Enhanced MAC-e PDU Creation for UMTS E-TFC Selection
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Solution Overview
Problem
Current E-TFC selection algorithms in UMTS networks are inefficient due to their inability to account for flexible RLC PDU sizes and segmentation, leading to performance limitations in high-speed uplink packet access as data rates increase and protocol overhead remains high.
Innovation Solution
The proposed solution involves enhanced E-TFC selection algorithms that support flexible RLC PDU sizes and MAC segmentation, allowing for optimal data transmission by determining the maximum available payload based on power and grant limitations, and incorporating techniques for creating MAC-e PDUs with variable-length headers to maximize data transmission while minimizing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current E-TFC selection algorithms are used with fixed RLC PDU sizes, then protocol simplicity is maintained, but data transmission efficiency and productivity are limited
Solution Approach 1:
The patent applies segmentation by dividing RLC PDUs into variable-sized segments that can be independently transmitted. The MAC layer segments RLC PDUs based on available transport block sizes, allowing efficient utilization of radio resources while maintaining protocol functionality. This resolves the contradiction by enabling flexible data transmission without requiring complete protocol redesign.
Solution Approach 2:
The patent implements dynamics by making RLC PDU sizes variable rather than fixed. The system dynamically adjusts PDU sizes based on current radio conditions, grant information, and available buffer occupancy. This dynamic adaptation improves data transmission efficiency while the MAC layer manages the complexity of size variation through standardized E-TFC selection algorithms.
2Productivity
If RLC PDU sizes are made flexible to maximize data transmission, then productivity improves, but the complexity of managing PDU creation and segmentation increases
Solution Approach 1:
The patent extracts the complexity management function from the RLC layer and places it in the MAC layer. The MAC layer handles PDU segmentation, size calculation, and E-TFC selection, while the RLC layer focuses on data assembly. This extraction resolves the contradiction by centralizing complexity management at the MAC layer where it can be efficiently handled through standardized algorithms.
Solution Approach 2:
The patent introduces the MAC layer as an intermediary between the RLC layer and the physical layer. The MAC layer acts as a mediator that manages the complexity of variable PDU sizes by translating RLC PDUs into appropriate E-TFC combinations for physical transmission. This intermediary function resolves the contradiction by providing a structured approach to PDU management.
3Productivity
If protocol overhead is reduced through flexible PDU sizes and segmentation, then data transmission efficiency improves, but the complexity of header creation and size calculation increases
Solution Approach 1:
The patent applies local quality by making header sizes variable based on the specific transmission conditions and PDU content. Rather than using a uniform fixed header size, the system adapts header lengths to match the actual data transmission requirements. This resolves the contradiction by optimizing overhead reduction while managing complexity through localized adaptation rather than global redesign.
Data Source
AI summary
Efficient enhanced transport format combination (E-TFC) selection methods and apparatus support flexible radio link control (RLC) packet data unit (PDU) size and medium access control (MAC) layer segmentation. Methods for filling an enhanced medium access control (MAC-e) packet data unit (PDU) with data from logical channels as part of E-TFC selection are provided. In one embodiment, the E-TFC selection algorithm employs a single request from the MAC layer to the RLC layer to request the number of bits it is allowed to send for a logical channel to create enhanced MAC-e PDUs. In another embodiment, the MAC entity performs multiple requests to the RLC entity. In another embodiment, the MAC entity makes a single request to the RLC entity to create one or more enhanced MAC-e PDUs of a set size. A technique is also provided for maintaining a guaranteed bit rate (GBR) for non-scheduled data flows with variable-length headers.