Dual-Connectivity Uplink Scheduling for LTE-NR Power Coordination
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Solution Overview
Problem
In non-standalone 5G and 4G LTE networks, independent UL schedulers can lead to inter-modulation products and power limitations, resulting in receive errors and degraded performance due to simultaneous UL transmissions exceeding wireless device capabilities, especially in EN-DC configurations.
Innovation Solution
Implement coordinated scheduling between LTE and NR UL schedulers using fixed timing relationships and flexible NR scheduling to manage power distribution and avoid errors, allowing for dynamic slot-by-slot sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If independent UL schedulers are used for LTE and NR, then device complexity is reduced and ease of operation is improved, but inter-modulation products are generated and power limitations are exceeded resulting in receive errors
Solution Approach 1:
A coordination entity acts as an intermediary between the LTE and NR schedulers, exchanging scheduling information and coordinating uplink transmissions. This mediator prevents inter-modulation products and power excesses by ensuring synchronized scheduling decisions across both networks, thereby maintaining reliability while preserving the operational simplicity of independent schedulers.
Solution Approach 2:
The scheduling functions of LTE and NR are merged through a coordination mechanism that combines their scheduling decisions. By merging the scheduling information exchange and coordination logic, the system achieves unified control over uplink transmissions, preventing power limitations and inter-modulation issues while maintaining the benefits of dual-network operation.
2Productivity
If simultaneous UL transmissions are allowed on LTE and NR, then productivity is improved through increased data throughput, but the wireless device exceeds its power transmission capabilities
Solution Approach 1:
The system dynamically adjusts uplink transmission parameters based on real-time power availability and scheduling conditions. The coordination mechanism enables flexible modulation of transmission power and resource allocation across LTE and NR, allowing simultaneous transmissions when power constraints are satisfied while maintaining optimal throughput.
Solution Approach 2:
The coordination entity changes transmission parameters such as power levels, resource block allocations, and modulation schemes based on the device's power capabilities and network conditions. By dynamically adjusting these parameters, the system maintains simultaneous uplink transmissions within power limits while maximizing productivity.
3Reliability
If TDM patterns are enforced to avoid inter-modulation products, then reliability is improved by reducing receive errors, but communication latency increases and flexibility is reduced
Solution Approach 1:
Instead of enforcing rigid periodic TDM patterns, the coordination mechanism uses flexible periodic scheduling with variable time offsets. This allows uplink transmissions to be coordinated in a periodic manner that prevents inter-modulation products while minimizing latency through optimized timing arrangements adapted to traffic conditions.
Solution Approach 2:
The schedulers exchange information in advance to pre-coordinate uplink transmissions, allowing the system to prepare non-conflicting transmission schedules before actual data transmission. This preliminary coordination prevents inter-modulation products without requiring strict TDM patterns, thereby reducing latency.
Data Source
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AI summary
A first network node in a first radio area network (RAN) is configured to communicate with at least a second node in a second RAN. The first node is configured to establish scheduling for a transmission from the first node to a wireless device (WD) based at least in part on scheduling of the second node for another transmission to the WD. The first node may be configured to change scheduling for the first node faster than scheduling for the second node. The first RAN may be based on 3rd Generation Partnership Project (3GPP), New Radio standards, and the second RAN based on 3GPP Long-Term-Evolution standards. The first node may set a timing parameter for a transmission such that a multi-slot time window exists to convey to the first node information about an uplink scheduling decision the second node has made for an uplink slot.