C-RAN Virtual Machine Relocation via Target Cell Handover

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Solution Overview

Problem

Current virtualized environments in centralized radio access networks (C-RAN) face challenges in seamlessly relocating base station processing between virtual machines, leading to unacceptable downtimes due to maintenance, resource demands, or equipment failures, which can cause interruptions in mobile radio access networks.

Innovation Solution

The method involves relocating base station processing from a first virtual machine to a second by introducing a target cell, simultaneously transmitting signals for both cells using the same antennas, and handover user terminals to the target cell, utilizing existing network mechanisms like LTE handover processes to minimize downtime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If base station processing is relocated between virtual machines in a virtualized C-RAN environment, then resource utilization and maintenance flexibility are improved, but service interruption and downtime occur

Engineering Contradiction:

Improvemaintenance flexibilityVSAvoidservice continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-configuring a target cell and target virtual machine before the source virtual machine needs to be relocated. The target cell is introduced in advance, and the target virtual machine is prepared to receive user terminals, ensuring that when the source VM is migrated, user terminals can immediately be handed over without service interruption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary mechanism by introducing a target cell as a bridge during the VM relocation process. The target cell acts as an intermediate entity that user terminals can connect to during the handover process, facilitating seamless transition from the source cell to the target cell while the source virtual machine is being migrated to the target virtual machine.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If base station processing is centralized at a data center with virtual machines, then load balancing and resource optimization are improved, but relocation downtime occurs during maintenance or failures

Engineering Contradiction:

Improveload balancing efficiencyVSAvoidrelocation downtime

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-configuring the target cell and preparing the target virtual machine before any relocation is needed. This includes setting up the target cell parameters, allocating resources in the target VM, and establishing the handover pathways in advance, so that when maintenance or failure occurs, the actual relocation can happen without time loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent ensures continuity of useful action by implementing a seamless handover mechanism where user terminals are continuously served throughout the VM relocation process. The target cell is activated and ready to serve users before the source VM is fully migrated, ensuring that base station processing functionality continues without interruption during the relocation.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If user terminals are handed over during virtual machine relocation, then service continuity is maintained, but handover complexity and signaling overhead increase

Engineering Contradiction:

Improveservice continuityVSAvoidhandover process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the handover process from the VM relocation process by separating these two operations. The target cell is introduced and configured independently before the VM relocation begins. This extraction allows the handover to be managed as a separate, standardized procedure using existing LTE handover mechanisms, reducing the complexity of coordinating VM migration with user terminal handover.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies universality by using the existing LTE handover mechanism for user terminal handover during VM relocation. The same standardized handover procedures and signaling protocols used in normal LTE operations are leveraged for this special scenario, avoiding the need to create complex custom handover logic and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10080172B2Method for operating a centralized radio access network

Publication Date: 2018.09.18 NEC CORP

AI summary

A method for operating a centralized radio access network (C-RAN) having a plurality of base stations, wherein at least a portion of base station processing is performed at a centralized processing entity, and wherein a virtualized environment is provided by the centralized processing entity such that the plurality of base stations run in virtual machines, includes relocating base station processing from a first virtual machine that performs base station processing for a first base station that serves an initial cell to a second virtual machine by: introducing a target cell for which the second virtual machine performs base station processing, simultaneously transmitting, via at least a portion of antennas of the first base station, signals for both the initial cell and the target cell, and handing over user terminals that are assigned to the initial cell to the target cell.