HP UE Dynamic Scheduling for SAR-Compliant Peak Power
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Solution Overview
Problem
High power UEs face a challenge in maintaining high transmit power levels to overcome interference while avoiding SAR limit violations, leading to increased risk of dropped calls and reduced network throughput.
Innovation Solution
A dynamic scheduling request framework that adjusts buffer status reports and resource block allocations to manage transmit power, allowing UEs to maintain high peak power without exceeding SAR limits, thereby improving SINR and reducing dropped calls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HP UE transmits at higher power levels to overcome interference, then SINR and coverage are improved, but SAR limit violations occur
Solution Approach 1:
The patent implements dynamic scheduling request adjustment where the UE monitors its transmit power and dynamically modifies BSR values based on current power conditions. When approaching SAR limits, the UE reduces scheduling requests to allow average power to decrease, while maintaining peak power capability when safe. This dynamic adaptation resolves the contradiction by making power transmission flexible rather than fixed.
Solution Approach 2:
The patent utilizes periodic timing relationships in wireless communication (slots, frames, subframes) to control when transmissions occur. By strategically timing transmissions within these periodic structures and adjusting BSR timing, the UE can concentrate transmissions to maintain peak power performance while creating idle periods that allow average power to remain below SAR limits.
2Object-affected harmful factors
If traditional power back-off is applied to prevent SAR violation, then SAR limit is respected, but peak transmit power is reduced and call reliability decreases
Solution Approach 1:
Instead of continuously reducing power (excessive back-off), the patent applies partial action by maintaining full peak power during specific transmission opportunities when it is safe to do so. The BSR adjustment mechanism allows the UE to request just enough resources to transmit data at peak power intermittently, rather than continuously, achieving SAR compliance while preserving peak power benefits when needed.
Solution Approach 2:
The patent changes the BSR parameter dynamically based on power conditions. When average power is low, the UE can report higher BSR values to request more resources and transmit at peak power. When average power approaches SAR limits, the UE reports lower BSR values to reduce scheduling requests. This parameter change strategy maintains call reliability by ensuring sufficient resources are available while preventing SAR violations.
3Object-affected harmful factors
If BSR is reduced to lower scheduling requests, then average transmit power decreases and SAR compliance improves, but data transmission efficiency may be affected
Solution Approach 1:
The patent implements a feedback mechanism where the UE continuously monitors its average transmit power and SAR compliance status, then uses this feedback to dynamically adjust BSR values. When power levels indicate SAR compliance, the UE increases BSR to improve data transmission efficiency. When power levels approach limits, the UE decreases BSR to ensure compliance. This closed-loop feedback resolves the contradiction by making transmission efficiency contingent on safety conditions.
Data Source
AI summary
A dynamic scheduling request framework reduces the need of a user equipment (UE) to reduce peak transmit power when approaching the specific absorption rate (SAR) limit. This preserves the ability of UEs to overcome interference (e.g., when near a cell edge), reducing dropped calls, and retains the advantages of high power UEs (HP UEs), such as power class 2 (PC2) devices. When the combination of the current buffer status report (BSR), indicating more data to transmit, with the current peak transmit power and historical average transmitted power indicates a risk that the UE will violate the SAR limit, logic in the UE and/or the network reduces the number of resource blocks (RBs) allocated to the UE. By dropping the duty cycle of the transmitter, even while retaining the current peak transmit power, the average transmitted power will drop. Upon the SAR violation risk abating, the RB allocation returns to normal.