Multi-Cell Uplink Power Control via Cell-Specific Parameters
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Solution Overview
Problem
In wireless communication systems, particularly in LTE, efficiently controlling the transmission power of physical random access channels across multiple cells is challenging, as the parameter calculated from the TPC command is not effectively managed.
Innovation Solution
The mobile station apparatus employs specific expressions to set and control the transmission power of physical uplink channels in each serving cell, using parameters like preamble initial received target power, power ramping step, and path loss to optimize power settings for PRACH, PUSCH, and PUCCH, based on TPC commands and path loss measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mobile station apparatus transmits physical random access channels in a plurality of cells to a base station apparatus, then the communication coverage and connectivity are improved, but the transmission power control becomes inefficient and difficult to manage
Solution Approach 1:
The patent segments the power control management by introducing cell-specific parameters (preamble initial received target power, power ramping step, path loss compensation factor) for each serving cell. This allows independent power control of PRACH in each cell, resolving the management difficulty when transmitting to multiple cells simultaneously.
Solution Approach 2:
The patent applies local quality by configuring cell-specific power control parameters tailored to each serving cell's characteristics. Each cell can have its own preamble initial received target power, power ramping step, and path loss compensation factor, enabling optimized local power control rather than a unified approach.
2Reliability
If transmission power is increased to ensure reliable communication across multiple cells, then communication reliability is improved, but energy consumption increases
Solution Approach 1:
The patent changes power control parameters dynamically based on cell-specific conditions. By adjusting preamble initial received target power, power ramping step, and path loss compensation factor per cell, the system achieves reliable communication only where necessary, optimizing energy consumption while maintaining communication reliability.
Solution Approach 2:
The patent implements feedback mechanisms where the base station apparatus provides TPC commands to the mobile station apparatus for power adjustment. This closed-loop control ensures reliable communication by adapting power levels to actual channel conditions, avoiding excessive energy consumption.
3Productivity
If cell aggregation is implemented to enhance data throughput, then productivity is improved, but the complexity of power control parameters increases
Solution Approach 1:
The patent applies universality by using a common power control framework (TPC commands, accumulation mechanism, path loss compensation) that works across multiple cells. While each cell has specific parameters, they all follow the same control logic, managing complexity through standardized multi-functional procedures.
Solution Approach 2:
The patent segments power control into cell-specific parameter sets that can be independently configured and managed. Each serving cell has its own parameter group, but they are controlled through a unified TPC command mechanism, balancing segmentation for performance with unified control for simplicity.
Data Source
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AI summary
A terminal apparatus, corresponding base station and methods, the terminal apparatus is configured to communicate with a base station by using a plurality of cells including at least a primary cell and a secondary cell and comprising: a recption unit configured to decode a physical downlink control channel, PDCCH, with downlink control information format, the downlink control information format including a transmission power control command field; a transmission unit configured to transmit a physical uplink control channel, PUCCH, in the primary cell; and a transmission power control unit configured to determine transmission power of the PUCCH in the primary cell, based on at least a PUCCH power control adjustment parameter based on a value indicated by the transmission power control command field; the reception unit is configured to receive a first random access response message, RARM, for the primary cell and a second RARM for the secondary cell; only in a case where the reception unit receives the first RARM, the physical uplink control adjustment parameter is reset.