Vehicle-to-everything ( V2X ) describes wireless communication between a vehicle and any entity that may affect, or may be affected by, the vehicle. Sometimes called C-V2X , it is a vehicular communication system that is intended to improve road safety and traffic efficiency while reducing pollution and saving energy.
114-406: The automotive and communications industries, along with the U.S. government, European Union and South Korea are actively promoting V2X and C-V2X as potentially live-saving, pollution-reducing technologies. The U.S. Department of Transport has said V2X technologies offer significant transportation safety and mobility benefits. The U.S. NHTSA estimates a minimum of 13% reduction in traffic accidents if
228-487: A pseudonoise code (PN code) that is specific to each phone. As the user moves from one cell to another, the handset sets up radio links with multiple cell sites (or sectors of the same site) simultaneously. This is known as "soft handoff" because, unlike with traditional cellular technology , there is no one defined point where the phone switches to the new cell. In IS-95 inter-frequency handovers and older analog systems such as NMT it will typically be impossible to test
342-676: A vehicular ad-hoc network as two V2X senders come within each other's range. Hence it does not require any communication infrastructure for vehicles to communicate, which is key to assure safety in remote or little-developed areas. WLAN is particularly well-suited for V2X communication , due to its low latency. It transmits messages known as Cooperative Awareness Messages (CAM) or Basic Safety Message (BSM), and Decentralised Environmental Notification Messages (DENM). Other roadside infrastructure related messages are Signal Phase and Timing Message (SPAT), In Vehicle Information Message (IVI), and Service Request Message (SRM). The data volume of these messages
456-572: A V2V and V2I communication system in the 700 MHz frequency band. In 2015 ITU published as summary of all V2V and V2I standards that are worldwide in use, comprising the systems specified by ETSI, IEEE, ARIB, and TTA (Republic of Korea, Telecommunication Technology Association). 3GPP started standardization work of cellular V2X (C-V2X) in Release 14 in 2014. It is based on LTE as the underlying technology. Specifications were published in 2017. Because this C-V2X functionalities are based on LTE, it
570-584: A V2V system were implemented, resulting in 439,000 fewer crashes per year. V2X technology is already being used in Europe and China. There are two standards for dedicated V2X communications depending on the underlying wireless technology being used: (1) WLAN -based, and (2) cellular -based. V2X also incorporates various more specific types of communication including : The history of working on vehicle-to-vehicle communication projects to increase safety, reduce accidents and driver assistance can be traced back to
684-401: A cellular network, compared with a network with a single transmitter, comes from the mobile communication switching system developed by Amos Joel of Bell Labs that permitted multiple callers in a given area to use the same frequency by switching calls to the nearest available cellular tower having that frequency available. This strategy is viable because a given radio frequency can be reused in
798-588: A communication environment consisting of ITS-G5 and cellular communication as envisioned by EU Member States. Various pre-deployment projects exist at EU or EU Member State level, such as SCOOP@F, the Testfeld Telematik, the digital testbed Autobahn, the Rotterdam-Vienna ITS Corridor, Nordic Way, COMPASS4D or C-ROADS. There exist real scenarios of implementation V2X standard as well. The first commercial project where V2X standard
912-426: A different area for an unrelated transmission. In contrast, a single transmitter can only handle one transmission for a given frequency. Inevitably, there is some level of interference from the signal from the other cells which use the same frequency. Consequently, there must be at least one cell gap between cells which reuse the same frequency in a standard frequency-division multiple access (FDMA) system. Consider
1026-513: A frequency reuse of 1. Since such systems do not spread the signal across the frequency band, inter-cell radio resource management is important to coordinate resource allocation between different cell sites and to limit the inter-cell interference. There are various means of inter-cell interference coordination (ICIC) already defined in the standard. Coordinated scheduling, multi-site MIMO or multi-site beamforming are other examples for inter-cell radio resource management that might be standardized in
1140-399: A large number of active phones in that area. All of the cell sites are connected to telephone exchanges (or switches), which in turn connect to the public telephone network . In cities, each cell site may have a range of up to approximately 1 ⁄ 2 mile (0.80 km), while in rural areas, the range could be as much as 5 miles (8.0 km). It is possible that in clear open areas,
1254-468: A limited, shared resource. Cell-sites and handsets change frequency under computer control and use low power transmitters so that the usually limited number of radio frequencies can be simultaneously used by many callers with less interference. A cellular network is used by the mobile phone operator to achieve both coverage and capacity for their subscribers. Large geographic areas are split into smaller cells to avoid line-of-sight signal loss and to support
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#17327801174641368-650: A minimum of three channels, and three towers for each cell and greatly increases the chances of receiving a usable signal from at least one direction. The numbers in the illustration are channel numbers, which repeat every 3 cells. Large cells can be subdivided into smaller cells for high volume areas. Cell phone companies also use this directional signal to improve reception along highways and inside buildings like stadiums and arenas. Practically every cellular system has some kind of broadcast mechanism. This can be used directly for distributing information to multiple mobiles. Commonly, for example in mobile telephony systems,
1482-402: A mobile phone network manages handover). The most common example of a cellular network is a mobile phone (cell phone) network. A mobile phone is a portable telephone which receives or makes calls through a cell site (base station) or transmitting tower. Radio waves are used to transfer signals to and from the cell phone. Modern mobile phone networks use cells because radio frequencies are
1596-455: A number of desirable features: Major telecommunications providers have deployed voice and data cellular networks over most of the inhabited land area of Earth . This allows mobile phones and mobile computing devices to be connected to the public switched telephone network and public Internet access . Private cellular networks can be used for research or for large organizations and fleets, such as dispatch for local public safety agencies or
1710-412: A number of frequency channels corresponding to a bandwidth of B/K , and each sector can use a bandwidth of B/NK . Code-division multiple access -based systems use a wider frequency band to achieve the same rate of transmission as FDMA, but this is compensated for by the ability to use a frequency reuse factor of 1, for example using a reuse pattern of 1/1. In other words, adjacent base station sites use
1824-530: A perception that an effect of NHTSA's regulatory activity is to protect the U.S. market for a modified oligopoly consisting of the three U.S.-based automakers and the American operations of foreign-brand producers. It has been suggested that the impetus for NHTSA's seeming preoccupation with market control rather than vehicular safety performance is a result of overt market protections such as tariffs and local-content laws having become politically unpopular due to
1938-485: A reference point where the User Equipment (UE), i.e. mobile handset, directly communicates with another UE over the direct channel. In this case, the communication with the base station is not required. In system architectural level, proximity service (ProSe) is the feature that specifies the architecture of the direct communication between UEs. In 3GPP RAN specifications, "sidelink" is the terminology to refer to
2052-481: A regulatory framework for V2X in the EU. It identified key approaches to an EU-wide V2X security Public Key infrastructure (PKI) and data protection, as well as facilitating a mitigation standard to prevent radio interference between ITS-G5 based V2X and road charging systems. The European Commission recognised ITS-G5 as the initial communication technology in its 5G Action Plan and the accompanying explanatory document, to form
2166-527: A result of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA–LU), the agency has issued a Final Rule requiring manufacturers to place NCAP star ratings on the Monroney sticker (automobile price sticker). The rule had a September 1, 2007 compliance date. The agency has an annual budget of $ 1.09 billion (FY2020). The agency classifies most of its spending under
2280-528: A result, it was no longer possible to import foreign vehicles into the United States as a personal import, with few exceptions—primarily vehicles meeting Canadian regulations substantially similar to those of the United States, and vehicles imported temporarily for display or research purposes. In practice, the gray market involved a few thousand cars annually, before its virtual elimination in 1988. In 1998, NHTSA exempted vehicles older than 25 years from
2394-566: A specified amount of money per life saved, or will save more money (in property damage, health care, etc.) than it costs. Requirements are balanced through estimated costs and estimated benefits. For example, FMVSS #208 effectively mandates the installation of frontal airbags in all new vehicles in the United States, for it is written such that no other technology can meet the stipulated requirements. It has been argued that even using conservative cost figures and optimistic benefit figures, airbags' cost–benefit ratio so extreme that it may fall outside of
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#17327801174642508-538: A stand-alone fashion in each user equipment (UE). In addition to the direct communication over PC5, C-V2X also allows the C-V2X device to use the cellular network connection in the traditional manner over Uu interface. Uu refers to the logical interface between the UE and the base station. This is generally referred to as vehicle-to-network (V2N). V2N is a unique use case to C-V2X and does not exist in 802.11p based V2X given that
2622-399: A taxicab company, as well as for local wireless communications in enterprise and industrial settings such as factories, warehouses, mines, power plants, substations, oil and gas facilities and ports. In a cellular radio system, a land area to be supplied with radio service is divided into cells in a pattern dependent on terrain and reception characteristics. These cell patterns roughly take
2736-530: A time when invited by the base station operator. This is a form of time-division multiple access (TDMA). The history of cellular phone technology began on December 11, 1947 with an internal memo written by Douglas H. Ring , a Bell Labs engineer in which he proposed development of a cellular telephone system by AT&T. The first commercial cellular network, the 1G generation, was launched in Japan by Nippon Telegraph and Telephone (NTT) in 1979, initially in
2850-416: A user may receive signals from a cell site 25 miles (40 km) away. In rural areas with low-band coverage and tall towers, basic voice and messaging service may reach 50 miles (80 km), with limitations on bandwidth and number of simultaneous calls. Since almost all mobile phones use cellular technology , including GSM , CDMA , and AMPS (analog), the term "cell phone" is in some regions, notably
2964-545: A vehicle's weight, engine size, or fuel economy in calculating vehicle registration taxes ( road tax ). In 1979, NHTSA created the/a New Car Assessment Program (NCAP) in response to Title II of the Motor Vehicle Information and Cost Savings Act of 1972, to encourage manufacturers to build safer vehicles and consumers to buy them. Since that time, the agency has improved the program by adding rating programs, facilitating access to test results, and revising
3078-408: A wide geographic area. This enables numerous portable transceivers (e.g., mobile phones , tablets and laptops equipped with mobile broadband modems , pagers , etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission. Cellular networks offer
3192-598: Is a telecommunications network where the link to and from end nodes is wireless and the network is distributed over land areas called cells , each served by at least one fixed-location transceiver (such as a base station ). These base stations provide the cell with the network coverage which can be used for transmission of voice, data, and other types of content. A cell typically uses a different set of frequencies from neighboring cells, to avoid interference and provide guaranteed service quality within each cell. When joined together, these cells provide radio coverage over
3306-555: Is based on spread spectrum technology developed for military use during World War II and improved during the Cold War into direct-sequence spread spectrum that was used for early CDMA cellular systems and Wi-Fi . DSSS allows multiple simultaneous phone conversations to take place on a single wideband RF channel, without needing to channelize them in time or frequency. Although more sophisticated than older multiple access schemes (and unfamiliar to legacy telephone companies because it
3420-517: Is based on the work done by the ASTM. Later on in 2012 IEEE 802.11p was incorporated in IEEE 802.11. Around 2007 when IEEE 802.11p got stable, IEEE started to develop the 1609.x standards family standardising applications and a security framework (IEEE uses the term WAVE), and soon after SAE started to specify standards for V2V communication applications. SAE uses the term DSRC for this technology (this
3534-477: Is called cellular V2X (or C-V2X) to differentiate it from the WLAN-based V2X. There have been multiple industry organizations, such as the 5G Automotive Association (5GAA) promoting C-V2X due to its advantages over WLAN based V2X (without considering disadvantages at the same time). C-V2X is initially defined as LTE in 3GPP Release 14 and is designed to operate in several modes: In 3GPP Release 15,
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3648-424: Is called the handover or handoff. Typically, a new channel is automatically selected for the mobile unit on the new base station which will serve it. The mobile unit then automatically switches from the current channel to the new channel and communication continues. The exact details of the mobile system's move from one base station to the other vary considerably from system to system (see the example below for how
3762-557: Is equipped with DSRC V2X. In 2016, 3GPP published V2X specifications based on LTE as the underlying technology. It is generally referred to as "cellular V2X" (C-V2X) to differentiate itself from the 802.11p based V2X technology. In addition to the direct communication (V2V, V2I), C-V2X also supports wide area communication over a cellular network (V2N). As of December 2017, a European automotive manufacturer has announced to deploy V2X technology based on 802.11p from 2019. While some studies and analysis in 2017 and 2018, all performed by
3876-545: Is how the term was coined in the US). In parallel at ETSI the technical committee for Intelligent transportation system (ITS) was founded and started to produce standards for protocols and applications (ETSI coined the term ITS-G5). All these standards are based on IEEE 802.11p technology. Between 2012 and 2013, the Japanese Association of Radio Industries and Businesses (ARIB) specified, also based on IEEE 802.11,
3990-478: Is no problem with two cells sufficiently far apart operating on the same frequency, provided the masts and cellular network users' equipment do not transmit with too much power. The elements that determine frequency reuse are the reuse distance and the reuse factor. The reuse distance, D is calculated as where R is the cell radius and N is the number of cells per cluster. Cells may vary in radius from 1 to 30 kilometres (0.62 to 18.64 mi). The boundaries of
4104-464: Is often referred to as LTE-V2X. The scope of functionalities supported by C-V2X includes both direct communication (V2V, V2I) as well as wide area cellular network communication (V2N). In Release 15, 3GPP continued its C-V2X standardization to be based on 5G. Specifications are published in 2018 as Release 15 comes to completion. To indicate the underlying technology, the term 5G-V2X is often used in contrast to LTE-based V2X (LTE-V2X). Either case, C-V2X
4218-417: Is referred to as Dedicated Short Range Communication ( DSRC ). DSRC uses the underlying radio communication provided by 802.11p. In 2016, Toyota became the first automaker globally to introduce automobiles equipped with V2X. These vehicles use DSRC technology and are only for sale in Japan. In 2017, GM became the second automaker to introduce V2X. GM sells a Cadillac model in the United States that also
4332-509: Is the generic terminology that refers to the V2X technology using the cellular technology irrespective of the specific generation of technology. In Release 16, 3GPP further enhances the C-V2X functionality. The work is currently in progress. In this way, C-V2X is inherently future-proof by supporting migration path to 5G. Study and analysis were done to compare the effectiveness of direct communication technologies between LTE-V2X PC5 and 802.11p from
4446-489: Is used for Intersection movement assist use-case. It has been realized in Brno City / Czech Republic where 80 pcs of cross intersections are controlled by V2X communication standard from public transport vehicles of municipality Brno. Spectrum allocation for C-ITS in various countries is shown in the following table. Due to the standardization of V2X in 802.11p preceding C-V2X standardization in 3GPP , spectrum allocation
4560-769: Is very low. The radio technology is part of the WLAN IEEE 802.11 family of standards and known in the US as Wireless Access in Vehicular Environments (WAVE) and in Europe as ITS-G5. To complement the direct communication mode, vehicles can be equipped with traditional cellular communication technologies, supporting V2N based services. This extension with V2N was achieved in Europe under the C-ITS platform umbrella with cellular systems and broadcast systems (TMC/DAB+). More recent V2X communication uses cellular networks and
4674-531: The 5G Automotive Association (5GAA) – the industry organisation supporting and developing the C-V2X technology – indicate that cellular-based C-V2X technology in direct communication mode is superior to 802.11p in multiple aspects, such as performance, communication range, and reliability, many of these claims are disputed, e.g. in a whitepaper published by NXP, one of the companies active in the 802.11p based V2X technology, but also published by peer-reviewed journals. This technology can be misused to remotely control
Vehicle-to-everything - Misplaced Pages Continue
4788-608: The California Air Resources Board . The Federal Motor Vehicle Safety Standards are contained in the United States 49 CFR 571 . Additional federal vehicle standards are contained elsewhere in the CFR. Another of NHTSA's activities is the collection of data about motor vehicle crashes, available in various data files maintained by the National Center for Statistics and Analysis, in particular
4902-713: The Corporate Average Fuel Economy (CAFE) system. FMVSS 209 was the first standard to become effective on March 1, 1967. NHTSA licenses vehicle manufacturers and importers, allows or blocks the import of vehicles and safety-regulated vehicle parts, administers the vehicle identification number (VIN) system, develops the anthropomorphic dummies used in U.S. safety testing as well as the test protocols themselves, and provides vehicle insurance cost information. The agency has asserted preemptive regulatory authority over greenhouse gas emissions , but this has been disputed by such state regulatory agencies as
5016-583: The Fatality Analysis Reporting System (FARS), the Crash Investigation Sampling System (CISS, where technicians investigate a random sample of police crash reports), and others. In 1964 and 1966, public pressure grew in the United States to increase the safety of cars , culminating with the publishing of Unsafe at Any Speed , by Ralph Nader , an activist lawyer, and the report prepared by
5130-530: The National Academy of Sciences entitled Accidental Death and Disability: The Neglected Disease of Modern Society . In 1966, Congress held a series of publicized hearings regarding highway safety, passed legislation to make the installation of seat belts mandatory, and created the U.S. Department of Transportation on October 15, 1966 ( Pub. L. 89–670 ). Legislation signed by President Lyndon Johnson earlier on September 9, 1966, included
5244-839: The National Traffic and Motor Vehicle Safety Act ( Pub. L. 89–563 ) and Highway Safety Act ( Pub. L. 89–564 ) that created the National Traffic Safety Agency, the National Highway Safety Agency, and the National Highway Safety Bureau, predecessor agencies to what would eventually become NHTSA. Once the Federal Motor Vehicle Safety Standards (FMVSS) came into effect, vehicles not certified by
5358-584: The UMTS system where it allows for low downlink latency in packet-based connections. In LTE/4G, the Paging procedure is initiated by the MME when data packets need to be delivered to the UE. Paging types supported by the MME are: In a primitive taxi system, when the taxi moved away from a first tower and closer to a second tower, the taxi driver manually switched from one frequency to another as needed. If communication
5472-600: The World Forum for Harmonization of Vehicle Regulations , which developed what became the UN Regulations on vehicle design, construction, and safety and emissions performance for vehicles and their components. While many countries adopted or required adherence to the UN Regulations, the United States did not recognize these standards and restricted the importation of vehicles and components not certified by manufacturers as compliant with U.S. regulations. Because of
5586-481: The driver safety heading, with a minority spent on vehicle safety, and a smaller amount on energy security matters of which it is in charge, i.e., vehicular fuel economy. [REDACTED] This article incorporates public domain material from websites or documents of the United States Department of Transportation . Cellular network A cellular network or mobile network
5700-580: The 1970s with projects such as the US Electronic Road Guidance System (ERGS) and Japan's CACS. Most milestones in the history of vehicle networks originate from the United States, Europe, and Japan. Standardization of WLAN-based V2X supersedes that of cellular-based V2X systems. IEEE first published the specification of WLAN-based V2X ( IEEE 802.11p ) in 2010. It supports direct communication between vehicles (V2V) and between vehicles and infrastructure (V2I). This technology
5814-510: The 2012 model year. This technology was first brought to public attention in 1997, with the Swedish moose test . Other than that, NHTSA has issued only a few regulations in the past 25 years . Most of the reduction in vehicle fatality rates during the last third of the 20th century were gained from the initial NHTSA safety standards during 1968–1984 and subsequent voluntary changes in vehicle crashworthiness by vehicle manufacturers. Audits by
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#17327801174645928-594: The Bell System , with cellular assets transferred to the Regional Bell Operating Companies . The wireless revolution began in the early 1990s, leading to the transition from analog to digital networks . The MOSFET invented at Bell Labs between 1955 and 1960, was adapted for cellular networks by the early 1990s, with the wide adoption of power MOSFET , LDMOS ( RF amplifier ), and RF CMOS ( RF circuit ) devices leading to
6042-602: The Inspector General's audit a decade before, in 2011. The 2018 audit found NHTSA incapable of conducting adequate, timely safety recalls. The 2015 audit found NHTSA's collection and analysis of safety-related data to be inadequate, and the agency to be lackadaisical and careless in examining safety defects. Government data (from FARS for the U.S.) in a 2004 book by former General Motors safety researcher Leonard Evans shows other countries achieving greater traffic safety improvements over time than those achieved in
6156-739: The U.S. Department of Transportation announced that it is awarding $ 60 million in grants to advance connected and interoperable vehicle technologies under a program called "Saving Lives with Connectivity: Accelerating V2X Deployment program". It said the grants to recipients in Arizona, Texas and Utah would serve as national models to accelerate and spur new deployments of V2X technologies. European standardisation body ETSI and SAE published standards on what they see as use cases. Early use cases focus on road safety and efficiency. Organizations such as 3GPP and 5GAA continuously introduce and test new cases. The 5GAA has published several roadmaps which highlight
6270-485: The U.S. Department of Transportation's Office of the Inspector General in 2011, 2014, 2015, 2016, 2018, and 2021 have concluded that NHTSA is ineffectual ; the 2021 audit found NHTSA failing to issue or update Federal Motor Vehicle Safety Standards effectively or to act within timeframes on petitions and investigations; having no process in place for critical agency responsibilities like evaluating petitions, and having failed to implement consensus recommendations derived from
6384-534: The U.S. legal system are incompatible with some aspects of the UN regulatory system. Studies have concluded that commonizing regulations between the US and the rest of the world (which uses U.N. Regulations ) would save significant money, likely without affecting safety. NHTSA uses cost–benefit analysis for every safety device, system, or design feature mandated for installation on vehicles. No device, system, or design feature may be mandated unless it costs no more than
6498-586: The US Department of Transportation (USDOT) has been working with a range of stakeholders on V2X. In 2012 a pre-deployment project was implemented in Ann Arbor, Michigan. 2800 vehicles covering cars, motorcycles, buses and HGV of different brands took part using equipment by different manufacturers. The US National Highway Traffic Safety Administration (NHTSA) saw this model deployment as proof that road safety could be improved and that WAVE standard technology
6612-709: The US, used interchangeably with "mobile phone". However, satellite phones are mobile phones that do not communicate directly with a ground-based cellular tower but may do so indirectly by way of a satellite. There are a number of different digital cellular technologies, including: Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), cdmaOne , CDMA2000 , Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT), Digital AMPS (IS-136/TDMA), and Integrated Digital Enhanced Network (iDEN). The transition from existing analog to
6726-496: The United States: Research suggests one reason the U.S. continues to lag in traffic safety is the relatively high prevalence in the U.S. of pickup trucks and SUVs, which a 2003 study by the U.S. Transportation Research Board found are significantly less safe than passenger cars. Comparisons of past data with the present in the U.S. can result in distortions, due to a significant population increase and since
6840-449: The V2X functionalities are expanded to support 5G . C-V2X includes support of both direct communication between vehicles (V2V) and traditional cellular-network based communication. Also, C-V2X provides a migration path to 5G based systems and services, which implies incompatibility and higher costs compared to 4G based solutions. The direct communication between vehicle and other devices (V2V, V2I) uses so-called PC5 interface. PC5 refers to
6954-477: The acronym Wireless Access in Vehicular Environments (WAVE) was first used for V2X communication. From 2004 onwards the Institute of Electrical and Electronics Engineers (IEEE) started to work on wireless access for vehicles under the umbrella of their standards family IEEE 802.11 for Wireless Local Area Networks (WLAN). Their initial standard for wireless communication for vehicles is known as IEEE 802.11p and
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#17327801174647068-430: The agency has not put this proposal into effect. NHTSA administers the Corporate Average Fuel Economy (CAFE), which is intended to incentivize the production of fuel-efficient vehicles by dint of fuel economy requirements measured against the sales-weighted harmonic average of each manufacturer's range of vehicles. Many governments outside North America promote fuel economy by heavily taxing motor fuel and/or by including
7182-471: The basis of 3G ). With FDMA, the transmitting and receiving frequencies used by different users in each cell are different from each other. Each cellular call was assigned a pair of frequencies (one for base to mobile, the other for mobile to base) to provide full-duplex operation. The original AMPS systems had 666 channel pairs, 333 each for the CLEC "A" system and ILEC "B" system. The number of channels
7296-405: The case of a taxi company, where each radio has a manually operated channel selector knob to tune to different frequencies. As drivers move around, they change from channel to channel. The drivers are aware of which frequency approximately covers some area. When they do not receive a signal from the transmitter, they try other channels until finding one that works. The taxi drivers only speak one at
7410-493: The cells can also overlap between adjacent cells and large cells can be divided into smaller cells. The frequency reuse factor is the rate at which the same frequency can be used in the network. It is 1/K (or K according to some books) where K is the number of cells which cannot use the same frequencies for transmission. Common values for the frequency reuse factor are 1/3, 1/4, 1/7, 1/9 and 1/12 (or 3, 4, 7, 9 and 12, depending on notation). In case of N sector antennas on
7524-418: The centers of the cells and were omnidirectional, a cellular map can be redrawn with the cellular telephone towers located at the corners of the hexagons where three cells converge. Each tower has three sets of directional antennas aimed in three different directions with 120 degrees for each cell (totaling 360 degrees) and receiving/transmitting into three different cells at different frequencies. This provides
7638-490: The context of no demonstrated safety benefit to amber over red. More recent NHTSA-sponsored research has demonstrated that amber rear turn signals provide significantly better crash avoidance than red ones, and NHTSA has found there is no significant cost penalty to amber signals versus red ones, yet the agency has not moved to require amber—instead proposing in 2015 to award extra NCAP points to passenger vehicles with amber rear turn signals. As of September 2022, however,
7752-489: The context of teleoperations for autonomous vehicles and platooning WLAN-based V2X communication is based on a set of standards drafted by the American Society for Testing and Materials (ASTM). The ASTM E 2213 series of standards looks at wireless communication for high-speed information exchange between vehicles themselves as well as road infrastructure. The first standard of this series was published 2002. Here
7866-550: The cost–benefit requirements for mandatory safety devices. Cost–benefit requirements have been used as the basis for lighting-related regulation in the U.S; for example, while many countries in the world since at least the early 1970s have required rear turn signals to emit amber light so they might be distinguished from adjacent red brake lamps, U.S. regulations permit rear turn signals to emit either amber or red light. This has historically been justified on grounds of lower manufacturing cost and greater automaker styling freedom in
7980-507: The desired service including mobility management, registration, call set-up, and handover . Any phone connects to the network via an RBS ( Radio Base Station ) at a corner of the corresponding cell which in turn connects to the Mobile switching center (MSC). The MSC provides a connection to the public switched telephone network (PSTN). The link from a phone to the RBS is called an uplink while
8094-615: The development and proliferation of digital wireless mobile networks. The first commercial digital cellular network, the 2G generation, was launched in 1991. This sparked competition in the sector as the new operators challenged the incumbent 1G analog network operators. To distinguish signals from several different transmitters, a number of channel access method s have been developed, including frequency-division multiple access (FDMA, used by analog and D-AMPS systems), time-division multiple access (TDMA, used by GSM ) and code-division multiple access (CDMA, first used for PCS , and
8208-546: The digital standard followed a very different path in Europe and the US . As a consequence, multiple digital standards surfaced in the US, while Europe and many countries converged towards the GSM standard. A simple view of the cellular mobile-radio network consists of the following: This network is the foundation of the GSM system network. There are many functions that are performed by this network in order to make sure customers get
8322-495: The direct communication over PC5. PC5 interface was originally defined to address the needs of mission-critical communication for public safety community (Public Safety-LTE, or PS-LTE) in release 13. The motivation of the mission-critical communication was to allow law enforcement agencies or emergency rescue to use the LTE communication even when the infrastructure is not available, such as natural disaster scenario. In release 14 onwards,
8436-588: The early 2020s, more than 40,000 U.S. residents died in automotive collisions every year. NHTSA has conducted numerous high-profile investigations of automotive safety issues, including the Audi 5000/60 Minutes affair, the Ford Explorer rollover problem, and the Toyota sticky accelerator pedal problem. The agency has introduced a proposal to mandate Electronic Stability Control on all passenger vehicles by
8550-429: The fact that, unless almost all vehicles adopt it, its effectiveness is limited. British weekly The Economist argued in 2016 that autonomous driving is more driven by regulations than by technology. However, a 2017 study indicated that there are benefits in reducing traffic accidents even during the transitional period in which the technology is being adopted in the market. Many books and papers have been written in
8664-612: The failure of DSRC to take off. The advocacy organizations ITS America and American Association of State Highway and Transportation Officials sued the FCC, arguing that the decision harms users of DSRC; on August 12, 2022, a federal court permitted the reassignment to go ahead. To acquire EU-wide spectrum, radio applications require a harmonised standard, in case of ITS-G5 ETSI EN 302 571, first published in 2008. A harmonised standard in turn requires an ETSI System Reference Document, here ETSI TR 101 788. Commission Decision 2008/671/EC harmonises
8778-400: The first results were released on October 15 that year. The agency established a frontal impact test protocol based on Federal Motor Vehicle Safety Standard 208 ("Occupant Crash Protection"), except that the frontal 4 NCAP test is conducted at 35 mph (56 km/h), rather than 30 mph (48 km/h) as required by FMVSS No. 208. To improve the dissemination of NCAP ratings, and as
8892-445: The form of regular shapes, such as hexagons, squares, or circles although hexagonal cells are conventional. Each of these cells is assigned with multiple frequencies ( f 1 – f 6 ) which have corresponding radio base stations . The group of frequencies can be reused in other cells, provided that the same frequencies are not reused in adjacent cells, which would cause co-channel interference . The increased capacity in
9006-406: The format of the information to make it easier for consumers to understand. NHTSA asserts the program has influenced manufacturers to build vehicles that consistently achieve high ratings. The United States was the first country/region to have an NCAP program, which was then copied by other NCAP programs. The first standardized 35 mph (56 km/h) front crash test was on May 21, 1979, and
9120-419: The front and 2.5 mph (4 km/h) at the rear. However, these regulations at low-speed collisions did not enhance occupant safety. Vehicle manufacturers have acknowledged the functional equivalence of the UN and U.S. regulations, encouraged developing countries to recognize and accept both, and advocated for equal recognition of both systems in developed countries. However, some structural features of
9234-613: The future. Cell towers frequently use a directional signal to improve reception in higher-traffic areas. In the United States , the Federal Communications Commission (FCC) limits omnidirectional cell tower signals to 100 watts of power. If the tower has directional antennas, the FCC allows the cell operator to emit up to 500 watts of effective radiated power (ERP). Although the original cell towers created an even, omnidirectional signal, were at
9348-460: The increasing popularity of free trade , thus driving the industry to adopt less visible forms of trade restrictions in the form of technical regulations different from those outside the United States. An example of the market-control effects of NHTSA's regulatory protocol is found in the agency's 1974 banning of the Citroën SM automobile, which contemporary journalists described as one of
9462-509: The lack of an immediate benefit for early adopters, the NHTSA proposed a mandatory introduction. On 25 June 2015 the US House of Representatives held a hearing on the matter, where again the NHTSA, as well as other stakeholders argued the case for V2X. On November 18, 2020, the FCC reallocated 45 MHz in the 5.850–5.895 GHz range to Wi-Fi , and the rest of the V2X band to C-V2X, citing
9576-646: The latter supports direct communication only. However, similar to WLAN based V2X also in case of C-V2X, two communication radios are required to be able to communicate simultaneously via a PC5 interface with nearby stations and via the UU interface with the network. While 3GPP defines the data transport features that enable V2X, it does not include V2X semantic content but proposes usage of ITS-G5 standards like CAM, DENM, BSM, etc. over 3GPP V2X data transport features. Through its instant communication, V2X enables road safety applications such as (non-exhaustive list): In June 2024
9690-517: The level of large commercial truck traffic has substantially increased from the 1960s, but highway capacity has not kept up. However, other factors exert significant influence; Canada has lower roadway death and injury rates despite a vehicle mix and regulations similar to those of the U.S. Nevertheless, the widespread use of truck-based vehicles as passenger carriers is correlated with roadway deaths and injuries not only directly by dint of vehicular safety performance per se , but also indirectly through
9804-743: The maker or importer as compliant with US safety standards were no longer legal to import into the United States. Congress established NHTSA in 1970 with the Highway Safety Act of 1970 (Title II of Pub. L. 91–605 , 84 Stat. 1713 , enacted December 31, 1970 , at 84 Stat. 1739 ). In 1972, the Motor Vehicle Information and Cost Savings Act ( Pub. L. 92–513 , 86 Stat. 947 , enacted October 20, 1972 ) expanded NHTSA's scope to include consumer information programs. Despite improvements in vehicle design and public awareness of issues like drunk driving, traffic fatalities have remained stubbornly high. In
9918-507: The metropolitan area of Tokyo . Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nationwide 1G network. It was an analog wireless network . The Bell System had developed cellular technology since 1947, and had cellular networks in operation in Chicago and Dallas prior to 1979, but commercial service was delayed by the breakup of
10032-410: The most important use of broadcast information is to set up channels for one-to-one communication between the mobile transceiver and the base station. This is called paging . The three different paging procedures generally adopted are sequential, parallel and selective paging. The details of the process of paging vary somewhat from network to network, but normally we know a limited number of cells where
10146-536: The number of subscribers per cell site, greater data throughput per user, or some combination thereof. Quadrature Amplitude Modulation (QAM) modems offer an increasing number of bits per symbol, allowing more users per megahertz of bandwidth (and decibels of SNR), greater data throughput per user, or some combination thereof. The key characteristic of a cellular network is the ability to reuse frequencies to increase both coverage and capacity. As described above, adjacent cells must use different frequencies, however, there
10260-431: The other way is termed downlink . Radio channels effectively use the transmission medium through the use of the following multiplexing and access schemes: frequency-division multiple access (FDMA), time-division multiple access (TDMA), code-division multiple access (CDMA), and space-division multiple access (SDMA). Small cells, which have a smaller coverage area than base stations, are categorised as follows: As
10374-606: The perspective of accident avoided and reduction in fatal and serious injuries. The study shows that LTE-V2X achieves higher level of accident avoidance and reduction in injury. It also indicates LTE-V2X performs higher percentage of successful packet delivery and communication range. Another link-level and system-level simulation result indicates that, to achieve the same link performance for both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios, lower signal-to-noise-ratio (SNR) are achievable by LTE-V2X PC5 interface compared to IEEE 802.11p. Cellular-based V2X solution also leads to
10488-508: The phone is located (this group of cells is called a Location Area in the GSM or UMTS system, or Routing Area if a data packet session is involved; in LTE , cells are grouped into Tracking Areas). Paging takes place by sending the broadcast message to all of those cells. Paging messages can be used for information transfer. This happens in pagers , in CDMA systems for sending SMS messages, and in
10602-441: The phone user moves from one cell area to another cell while a call is in progress, the mobile station will search for a new channel to attach to in order not to drop the call. Once a new channel is found, the network will command the mobile unit to switch to the new channel and at the same time switch the call onto the new channel. With CDMA , multiple CDMA handsets share a specific radio channel. The signals are separated by using
10716-479: The possibility of further protecting other types of road users (e.g. pedestrian, cyclist) by having PC5 interface to be integrated into smartphones, effectively integrating those road users into the overall C-ITS solution. Vehicle-to-person (V2P) includes Vulnerable Road User (VRU) scenarios to detect pedestrians and cyclists to avoid accident and injuries involving those road users. As both direct communication and wide area cellular network communication are defined in
10830-483: The receiving end to produce a somewhat normal-sounding voice at the receiver. TDMA must introduce latency (time delay) into the audio signal. As long as the latency time is short enough that the delayed audio is not heard as an echo, it is not problematic. TDMA is a familiar technology for telephone companies, which used time-division multiplexing to add channels to their point-to-point wireline plants before packet switching rendered FDM obsolete. The principle of CDMA
10944-718: The relatively low fuel costs that facilitate the use of such vehicles in North America. Motor vehicle fatalities decline as gasoline prices increase. In 1958, under the auspices of the United Nations, a consortium known as the Economic Commission for Europe was established to standardize vehicle regulations across Europe. Its goals included promoting best practices in vehicle design and equipment and reducing technical barriers to pan-European vehicle trade and traffic. This organization eventually evolved into
11058-521: The rules it administers, since these are presumed to be collector vehicles. In 1999, certain very low production volume specialist vehicles were also exempt for " Show and Display " purposes. In the mid-1960s, when the framework was established for US vehicle safety regulations, the US auto market was an oligopoly , with three companies ( GM , Ford , and Chrysler ) controlling 85% of the market. The ongoing ban on newer vehicles considered safe in countries with lower vehicle-related death rates has created
11172-591: The safest vehicles available at the time. NHTSA disapproved the SM's designs featuring steerable headlamps that were not of the sealed beam design that was then mandatory in the U.S. as well as its height adjustable suspension , which made compliance with the 1973 bumper requirements cost-prohibitive. The initial bumper regulations were intended to prevent functional damage to a vehicle's safety-related components such as lights and fuel system components when subjected to barrier crash tests at 5 miles per hour (8 km/h) at
11286-415: The same base station site, each with different direction, the base station site can serve N different sectors. N is typically 3. A reuse pattern of N/K denotes a further division in frequency among N sector antennas per site. Some current and historical reuse patterns are 3/7 (North American AMPS), 6/4 (Motorola NAMPS), and 3/4 ( GSM ). If the total available bandwidth is B , each cell can only use
11400-462: The same frequencies, and the different base stations and users are separated by codes rather than frequencies. While N is shown as 1 in this example, that does not mean the CDMA cell has only one sector, but rather that the entire cell bandwidth is also available to each sector individually. Recently also orthogonal frequency-division multiple access based systems such as LTE are being deployed with
11514-399: The same functionality in other European markets over time. In the medium term, V2X is perceived as a key enabler for autonomous driving, assuming it would be allowed to intervene into the actual driving. In that case, vehicles would be able to join platoons the way HGVs do. With the advent of connected and autonomous mobility, V2X discussions are seen to play an important role, especially in
11628-545: The same standard (3GPP), both modes of communication will likely be integrated into a single chipset. Commercialization of those chipsets further enhances economy of scale and leads to possibilities to wider range of business models and services using both types of communications. In 1999 the US Federal Communications Commission (FCC) allocated 75 MHz in the spectrum of 5.850-5.925 GHz for intelligent transport systems. Since then
11742-598: The technical potential and challenges of new use cases. Some use cases address high levels of automation. C-V2X offers further use cases including slippery road, roadworks and road hazard information to cars and trucks over hills, around curves and over longer distances than is possible with direct communications. Volvo, for example, has sold new cars that warn other Volvos of slippery roads ahead using C-V2X communications since 2016 in Denmark, and has announced plans to complement that with general accident-ahead warnings and offer
11856-561: The topic: National Highway Traffic Safety Administration The National Highway Traffic Safety Administration ( NHTSA / ˈ n ɪ t s ə / NITS -ə ) is an agency of the U.S. federal government , part of the Department of Transportation , focused on transportation safety in the United States . NHTSA is charged with writing and enforcing Federal Motor Vehicle Safety Standards as well as regulations for motor vehicle theft resistance and fuel economy , as part of
11970-513: The two technologies starting around 2020 and its proportion on the road is expected to increase gradually. The Volkswagen Golf 8th generation was the first passenger car to be fitted with V2X technology powered by NXP technology. In the meantime, existing (legacy) vehicles will continue to exist on the road. This implies that the V2X capable vehicles will need to co-exist with non-V2X (legacy) vehicles or with V2X vehicles of incompatible technology. The main obstacles to its adoption are legal issues and
12084-455: The unavailability in America of certain vehicle models, a grey market arose in the late 1970s. This provided a method to acquire vehicles not officially offered in the United States, but enough vehicles imported this way were faulty, shoddy, and unsafe that Mercedes-Benz of North America helped launch a successful congressional lobbying effort to close down the grey market in 1988. As
12198-449: The use of PC5 interface has been expanded to meet various market needs, such as communication involving wearable devices such as smartwatch . In C-V2X, PC5 interface is re-applied to the direct communication in V2V and V2I. The Cellular V2X mode 4 communication relies on a distributed resource allocation scheme, namely sensing-based semipersistent scheduling which schedules radio resources in
12312-584: The use of the 5875 to 5905 MHz frequency band for transport safety ITS applications. In 2010 the ITS Directive 2010/40/EU was adopted. It aims to assure that ITS applications are interoperable and can operate across national borders, it defines priority areas for secondary legislation, which cover V2X and requires technologies to be mature. In 2014 the European Commission's industry stakeholder “C-ITS Deployment Platform” started working on
12426-479: The vehicle. The Police of the Czech Republic(2024) announced, in cooperation with universities, has developed a system for remote stopping of vehicles with reference to the fact that such a procedure is legal even under the current legislation. The original V2X communication uses WLAN technology and works directly between vehicles (V2V) as well as vehicles and traffic infrastructure (V2I), which form
12540-622: Was expanded to 416 pairs per carrier, but ultimately the number of RF channels limits the number of calls that a cell site could handle. FDMA is a familiar technology to telephone companies, which used frequency-division multiplexing to add channels to their point-to-point wireline plants before time-division multiplexing rendered FDM obsolete. With TDMA, the transmitting and receiving time slots used by different users in each cell are different from each other. TDMA typically uses digital signaling to store and forward bursts of voice data that are fit into time slices for transmission, and expanded at
12654-469: Was interoperable. In August 2014 NHTSA published a report arguing vehicle-to-vehicle technology was technically proven as ready for deployment. On 20 August 2014 the NHTSA published an Advance Notice of Proposed Rulemaking (ANPRM) in the Federal Register, arguing that the safety benefits of V2X communication could only be achieved if a significant part of the vehicles fleet was equipped. Because of
12768-438: Was interrupted due to a loss of a signal, the taxi driver asked the base station operator to repeat the message on a different frequency. In a cellular system, as the distributed mobile transceivers move from cell to cell during an ongoing continuous communication, switching from one cell frequency to a different cell frequency is done electronically without interruption and without a base station operator or manual switching. This
12882-471: Was not developed by Bell Labs ), CDMA has scaled well to become the basis for 3G cellular radio systems. Other available methods of multiplexing such as MIMO , a more sophisticated version of antenna diversity , combined with active beamforming provides much greater spatial multiplexing ability compared to original AMPS cells, that typically only addressed one to three unique spaces. Massive MIMO deployment allows much greater channel reuse, thus increasing
12996-473: Was originally intended for the 802.11p based system. However, the regulations are technology neutral so that the deployment of C-V2X is not excluded. In 2022, US Federal Courts told the FCC that it could reallocate 45 MHz of V2X spectrum to wireless and cellular carriers, citing years of no use by V2X constituents. The deployment of V2X technology (either C-V2X or 802.11p based products) will occur gradually over time. New cars will be equipped with either of
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