Concurrent TTI Support in Uplink Resource Allocation
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Solution Overview
Problem
Current wireless communication systems, particularly in UMTS networks, face limitations in resource assignment for uplink transmissions in the Cell_FACH state, where all mobile stations must use the same transmission time interval, leading to inefficiencies as not all stations benefit equally from the same interval, and there is a lack of flexibility in resource allocation.
Innovation Solution
The system allows a single cell to concurrently support both 2ms and 10ms transmission time intervals (TTIs) for uplink transmissions and enables user equipment (UEs) to transmit data using either E-DCH resources or legacy Rel-99 PRACH messages, with the network having the option to override UE choices for resource assignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all mobile stations in Cell_FACH use the same transmission time interval for uplink transmissions, then resource allocation is simplified and network control is easier, but resource utilization efficiency deteriorates and adaptability to different user needs is reduced
Solution Approach 1:
The patent segments the transmission time interval resources by dividing them into multiple groups, where each group corresponds to a specific TTI duration (e.g., 2ms, 10ms). Mobile stations can be assigned to different groups based on their needs, allowing the network to maintain simplified control through group-based management while providing adaptability through multiple segmented options.
Solution Approach 2:
The patent enables dynamic TTI selection by allowing mobile stations to indicate their preferred TTI duration through signature sequence selection during random access. The network can then dynamically assign appropriate TTI groups based on current network conditions and user requirements, transforming the static resource allocation into a dynamic system that adapts to changing conditions.
2Device complexity
If a single transmission time interval is used for all mobile stations in Cell_FACH, then system simplicity is maintained, but resource utilization efficiency and data rates deteriorate
Solution Approach 1:
The patent changes the TTI duration parameter by introducing multiple TTI options (different durations) that can be assigned to different mobile stations. This allows the system to optimize resource utilization efficiency by selecting appropriate TTI lengths based on user needs while maintaining relatively simple system architecture through standardized assignment procedures.
3Adaptability or versatility
If mobile stations are given flexible resource assignment options, then adaptability and resource efficiency improve, but device complexity and signaling overhead increase
Solution Approach 1:
The patent enables mobile stations to self-select their preferred TTI duration by choosing appropriate signature sequences during random access procedures. This self-service mechanism reduces the need for complex network-controlled assignment and signaling, as mobile stations autonomously indicate their preferences through standardized signaling procedures.
Solution Approach 2:
The patent uses signature sequences that serve multiple functions: they identify the mobile station during random access and simultaneously indicate the preferred TTI duration. This multi-functionality reduces signaling overhead and simplifies the overall mechanism by combining identification and resource preference indication into a single universal signaling element.
Data Source
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AI summary
A random access procedure for UEs in Cell_FACH or another suitable non-DCH state, which enables concurrent deployment of 2ms and 10ms TTIs for uplink transmissions on the E-DCH. In some examples, the procedure may further enable utilization of a Rel-99 PRACH transmission by UEs in the Cell_FACH or other suitable non-DCH state.