TFC Selection for Wireless Transmit Receive Unit Power Management
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Solution Overview
Problem
Current 3GPP standards lack an efficient method for selecting a combination of transport format combinations (TFCs) for multiple coded composite transport channels (CCTrCHs) in uplink transmissions, leading to suboptimal determination of transmit power and potential exceedance of maximum allowed transmission power.
Innovation Solution
A method where the WTRU estimates and selects TFCs for a dedicated channel and an enhanced uplink channel independently, ensuring the sum of their transmit powers does not exceed the maximum allowed WTRU transmit power, with provisions for a reserved minimum set of TFCs to maintain basic services and scale down power as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If joint TFC determination for multiple CCTrCHs is used, then uplink coverage and throughput are improved, but transmit power management becomes complex and may exceed maximum allowed power
Solution Approach 1:
The patent segments the TFC selection process into separate independent selections for each CCTrCH (dedicated channel and enhanced uplink channel). Instead of jointly determining TFCs for multiple channels, the WTRU selects TFC for the dedicated channel first, then independently selects TFC for the enhanced uplink channel from remaining options. This segmentation simplifies the selection complexity while still managing total transmit power effectively.
2Device complexity
If independent TFC selection for each CCTrCH is used, then selection complexity is reduced, but transmit power may exceed maximum allowed limits
Solution Approach 1:
The patent implements a feedback mechanism where the WTRU monitors the total transmit power resulting from independent TFC selections for multiple CCTrCHs. When the combined power exceeds the maximum allowed transmit power, the system provides feedback to adjust the TFC selection, particularly for the enhanced uplink channel, to ensure compliance with power limits while maintaining optimal performance.
3Length of moving object
If maximum power is allocated to enhance uplink channel, then uplink coverage is improved, but dedicated channel transmission may be compromised
Solution Approach 1:
The patent employs dynamic power allocation where the WTRU can adjust the transmit power for the enhanced uplink channel based on current channel conditions and dedicated channel requirements. The system dynamically determines the appropriate power level for each channel, allowing flexible adaptation between enhancing uplink coverage and maintaining dedicated channel reliability depending on instantaneous needs.
Data Source
AI summary
A method and apparatus for selecting a TFC in a wireless transmit/receive unit (WTRU) is disclosed. The WTRU estimates a transmit power for each of a plurality of available transport format combinations (TFCs). A TFC is selected for an uplink dedicated channel and a TFC is selected for an enhanced uplink (EU) channel. The TFC for the dedicated channel is selected first and independently of the TFC selection of the EU channel. The TFC for the EU channel is selected within a remaining WTRU transmit power after the TFC selection for the dedicated channel.