LTE-A Transmission Power Control for Access Method Switching
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Solution Overview
Problem
When switching between DFT-S-OFDM and Clustered DFT-S-OFDM access methods in LTE-A systems, existing transmission power control (TPC) methods do not consider frequency-selective diversity effects, leading to unnecessary high power usage or power deficiencies in mobile station apparatuses.
Innovation Solution
A wireless communication system that dynamically adjusts transmission power control based on communication characteristics, including frequency-selective diversity effects, by switching between contiguous and discrete frequency band allocations, and considering factors like channel quality, moving speed, and resource block configurations, to ensure optimal power usage without increasing TPC notification frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing TPC methods are used without considering frequency-selective diversity effects, then the system maintains simplicity in TPC implementation, but mobile station apparatuses use unnecessarily high power or experience power deficiencies during access method switching
Solution Approach 1:
The patent changes the TPC parameters by introducing frequency-selective diversity effects into the power control calculations. The base station determines appropriate TPC values based on the specific access method (DFT-S-OFDM or Clustered DFT-S-OFDM) being used, adjusting power control parameters to match the characteristics of each method and the allocated resource blocks.
2Use of energy by moving object
If TPC is adjusted to account for frequency-selective diversity effects during access method switching, then power usage optimization is achieved, but the complexity of TPC control increases
Solution Approach 1:
The patent segments the TPC control into distinct modes corresponding to different access methods. The base station selects and applies appropriate TPC values based on whether DFT-S-OFDM or Clustered DFT-S-OFDM is being used, with each segment having optimized parameters for its specific characteristics. This segmentation manages complexity by providing clear, method-specific control rules.
Solution Approach 2:
The TPC system dynamically adapts to access method switching by the base station determining and notifying appropriate TPC values when the mobile station switches between DFT-S-OFDM and Clustered DFT-S-OFDM. The system transitions smoothly between different power control regimes based on the current access method and resource block allocation.
3Reliability
If the base station determines and notifies TPC values for different access methods, then communication quality is maintained during switching, but the control signaling overhead increases
Solution Approach 1:
The patent merges the TPC notification with existing uplink grant signaling. The base station includes TPC values in the same control messages that allocate resource blocks for uplink transmission, combining multiple control functions into a single signaling mechanism. This approach maintains communication quality during access method switching while minimizing additional signaling overhead.
Data Source
AI summary
To perform control so as to achieve a transmission power that satisfies a desired communication quality by an access method which a mobile station apparatus uses, in consideration of the frequency-selective diversity effect, when switching an access method to the one having a different frequency-selective diversity effect. In a wireless communication system in which a communication control apparatus and a communication terminal apparatus that are able to use a plurality of types of access methods perform wireless communication using any of the access methods, the communication control apparatus, when the necessity of changing the access method arises, determines the access method after change and notifies the communication terminal apparatus of switching the access method before change to the determined access method, and performs the transmission power control in accordance with communication characteristics of the determined access method.