"This knowledge is not too cold" Inventory of wireless technologies in the Internet of Vehicles
The "This Knowledge Is Not So Cold" series aims to help friends wake up their knowledge memories. It will select some key knowledge points highlighted by Qorvo and interpret them in combination with the current state of the industry to review the past and learn new things, and fill in the gaps. This article will introduce you to some of the main wireless technologies used in the Internet of Vehicles .
In previous generations of cars, cables were used to connect CD/DVD players and USB ports for smartphones and memory sticks. Today, Wi-Fi , Bluetooth , cellular networks (Long Term Evolution [LTE] and 5G), and ultra-wideband (UWB) technologies have enabled low-latency, hands-free connectivity. Vehicles can now use these wireless technologies to communicate with dealers to receive system updates or service information via over-the-air (OTA) downloads.
Globally, the 5.9GHz band has been designated for automotive safety communications. Its main uses include vehicle-to-vehicle (V2V) , vehicle-to-infrastructure (V2I) , and vehicle-to-pedestrian (V2P) wireless communications.
Although all countries agree to use this frequency band, the rules on how to divide the frequency band for use in intelligent transportation systems vary. Table 2-1 summarizes these main differences; Figure 2-1 summarizes these differences in graphical form.
Table 2-1: Spectrum used by vehicles in various countries
Figure 2-1: Spectrum of vehicles used in various countries
The 5850 to 5925MHz band was reserved decades ago by regulators in the United States and the European Union (EU) for wireless communications in vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) environments (WAVE). The band was originally used by dedicated short-range communications (DSRC, also known as 802.11p ) , but due to low utilization, the Federal Communications Commission (FCC) reduced the 75MHz band to 30MHZ (5895-5925MHz). The FCC designated this 30MHz band for cellular vehicle-to-everything (C-V2X) communications .
Figure 2-2 shows the automotive frequency bands in the EU and the US and their correspondence with the Unlicensed National Information Infrastructure (U-NII) frequency bands.
Figure 2-2: Car Wi-Fi spectrum in the EU and the US.
The 3rd Generation Partnership Project (3GPP)
is
a collaborative effort between telecommunications organizations to develop global standards
, with
C-V2X
being the collective name for all 3GPP vehicle-to-everything (V2X) technologies
.
3GPP standards are not static. As shown in Figure 2-3, the roadmap clearly defines the goals for future standard updates.
Figure 2-3: 3GPP version use case roadmap
Wireless connectivity is becoming increasingly important in differentiating vehicles as manufacturers integrate advanced Wi-Fi infotainment systems into vehicles for a more social , connected , and safety-focused driving experience. Premium models are often equipped with Wi-Fi, enabling cars and devices to connect to the cloud while being continually updated to the latest Wi-Fi standards to address future needs. Modern connected cars generate about 25GB of data per hour , and this number is expected to reach tens of terabytes as more sensors and services are added and autonomous driving technology emerges. Much of this data is uploaded to the cloud for analysis.
Wi-Fi extends tri-band capabilities into the 6GHz realm , helping to achieve fast terabyte-level data transfers for telematics or new firmware downloads while avoiding interference and network congestion. However, Wi-Fi use is limited because vehicles must be close to a Wi-Fi network access point to operate. New Wi-Fi standards in cars extend the RF range, helping cars to upload data using external Wi-Fi roadside infrastructure and enhance connectivity links.
We will continue to introduce other major wireless technologies for connected vehicles, such as the Internet of Things, predictive edge analytics, Bluetooth, and ultra-wideband, in subsequent chapters . Stay tuned~
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