Handling Unreliable Scheduling Grants in WCDMA Networks
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Solution Overview
Problem
In WCDMA communication systems, unreliable scheduling grants can lead to interference and throughput loss due to misinterpretation by user equipment, and the network is unaware of grant reliability, resulting in excessive interference in neighboring cells.
Innovation Solution
User equipment detects unreliable scheduling grants and adjusts its serving grant accordingly, while reporting continuous unreliable grants to the network, which adapts power offsets and downlink load to improve grant reliability and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the network transmits scheduling grants at every TTI to control uplink resources, then uplink resource management is improved, but the risk of unreliable grants increases due to power limitations and interference
Solution Approach 1:
The patent implements a feedback mechanism where the user equipment reports unreliable scheduling grants to the network. The network receives this feedback and adjusts its transmission parameters (such as power offset) to improve grant reliability. This closed-loop feedback system allows the network to learn from previous transmission failures and modify future transmissions accordingly.
Solution Approach 2:
The patent changes transmission parameters dynamically based on reliability conditions. When unreliable grants are detected, the network adjusts the power offset parameter and other transmission parameters to ensure more reliable delivery of scheduling grants in subsequent TTIs. This adaptive parameter adjustment resolves the contradiction by modifying system behavior based on observed reliability.
2Productivity
If the user equipment uses received scheduling grants to adjust bit rate, then uplink throughput is improved, but interference increases when grants are misinterpreted
Solution Approach 1:
The user equipment monitors the reliability of received scheduling grants and provides feedback to the network. When grants are found to be unreliable (leading to potential bit rate adjustments that cause interference), the equipment reports this to the network, which then adjusts transmission parameters to prevent similar situations in the future.
Solution Approach 2:
The patent applies preliminary anti-action by detecting unreliable grants before they cause significant interference. The system identifies when a scheduling grant cannot be reliably received and takes preemptive action to adjust transmission parameters, preventing the harmful effect of excessive interference in neighboring cells before it fully occurs.
3Reliability
If the network increases power offset to improve grant reception, then scheduling grant reliability is improved, but downlink load increases
Solution Approach 1:
The patent implements dynamic adjustment of the power offset parameter based on actual reliability conditions. Rather than using a fixed high power offset, the system dynamically modifies the power offset in response to detected unreliable grants, increasing it only when necessary to achieve reliable reception, thereby avoiding unnecessary power consumption during normal operation.
Solution Approach 2:
The network dynamically changes the power offset parameter based on feedback about grant reliability. When unreliable grants are detected, the power offset is increased to improve reception. When grants are received reliably, the power offset is reduced or maintained at lower levels, thus optimizing the trade-off between reliability and power consumption.
Data Source
AI summary
The present invention relates to methods and arrangements for handling unreliable scheduling grants in a WCDMA-communication system. A user equipment detects that a received scheduling grant is unreliable and adjust its serving grant based on that information. The user equipment is also able to report continuously received unreliable grants as an event to the network, allowing the network to adapt its operation to reduce the unreliable grants.