RNC TBS Signaling for Uplink Interference Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Uplink interference in WCDMA systems, particularly in the CELL_FACH state, becomes severe due to increased data rates and lack of soft handover and transmit power control, posing challenges for network operators in managing intercell interference effectively.
Innovation Solution
A method where the RNC signals a maximum Transport Block Size (TBS) value to NodeBs, especially for cell edge UEs in the CELL_FACH state, using NBAP or RNSAP signaling, to control uplink interference by limiting E-DCH transmissions, thereby managing intercell interference and improving network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If E-DCH transmissions are enabled in CELL_FACH state to improve data rates, then uplink throughput is improved, but intercell interference increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the maximum Transport Block Size (TBS) for E-DCH transmissions in CELL_FACH state. The RNC configures different max_TBS values based on cell conditions, UE capabilities, and interference levels, thereby optimizing the balance between uplink throughput and intercell interference. This is implemented through NBAP/RNSAP signaling that configures the max_TBS parameter in the E-DCH configuration.
Solution Approach 2:
The patent implements feedback mechanisms where the RNC monitors uplink interference conditions and adjusts the max_TBS configuration accordingly. The system uses feedback from interference measurements and UE transmission reports to dynamically reconfigure TBS limits, ensuring that throughput is maintained while interference remains controlled. This closed-loop control is achieved through continuous signaling between RNC and NodeB.
2Object-generated harmful factors
If maximum TBS is limited to reduce interference, then intercell interference is reduced, but uplink data rate decreases
Solution Approach 1:
The patent applies dynamics by making the max_TBS configuration flexible and adaptive rather than static. The RNC can dynamically adjust max_TBS values based on real-time network conditions, UE requirements, and interference levels. This allows the system to optimize the trade-off between interference reduction and data rate maintenance, configuring higher TBS when interference is low and lower TBS when interference is high.
Solution Approach 2:
The patent implements local quality by allowing different max_TBS configurations for different UEs and different cells. Instead of a uniform limit, the system tailors the TBS configuration to local conditions - cell edge UEs may have lower max_TBS to protect neighboring cells, while cell center UEs can have higher max_TBS. This localized optimization maintains overall network performance while reducing interference where critical.
3Productivity
If E-DCH is activated for CELL_FACH UEs to support background traffic, then network efficiency is improved, but interference management complexity increases
Solution Approach 1:
The patent uses the RNC as an intermediary to manage E-DCH configurations for CELL_FACH UEs. The RNC acts as a central controller that coordinates between UEs, NodeBs, and the core network, handling the complexity of interference management through standardized NBAP/RNSAP signaling. This intermediary approach simplifies the overall system by centralizing control logic and providing a unified interface for configuration and management.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Systems and methods according to these exemplary embodiments provide for network control of interference associated with uplink transmissions by user equipments, UEs, (14) operating in a random access state, e.g., the CELL F ACH state. A radio network controller, RNC, (18) can determine, and then transmit, a limitation on uplink transmissions for such UEs, e.g., a maximum transport block size, TBS.