ACB Skip Mechanism for D2D Discovery in LTE Networks
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Solution Overview
Problem
Current access-class barring mechanisms in congested 3GPP LTE networks can prohibit UEs from establishing RRC connections for D2D communication, even when D2D communication would not consume core network resources, leading to inefficiencies and potential service disruptions.
Innovation Solution
Introducing ACB skip functionality and specific D2D resource allocation modes, where UEs can skip access class barring for D2D communication purposes, allowing them to use D2D resource allocation mode 2 when mode 1 is barred, and configuring different ACB parameters in System Information Block 2 (SIB2) to prioritize D2D communication based on congestion conditions and UE categories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If access class barring mechanism is applied to control network access during congestion, then core network resource consumption is reduced, but D2D communication capability is blocked
Solution Approach 1:
The patent segments the access control mechanism by introducing separate access class barring parameters for D2D communication (ac-BarringForD2D) and traditional cellular communication. This allows independent control of D2D access during congestion, enabling D2D devices to bypass standard ACB restrictions and maintain direct communication capability while core network resources are conserved for cellular services.
Solution Approach 2:
The patent introduces an intermediary mechanism where the eNodeB broadcasts system information (SIB2) containing D2D-specific ACB parameters. This intermediary allows UEs to make informed decisions about whether to attempt D2D connection establishment based on current network conditions, mediating between the need for D2D availability and core network congestion avoidance.
2Reliability
If UEs attempt to establish RRC connection for D2D communication during network congestion, then D2D service availability is maintained, but core network resources are consumed
Solution Approach 1:
The patent applies local quality by providing D2D-specific ACB parameters (ac-BarringForD2D, ac-BarringTimeForD2D, ac-BarringFactorForD2D) that are tailored specifically for D2D communication needs rather than applying uniform ACB to all services. This localized control ensures D2D services maintain availability during congestion while preventing excessive core network resource consumption through parameter-based regulation.
3Productivity
If access class barring parameters are configured for D2D communication, then resource usage is optimized, but system complexity increases
Solution Approach 1:
The patent achieves universality by integrating D2D-specific ACB parameters into the existing SIB2 broadcast mechanism and RRC connection establishment procedure. Rather than creating separate complex control systems, the solution leverages existing universal cellular infrastructure components to handle D2D access control, thereby optimizing resource usage while minimizing additional system complexity.
Data Source
AI summary
Technology to support access-class-barring (ACB) skipping for commercial and public-safety user equipments (UEs) is disclosed. A cellular mobile network experiencing congestion at the core network level can be configured to send a communication to UEs indicating that ACB may be skipped by UEs seeking to establish device-to-device (D2D) communication using a first mode of D2D resource allocation wherein D2D resources are allocated by the network. In addition, the network can be configured to send a communication indicating that a second mode of D2D resource allocation wherein D2D resources are allocated by the UEs may be used as an alternative to the first mode. The network may also indicate that the second mode can be used as a fallback when current ACB parameters indicate that use of the first mode is not currently permitted.