SRS Frequency Hopping for Cell-Edge Uplink Sounding
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Solution Overview
Problem
In next-generation wireless communication systems, user equipment (UEs) at the cell edge face challenges in performing full-band sounding due to link budget limitations, which restricts their ability to transmit sounding reference symbols (SRS) across the entire bandwidth.
Innovation Solution
The method allows UEs to perform UL full-band sounding by hopping across multiple symbols or slots, enabling subband sounding, and configures SRS hopping patterns to optimize SRS transmission, particularly for UEs with narrow band RF capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UEs at cell edge perform UL full-band SRS transmission, then full-band sounding capability is achieved, but link budget limitation prevents successful transmission
Solution Approach 1:
The patent divides the uplink bandwidth into multiple subbands and configures separate SRS resources for each subband. Cell-edge UEs transmit SRS on one subband at a time rather than attempting full-band transmission simultaneously, making the transmission feasible within their link budget constraints while still enabling full-band channel sounding through sequential subband measurements.
Solution Approach 2:
The patent introduces frequency domain segmentation as an additional dimension for SRS resource allocation. By configuring SRS resources across multiple frequency subbands with different time offsets, the system enables cell-edge UEs to perform full-band sounding by hopping through subbands in the frequency dimension, overcoming the power limitation in the time dimension.
2Use of energy by moving object
If subband sounding is implemented, then cell-edge UEs can transmit within link budget limits, but full-band sounding capability is lost
Solution Approach 1:
The patent configures SRS resources periodically across multiple subbands with different time offsets. Cell-edge UEs sequentially transmit SRS on different subbands in a periodic manner, allowing the gNB to reconstruct full-band channel state information from these periodic subband measurements, thus achieving both link budget compliance and full-band sounding capability.
Solution Approach 2:
The gNB preliminarily configures multiple SRS resource sets with subband allocations and time offset patterns before UE transmission. This preliminary configuration enables cell-edge UEs to know in advance which subband to transmit on and when, allowing them to perform full-band sounding through coordinated subband hopping without requiring real-time full-band transmission capability.
3Device complexity
If SRS resources are allocated in one symbol, then transmission simplicity is maintained, but channel coherence is lost when hopping occurs
Solution Approach 1:
The patent dynamically allocates SRS resources across multiple symbols based on the hopping pattern and subband configuration. When frequency hopping is enabled, SRS transmissions are scheduled in different symbols to ensure that each subband transmission occurs during a coherent channel period, while the overall system remains flexible and adaptable to different hopping scenarios.
Data Source
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AI summary
A method of transmitting a sounding reference symbol (SRS) at a user equipment (UE) includes receiving, from a base station, first information including information on at least one predetermined SRS sequence parameter configured in association with a frequency hopping pattern among SRS sequence parameters, generating an SRS sequence using a value of a parameter corresponding to a frequency hopping pattern configured in the UE with respect to the at least one predetermined SRS sequence parameter, and transmitting the SRS, to which the generated SRS sequence is applied, to the base station through SRS resources.