U-RNTI Allocation in Home Node Base Stations

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Solution Overview

Problem

In 3GPP mobile telecommunication networks, particularly with the introduction of Home Base Stations (HNBs), there is ambiguity regarding the allocation of U-RNTI (UTRAN Radio Network Temporary Identifier) between the HNB and HNB-GW, and mobility of User Equipment (UE) in the CELL FACH state is not supported in Release 8, requiring clarification for efficient handover processes.

Innovation Solution

A method where the Home Base Station requests and receives a U-RNTI from a Gateway Device, with the Gateway Device generating and sending the identifier, ensuring proper allocation and registration of User Devices, and maintaining context across state changes, facilitating efficient cell updates and handovers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the HNB allocates U-RNTI locally, then the allocation speed increases and registration overhead decreases, but the risk of identifier conflicts increases and network coordination becomes difficult

Engineering Contradiction:

ImproveU-RNTI allocation speedVSAvoididentifier uniqueness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The U-RNTI space is segmented into multiple ranges, with each HNB assigned a unique range by the HNB-GW. This allows local allocation without conflicts while maintaining centralized coordination through the gateway.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The HNB-GW performs preliminary action by allocating U-RNTI ranges to HNBs during registration, before actual UEs need identifiers. This pre-configuration enables fast local allocation while ensuring uniqueness through centralized planning.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the HNB-GW allocates U-RNTI centrally, then identifier uniqueness is guaranteed, but the registration overhead increases and allocation latency increases

Engineering Contradiction:

Improveidentifier uniquenessVSAvoidregistration overhead

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The centralized allocation process segments the U-RNTI management into range allocation (done once during HNB registration) and specific identifier assignment (done locally when UEs connect). This reduces repeated overhead while maintaining uniqueness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The HNB-GW performs the time-consuming range allocation activity in advance during HNB registration, so that subsequent UE connections can use pre-configured ranges without additional gateway communication overhead.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If mobility in CELL FACH state is not supported, then the network complexity remains low, but the user experience deteriorates and handover efficiency decreases

Engineering Contradiction:

Improvenetwork complexityVSAvoidhandover efficiency

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent implements partial mobility support in CELL FACH state by allowing limited handovers without full RRC connection re-establishment. This provides improved user experience for common scenarios while avoiding the full complexity of complete mobility support.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10623948B2Communication system

Publication Date: 2020.04.14 NEC CORP

AI summary

A communication system is described in which mobile telephones are able to roam between neighbouring home node base stations. Techniques are described for allocating U-RNTIs to mobile telephones by the home base stations or the home base station gateway. Techniques are also disclosed for target home base stations to be able to retrieve information needed to respond to a Cell Update request received from a mobile telephone.