Per-link Redundancy Version Assignment for Uplink Relay Coverage
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Solution Overview
Problem
Current wireless communication systems face challenges in providing reliable uplink coverage for user equipment (UEs) due to variations in channel quality between UEs and base stations, leading to unsuccessful data transmissions and reduced system throughput.
Innovation Solution
Implementing per-link redundancy version assignment for uplink relays, where source UEs and relay UEs use non-overlapping subsets of redundancy version sequences for transmissions, allowing the relay UE to decode and retransmit data using self-decodable RVs, thereby enhancing coverage and combining multiple instances of communications at the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay UEs transmit uplink communications using the same redundancy version sequences as source UEs, then the base station receives redundant transmissions, but collision occurs between source UE and relay UE transmissions causing decoding failures
Solution Approach 1:
The patent segments the redundancy version sequences into distinct sets: a first set of redundancy versions for source UEs and a second set of redundancy versions for relay UEs. This segmentation prevents transmission collisions by ensuring that source UEs and relay UEs use different redundancy versions, allowing the base station to distinguish and properly decode transmissions from each source without interference.
2Loss of information
If relay UEs use different redundancy version sequences than source UEs, then transmission collisions are avoided, but the relay UE cannot decode source UE transmissions for retransmission
Solution Approach 1:
The patent applies parameter changes by configuring relay UEs with a mapping relationship between the first redundancy version set (used by source UEs) and the second redundancy version set (used by relay UEs). This mapping allows relay UEs to translate and decode source UE transmissions using their own redundancy version set, enabling successful decoding and retransmission while avoiding collisions at the base station.
3Device complexity
If the base station receives transmissions from both source UE and relay UE using the same RV sequence, then combining is simplified, but the base station cannot distinguish which transmission belongs to which source
Solution Approach 1:
The patent uses redundancy version assignments as identifying markers (analogous to color changes) to distinguish transmissions from different sources. By assigning different redundancy version sets to source UEs and relay UEs, the base station can identify which transmission originated from which source based on the redundancy version used, enabling proper processing while maintaining simplicity.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described for a relay UE and a source UE to provide transmissions of uplink communications in a decode and forward procedure in which redundancy version (RV) identifications of each instance of a transmission or retransmission are associated with a particular link of the source UE or relay UE. A set of RV sequences may be configured, with the source UE using a first subset of the RV sequences, and the relay UE using a second subset of RV sequences that is non-overlapping with the first subset. A base station or destination UE that receives the transmissions from the source UE and relay UE may thus receive RVs in accordance with the set of RV sequences.