Virtualized Mobile Device Architecture for Secure Baseband Isolation

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Solution Overview

Problem

Mobile devices face limitations in memory and CPU resources, making it challenging to effectively utilize multiple operating systems and secure the baseband stack, which is critical for cellular network interactions.

Innovation Solution

A virtualized mobile device architecture is implemented, using a hypervisor to run multiple virtual machines (VMs) with isolated guest operating systems and device drivers, which interact with emulated or virtualized devices through a transformer stack, enabling secure and efficient management of physical devices and network communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple operating systems are run on a mobile device, then system versatility and functionality are improved, but memory and CPU resource constraints are worsened

Engineering Contradiction:
Improvesystem versatilityVSAvoidmemory resources
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the mobile device into multiple isolated virtual machines, each running a separate operating system. The hypervisor divides the physical memory and CPU resources into virtual memory spaces and processing contexts for each VM, allowing multiple OSes to coexist with dedicated resource allocation rather than competing for shared resources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a vertical layering dimension by placing the hypervisor between the physical hardware and the guest operating systems. This creates a hierarchical structure where resources are allocated in layers: physical resources at the bottom, virtualized resources in the middle, and multiple isolated OS environments at the top, effectively adding a dimension to resource management.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple operating systems are run on a mobile device, then system versatility and functionality are improved, but CPU resource constraints are worsened

Engineering Contradiction:
Improvesystem versatilityVSAvoidCPU resources
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The hypervisor segments the CPU execution flow by creating separate virtual CPU contexts for each guest OS. Each VM gets dedicated time slices and resource quotas, preventing any single OS from monopolizing CPU resources. The processor is divided into virtual processing units that can be dynamically allocated based on system needs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic context switching between virtual machines, where the hypervisor alternates CPU allocation in time slices. This periodic scheduling ensures that each guest OS receives fair CPU access over time while preventing resource starvation, effectively managing limited CPU power across multiple OS environments.

Inventive Principle:
Principle #19Periodic action

3Reliability

If virtual machines are isolated from each other, then security is improved, but device complexity is worsened

Engineering Contradiction:
ImprovesecurityVSAvoidarchitecture complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hypervisor serves as an intermediary layer between the physical hardware and guest operating systems, and between isolated VMs. It mediates all resource access requests, enforcing security boundaries while providing a standardized interface. This intermediary absorbs the complexity of isolation enforcement, presenting a simple interface to each VM while handling complex security policies internally.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates virtual copies of hardware devices for each VM through device emulation. Instead of giving direct access to physical devices, the hypervisor creates virtual device models that replicate hardware behavior. Each VM interacts with its own copied device interfaces, providing isolation while maintaining familiar hardware abstractions, thereby managing complexity through virtualization rather than direct hardware management.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2446355B1Virtualized mobile devices
Publication Date: 2021.05.12 VMWARE INC
  • EP2446355B1 patent drawingFigure 1

AI summary

One embodiment is a virtualized mobile device including virtualization software that supports one or more virtual machines and further includes: (a) device emulation software that communicates with device driver software in the one or more virtual machines; (b) device driver software that communicates with one or more physical devices of the mobile device; and (c) transformer stack software that interacts with the device emulation software and the device driver software.