LTE-U Uplink Waveform Variable Multi-Subframe Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication networks, particularly in LTE-U systems, face interference and congestion due to increasing demand for mobile broadband access, which degrades performance and requires efficient uplink resource management in unlicensed bands.
Innovation Solution
The method involves determining uplink resource block configurations, broadcasting channel use beacon signals, and performing clear channel assessments to optimize transmissions in LTE-U systems, allowing for dynamic scheduling and continuous transmission in unlicensed carrier bands, while maintaining orthogonality and power control across multiple subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If more UEs access the wireless communication networks to meet growing demand for mobile broadband access, then network capacity and user coverage are improved, but interference and congestion increase degrading network performance
Solution Approach 1:
The patent segments the system into two distinct parts: licensed carrier operations (base station to UE) and unlicensed carrier operations (UE to base station). This segmentation allows independent optimization of each carrier type, enabling the network to accommodate more UEs on licensed carriers while using unlicensed carriers specifically for uplink capacity expansion without interfering with downlink operations.
Solution Approach 2:
The patent introduces an intermediary mechanism where UEs perform clear channel assessment (CCA) before transmitting on unlicensed carriers. This intermediary step detects and avoids interference from other wireless systems (like Wi-Fi), allowing the network to expand capacity by utilizing unlicensed spectrum while maintaining performance through intelligent interference avoidance.
2Productivity
If unlicensed carrier bands are used for uplink transmissions to increase network capacity, then more users can be served, but interference from other wireless RF transmitters degrades performance
Solution Approach 1:
The patent implements preliminary action by requiring UEs to perform clear channel assessment (CCA) before initiating uplink transmissions on unlicensed carriers. This preliminary detection step identifies available frequency resources and avoids interference from other wireless systems, ensuring that capacity expansion through unlicensed carriers does not compromise transmission quality.
Solution Approach 2:
The patent employs feedback mechanisms where base stations send scheduling assignments to UEs indicating which unlicensed carrier resources are available for uplink transmission. This feedback loop allows the system to dynamically adapt to changing interference conditions, maintaining optimal performance while utilizing unlicensed spectrum for capacity expansion.
3Productivity
If variable multi-subframe scheduling is implemented to optimize resource allocation, then channel utilization improves, but system complexity increases
Solution Approach 1:
The patent implements dynamic scheduling where the number of uplink subframes can vary based on channel conditions and traffic demands. This dynamic approach allows the system to optimize channel utilization by allocating more uplink resources when needed while maintaining simplicity during low-demand periods, achieving high productivity without permanent complexity overhead.
Solution Approach 2:
The patent changes key scheduling parameters including the number of uplink subframes, resource block allocations, and modulation schemes based on real-time channel conditions. These parameter adjustments enable flexible resource optimization across multiple subframes, improving overall channel utilization while using standardized LTE mechanisms to manage complexity.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Uplink waveforms for operating long term evolution (LTE) in an unlicensed band (i.e., long term evolution-unlicensed (LTE-U) communication) are disclosed. Carrier aggregation (CA) and standalone (SA) are disclosed. LTE on the licensed channel may provide both control and data, LTE on the unlicensed channel may provide data. Managing variable transmission time interval (TTI) continuous transmission is disclosed for transmission over multiple subframes of an unlicensed carrier in LTE-U. Listen-before-talk (LBT) requirements of unlicensed carriers provide for additional channel occupancy constraints when scheduling resources for multiple UEs for variable TTI continuous uplink transmissions over multiple subframes. A joint control channel is disclosed that provides control information for all of the potentially available subframes to be scheduled for the uplink transmissions. In addition to management of the variable TTI continuous transmissions, adjustments to uplink signal parameters are also disclosed that address the constraints due to the LBT requirements of unlicensed carriers.