Aperiodic SRS Triggering via PDCCH for Wireless Channel Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, the method of assigning reference signals between data subcarriers leads to low density and deteriorated channel estimation performance, while assigning them to all subcarriers increases data throughput but reduces data transmission, necessitating a method to properly arrange reference signals for improved channel estimation.
Innovation Solution
A method for transmitting an aperiodic sounding reference signal (SRS) by a user equipment (UE) in a wireless communication system, where the UE receives a downlink control information (DCI) format with a triggering signal via a physical downlink control channel (PDCCH) and transmits the aperiodic SRS based on this signal, allowing for dynamic triggering of SRS transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference signals are assigned to all subcarriers, then channel estimation performance is improved, but data transmission capacity is reduced
Solution Approach 1:
The patent segments reference signals into different types (DMRS for demodulation and SRS for channel sounding) with different functions and transmission characteristics. DMRS is transmitted on specific subcarriers paired with data, while SRS is transmitted on dedicated subcarriers, allowing the system to obtain channel information without requiring reference signals on all subcarriers, thus balancing estimation performance with data capacity
Solution Approach 2:
The patent introduces a new dimension for channel estimation by adding SRS transmission in the frequency domain on specific subcarriers, complementing the time-domain DMRS approach. This multi-dimensional reference signal structure enables accurate channel estimation without occupying all subcarriers, resolving the contradiction between estimation accuracy and data throughput
2Productivity
If reference signals are assigned between data subcarriers, then data transmission capacity is increased, but channel estimation performance is deteriorated
Solution Approach 1:
The patent applies local quality by assigning reference signals to specific local regions (subcarriers) rather than uniformly distributing them. DMRS is placed locally adjacent to data subcarriers for demodulation, while SRS is placed on dedicated subcarriers for channel sounding, allowing accurate local channel estimation without sacrificing overall data capacity
3Reliability
If periodic SRS transmission is used, then channel information is continuously available, but system resources are wasted when channel estimation is not needed
Solution Approach 1:
The patent implements dynamic SRS transmission controlled by triggering mechanisms (implicit triggering via PDCCH, explicit triggering, or aperiodic triggering). The UE transmits SRS only when triggered by the base station, allowing the system to adapt channel estimation activity to actual needs, thus maintaining reliability when required while minimizing resource waste during normal operation
Data Source
AI summary
A method and apparatus for transmitting an aperiodic sounding reference signal (SRS) in a wireless communication system is provided. The method include receiving a downlink control information (DCI) format including a triggering signal for triggering a transmission of an aperiodic SRS from a base station (BS) via a physical downlink control Channel (PDCCH), blind-decoding the PDCCH in a UE-specific search space, and transmitting the aperiodic SRS triggered based on the triggering signal to the BS.