E-DCH Resource Pooling for Concurrent TTI Deployment

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Solution Overview

Problem

Current 3GPP specifications for UTRAN do not allow flexible configurations of Transmission Time Interval (TTI) for common E-DCH resources, limiting network efficiency and user equipment (UE) performance, especially in scenarios where concurrent deployment of 2-millisecond and 10-millisecond TTIs is desired to optimize resource utilization.

Innovation Solution

The UE selects the TTI for common E-DCH resources, and the Node B indicates to the RNC whether data was transmitted using a 2-millisecond or 10-millisecond TTI through a spare bit in an uplink data frame, allowing the RNC to efficiently allocate resources and manage buffer and bandwidth usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If all common E-DCH resources are configured with a single TTI (either 2ms or 10ms), then configuration simplicity is maintained, but network resource utilization efficiency deteriorates because UEs in good radio conditions cannot benefit from shorter TTI while UEs in poor conditions cannot use longer TTI

Engineering Contradiction:
Improvenetwork resource utilization efficiencyVSAvoidconfiguration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the common E-DCH resources into multiple resource pools, each configured with a specific TTI (2ms or 10ms). UEs are assigned to appropriate resource pools based on their radio conditions and traffic characteristics, enabling differentiated TTI configuration without requiring complex per-UE configuration management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different TTI configurations are applied to different local conditions: UEs in good radio conditions are assigned to 2ms TTI resource pools for higher throughput, while UEs in poor conditions or with specific traffic patterns are assigned to 10ms TTI resource pools. This local optimization resolves the contradiction between overall efficiency and configuration simplicity.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the network deploys concurrent 2ms and 10ms TTIs for common E-DCH resources, then flexibility and resource optimization improve, but the complexity of managing multiple TTI configurations and tracking UE assignments increases

Engineering Contradiction:
Improveconfiguration flexibilityVSAvoidmanagement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides common E-DCH resources into separate resource pools with distinct TTI configurations. Each pool is independently managed with its own configuration parameters, allowing the network to deploy multiple TTIs concurrently without requiring complex per-resource configuration tracking. The segmentation simplifies management by creating clear boundaries between different TTI domains.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of configuring each individual E-DCH resource with its own TTI parameter (which would increase management complexity), the patent inverts the approach by organizing resources into pre-configured pools with fixed TTI characteristics. This inversion reduces management complexity while maintaining the flexibility of concurrent TTI deployment.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If a single TTI is used for all common E-DCH resources, then signaling and configuration overhead are reduced, but the ability to optimize uplink throughput and network capacity for different UEs deteriorates

Engineering Contradiction:
Improvesignaling overheadVSAvoiduplink throughput
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments common E-DCH resources into multiple pools with different TTI configurations (2ms and 10ms). Each pool maintains its own configuration parameters, but the segmentation allows UEs to be assigned to appropriate pools based on their needs, optimizing uplink throughput without requiring complex per-UE signaling. The pool-based approach reduces signaling overhead compared to individual resource configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the TTI parameter at the resource pool level rather than at the individual resource or UE level. By organizing resources into pools with fixed TTI characteristics, the system enables parameter differentiation (2ms vs 10ms) while maintaining simpler signaling. UEs are assigned to pools based on their radio conditions and traffic requirements, achieving throughput optimization with reduced signaling overhead.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2764746B1Methods and apparatuses in a mobile communication network
Publication Date: 2015.12.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2764746B1 patent drawingFigure 1
  • EP2764746B1 patent drawingFigure 2
  • EP2764746B1 patent drawingFigure 3~4

AI summary

Techniques for supporting concurrent deployment of 2-millisecond and 10-millisecond TTI for E-DCH transmissions in CELL_FACH state and Idle Mode are disclosed. One example method comprises receiving a (310) transport block from a mobile terminal, wherein said transport block is transmitted using either a 10-millisecond or 2-millisecond TTI, and sending (320), to an RNC, an indication of whether data carried by the transport block was transmitted using the 10-millisecond TTI or the 2-millisecond TTI. In some embodiments, the indication is sent in a user plane frame sent over a base-station-to-RNC interface. A spare bit in an uplink data frame sent to the RNC may be used, for example.