1. Introduction


A Scalable WiFi Virtualization Solution called Wireless Mediated Pass-Though with WiFi SoC Chip Virtualization (vWiFi) is proposed to create many virtual WiFis on one physical WiFi SoC chip. Different vWiFis can be configured as APs or STAs and run in different WiFi channels independently without influencing each other.

Intel lost the embedded devices in the competition with ARM. However, x86 has its advantage that is better single core performance, which is especially suitable for workload consolidation. Therefore, to utilize the computing power by workload consolidation becomes one of intel strategy in IoT. While Arm CPUs have lower energy consumption but lower single core performance. So multiple-core processors is commonly used to increase computing power. With the development of semiconductor technology, we will have more and more redundant computing power in single device. We need a way to make full use of these power.

Virtualization which is a technology widely used in cloud computing data center servers can also be applied to edge devices. Imagine the following scenarios:

  • Virtual Machines in the same physical machine can share the same WiFi device. Each virtual machine can have full wireless capability just like working on a physical WiFi device and independently configure their working WiFi channels without influencing each other.
  • Dozens of WiFi access points can be hosted in one WiFi router without influencing each other.


Let’s see some cases in Figure 1:


Figure 1a: Software Defined vWiFi on Virtualization WiFi Chip



Figure 1b: Software Defined vWiFi on Virtualization WiFi Chip


To sum up, we may need a software-definable virtualization WiFi chip to instead of traditional WiFi chip for better scalability, which can help to build a modern wireless data center and save hardware costs.


2. Existing Solutions


2.1 Traditional WiFi Stack without Virtualization


Figure 2: Traditional WiFi Stack without Virtualization


Characteristics:

  • A bare-mental firmware (usually, a while (1) event handler implementing WiFi protocol) running in the WiFi SOC chip.
  • The SOC uses serial, SDIO, PCI or PCIe interfaces to connect to the host machine.
  • No device sharing at all.


2.2 Ethernet Emulation


Figure 3: Ethernet Emulation


Characteristics:

  • Guests share the same physical WiFi device.
  • Guests see Ethernet devices without wireless capability.


2.3 Wireless Emulation


Figure 4: Wireless Emulation


Characteristics:

  • Guests share the same physical WiFi device.
  • Guests see WiFi devices but share one physical WiFi channel and the same access point (AP). Configuration in one Guest will influence the others.


2.4 Wireless Direct Pass-Though


Figure 5: Wireless Direct Pass-Though


Characteristics:

  • No device sharing among guests. Each guest has its own dedicated physical WiFi.
  • Guests see WiFi devices and can operate in different WiFi Channels without influencing each other.


3. Wireless Mediated Pass-Through with WiFi SoC Chip Virtualization


3.1 Overview


Figure 6: Wireless Mediated Pass-Through with WiFi SoC Chip Virtualization


Characteristics:

  • Guests share the same SoC Physical WiFi Device (WiFi SoC Chip).
  • Guests see WiFi devices. One Guest provides one vWiFi service. Guests can operate in different WiFi Channels without influencing each other.


3.2 WiFi SoC Chip Virtualization


Figure 7: WiFi SoC Chip Virtualization


  • A tiny hypervisor (virtual machine monitor, VMM) runs in the physical CPUs of the WiFi SoC.
  • The WiFi firmware runs in a VCPU (virtual CPU) as a virtual machine.
  • Each VCPU simulates a SoC Logical WiFi Device and the hypervisor is responsible to schedule the SoC Logical WiFi Devices to run on the SoC Hardware.


Figure 8: Wireless Mediated Pass-Through


  • All Guest OS share the same SoC Physical WiFi Device (WiFi SoC Chip).
  • The Host OS WiFi Driver communicates with the virtualized WiFi SoC Chip. It installs SoC Logical WiFi Devices into Host OS as Host Logical WiFi Devices.
  • The Device Model pass through the Host Logical WiFi Devices into the guest OS as Guest Virtual WiFi Devices.
  • The Guest driver runs on the Guest Virtual WiFi Device to provide vWiFi service. Many Guests one-one mapping to many vWiFis.


Definitions:

  • SoC Physical WiFi Device: The physical WiFi device from the perspective of WiFi SoC Chip.
  • SoC Logical WiFi Device: The WiFi device simulated by the WiFi SoC hypervisor.
  • Host Logical WiFi Device: The SoC Logical WiFi device from the perspective of the Host OS.
  • Guest Virtual WiFi Device: The WiFi device from the perspective of the Guest OS.
  • vWiFi: The WiFi service provided by the Guest OS.


3.3 Comparison


Table 1: Comparison of The Existing Solutions and vWiFi


4. Summary


vWiFi which is based on the technology named Wireless Mediated Pass-Though with WiFi SoC Chip Virtualization is a a Scalable WiFi Virtualization Solution that utilizes virtualization technology to build many independent WiFis on a SoC Physical WiFi Device. It can be used to save hardware costs and build wireless data center.