions: backhaul beam failure detection at the IAB RN, separate notification signaling to child nodes, and independent route switching at child nodes. This segmentation allows each component to operate efficiently with minimal complexity, resolving the contradiction between fast recovery and system simplicity.
3Measurement precision
If periodic reference signal decoding is performed for beam failure detection, then measurement precision improves for detecting beam failures, but use of energy increases due to continuous monitoring
Solution Approach 1:
The patent implements periodic action by configuring the IAB RN to decode periodic reference signals at specified intervals rather than continuously. This periodic monitoring maintains adequate beam failure detection precision while significantly reducing energy consumption compared to continuous monitoring, thus resolving the contradiction between measurement precision and energy usage.
Data Source
AI summary
Technology is disclosed for a relay node (RN) operable for backhaul beam failure recovery (BFR) in a fifth generation (5G) new radio (NR) integrated access and backhaul (IAB) network. The relay node can be configured to: decode a periodic reference signal for beam failure instance detection received from a donor node (DN); identify abeam failure between the RN and the DN, wherein the beam failure occurs when N beam failure instances are identified, wherein N is a positive integer; identify whether a candidate beam of one or more candidate beams at the RN has a reference signal greater than a threshold; prepare a BFR request; and encode the BFR request.