Uplink Timing Derivation via TRP-Specific Downlink Reference Signals
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Solution Overview
Problem
In wireless communication networks with multiple transmission and reception points (TRPs), existing systems assume full time and frequency synchronization among TRPs, which may not always be true, leading to challenges in deriving accurate timing and frequency for uplink transmission.
Innovation Solution
A network node configures and indicates a specific downlink reference signal for a wireless device to use for deriving uplink transmission parameters, establishing a semi-static or dynamic time or frequency relation, allowing for accurate timing and frequency derivation even when TRPs are not fully synchronized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If full time and frequency synchronization among TRPs is assumed, then system complexity is reduced and ease of operation is improved, but measurement precision and reliability of uplink transmission deteriorate when synchronization is not actually achieved
Solution Approach 1:
The patent segments the downlink reference signals into multiple TRP-specific signals (first DL RS from first TRP, second DL RS from second TRP). The wireless device separately processes each DL RS to derive uplink parameters, allowing independent timing and frequency adjustment for each TRP without requiring global synchronization across all TRPs.
Solution Approach 2:
The patent applies local quality by allowing different uplink transmission parameters to be derived for different TRPs based on their respective DL RS characteristics. Each TRP can have its own timing advance and frequency offset values, optimizing the uplink transmission quality specifically for that TRP rather than using a single global parameter set.
2Device complexity
If a single downlink reference signal is used for uplink parameter derivation, then device complexity is reduced, but adaptability to multiple TRPs with different synchronization states deteriorates
Solution Approach 1:
The patent implements dynamics by enabling the wireless device to dynamically select which DL RS to use for deriving uplink parameters based on the target TRP. The system can adaptively switch between using the first DL RS, second DL RS, or both, depending on which TRP the uplink transmission is intended for, providing flexibility without significantly increasing device complexity.
Solution Approach 2:
The patent achieves universality by designing a framework where multiple DL RS serve multiple purposes: each can independently provide timing and frequency references for uplink transmissions to its corresponding TRP. The same DL RS can also be used for other functions like channel estimation and quality measurement, maximizing the utility of the reference signals.
3Adaptability or versatility
If TRPs operate without full synchronization, then deployment flexibility and adaptability to diverse scenarios are improved, but the reliability of uplink transmission parameter derivation deteriorates
Solution Approach 1:
The patent introduces the DL RS as an intermediary between each TRP and the wireless device for parameter derivation. The network node configures and indicates specific DL RS as intermediaries that carry the necessary timing and frequency information from each TRP to the device, ensuring reliable parameter derivation even when TRPs are not synchronized with each other.
Solution Approach 2:
The patent implements feedback mechanisms where the network node monitors the uplink transmission quality and can reconfigure or reindicate DL RS for parameter derivation. Based on observed performance, the network can provide feedback to adjust which DL RS is used or how parameters are derived, maintaining reliability in asynchronous TRP operations.
Data Source
AI summary
A method, system and apparatus are disclosed. According to some embodiments, a network node is provided which is configured to communicate with a wireless device using at least one of a plurality of transmission and reception points, TRPs. The network node includes processing circuitry configured to indicate to the wireless device a first downlink reference signal, DL RS, of a plurality of downlink reference signals, DL RSs, to use for deriving an uplink, UL, transmission parameter for an UL transmission, each of the plurality of DL RSs being associated with a respective one of the plurality of TRPs. The processing circuitry is further configured to receive the UL transmission, the UL transmission being based on the derived UL transmission parameter.