Technical Tip: How to configure MIMO mode

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Description

This article describes the steps to configure MIMO mode on the wtp-profile on FortiOS 7.4.1 or earlier.

Scope

Feature available only in FortiOS 7.4.1 or earlier.

Solution

MIMO (Multiple-Input, Multiple-Output) technology is a game-changer in wireless communication. By using multiple antennas at both ends of a connection, it boosts network performance significantly. MIMO configurations, like 1x1, 2x2, 3x3, 4x4, or 8x8, offer unique benefits and trade-offs. This article explores MIMO's fundamentals and the impact of these configurations on the wireless network's speed, reach, and reliability.

Benefits of Different MIMO Configurations:

• 1x1 MIMO: Suitable for low-power devices like IoT sensors. Offers basic connectivity and conserves energy.
• 2x2 MIMO: Balances performance and energy efficiency. Ideal for standard devices like smartphones and laptops.
• 3x3 MIMO: Enhances throughput and range. Useful for demanding applications like video streaming and online gaming.
• 4x4 MIMO: Maximizes speed and coverage. Great for crowded networks and bandwidth-intensive tasks.
• 8x8 MIMO: Provides top-tier performance but requires ample space and power. Best for large-scale deployments and high-density environments.

It is worth emphasizing that currently, the most robust devices available in the market are equipped with 3x3:3 MIMO configurations. Beyond this, there is no practical advantage to having 4 or even 8 spatial streams. In reality, the majority of client devices commonly employ 2x2:2 MIMO radios.

Note: MIMO Negotiation and Limitations:

It is important to note that MIMO configurations are negotiated dynamically between the Access Point (AP) and the connected Station (STA or client device). The AP and STA communicate to determine the highest common MIMO configuration they can both support.

This means that even if the AP is configured for 4x4 MIMO, it will only operate at that level if the connected STA also supports it. If the STA supports a lower MIMO configuration, the network will operate at that level, limiting the overall performance.

By understanding these configurations and negotiation dynamics, it is possible to tailor the network for optimal performance, ensuring that every device gets the best possible connection while considering its individual capabilities.

In FortiOS version 7.4.1 and onwards, it is possible to have the flexibility to configure the radio MIMO mode as default, 1x1, 2x2, 3x3, 4x4, or 8x8. This configuration can be set within the wtp-profile and for each individual radio. The respective commands are outlined below:

config wireless-controller wtp-profile
    edit <name>
        config radio-x
            set mimo-mode [default|1x1|2x2|3x3|4x4|8x8]
            next
        end
    next
end

Note that this configuration is possible only in the following:

Related documents:

Support for MIMO mode configuration

MIMO

Does the Number of Spatial Streams in 802.11ax Really Matter?

8x8:8 versus 4x4:4 - More is Not Better!

Spatial Streams Decoded – The Difference Between 1×1 and 4×4 WiFi Radios

802.11ac wireless: Channel Bonding, MIMO, Spatial Streams, and Beamforming