Beam-Based Uplink Scheduling to Reduce 5G NR Misalignment
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Solution Overview
Problem
Uplink beam misalignment between the gNB and UE in mm-wave bands leads to inefficient and unreliable configured grant-based transmission in 5G NR networks, causing high latency and low reliability due to frequent retransmissions and beam failure.
Innovation Solution
Assign preconfigured resources for scheduling occasions that are mapped to specific beams, allowing UEs to transmit using shared resources without additional signaling, and enabling autonomous retransmissions to enhance beam alignment and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If configured grant-based transmission is used in mm-wave bands, then uplink data transmission can be performed without additional signaling, but beam misalignment occurs leading to transmission failure
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple uplink grants with different spatial relations (beams) before transmission. When the wireless device detects beam failure or misalignment, it can autonomously select and switch to a pre-configured grant with a different spatial relation without requiring additional signaling from the network, thus maintaining reliability while preserving ease of operation.
Solution Approach 2:
The patent changes the spatial relation parameter of the uplink transmission by allowing the wireless device to switch between different pre-configured grants that have different spatialRelationInfo parameters. This enables adaptation to changing beam conditions in mm-wave bands while maintaining the configured grant-based transmission mode.
2Reliability
If beam switching is implemented to handle misalignment, then transmission reliability improves, but transmission latency increases due to retransmissions
Solution Approach 1:
The patent eliminates retransmission delays by having the wireless device autonomously switch to a pre-configured grant with correct spatial relation upon detecting beam failure. The alternative grants are already configured with proper spatial parameters, allowing immediate retransmission without waiting for network signaling or acknowledgment, thus improving reliability while minimizing latency loss.
Solution Approach 2:
The wireless device performs self-service by autonomously detecting beam failure and selecting appropriate pre-configured grants without network intervention. This self-service mechanism allows immediate beam switching and retransmission, reducing the time loss that would otherwise occur due to signaling delays and network-coordinated beam recovery procedures.
3Reliability
If multiple preconfigured grants with different spatial relations are assigned, then beam misalignment is reduced, but device complexity increases
Solution Approach 1:
The patent segments the uplink grant configuration into multiple independent grants, each with distinct spatial relation parameters. This segmentation allows the wireless device to independently select and switch between grants based on beam conditions without managing a single complex configuration, reducing the complexity of beam management while improving alignment accuracy.
Solution Approach 2:
The patent uses multiple pre-configured grants as disposable fallback options. When one grant's spatial relation becomes misaligned, the device can discard it and immediately use another pre-configured grant without requiring complex real-time optimization or long-term management of spatial parameters. This approach reduces device complexity by using simple, pre-prepared transmission options.
Data Source
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AI summary
According to some embodiments, a method performed by a wireless device comprises obtaining an indication of an initial resource region. The initial resource region comprising time frequency resources, wherein the time frequency resources are divided into a plurality of scheduling occasions (SOs) and each of the plurality of SOs is associated with an uplink beam. The method further comprises: determining the wireless device has moved out of coverage of a first beam and that uplink resources associated with the first beam should no longer be used; selecting a second beam for uplink transmission; selecting a SO associated with the second beam from the initial resource region; and transmitting an initial transmission of uplink data in the selected SO using the second beam.