The new generation 802.11 standard, 802.11ax, uses the 2.4 GHz or 5 GHz band and is further committed to increasing connection speed and supports OFDM, up to 1024QAM and multi-user multiple input multiple output (MIMO) technology.
Consumers and businesses are now inseparable from wireless data access. Over the past 30 years, information has tended to be freely circulated, driving the transformation and growth of the overall industry, which not only helps to increase productivity, but also creates greater profits for the industry. Wi-Fi technology under the IEEE 802.11 standard has become a key enabler in the transformation process, providing users with a wide range of wireless connections with low cost and fast transmission rate.
The new generation 802.11 standard, 802.11ax, uses the 2.4 GHz or 5 GHz band and is further committed to increasing connection speed and supports OFDM, up to 1024QAM and multi-user multiple input multiple output (MIMO) technology.
Although the 802.11ax standard is still in the early stage of development, the industry is optimistic, especially because it has the advantage of achieving high-density deployment in indoor and outdoor environments. However, like all emerging standards, as technology continues to evolve, it is accompanied by new testing challenges.
Learn more about 802.11axIn order to gain a deeper understanding of the 802.11ax standard, you must first review the 802.11ac standard. The 802.11ac standard supports up to four spatial data streams; the 802.11ax draft specification announced in January 2016 is based on 802.11ac and doubles the number of spatial streams, greatly increasing the efficiency of each spatial stream. (and data throughput). Similar to 802.11ac, 802.11ax also operates in the 5 GHz band to provide a wider spectrum space for 80 MHz and 160 Hz channels.
The reason why 802.11ax is so attractive is that it can significantly improve throughput while effectively improving the power utilization of mobile devices. And in addition to improving the theoretical system throughput (such as the standard specifications claimed by various new technologies), even in the user's actual environment, including densely populated places, indoor and outdoor environments with interference sources, Can achieve the effect of improving throughput.
Simply put, 802.11ax promises consumers a better user experience and covers all possible application scenarios. This is great news for the development of emerging applications such as interactive high-definition (HD) video, which typically require operation in the harsh environments of many Wi-Fi users (such as stadiums and mass transit systems).
In order to achieve these goals, 802.11ax must use a number of different technologies. Although this standard is expected to be based on OFDM, there are other technologies to choose from, including OFDMA, MU-MIMO, and high-order modulation. OFDM is typically used in high data rate systems to combat channel irregularities (eg, selective attenuation). However, OFDM technology must be adapted to 802.11ax to use a narrower subcarrier spacing (4 times the symbol length) and more variable loop preamble (CP) intervals to accommodate different usage scenarios, especially outdoor long channels. It is crucial to choose between efficiency and stability.
Another candidate for improving network performance is the Overlay Basic Service Set (OBSS) anti-jamming process. OBSS technology comes in many different forms and may include some variations in beamforming reception, which is increasingly important as the access point (AP) is widely deployed. This type of deployment highlights the importance of spectrum management and reduced interference from neighboring APs, and OBSS technology is born for this purpose. The aforementioned OFDM, OFDMA, MU-MIMO and high-order modulation techniques will enhance the spatial reuse and spectral efficiency of 802.11ax and achieve the goal of improving system performance.
Challenges cannot be ignoredLike all emerging standards, the technologies used in 802.11ax, such as OFDM and anti-jamming processing, dramatically increase design complexity and bring engineers a whole new set of testing challenges. Some of the challenges involve basic measurements, as shown in the table, while others come from new test requirements. For example, the transmitter test and key receiver tests defined in the 802.11ax specification, although inheriting 802.11ac, have also added test items for multiple user (MU) transmissions. MU transmission is one of the most important new features of 802.11ax, which enhances efficient operation by providing transmission accuracy and synchronizing STAs. As a result, a variety of new test requirements to support MU transmission have come out.
Table 1: Even basic measurements, many test challenges due to the new technology used in 802.11ax
In addition to the aforementioned test requirements, there are many design challenges that need to be overcome. These include: __ Establishing an indoor/outdoor channel model: __IEEE The goal of 802.11ax is to increase the throughput of each station during indoor and outdoor operations. Outdoor channels typically have larger delay spreads and channel time variations than indoor channels. In view of this, the industry selected 3GPP ITU-R Urban Micro (UMi) and Urban Macro (UMa) channel models as the benchmark for the 802.11ax outdoor space channel model.
However, these models also need to be appropriately modified to suit the new specifications. For example, the ITU-R channel model needs to be expanded to support the 160MHz bandwidth of 802.11ax. Once the modification is complete, modeling, resampling, and interpolation are also required to get the required system bandwidth.
In addition, since path loss is a major problem for 802.11ax, establishing a path loss model for indoor and outdoor scenarios has become a top priority. The TGn channel B and D models have been widely used in indoor situations to simulate the signal penetration capability of walls and floors, while the outdoor scenarios will be developed based on the UMi path loss model.
__Narrowband interference: __Narrowband interference is one of the issues that 802.11ax must consider. This is mainly due to internal transmission signals, or signals/harmonics generated by other devices, which fall into the same frequency band of the 802.11ax system. The problem. The industry is using many new technologies to handle receivers to mitigate the negative effects of such interference, such as after fast Fourier transform (FFT), notch filtering, and CP/ZP-OFDM, which can be used with tone cancellation. technology. Dual Subcarrier Modulation (DCM) was originally an alternative modulation for BPSK, QPSK and 16QAM modulation, and is now another viable solution. Ensuring that 802.11ax measurement solutions fully support these technologies is important.
__ Perform higher-order modulation: The main goal of __802.11ax is to increase the speed of the client's wireless network by 4 times to 10 Gbps by adopting the new modulation and coding (MCS) index levels 10 and 11, and With 1024QAM modulation mechanism. With higher order modulation, the system will become more sensitive to internal and external attenuation and therefore require a higher SNR to maintain an acceptable BER/FER level. If the system's SNR is higher than 35dB, it will be difficult to deal with the economical hardware because it exceeds the noise figure, loss and loss of typical transceivers, especially in RF circuits and ADCs/DACs. Therefore, only with accurate analog capabilities can you master the true demodulation of non-ideal hardware signals, and the resulting BER/FER effect.
__MIMO detection technology: __ In terms of receivers, the main technical bottleneck faced by MIMO systems using 1024QAM lies in the scalability of existing MIMO detection technologies. There are currently many mainstream detectors in MIMO systems, such as zeroing (ZF), minimum mean square error (MMSE), and extremely complex maximum similarity (ML) detectors. There are also many sub-optimal detectors that can assist in the trade-offs of complexity/system performance. However, with the advent of 802.11ax, building models and testing the simulation results of the new detection algorithms has become the current top priority.
Face the challengeTo meet these challenges, engineers must use appropriate test and measurement solutions to perform simulation, signal generation, and signal analysis to solve problems throughout the product lifecycle, from design and verification to final manufacturing. Since 802.11ax is the latest revision of the 802.11 standard, it is still in the development stage, and many measurement solutions are still being developed or expanded to support emerging standards.
However, 802.11ax system design engineers do not have to wait until the standard specifications are officially approved, there are test options available. One such solution is to quickly emulate a new 802.11ax system using existing IP. This can be done with Electronic System Level (ESL) design software. Flexible ESL software helps engineers modify current 802.11ac databases and OFDM reference transmitter/receiver models and connect through flexible 3GPP channel models to accommodate changes in emerging standards. With this software, engineers can develop the necessary digital signal processing algorithms (such as optimized MIMO detection), simulate fundamental frequency signal processing, build models of RF transceivers, and even establish wireless channels - everything is done between the fingers.
After the ESL software is connected to a wide variety of hardware, engineers can access their simulated waveforms and view them through actual test instruments. This is the ideal way to test an initial 802.11ax device (see Figure 1).
Figure 1: The initial 802.11ax device evaluation flow chart is shown. At the heart of the process is the Keysight systemVue ESL software, which has the power and flexibility to solve the challenges associated with 802.11ax device design and testing. With SystemVue, the IP developed in the draft standard phase can be quickly connected to various instruments for design verification testing.
In addition to flexible ESL software, there are several other solutions that can be used during testing to meet the requirements of the 802.11ax specification. The Signal Studio software for the 802.11 standard is enhanced to support 802.11ax. With this software, engineers can generate test signals quickly and easily, with or without loss, and then download the waveform to the signal generator.
This ideal 802.11ax signal generation software supports all the features of the new generation of 802.11ax, including 1024QAM, Long Symbol/Guard, OFDMA, MU-MIMO and DCM; it also produces multi-user signal waveforms. Not only that, Signal Studio software has flexible hierarchical parameters to support the 802.11ax format of a new generation of high efficiency (HE) PLCP Protocol Data Units (PPDUs).
The Keysight 89600 VSA software assists engineers in demodulating and analyzing 802.11ax signals. In general, signal generation and signal analysis hardware platforms should be optimized for performance and test conditions to meet R&D and manufacturing needs.
Figure 2: The 802.11ax analysis process is shown using the Keysight 89600 VSA software and the X-Series measurement application software and executed by a signal analyzer. Each solution features 802.11ax modulation analysis options covering all bandwidth and adjustment types to support up to 8x8 MIMO. Both support multiple hardware configurations to meet engineers' needs for performance, bandwidth and channel
Conclusion802.11ax is the next-generation specification for the 802.11 family of standards, not only promises to provide higher throughput, but is also expected to improve end-user experience, especially for dense deployment. Although it is still not the final standard specification, it is clear that the technology and methods it uses will present engineers with many unique challenges in the design and testing of 802.11ax devices.
Fortunately, there are numerous measurement solutions available for engineers to perform simulation, signal generation, and signal analysis to test 802.11ax devices and help them face the future challenges that will occur at all stages of the product lifecycle.
In addition, the functionality of these solutions will go hand in hand with the 802.11ax specification until the standard specification is officially announced. In the process, these solutions not only ensure that engineers have the right tools to design and test 802.11ax devices, but also help to quickly deploy these 802.11ax devices to promote widespread acceptance in the industry.
Bottle Straw Vape 6000,Vgod Vape Pen Retailers,Aroma King Cigarette Suppliers,Smok E Cigarette
Shenzhen Niimoo Innovative Technology Co., Ltd , https://www.niimootech.com