Wi-Fi 7 testing

Wi Fi 7 test solutions

Meet the new design challenges of the Wi Fi 7 standard

Wi-Fi 6 is set to dominate the market, with regulatory authorities opening up the 6 GHz spectrum for Wi-Fi 6E. However, Wi-Fi 7 or WLAN for extremely high throughput (EHT), as defined by IEEE 802.11be, is already entering the market.

The primary goal of 802.11be is to increase data throughput to tens of gigabits per second at low latency. The purpose of this is to meet the demands of applications such as ultra high definition video streaming, virtual reality and augmented reality. Like Wi-Fi 6E, Wi-Fi 7 will operate in the 2.4 GHz, 5 GHz and 6 GHz bands, with minor adaptations to the tone plan.

Key elements for achieving higher throughput include an increased channel bandwidth of 320 MHz, 4096QAM modulation and a new feature called multi link operation (MLO). These advanced features are challenging for legacy Wi-Fi test setups, which is why Rohde & Schwarz offers test solutions tailored specifically to new and future generations of Wi-Fi.

Supporting extremely high throughput (EHT)

The foundation for EHT relies on support for wider channels and higher modulation schemes. However, these alone are not sufficient to meet future application requirements. This is why MLO - a completely new functionality on the MAC layer - has been introduced. MLO allows a station (STA) to establish and use multiple physical links for communication with an access point (AP) in different operational modes, depending on the physical layer capabilities of the multi link device.

For efficient use of the new 6 GHz spectrum, features like multiple resource units (MRU) and preamble puncturing are highly relevant. These features introduce a new level of complexity, necessitating innovative test solutions.

Key technology elements of the Wi-Fi 7 standard

The 6 GHz band provides a limited number of 320 MHz channels, with only two overlapping channels in Europe and six in North America, for example. However, now that the 6 GHz band is free for license exempt use, it is now possible to fully leverage the power of Wi-Fi 7. The availability of 160/320 MHz wide channels and the preamble puncturing introduced in Wi-Fi 6 will become increasingly important.

In this context, the introduction of multiple resource units (MRU) becomes relevant to more efficiently use spectrum resources. The optional feature of the next higher modulation scheme, 4096QAM, allows for higher data throughput under optimal radio conditions (high signal to noise ratio), making it most suitable for short range communication between Wi-Fi devices.

MLO will be introduced in different variations. Generally, a multi link device (MLD) can simultaneously establish and operate multiple links on different channels. This improves overall throughput, latency and reliability, especially in a busy radio environment. For this purpose, the MAC layer is divided into upper and lower sublayers: the upper sublayer handles functionalities common across all links, while the lower sublayer handles link specific functionalities.

Depending on the radio capabilities of the MLD, two modes of operation are defined:

• Simultaneous transmit and receive (STR)
• Non simultaneous transmit and receive (NSTR)

Specific operational models are defined for mobile, battery powered devices with limited radio capability. These models include the enhanced multi link single radio (EMLSR) mode for STAs and NSTR mobile AP MLD operation.

Your 802.11be test challenges

The 802.11be standard defines various transmitter and receiver tests, including error vector magnitude (EVM), transmit (TX) power, spectrum emissions and sensitivity. For instance, 4096QAM modulation requires signal generators that can transmit signals with very low distortion over bandwidths up to 320 MHz, as well as spectrum analyzers with the necessary analysis bandwidth to perform with very low residual EVM.

Advanced features like orthogonal frequency division multiple access (OFDMA) and MRU assignment in multi user operation and MLO increase the demand for signaling test solutions. These requirements introduce more complexity and variants to be tested, necessitating innovative test solutions that address diverse demands throughout the product lifecycle.

High-performance Wi-Fi 7 test solutions

Rohde & Schwarz continuously enhances its wireless test portfolio to support the latest technological innovations. We are dedicated to offering a comprehensive range of solutions for Wi-Fi AP testing and Wi-Fi STA testing:

• RF components
• Chipsets
• Modules
• Devices

Our solutions span all application layers, from RF and signaling testing to end to end data application testing.