Opportunistic Downlink Retransmission via Dynamic Resource Reassignment
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE and NR technologies, face challenges in efficiently managing downlink resources, leading to issues with resource allocation and reliability, especially in mission-critical applications like factory automation where latency and reliability are stringent.
Innovation Solution
The implementation of an opportunistic retransmission scheme based on dynamic reassignment of downlink resources, where a base station identifies and reallocates resources to user equipment (UEs) that failed to acknowledge initial communications, using a predetermined resource reallocation scheme to ensure reliable and low-latency communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downlink resources are statically allocated to ensure reliable communication, then reliability is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent implements dynamic resource allocation where previously allocated downlink resources are reassigned to UEs that failed to decode initial transmissions. The base station identifies decoding failures through lack of ACK/NACK feedback and dynamically reallocates resources from successfully decoded UEs to those needing retransmission, creating a flexible system that adapts to actual communication needs rather than maintaining static allocations.
Solution Approach 2:
The system changes the allocation status parameter of downlink resources from fixed to variable. Resources are initially allocated to specific UEs but can be reassigned based on decoding outcomes. This parameter change enables the system to transition between guaranteed allocation (for reliability) and efficient sharing (for productivity) based on real-time communication success rates.
2Reliability
If retransmission resources are pre-allocated for all UEs, then reliability is improved, but resource waste increases
Solution Approach 1:
The system uses the feedback mechanism (or lack thereof) from UEs to self-identify which retransmissions are needed. UEs that successfully decode transmissions implicitly signal their success by not sending NACK, allowing the base station to automatically determine which resources should be reassigned without requiring explicit retransmission requests from each UE.
Solution Approach 2:
The patent recovers downlink resources from UEs that successfully decoded their transmissions and discards the original allocation, making these resources available for recovery/reassignment to UEs that failed to decode. This allows the system to reuse resources that would otherwise be wasted on successful transmissions for actual retransmission needs.
3Manufacturing precision
If individual scheduling messages are sent to each UE for resource reallocation, then allocation precision is improved, but signaling overhead increases
Solution Approach 1:
The patent merges multiple individual scheduling messages into a single group scheduling message that can reallocate resources for multiple UEs simultaneously. This group-based approach maintains precise resource allocation for each UE while dramatically reducing the total signaling overhead by consolidating what would otherwise require separate control messages for each affected UE.
Solution Approach 2:
The group scheduling message serves multiple functions: it identifies multiple UEs requiring retransmission, allocates specific resources to each UE, and coordinates the retransmission schedule all in a single message. This multi-functional approach replaces what would otherwise require multiple specialized messages, reducing overhead while maintaining allocation precision.
Data Source
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AI summary
In an embodiment, a BS transmits, on a set of resources, a first communication to each of a plurality of UEs. The BS receives ACKs to the transmitted first communications from a first subset of UEs, and determines that a second subset of UEs fails to ACK the transmitted first communication (via implicit or explicit NACKs). The BS configures a group scheduling message that indicates an allocation of the set of resources to the second subset of UEs (a different subset of the set of resources being allocated to each UE in the second subset of UEs) based on a predetermined resource reallocation scheme. The BS transmits the group scheduling message to the second subset of UEs, and transmits, on the set of resources, a second communication to each UE in the second subset of UEs in accordance with the indicated allocation from the group scheduling message.