Uplink Transport Format Selection for Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transitioning mobile terminals from idle mode to connected mode due to resource inefficiencies and latency issues, particularly in scenarios where the base station lacks knowledge of channel propagation conditions and UE buffer status.
Innovation Solution
Implementing a method that allows mobile terminals to select a suitable transport format from a set of available options for uplink transmissions, enabling resource-efficient and speedy transitions by considering channel conditions and buffer status, without altering the standard UL grant transmission process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the base station uses a fixed transport format for uplink transmissions, then the scheduling is simple and resource allocation is deterministic, but the resource utilization efficiency deteriorates when channel conditions and buffer status vary
Solution Approach 1:
The patent combines multiple transport formats into a single Transport Format Indication (TFI) field in the UL grant. The base station selects a set of candidate transport formats and encodes them into a single TFI value, which the UE uses to identify the appropriate transport format from the set. This merging approach allows flexible adaptation to varying channel conditions and buffer status while keeping the signaling overhead minimal.
Solution Approach 2:
The patent introduces dynamic transport format selection where the base station can adaptively choose from multiple transport formats based on current channel propagation conditions and UE buffer status. The transport format is no longer fixed but dynamically adjusted through the TFI indication, allowing the system to optimize resource utilization efficiency according to real-time conditions while the UE selects the appropriate format from the indicated set.
2Reliability
If the base station transmits detailed channel information and buffer status to the UE, then the UE can select the optimal transport format, but the signaling overhead increases
Solution Approach 1:
The patent extracts the essential transport format selection information and encodes it into a compact Transport Format Indication (TFI) field within the UL grant. Instead of transmitting detailed channel information and buffer status separately, the base station combines these factors into a single TFI value that directly indicates the selected transport format from a predefined set, significantly reducing signaling overhead while maintaining selection accuracy.
Solution Approach 2:
The patent changes the parameter representation by using a condensed TFI field instead of transmitting full channel state information and buffer status details. The TFI serves as a compact parameter that encapsulates the result of complex base station measurements and decisions, allowing the UE to determine the appropriate transport format with minimal additional signaling.
3Productivity
If the base station waits for complete channel information before granting uplink resources, then the transport format can be optimized, but the transition time from idle to connected mode increases
Solution Approach 1:
The patent implements preliminary action by having the base station prepare and indicate a set of candidate transport formats to the UE in advance, through the TFI field in the UL grant. The UE can then immediately select and use the appropriate transport format without waiting for additional channel information exchanges, thereby accelerating the transition from idle to connected mode while maintaining transmission reliability through the pre-indicated format options.
Data Source
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AI summary
The present invention relates to methods and apparatus for performing uplink transmission in a wireless communications system. A mobile terminal is provided with a set of available transport formats by receiving at least one UL grant comprising a transport format indication pointing to one or more transport formats. The mobile terminal then selects a suitable transport format from the set, for example in dependence on propagation channel conditions, for transmission of a scheduled transmission.