SRS Frequency Hopping Across BWPs for Accurate Channel Estimation
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Solution Overview
Problem
As system bandwidth increases, the power spectrum density of uplink reference signals (SRS) decreases, leading to inaccurate channel estimation and reduced system performance due to uneven power allocation across broader bandwidths, and the need for longer measurement times, which affects channel quality measurement efficiency.
Innovation Solution
The SRS is sent on flexible frequency domain resources, with varying frequency domain units across different frequency hopping subbands, ensuring even distribution and accurate channel estimation across bandwidth parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the bandwidth occupied by each symbol of the SRS is increased, then the measurement time is reduced, but the received power spectrum density decreases leading to inaccurate channel estimation
Solution Approach 1:
The system bandwidth is divided into multiple bandwidth parts (BWPs), and the SRS transmission bandwidth is segmented into multiple frequency domain units within each BWP. This segmentation allows the SRS to cover the entire system bandwidth through frequency hopping across multiple BWPs and frequency domain units, resolving the contradiction between measurement time and channel estimation accuracy by distributing measurements across multiple segments rather than requiring a single wideband measurement
Solution Approach 2:
The patent implements dynamic frequency hopping where the SRS frequency domain position changes across different time instances and bandwidth parts. The terminal device transmits SRS on different frequency domain units in different BWPs according to a hopping pattern, enabling the system to achieve comprehensive channel estimation across the entire bandwidth while maintaining adequate power spectrum density at each transmission instance
2Power
If the SRS is sent on a fixed bandwidth part, then the power allocation is concentrated, but the channel estimation of other bandwidth parts becomes inaccurate
Solution Approach 1:
The SRS transmission mechanism is designed to serve multiple bandwidth parts through frequency hopping. A single SRS configuration can provide channel estimation information for multiple BWPs by transmitting on different frequency domain units within those BWPs at different time instances. This multi-functionality resolves the contradiction by allowing concentrated power transmission at each instance while still achieving comprehensive channel estimation coverage across all BWPs
Solution Approach 2:
The patent introduces a time dimension to the frequency-domain SRS transmission by implementing frequency hopping across multiple time instances. Instead of attempting to transmit SRS simultaneously across all bandwidth parts in frequency domain (which would require excessive power), the system uses time-domain hopping to sequentially measure different BWPs, transforming the problem from a frequency-domain limitation to a time-frequency resource allocation solution
3Productivity
If the system bandwidth is increased, then the system capacity is improved, but the power spectrum density of SRS decreases exponentially
Solution Approach 1:
The system bandwidth is segmented into multiple bandwidth parts (BWPs), each further divided into multiple frequency domain units. The SRS transmission is segmented across these BWPs and frequency domain units through frequency hopping. This segmentation allows the system to support large total bandwidths while maintaining adequate power spectrum density within each individual BWP or frequency domain unit, as the transmit power is concentrated on smaller bandwidth segments at each transmission instance
Solution Approach 2:
The patent implements periodic frequency hopping where the SRS transmission cycles through different bandwidth parts and frequency domain units in a structured pattern. This periodic action allows the system to sequentially measure all BWPs over time while maintaining consistent power spectrum density characteristics across the hopping pattern, effectively supporting large system bandwidths without sacrificing power efficiency
Data Source
AI summary
A communication method and apparatus are provided. The method includes: a terminal device receives first information, and sends an SRS based on the first information. The first information indicates an SRS frequency domain resource. The SRS frequency domain resource includes a first frequency domain unit and a second frequency domain unit. The first frequency domain unit is different from the second frequency domain unit. The first frequency domain unit is a frequency domain resource occupied by the SRS on a first frequency hopping subband in a first frequency hopping period. The second frequency domain unit is a frequency domain resource occupied by the SRS on the first frequency hopping subband in a second frequency hopping period. The first frequency hopping subband is one of a plurality of frequency hopping subbands.