SRS Transmission in PUSCH Subframes for Unlicensed Spectrum
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Solution Overview
Problem
In wireless communication networks, especially in unlicensed spectrum access using LTE-U and MulteFire, the existing methods for transmitting Sounding Reference Signals (SRS) require additional Listen-Before-Talk (LBT) procedures, which increase latency and resource usage, and do not efficiently coexist with other technologies like Wi-Fi, leading to suboptimal performance and spectrum utilization.
Innovation Solution
The proposed solution involves transmitting SRS alongside PUSCH signaling in the same subframe, using frequency division multiplexing and cyclic shifts, allowing SRS to occupy the last symbol of the PUSCH subframe, thereby eliminating the need for extra LBT procedures and enabling efficient resource use without compromising coexistence with other wireless technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SRS is transmitted separately from PUSCH in unlicensed spectrum, then channel sounding can be performed, but additional LBT procedures increase latency and reduce transmission efficiency
Solution Approach 1:
The patent combines SRS and PUSCH transmissions into the same subframe by frequency division multiplexing, where SRS occupies the last symbol of the subframe and PUSCH occupies the remaining symbols. This merging eliminates the need for separate LBT procedures for SRS, reducing latency while maintaining channel sounding functionality.
2Measurement precision
If SRS is transmitted separately from PUSCH in unlicensed spectrum, then channel sounding can be performed, but additional LBT procedures increase resource usage
Solution Approach 1:
The patent merges SRS and PUSCH into a single transmission opportunity by allocating SRS to the last symbol and PUSCH to the remaining symbols within the same subframe. This approach allows both channel sounding and data transmission to occur simultaneously under a single LBT procedure, improving resource utilization and transmission efficiency.
Solution Approach 2:
The patent enables a single LBT procedure to serve multiple functions by allowing both SRS (for channel sounding) and PUSCH (for data transmission) to share the same transmission opportunity. This multi-functionality approach reduces the number of LBT procedures required while maintaining both channel access control and efficient resource utilization.
3Reliability
If separate LBT procedures are used for SRS and PUSCH, then channel access control is maintained, but coexistence with other wireless technologies deteriorates
Solution Approach 1:
The patent combines SRS and PUSCH transmissions into the same subframe under a single LBT procedure, reducing the number of channel access attempts. This merging approach minimizes interference with other wireless technologies like Wi-Fi while maintaining reliable channel access control through the unified LBT mechanism.
Data Source
AI summary
There is disclosed a User Equipment for a MulteFire wireless communication network. The User Equipment comprises processing circuitry and a transmitter, the User Equipment being adapted for utilizing the processing circuitry and the transmitter for performing a Listen-Before-Talk (LBT) procedure for one or more transmission bandwidths; transmitting Physical Uplink Shared CHannel (PUSCH) signaling in a PUSCH subframe on one or more interlaces within the one or more transmission bandwidths; and transmitting Sounding Reference Signaling on the one or more interlaces in the PUSCH subframe.