E-DCH Resource Release via Layer 2 Signaling in CELL_FACH
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Solution Overview
Problem
The existing cellular radio systems face inefficiencies in managing and allocating Enhanced Dedicated Channel (E-DCH) resources, particularly in the CELL_FACH state, due to limited resource availability and the need for timely resource release to accommodate multiple users.
Innovation Solution
A method is introduced where User Equipment (UE) and NodeB utilize existing Layer 2 or Layer 1 signaling fields to quickly release E-DCH resources, with configurations allowing UE to signal buffer status and NodeB to release resources upon completion of HARQ processes or timer expiration, enabling faster resource reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If common E-DCH resources are allocated to multiple users in CELL_FACH state, then uplink capacity is improved, but resource management complexity increases
Solution Approach 1:
The UE autonomously monitors its own E-DCH resource status and detects when resources are no longer allocated to it. The UE self-determines resource release based on monitoring grant messages and inactivity conditions, eliminating the need for explicit release signaling and reducing network-side management complexity.
Solution Approach 2:
The system implements feedback mechanisms where the NodeB monitors UE uplink activity and sends grant messages to indicate resource allocation status. The UE feedback loop involves monitoring these grants and autonomously releasing resources when grants indicate resource reassignment or when inactivity thresholds are met, enabling efficient resource recycling.
2Reliability
If E-DCH resources are held for extended periods, then transmission reliability is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The system employs periodic grant messages from NodeB to UE to maintain resource allocation status. Resources are held for defined periods (HARQ processes, inactivity timers) and automatically released when periodic grants indicate reassignment or when time thresholds expire, balancing reliability needs with efficient resource turnover.
Solution Approach 2:
The resource allocation duration is made dynamic rather than static. Resources are initially allocated for reliable transmission completion (HARQ processes), but can be extended or released based on ongoing activity monitoring. This dynamic adjustment allows the system to maintain reliability when needed while freeing resources quickly when not needed.
3Measurement precision
If explicit resource release signaling is implemented, then resource release accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts the resource release indication from separate explicit signaling and embeds it within existing grant messages. The release information is taken out as a distinct release indication field in the grant message structure, allowing accurate resource release signaling without requiring completely new message types or protocols.
Solution Approach 2:
Existing grant messages serve multiple functions: they continue to allocate resources when needed while also indicating resource release when appropriate. This multi-functionality eliminates the need for separate release signaling messages, reducing overhead while maintaining accurate resource management through the dual-purpose grant structure.
Data Source
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AI summary
In a method and a system for managing resources in a cellular radio system comprising an Enhanced Dedicated Channel, the release of the common E-DCH resources is signaled between UE and NodeB using existing signaling fields on Layer 2 (L2) or Layer 1 (Ll). These signaling fields are already in use in CELL_DCH, but their interpretation is changed for users in CELL FACH. In another embodiment, a grant on E-AGCH indicating INACTIVE on all HARQ processes is sent as a release command to the UE. In still another embodiment, the common E-DCH resource is released upon expiry of a release timer.