UE Cyclic Delay Reporting for Accurate Uplink Channel Measurement
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Solution Overview
Problem
In wireless communications systems, the lack of knowledge about cyclic delay diversity (CDD) values at the receiving device leads to inaccurate channel measurements and decoding, resulting in degraded channel quality and service.
Innovation Solution
User Equipment (UE) reports cyclic delay values to the network entity, enabling accurate channel measurements and decoding by transmitting SRSs or PUSCH signals based on calculated SD-CDD values, using control signaling to allocate resources and indicate these values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic delay diversity (CDD) values are applied for signal transmission via multiple antennas, then transmission diversity and signal reliability are improved, but the receiving device lacks knowledge of these values leading to inaccurate channel measurements and decoding
Solution Approach 1:
The UE explicitly reports the CDD values used for signal transmission to the network entity through feedback signaling. This feedback mechanism ensures that the network entity receives accurate channel state information including the CDD values, enabling proper channel measurements and decoding while maintaining the diversity benefits of CDD transmission
Solution Approach 2:
The patent introduces an intermediary reporting mechanism that conveys CDD value information from the UE to the network entity. This intermediary channel carries the necessary metadata about CDD values without requiring changes to the primary signal transmission path, resolving the information loss problem while preserving transmission reliability
2Measurement precision
If CDD values are reported by UE to network entity, then channel measurement accuracy is improved, but additional signaling overhead and processing complexity are introduced
Solution Approach 1:
The network entity configures the UE with CDD values or indicates expected CDD patterns in advance through control signaling. This preliminary configuration reduces the need for extensive feedback reporting, as the UE can directly use pre-configured values, thereby reducing signaling overhead while maintaining measurement accuracy
Solution Approach 2:
The patent employs parameter mapping and encoding techniques to represent CDD values efficiently in the feedback signaling. By changing how the information is encoded and mapped to existing signaling structures, the patent reduces the overhead required to convey CDD values while maintaining complete information for accurate channel measurements
3Reliability
If multiple instances of signals are transmitted via respective antennas with different cyclic delays, then diversity gain is improved, but the complexity of signal processing and synchronization at the receiving device increases
Solution Approach 1:
By providing feedback about the CDD values used, the patent enables the network entity to properly compensate for the delays during signal processing. This feedback allows the receiving device to adjust its processing parameters to account for the introduced delays, maintaining diversity gain while managing processing complexity through informed processing decisions
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. In some examples, a user equipment (UE) may receive control signaling allocating one or more uplink resources. The UE may transmit an indication of one or more cyclic delay values in accordance with receiving the control signaling, where each cyclic delay value of the one or more cyclic delay values may correspond to a delay between one or more instances of a signal, where each instance of the signal may be transmitted via a respective antenna at the UE. The UE may transmit one or more uplink signals in accordance with the one or more cyclic delay values, in accordance with the control signaling, or both.