Uplink Channel Estimation via Downlink Delay Information
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Solution Overview
Problem
In time division duplex (TDD) multiple input multiple output (MIMO) technology, the low uplink transmit power and strong interference result in a low signal-to-interference plus noise ratio, making it difficult to accurately estimate uplink channel information using sounding reference signals (SRS).
Innovation Solution
A communication method that involves sending uplink pilot signals and receiving downlink pilot signals to determine a delay information set, which is then used for improved uplink channel estimation by jointly considering the delay information with the uplink pilot signals, allowing for more accurate channel estimation without increasing SRS overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uplink transmit power is increased to improve signal quality, then signal-to-interference plus noise ratio improves, but uplink power consumption increases and may cause interference to other users
Solution Approach 1:
The patent introduces downlink pilot signals and delay information as intermediaries to indirectly obtain uplink channel characteristics. Instead of directly transmitting high-power uplink pilot signals, the system uses downlink pilot signals (which have higher power) to estimate channel delay information, which then serves as a reference for uplink channel estimation. This mediator approach allows accurate channel estimation without increasing uplink power consumption.
Solution Approach 2:
The patent inverts the traditional channel estimation approach by using downlink channel information to estimate uplink channel characteristics. Instead of sending uplink pilot signals for direct estimation, the system transmits downlink pilot signals and uses the received delay information to infer uplink channel properties. This inversion leverages the higher downlink transmit power to achieve what would otherwise require high uplink power.
2Measurement precision
If traditional uplink channel estimation methods are used, then implementation is simple, but estimation accuracy is poor due to low signal-to-interference plus noise ratio
Solution Approach 1:
The patent performs preliminary channel characterization by obtaining downlink delay information before uplink channel estimation. The system first transmits downlink pilot signals, estimates the downlink channel delay profile, and uses this pre-obtained delay information as a foundation for subsequent uplink channel estimation. This preliminary action provides a structural framework that simplifies the final estimation process while improving accuracy.
Solution Approach 2:
The patent uses downlink delay information as an intermediary to bridge the gap between downlink and uplink channel characteristics. This intermediary provides a reference framework that guides the uplink channel estimation process, allowing the system to achieve high accuracy without requiring complex direct uplink measurement methods. The delay information acts as a mediator that translates downlink observations into uplink predictions.
Data Source
AI summary
This application provides a communication method and apparatus, so that a terminal device sends uplink pilot signals, the terminal device obtains a first delay information set based on downlink pilot signals from a network device, and the network device jointly considers the first delay information set and the uplink pilot signals to perform uplink channel estimation. The first delay information set may indicate a delay position of a strong path, and uplink channel estimation accuracy can be improved.