Uplink Data Transmission in Unlicensed Spectrum
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Solution Overview
Problem
In LTE systems, the transmission efficiency of uplink data in unlicensed spectra is decreased due to UEs not sending PUSCH in the last symbol of the uplink subframe configured for SRS, leading to interference and channel access issues among multiple operators.
Innovation Solution
An access network device sends signal sending indication information to UEs to dynamically schedule SRS and PUSCH transmission in specific symbols of the uplink subframe, allowing UEs to send SRS and PUSCH based on indicated symbols, thereby avoiding conflicts and improving channel access efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UEs send PUSCH in the last symbol of the uplink subframe configured for SRS, then uplink data transmission is continuous, but interference between SRS and PUSCH occurs and channel access efficiency decreases
Solution Approach 1:
The uplink subframe is segmented into different symbol sets: a first symbol set for SRS transmission and a second symbol set for PUSCH transmission. By dividing the subframe into distinct symbol sets, the patent eliminates time-domain overlap between SRS and PUSCH, resolving the interference issue while maintaining transmission efficiency.
Solution Approach 2:
The patent dynamically determines the symbol sets for SRS and PUSCH transmission based on scheduling information. The access network device sends indication information to dynamically adjust which symbols are allocated for SRS and which for PUSCH, allowing flexible resource allocation that avoids fixed conflicts while optimizing channel access efficiency.
2Reliability
If UEs perform CCA before channel access in unlicensed spectrum, then channel access rules are followed, but transmission opportunities are lost when channel appears busy
Solution Approach 1:
The access network device performs CCA detection before scheduling UEs for uplink transmission in unlicensed spectrum. This preliminary action ensures the channel is idle before allocating resources, allowing the system to follow LBT rules while maximizing channel access opportunities by proactively identifying available time windows.
Solution Approach 2:
The access network device receives feedback information from UEs about channel conditions and uses this feedback to adjust scheduling decisions. This feedback mechanism allows the system to adapt to changing channel conditions, maintaining compliance with LBT rules while optimizing transmission opportunities based on real-time channel status.
3Productivity
If the access network device schedules SRS and PUSCH in the same subframe, then resource utilization is high, but symbol allocation conflicts occur
Solution Approach 1:
The patent segments the uplink subframe into a first symbol set for SRS and a second symbol set for PUSCH. This segmentation allows both SRS and PUSCH to be scheduled in the same subframe without symbol allocation conflicts, maintaining high resource utilization while simplifying the allocation process through clear set separation.
Solution Approach 2:
Different symbol sets are assigned different qualities or characteristics: the first symbol set is designated for SRS with specific properties, and the second symbol set is designated for PUSCH. This local quality differentiation allows the system to optimize each symbol set for its specific function while avoiding conflicts between the two types of transmission.
Data Source
AI summary
A terminal (e.g. user equipment (UE)) receives signal sending indication information that is sent by an access network device for an uplink subframe, where the signal sending indication information is used to instruct the terminal to send a sounding reference signal SRS in a first symbol of the uplink subframe, and/or used to instruct the terminal to send a PUSCH in a symbol that is included in a second symbol set of the uplink subframe. The terminal sends an SRS and/or a PUSCH in the uplink subframe based on the signal sending indication information.