China’s consultation on connected cars
In order to promote the application and development of intelligent networked vehicles in China and to meet the development needs of intelligent traffic information systems such as the Internet of Vehicles, in accordance with the Radio Regulations of the People's Republic of China and the Radio Frequency Division Regulations of the People's Republic of China, the Radio Management Bureau of the Ministry of Industry and Information Technology (MIIT) has issued a consultation on the use of the 5905-5925MHz band for connected cars in early July 2018 [1].
In particular, the 5905-5925 MHz frequency band is planned as the working frequency band of the direct communication of the Internet of Vehicles based on LTE-V2X technology. The direct communication of the Internet of Vehicles refers to the direct transmission and information exchange:
- Between the roadside, the vehicle and the portable radio through the radio transmission
- Between vehicles
- Between the vehicle and the roadside, and
- Between the vehicle and the person
There are three main components of this consultation, namely registration, interference protection, and technical parameters.
Registration: To set up and use roadside radio equipment in the 5905-5925 MHz band, one should apply for a radio frequency license from the national radio regulatory agency. Roadside radio equipment that does not have a radio station license shall not transmit radio signals and shall not be protected by radio interference.
The setup and use of in-vehicle and portable radio equipment in the 5905-5925 MHz band does not require any application of frequency license and radio station license. In addition, effective immediately, application for new frequency license for satellite earth stations (except measurement and control stations) in the 5850-5925 MHz band will no longer be accepted and approved.
Interference protection: The use of the Internet of Vehicles direct communication radio equipment in the 5905-5925 MHz frequency band shall not cause harmful interference to radio services such as fixed satellite and radio positioning in the same or adjacent frequency bands.
To protect the normal operation of existing legal radio services and car-connected radio equipment, the use of the Internet of Vehicles direct communication radio equipment in the 5905-5925 MHz frequency band should, in principle, be separated from the radar station by 7 km and the satellite earth station by more than 2 km.
Prior to the set up and use of the roadside radio equipment in the 5905-5925 MHz band, electromagnetic environment testing should be done to minimize radio interference and eliminate radio interference. The use of the Internet of Vehicles direct communication radio equipment in the 5905-5925 MHz frequency band is not bounded for any interference protection.
If it is subject to external harmful interference, it can be assisted and coordinated by the radio regulatory agency where the interference occurs.
Technical parameters: MIIT has proposed the following parameters to be used in the 5905-5925 MHz band for connected cars:
|
Channel bandwidth |
10 MHz, 20 MHz |
|
Transmit power limit for car and portable radio equipment |
23 dBm per port |
|
Transmit power limit for roadside radio equipment |
26 dBm per port for 5915-5925 MHz band or 23 dBm per port for 5905-5925 and 5905-5915 MHz band |
|
Maximum antenna gain |
3 dBi |
|
Carrier frequency tolerance |
0.2 × 10-6 |
|
Adjacent channel suppression ratio |
Greater than 31 dB |
|
Unwanted emission limits in the downlink receiving frequency band of existing public mobile communications |
-50 dBm/MHz |
Update on IEEE 802.11 new study group for next generation V2X
In the last Standards article, it was reported that IEEE 802.11 Working Group has approved the formation of the Next Generation V2X Study Group (a.k.a. NGV) [2]. Tentative agenda items include the discussion on the scope of work, requirements, and use cases, and the preparation of the following two official deliverables of the study group, namely the project authorization request (PAR) [3] and criteria for standards development (CSD) documents [4].
In the IEEE 802.11 May 2018 interim and July 2018 plenary sessions, the Study Group has been working on these two official deliverables with September 2018 as the target to consider approval. The Study Group has also prepared a baseline use case document [5] that covers basic safety messages, sensor sharing, multi-channel operation, infrastructure applications, vehicular positioning and location, and automated driving assistance.
The study group also hears many submissions covering different topics such as use cases, channel model and technical feasibility were presented and discussed. For further details, visit the IEEE 802.11 Next Gen V2X study group's website.
References
[1] Link to Reference 1
[2] Link to Reference 2
[3] Link to Reference 3
[4] Link to Reference 4
[5] Link to Reference 5 | 
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