Parallel Preamble Transmission Power Management in LTE Dual-Connectivity
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Solution Overview
Problem
In communication systems, particularly in LTE with dual-connectivity, power limited situations can lead to overlapping random access procedures between master and secondary cell groups, causing UE to drop transmissions due to lack of knowledge about preamble powers at the MAC layer, resulting in inefficient resource allocation and potential handover issues.
Innovation Solution
The physical layer determines a power limited situation and communicates this to higher layers, enabling the MAC layer to select resources appropriately, postpone or drop preamble transmissions, and control resource allocation or handovers between cell groups to avoid power overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE transmits overlapping preambles for MCG and SCG random access procedures simultaneously, then the random access capacity is improved, but the transmit power exceeds the maximum value due to power limitations
Solution Approach 1:
The patent implements dynamic power scaling where the UE adjusts the power of overlapping preambles based on detected power limitations. The physical layer monitors power conditions and triggers power scaling adjustments when simultaneous MCG and SCG preamble transmissions would exceed maximum transmit power, allowing flexible adaptation to power constraints while maintaining dual-connectivity random access capability
Solution Approach 2:
The patent changes the power parameter of preambles dynamically based on power limitation detection. When power limited situations are detected, the UE modifies preamble power levels through scaling factors, transitioning from fixed power transmission to adaptive power transmission that responds to real-time power conditions
2Power
If the MAC layer performs power scaling according to priority rules, then the transmit power is controlled within limits, but the UE may completely drop one of the transmissions
Solution Approach 1:
The patent implements preliminary detection of power limited situations by the physical layer before transmissions occur. By detecting power constraints in advance and triggering early power scaling adjustments, the system prevents complete transmission drops rather than reacting after the fact
Solution Approach 2:
The patent establishes a feedback mechanism where the physical layer monitors power conditions and provides information to the MAC layer about power limited situations. This feedback loop enables the MAC layer to adjust power scaling decisions based on actual physical layer power conditions, improving transmission reliability
3Reliability
If PRACH resources are configured to never overlap in MCG and SCG, then power limited situations are avoided, but the RACH capacity is limited as resources are divided between cells
Solution Approach 1:
The patent makes PRACH resource allocation dynamic rather than statically separated. The system allows temporal overlap of MCG and SCG PRACH resources but applies dynamic power scaling when overlaps occur, enabling full utilization of available resources while managing power constraints through real-time adjustments
4Adaptability or versatility
If dual-connectivity is supported in asynchronous networks, then the network flexibility is improved, but power limited situations may occur due to lack of synchronicity knowledge
Solution Approach 1:
The patent implements self-service power management where the UE autonomously detects power limited situations and performs power scaling without requiring network coordination or synchronicity knowledge. The physical layer monitors power conditions and triggers power scaling independently, enabling dual-connectivity operation in asynchronous networks
Data Source
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AI summary
Various communication systems may benefit from parallel preamble transmissions. In particular, communication systems of the long term evolution of the third generation partnership project may benefit from methods and systems for parallel preamble transmission in power limited situations. A method can include determining at a physical layer of a device that a predetermined condition has been met with respect to a power limited situation. The method can also include communicating an indication that the predetermined condition has been met to a higher layer of the device based on the determining that the predetermined condition has been met.