Relay Node MME Pool Selection for LTE Handover Failures
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Solution Overview
Problem
In LTE wireless networks, relay nodes face ambiguity in determining whether an X2 handover is supported by a target node, leading to inefficiencies and increased latency due to the invisibility of MME pool mismatches, resulting in excessive X2 handover failures and resource wastage.
Innovation Solution
A method where a donor eNB selects a single MME pool for all UEs connected to a relay node and communicates the globally unique group identifier list to the relay node, ensuring that only supported MME pools are used for handovers, thereby initiating either X2 or S1 handovers based on the target node's capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay nodes perform X2 handovers without MME pool information, then handover flexibility is maintained, but handover failure rate increases due to MME pool mismatches
Solution Approach 1:
The donor eNB performs preliminary configuration of the relay node by providing a filtered list of MME pool identifiers that are supported by neighbor nodes before handover operations commence. This preliminary action prevents MME pool mismatches during actual handovers, thereby improving handover success rate without adding operational complexity.
Solution Approach 2:
The donor eNB acts as an intermediary between the core network and the relay node, filtering and translating MME pool information. Instead of the relay node directly querying all possible MME pools, the donor eNB intermediates by providing a pre-filtered subset, reducing the complexity burden on the relay node while ensuring compatibility.
2Adaptability or versatility
If relay nodes attempt X2 handovers to all potential targets, then handover options are maximized, but resource wastage increases due to failed handovers
Solution Approach 1:
The system performs preliminary filtering of handover targets by excluding those that do not support the relay node's MME pool identifiers. This preliminary action prevents the relay node from attempting handovers to incompatible targets, thereby maximizing adaptability to supported targets while minimizing resource wastage from failed handover attempts.
Solution Approach 2:
Instead of attempting handovers to all potential targets (excessive action), the relay node performs handovers only to a subset of targets that are known to be compatible based on MME pool matching. This partial action approach avoids the resource wastage of attempting incompatible handovers while maintaining sufficient adaptability.
3Productivity
If MME pool information is provided to relay nodes, then handover efficiency is improved, but information management complexity increases
Solution Approach 1:
The donor eNB extracts only the necessary MME pool identifier information from the complete network state and provides this filtered subset to the relay node. This extraction approach improves handover processing speed by providing only relevant information, while minimizing information management overhead by excluding unnecessary MME pool details.
Solution Approach 2:
Each relay node receives a customized, local set of MME pool identifiers that are relevant to its specific geographic location and neighbor relationships, rather than a global list of all MME pools. This local quality approach improves handover efficiency for each specific relay node while reducing the overall information management burden across the network.
Data Source
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AI summary
Systems and techniques for avoiding inefficiencies resulting from failed handover attempts. A base station selects one or more mobility management entity (MME) pools for assignment to a relay node, with the selection being performed so as to minimize or eliminate handover attempts requiring that a target device support a particular MME pool when the MME pool is not supported by the MME. A base station selects, when communicating with a relay node, a subset of the MME pools that it supports and assigns the subset to the base station. UEs served by the relay node are assigned the MME pool or MME pools assigned to the relay node. The relay node is informed of the MME pools supported by one or more neighbor nodes and, when attempting a handover to a neighbor node, attempts an X2 handover only to neighbor nodes supporting an MME pool assigned to the relay node.