Wi-Fi 6 | The solution to bandwidth congestion in automotive wireless communications!

As cars become more and more dependent on wireless connectivity technology, the demand for in-vehicle Wi-Fi is also growing. Wi-Fi 6 can accelerate and simplify automotive wireless communications, increase data transmission capacity, and provide greater flexibility inside and outside the car. This article will analyze the current status of the Internet of Vehicles industry, future-oriented broadband solutions, key factors of Wi-Fi 6 technology and its special features, to help you quickly understand Wi-Fi 6 technology and adapt to the growing trend of Internet of Vehicles.

With the growing development of the Internet of Vehicles, more and more cars are connected to the Internet, other vehicles and traffic management systems through high-performance electronic components. Just looking at Bluetooth and Wi-Fi, we can see the iterative upgrades in functionality over the past decade. Initially, it was a simple Bluetooth hands-free profile (HFP) and Wi-Fi hotspot, followed by Bluetooth-enabled audio streaming (A2DP), as well as multi-role, multi-purpose Wi-Fi and Wi-Fi-enabled screen sharing. Today, more advanced features are becoming mainstream, including wireless sensor data collection, wireless firmware updates, continuous data uploads, electric vehicle charging control, and local network connections (such as in parking lots).

The reliance of cars on wireless data transmission will continue to grow. As autonomous driving systems enter different market stages, we see that the demand for data transmission between cars and different cloud systems and between traffic vehicles will further increase. In the long run, V2X Wi-Fi-based dedicated solutions (IEEE802.11p/bd) are expected to be used in combination with cellular V2X (C-V2X).

△Today's vehicles use several wireless connection technologies, and this number will only increase in the future.

In addition, in-car entertainment systems are becoming more and more popular and attract much attention, so the bandwidth demand cannot be underestimated. Ericsson's mobile communications report predicts that mobile video traffic and its proportion of total mobile data traffic will continue to grow, from 38EB/month and 63% in the third quarter of 2019 to 160EB/month and 75% in 2025. As in-car displays become more popular and infotainment systems become more advanced, video entertainment consumption in cars is expected to increase further.

At the same time, as the number of automotive wireless connection applications continues to increase, the risk of signal congestion also increases, and the subsequent problem is the impact on performance. Preventing such system performance degradation has become a challenge that the industry strives to overcome. In-car signals are becoming more and more congested, filled with countless application combinations, and each application has its own characteristics and system requirements, which puts higher demands on how Wi-Fi systems handle their resources.

Wi-Fi 6 is the latest generation of Wi-Fi technology introduced in the automotive field. With its outstanding comprehensive performance, it can speed up and simplify the wireless connection of automobiles to solve these emerging challenges. In the next few years, Wi-Fi 6 (also known as 802.11ax in the standardization community) is expected to become a key enabler across various automotive system fields, including infotainment units, connected car terminals and advanced driver assistance systems. ABI Research estimates that by 2023, 50% (35 million units) of automotive Wi-Fi chipset shipments will be Wi-Fi 6, and by 2024, 70% (50 million units) will be Wi-Fi 6.

△ More and more use cases inside and around vehicles compete for the same spectrum and resources, increasing the possibility of signal congestion and performance degradation.

Bluetooth and the original 802.11b/g Wi-Fi both operate in the 2.4 GHz band, so they compete for the same spectrum resources. As the bandwidth requirements of emerging Wi-Fi use cases continue to increase, more and more Wi-Fi use cases are being addressed in the 5 GHz band and the combined 2.4 GHz and 5 GHz bands , or once Wi-Fi 6E is launched, in the new 6 GHz band. As more data traffic migrates to higher frequencies, resources in the 2.4 GHz band will be freed up, creating more opportunities for further expansion of low-cost, low-power Bluetooth connections.

In addition to relying on Bluetooth and Wi-Fi, 4G and 5G cellular technologies can provide better user experience and security in order to achieve longer communication distances, wider coverage, higher data rates, and lower latency. In situations where data rates are very high and many cars are located in a limited area, cellular communications and Wi-Fi can operate simultaneously, and in scenarios where Wi-Fi is expected to become the main data transmission medium (such as garages, gas stations, charging stations, or parking lots), Wi-Fi itself can handle high data rate issues.

These wireless capabilities, and the performance and functionality improvements they bring, come at the expense of higher vehicle power consumption. However, with the latest wireless standards, chipset evolution, and efficient software protocols, vehicles are able to offer capabilities far beyond the early concept of a “smartphone in the car.”

Wi-Fi 6将成为真正实现汽车互联的关键推动因素。 与前一代相比，Wi-Fi 6最显著的改进在于它提高了频谱效率，使带宽容量增加了四倍。这允许每个接入点连接更多的客户端，或者启用新的高带宽用例，例如传输超高分辨率视频。这提高了Wi-Fi 6的灵活性，使其可以更加出色地服务于使用较小数据块的客户端，并减少带宽开销。

In addition, while previously released Wi-Fi was tailored for a small number of clients (mainly indoor clients), the research and development of Wi-Fi 6 focuses on providing high-quality experience for many clients in signal congested environments. For automotive use cases, it is particularly attractive because of its longer outdoor communication distance and wider outdoor coverage.

By utilizing bandwidth more efficiently for small amounts of data traffic and using chip configurations with no more than 20 MHz of bandwidth, Wi-Fi 6 technology enables simple, low-power Wi-Fi-based solutions for the IoT market on constrained devices.

How does Wi-Fi 6 do this? First, it uses an Orthogonal Frequency Division Multiple Access (OFDMA) digital modulation scheme in both the uplink and downlink. This increases the number of users that can communicate simultaneously by dividing each OFDMA transmission channel into many small sub-channels (resource units) that can transmit data packets from one access point to multiple users concurrently.

Secondly, OFDMA uses longer orthogonal frequency domain multiplexing signals , so it can achieve better sub-channel utilization efficiency and higher multipath fading protection capabilities by adding longer cyclic prefixes between single symbols. Coupled with the new PHY header, the robustness of Wi-Fi 6 in outdoor environments is enhanced.

In addition, Wi-Fi 6 uses up to 8X8 Multi-User Multiple Input Multiple Output (MU-MIMO) in both uplink and downlink to provide higher throughput and more spatial streams, and uses 1024 Quadrature Amplitude Modulation (1024-QAM) to provide higher peak throughput at short distances.

Other features include spatial reuse (also known as BSS coloring), which allows multiple channels with the same "color code" to be combined to transmit information. In addition, target wake time (TWT) allows clients to enter low-power modes when idle to save power.

△Using the OFDMA digital modulation scheme, Wi-Fi 6 can divide each transmission channel into many small sub-channels (resource units) that can transmit data packets from one access point to multiple users concurrently, thereby increasing bandwidth capacity. Image from Intel

We expect the automotive industry to embrace the new wireless standard, as it brings greater capacity, greater flexibility, higher bandwidth, and improved coverage. Specifically, it remains to be seen how various OEMs and Tier 1 suppliers implement Wi-Fi 6. Over the years, we have seen different manufacturers adopt different approaches and strategies on how to segment the various Wi-Fi systems in the vehicle: adapting to functional usage (TCU, IVI, ADAS, EVCC), cost-optimized usage combinations, and more practical deployments (such as in-car or out-of-car communications). This diversity of approaches is expected, as the development of the technology is accompanied by an increasing number of use cases and usage areas.

The same is true for the implementation of the Wi-Fi and Bluetooth solutions themselves. Some manufacturers prefer an on-board implementation, where the Wi-Fi chip is deployed into the PCB solution by the Tier 1 supplier or the OEM itself. In rare cases, a highly customized or flexible solution may be available with an optimized bill of materials. That said, in most cases, pre-certified module solutions will bring more advantages, usually reducing development time, simplifying PCB and component design, and facilitating migration to next-generation technologies. Together, these advantages can ensure time to market, improve overall direct and indirect costs, and reduce risk.

As vehicles adopt more and more advanced features to improve safety, comfort and convenience, Wi-Fi will become more important as a key enabler of wireless connectivity inside, outside and between vehicles, ensuring reliable connections for a growing number of use cases . Current Wi-Fi technologies will remain suitable for deployment in cars for the next few years, but relying solely on them to meet the growing demand for wireless connectivity in and around the car will increase the risk of signal congestion and degraded performance. By increasing bandwidth capacity, Wi-Fi 6 allows each access point to connect more clients, enabling new high-bandwidth use cases, and extending outdoor coverage, thereby providing a solution to the growing bandwidth congestion problem.

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Swiss u-blox (SIX:UBXN) is a leading supplier of positioning and wireless communication technologies for the automotive, industrial and consumer markets. Its solutions enable accurate positioning of people, vehicles and machines and wireless communication over cellular and short-range networks. With a broad and diverse portfolio of chips, modules and a growing ecosystem of product-supported data services, u-blox is uniquely positioned to help its customers develop innovative solutions for the Internet of Things quickly and cost-effectively. Headquartered in Thalwil, Switzerland, u-blox currently has offices in Europe, Asia and the United States. www.u-blox.com

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