LTE Cell Reselection via Customized RRC Parameters
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Solution Overview
Problem
In LTE cellular networks, the homogeneous idle mode reselection behavior of user entities (UEs) across different eNodeBs leads to underutilization of small cell networks, as UEs prefer connecting to macrocells due to stronger signal strength, even though small cells are authorized for access, resulting in reduced network utilization.
Innovation Solution
Configuring eNodeBs to send customized reselection parameters to UEs, particularly those subscribed to small cell networks, using Radio Resource Control (RRC) messages to override standard System Information Block (SIB) parameters, prioritizing small cell connections and promoting reselection to small cells over macrocells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If eNodeBs broadcast the same reselection parameters to all UEs via SIB messages, then all UEs follow homogeneous reselection behavior, but this causes underutilization of small cell networks as UEs prefer macrocells with stronger signal strength
Solution Approach 1:
The patent applies local quality by providing different reselection parameters to different UEs based on their subscription information. The MME retrieves subscription data from HSS and sends customized RRC connection release messages with specific reselection parameters to UEs subscribed to small cell networks, while other UEs receive standard SIB parameters. This allows small cell-authorized UEs to prioritize small cell reselection while maintaining homogeneous behavior for non-subscribed UEs.
Solution Approach 2:
The patent changes the reselection parameters dynamically based on UE subscription status. For UEs subscribed to small cell networks, the MME sends RRC connection release messages with modified reselection parameters that prioritize small cell frequencies and adjust reselection thresholds. This parameter change enables these UEs to select small cells even when macrocell signal strength is higher, thereby increasing small cell network utilization.
2Reliability
If UEs select eNodeBs based solely on signal strength, then UEs connect to macrocells with stronger signals, but this results in reduced utilization of authorized small cell networks
Solution Approach 1:
The patent modifies reselection parameters for UEs subscribed to small cell networks, changing the decision criteria from signal-strength-only to a composite metric that includes subscription-based priorities. The MME sends customized RRC messages with adjusted reselection thresholds and frequency priorities, enabling UEs to select small cells based on both signal quality and network authorization status.
Solution Approach 2:
The system implements feedback by having the MME retrieve subscription information from HSS and use this information to dynamically adjust reselection parameters sent to UEs. This feedback loop ensures that UEs receive appropriate reselection guidance based on their network authorization status, optimizing both connection quality and resource allocation.
3Productivity
If customized reselection parameters are sent to specific UEs using RRC messages, then small cell network utilization increases, but this requires additional network signaling and processing complexity
Solution Approach 1:
The system applies self-service by having the MME automatically retrieve subscription information from HSS and generate appropriate customized RRC messages without manual intervention. The network infrastructure autonomously identifies which UEs require customized parameters and sends the appropriate messages, reducing the need for manual configuration and minimizing operational complexity.
Solution Approach 2:
The patent uses a universal approach by implementing the customization mechanism within the existing MME and HSS architecture. The same MME that performs standard mobility management also handles subscription-based parameter customization, and the HSS provides subscription information for multiple purposes including authentication and now reselection parameter determination. This multi-functionality reduces the need for separate dedicated systems.
Data Source
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AI summary
An LTE cellular network having management mobility servers (MMEs), base stations (enodeBs) and mobile user equipment (UE). The network supporting two groups of mobile device subscribers; subscribers of a macroceli network and subscribers of a small cell network. The base stations being configured to broadcast network information and device configuration information to the mobile devices through System Information Block messages. The base stations being configured to selectively send override parameters to subscribers of the mobile devices to alter the idle mode reselection processing to prefer connections to the small cell network.