An article to help you understand Wi‑Fi 7 and its testing.
2024-01-29
Key Wi‑Fi Technologies and the Advantages of the Latest Wi‑Fi 7
- Preface
Wireless communication technology is thriving. such as 5G NR, satellite communications, Bluetooth transmission, and IoT communications. With the evolution of WiFi protocols, the latest-generation WiFi 7 has achieved further performance breakthroughs. Wi‑Fi technology is one of the most widely deployed and widely adopted wireless communication technologies. Today’s wireless networks can adapt to increasingly complex production environments and business scenarios, integrating the Internet of Things with mobile communications to drive core business transformation and enhance operational efficiency.
- Wi-Fi Key Communication Technologies
Wi‑Fi is a wireless local area network technology based on the IEEE 802.11 standard. From Since the release of the first-generation IEEE 802.11 standard in 1997, the 802.11 standard has undergone multiple revisions and evolutions.
- Orthogonal Frequency Division Multiplexing Technology O FDM
Orthogonal signals can be separated at the receiver by employing correlation techniques, thereby reducing inter‑subchannel interference. (ISI). The signal bandwidth on each subchannel is smaller than the channel’s coherence bandwidth, so each subchannel can be treated as experiencing flat fading, thereby eliminating inter‑symbol interference. Moreover, since the bandwidth of each subchannel is only a small fraction of the original channel bandwidth, channel equalization becomes relatively straightforward.
W IFI Capable of high-speed data transmission, orthogonal frequency-division multiplexing technology O FDM It is one of its most critical technologies, enabling more efficient carrier modulation within the allocated spectrum and fully leveraging frequency resources for data transmission. 802.11 g /n/a/ac , data transmission uses In OFDM mode, users are distinguished by different time slots. In each time slot, a single user occupies all subcarriers and transmits an entire data packet. 。
W IFI6 A more efficient data transmission mode has been introduced, called OFDMA achieves multi‑user multiplexing of channel resources by assigning subcarriers to different users and incorporating multiple access into the OFDM system. From the perspective of the overall time–frequency resource, multiple users may transmit simultaneously within each time slot. OFDMA allows independent power control for each channel or subcarrier, whereas OFDM requires maintaining the same power level across all subcarriers.
In In OFDMA, by dividing the Wi‑Fi channel into smaller dedicated sub‑channels—resource units (RUs)—the Wi‑Fi channel can be shared among multiple OFDMA users. In Wi‑Fi 6, each user is restricted to transmitting or receiving frames only on its assigned RU, which significantly limits the flexibility of spectrum resource allocation. To address this issue and further enhance spectral efficiency, WiFi 7 defines a mechanism that allows multiple RUs to be allocated to a single user.
- Quadrature Amplitude Modulation Q AM
of the analog signal 3 Basic Modulation Scheme A M 、 F M 、 P M , known as amplitude modulation, frequency modulation, and phase modulation. 
BPSK Modulation QPSK Modulation
The constellation diagram of PSK can be visualized as all signal points lying on a common circle, as shown in the figure above; the radius of this circular constellation equals the signal amplitude. But what if we combine phase modulation with amplitude modulation?
With the advancement of technology, amplitude modulation parameters have been incorporated, enabling simultaneous phase and amplitude modulation. Q AM Modulation. QAM stands for Quadrature Amplitude Modulation. In the field of communications, “quadrature” means that the two constituent signals are 90° out of phase. In other words, QAM combines both phase modulation and amplitude modulation. Consequently, at a given power level, as the amplitude increases, different amplitudes corresponding to the same phase give rise to additional constellation points; for example, 1 6QAM . The constellation diagram is shown below; each blue dot represents a modulated signal, using It is represented by 4 bits of data, meaning that a single signal comprises 4 bits.
16QAM Constellation diagram
At the same time, expanding further yields 64-QAM、256-QAM、1024-QAM。。。 The latest W IFI7 The highest-order modulation scheme is used. 4096-QAM , that is, a single signal carries 12 One bit of information.
WIFI6 Maximum modulation method WIFI7 Maximum modulation method
N-QAM modulation and its associated bit information
- M IMO Technology
MIMO refers to multiple transmit and receive antennas, enabling continuous signal transmission between the transmitter and receiver to enhance overall transmission quality. 。 This technology makes full use of spatial resources, doubling the system’s channel capacity without increasing spectrum allocation or antenna transmission power. It is regarded as a core technology for next-generation mobile communications. 。
If the router Wi‑Fi routers with two antennas supporting 5 GHz are typically described as supporting 2×2 MIMO; similarly, three antennas correspond to 3×3 MIMO. The greater the number of MIMO streams, the higher the network throughput. Channel throughput scales linearly with the number of streams: for example, in 80 MHz Wi‑Fi 6, a single stream (antenna) delivers about 600 Mbps; 2×2 yields roughly 1,200 Mbps; 3×3 reaches approximately 1,800 Mbps, and so on. ， Wi‑Fi 7 routers can support up to 16×16 MIMO. 。
In In MIMO systems, the AP can communicate with only one terminal at a time, which is why it is also referred to as SU‑MIMO, or single‑user MIMO. When the number of antennas on the terminal matches that of the AP, the AP’s spatial resources can be fully exploited.
However, in practical applications, it is usually The number of transmit and receive antennas on an AP and a terminal is mismatched: APs typically have three or four antennas, or even more, whereas terminals—such as smartphones—usually have only one or two. This leads to underutilization of some of the AP’s spatial resources.
Antenna Transceiver Matching Diagrams for Different Configurations
MU-MIMO, or multi-user multiple-input multiple-output technology, enables a router to communicate with multiple devices simultaneously rather than sequentially, thereby increasing the overall system capacity. MU-MIMO leverages spatial diversity in the wireless channel to transmit independent data streams over the same bandwidth, allowing all users to utilize the full bandwidth and delivering multiplexing gains. 。Wi-Fi7 Supports bidirectional MU-MIMO, with the number of terminals expanded to 1. 6 One, that is, support 16X16 MU-MIMO.
- Higher frequency and greater bandwidth: The unlicensed spectrum in the 2.4 GHz and 5 GHz bands is limited and congested. To achieve a target maximum throughput of at least 30 Gbps, Wi‑Fi 7 will continue to leverage the 6 GHz band and introduce new bandwidth configurations, including contiguous 240 MHz, non-contiguous 160+80 MHz, contiguous 320 MHz, and non-contiguous 160+160 MHz.
- M LO Carrier aggregation significantly boosts throughput: Wi‑Fi 6 allows devices to connect to only one of the 2.4 GHz or 5 GHz bands at a time, whereas Wi‑Fi 7 supports Multi‑Link Operation (MLO), enabling the simultaneous aggregation of both frequency bands, thereby allowing… The terminal device is connected simultaneously. With both the 2.4 GHz and 5 GHz bands, the effective data throughput has been significantly improved. Meanwhile, when encountering interference on a particular frequency band or under heavy load, the system can automatically switch to another band, enhancing anti‑interference performance, reducing latency, and optimizing the online experience.
Differences between MLO band aggregation and single-band operation
- More MIMO antenna support, more data streams: ： WiFi 7 defines a mechanism that allows multiple RUs to be allocated to a single user. To balance implementation complexity and spectral efficiency, the protocol specifies… The RU configuration imposes certain restrictions, prohibiting the mixed use of small‑size RUs and large‑size RUs.
- Introduce a higher-order 4096-QAM modulation technology: The highest modulation scheme in Wi‑Fi 6 is 1024‑QAM, where each modulation symbol carries 10 bits. To further boost data rates, Wi‑Fi 7 will introduce 4096‑QAM, enabling each symbol to carry 12 bits. Under the same coding scheme, Wi‑Fi 7’s 4096‑QAM delivers a 20% higher throughput compared to Wi‑Fi 6’s 1024‑QAM.
|
|
WIFI 1-3 |
Wi-Fi 4 |
Wi-Fi 5 |
Wi-Fi 6 |
Wi-Fi 6E |
Wi-Fi7 |
|
Establishment Time |
1999-2003 |
2007 |
2013 |
2019 |
2021 |
2024 |
|
IEEE |
802.11b/g |
802.11n |
802.11ac |
802.11ax |
802.11be |
|
|
Maximum rate |
11-54Mbps |
1.2Gbps |
3.5Gbps |
9.6Gbps |
46Gbps |
|
|
Supported frequency bands |
2.4GHz |
2.4 GHz, |
5GHz |
2.4 GHz, |
6GHz |
2.4 GHz, 5 GHz |
|
Channel bandwidth |
20MHz |
20.40MHz |
20,40,80,80+ |
20, 40, 80, 80+80, 160 MHz |
320MHz |
|
|
Modulation method |
64-QAM |
64-QAM |
256-QAM |
1024 QAM OFDMA |
4096-QAM |
|
|
MIMO |
/ |
4X4 MIMO |
4X4 MIMO, |
8x8 UL/DL MU-MIMO |
16X16MU- |
|
A historical overview of Wi‑Fi technologies across generations
IV. WIFI7 Test Plan
Zhongwei Puye has long been committed to RF testing of radio‑frequency and microwave technologies throughout the R&D and manufacturing processes of communication equipment and end‑user products. The product primarily comprises terminal RF conduction. /OTA Test system, RF switch matrix, power test module, and related RF components for testing (antennas, LNA , filters, cables, connectors, etc.).
Targeting WIFI7 The targeted test solutions for this new communication standard are as follows:
Multi-channel Power Acquisition Instrument: Provided by Aumiwalker 16/32 The channel power meter can measure the quantity under test. Wi-Fi Product transmit power, network name, version, MAC Address, battery level detection, and other testing functions. It is suitable for production-line testing conditions and offers significant cost‑efficiency advantages.
RF Conformance Test Workstation: Based on a spectrum analyzer / The comprehensive tester is being developed, and by combining a reverberation suppression chamber with an RF link module, it can support multiple ( ≤4 ) Under parallel conditions for the end product: carrier frequency transmit power, harmonic transmit power, spurious emissions at specified frequency points, network name, version, MAC Address, battery level detection, and other testing functions, and with MES System integration, real-time production report generation, and upload.
Test Content
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