Relay Backhaul Link Quality in Mobility Procedures
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Solution Overview
Problem
In wireless communication networks with relay nodes, calculating the overall signal quality between a user equipment (UE) and the core network is complicated due to multiple wireless links, leading to suboptimal cell selection and handover decisions, as the traditional method of selecting access nodes based on direct link quality does not account for the impact of backhaul link quality on composite signal quality.
Innovation Solution
The proposed solution involves considering the composite, end-to-end signal-to-noise ratios (SNR) including both access link and backhaul link qualities to determine the optimal access node or relay node for UE mobility procedures such as cell selection, cell reselection, and handover, using equations to calculate the composite SNR and spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cell selection and handover methods are used based on direct link quality only, then the procedure is simple and fast, but the overall signal quality and data throughput are suboptimal due to ignoring backhaul link quality
Solution Approach 1:
The patent applies preliminary action by having the relay node pre-calculate and report the backhaul link quality (CQI) to the eNB before the UE needs to make mobility decisions. This allows the UE to consider both access link and backhaul link qualities when selecting cells or performing handover, improving overall signal quality without significantly increasing UE complexity since the backhaul quality information is provided in advance by the network side.
Solution Approach 2:
The patent uses the relay node as an intermediary that bridges the gap between the UE and the core network. The relay node measures and reports backhaul link quality to the eNB, which then provides this information to the UE for mobility decisions. This intermediary approach allows the system to consider end-to-end link quality while keeping the UE implementation relatively simple.
2Productivity
If cell selection is based only on access link quality (direct link between UE and access node), then the selection process is fast and simple, but the composite signal quality (including backhaul) is not optimized
Solution Approach 1:
The relay node performs preliminary measurement and calculation of backhaul link quality (CQI) and provides this information to the eNB, which then includes it in the system information broadcast to UEs. This preliminary action allows UEs to make more informed mobility decisions that consider both access and backhaul link qualities, improving data throughput without requiring real-time complex calculations at the UE.
Solution Approach 2:
The patent implements feedback mechanisms where the relay node continuously monitors backhaul link quality and reports it to the eNB, which then uses this feedback information to guide UE mobility decisions. This feedback loop ensures that cell selection and handover decisions are based on current end-to-end link conditions, optimizing data throughput while maintaining efficient decision-making.
3Reliability
If relay nodes are introduced to extend coverage and improve signal quality, then network coverage is enhanced, but the complexity of calculating overall signal quality increases due to multiple wireless links
Solution Approach 1:
The patent segments the end-to-end link quality measurement into two independent parts: access link quality (measured by UE) and backhaul link quality (measured by relay node and reported to eNB). This segmentation allows each part to be measured and optimized independently, simplifying the overall measurement process while still achieving comprehensive signal quality assessment in relayed networks.
Solution Approach 2:
The relay node serves as an intermediary that handles the complex task of measuring and reporting backhaul link quality. By offloading this measurement function to the relay node (which has direct access to both the UE and the backhaul link), the patent simplifies the overall system architecture compared to requiring the UE to measure both links independently.
4Reliability
If backhaul link quality information is not provided to UEs, then the network structure remains simple, but mobility procedures cannot optimize for end-to-end signal quality
Solution Approach 1:
The relay node performs preliminary calculation of backhaul link quality (CQI) and provides this information to the eNB, which then broadcasts it to UEs through system information. This preliminary action ensures that UEs receive the necessary backhaul quality information in advance, enabling them to make optimized mobility decisions without requiring complex real-time communication protocols.
Solution Approach 2:
The patent makes the backhaul link quality information universally available to all UEs through the eNB's system information broadcast mechanism. This universal provision of information allows any UE in the network to make informed mobility decisions based on end-to-end link quality, without requiring individualized or complex information delivery mechanisms.
Data Source
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AI summary
A system including a processor configured to determine whether or not to perform a mobility procedure based at least in part on a backhaul link quality between a relay node and an access node.