Network-Indicated Precoder Sequence for Uplink
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Solution Overview
Problem
Wireless communication systems face high signaling overhead and latency in indicating precoding parameters, especially for reduced capability devices like industrial sensors and video surveillance cameras, due to frequent changes in channel conditions.
Innovation Solution
A network-indicated precoder sequence is configured by a base station to indicate a sequence of precoding parameters for multiple uplink messages, reducing the need for frequent parameter updates by using previously transmitted sounding reference signals to predict optimal precoding settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequent signaling of precoding parameters is used to adapt to channel changes, then communication reliability is improved, but signaling overhead increases
Solution Approach 1:
The base station performs preliminary channel estimation using sounding reference signals (SRS) transmitted by the UE, and pre-determines a sequence of precoding parameters before actual uplink data transmission. This preliminary action allows the system to adapt to channel changes without requiring frequent real-time signaling during data transmission, thereby reducing signaling overhead while maintaining communication reliability.
Solution Approach 2:
The system dynamically adjusts the precoding parameters based on the estimated channel conditions from SRS. The base station generates a time-varying sequence of precoding parameters that adapts to channel changes, allowing the system to maintain reliability while using a more efficient signaling mechanism compared to frequent real-time updates.
2Productivity
If frequent signaling of precoding parameters is used to maximize link throughput, then spectral efficiency is improved, but latency increases
Solution Approach 1:
The base station performs channel estimation and determines the precoding parameter sequence in advance, before actual data transmission begins. This preliminary action eliminates the need for iterative feedback and adjustment during transmission, thereby reducing signaling latency while maintaining the ability to maximize link throughput through adaptive precoding.
Solution Approach 2:
The system establishes a continuous precoding parameter sequence that spans multiple uplink transmissions without requiring intermittent signaling interruptions. This continuous approach allows data transmission to proceed without breaks for parameter updates, reducing latency while maintaining spectral efficiency through adaptive precoding throughout the transmission sequence.
3Measurement precision
If codebook-based precoding with frequent parameter updates is used, then directional beam accuracy is improved, but device complexity increases
Solution Approach 1:
The base station performs the complex channel estimation and precoding parameter determination in advance using SRS, before actual data transmission. This shifts the computational complexity from the reduced-capability UE to the base station, allowing the UE to simply apply predetermined precoding parameters without performing complex real-time calculations, thereby maintaining beam accuracy while reducing device complexity.
Solution Approach 2:
The sounding reference signal (SRS) acts as an intermediary that carries channel information from the UE to the base station. The base station uses this intermediary information to determine the precoding parameter sequence, eliminating the need for the UE to perform complex real-time channel analysis and parameter selection, thus reducing device complexity while maintaining directional beam accuracy.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. To indicate a precoder sequence for uplink transmissions, a base station may transmit a message to a UE that configures a sequence of at least two sets of precoding parameters. Each set of precoding parameters may correspond to an uplink message. For example, a first set of precoding parameters of the sequence may correspond to a first uplink message and a second set of precoding parameters of the sequence may correspond to a second uplink message that is subsequent to the first uplink message in a time domain. The UE may receive the message and transmit, to the base station, the first uplink message using the first set of precoding parameters and the second uplink message using the second set of precoding parameters based on the sequence of the at least two sets of precoding parameters.