SRS Frequency Positioning in TDD UpPTS to Avoid PRACH Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In TDD systems, there is a challenge in sending SRS signals within the UpPTS without interfering with PRACH signals, while also enabling channel sounding for broader bandwidths.
Innovation Solution
The method involves calculating the frequency domain starting position of the maximum SRS-Bandwidth in the UpPTS, using specific formulas to determine the index of the first sub-carrier, ensuring minimal interference with PRACH and allowing for wider bandwidth channel sounding by configuring the SRS-Bandwidth within the frequency band range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If SRS signals are transmitted in UpPTS to enable wider bandwidth channel sounding, then the bandwidth coverage is improved, but interference with PRACH signals occurs
Solution Approach 1:
The UpPTS time slot is segmented into distinct frequency regions: one region allocated for PRACH transmission and another region allocated for SRS transmission. This segmentation allows both signals to coexist in the same time slot without interfering with each other, enabling wider bandwidth channel sounding while maintaining random access functionality.
Solution Approach 2:
Different frequency regions within UpPTS are assigned different functional qualities: the first region is optimized for PRACH with specific bandwidth and frequency positioning, while the second region is optimized for SRS with alternate one-side mapping. This local differentiation allows each signal type to operate with its optimal characteristics without mutual interference.
2Adaptability or versatility
If alternate one-side mapping is used for SRS in frequency domain, then frequency diversity is improved, but resource allocation complexity increases
Solution Approach 1:
The alternate one-side mapping for SRS follows a periodic pattern where subcarriers are selected at regular intervals (e.g., every other subcarrier) within the allocated frequency region. This periodic structure provides frequency diversity by spreading SRS energy across multiple frequency components while maintaining a simple and predictable resource allocation pattern that reduces computational complexity.
Data Source
Figure 1
Figure 2~5A
Figure 5B~6B
AI summary
A method for sending a sounding reference signal (SRS) of uplink channel in a time division duplex system is provided, a terminal calculates the parameters of the resource for sending an SRS in an uplink pilot time slot (UpPTS) according to the configuration information related to the sounding reference signal (SRS) of the uplink channel, the parameters include the frequency domain start position of the resource, and then the SRS is sent over the resource; wherein when the frequency domain start position of the resource is calculated, it is necessary to determine the index of the first sub-carrier in the maximum SRS bandwidth; the terminal determines the index according to the frequency domain position of one PRACH or that of more PRACHs in the uplink pilot time slots, when the PRACH includes the sub-carrier at the lower boundary of the system bandwidth, the upper boundary of the system bandwidth is used as the end position of the maximum SRS bandwidth and the start position of the maximum SRS bandwidth is calculated; and when the PRACH includes the sub-carrier at the upper boundary of the system bandwidth, the lower boundary of the system bandwidth is used as the start position of the maximum SRS bandwidth, and then the index is determined through the start position of the maximum SRS bandwidth plus the offset parameter configured for the terminal. With the sending position of the maximum SRS bandwidth in the UpPTS, which is obtained by the method of the present invention, the interference between the UpPTS signal and the PARCH can be avoided, and it is possible to implement the channel sounding for more bandwidth.