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76-510: TETRA is a European Telecommunications Standards Institute (ETSI) standard, first version published 1995; it is mentioned by the European Radiocommunications Committee (ERC). TETRA uses time-division multiple access (TDMA) with four user channels on one radio carrier and 25 kHz spacing between carriers. Both point-to-point and point-to-multipoint transfer can be used. Digital data transmission

152-464: A Belgian company, has also worked to build small cells for LTE-TDD networks. Trials of LTE-TDD technology began as early as 2010, with Reliance Industries and Ericsson India conducting field tests of LTE-TDD in India , achieving 80 megabit-per second download speeds and 20 megabit-per-second upload speeds. By 2011, China Mobile began trials of the technology in six cities. Although initially seen as

228-411: A coalition of international companies that worked to develop and test the technology. China Mobile was an early proponent of LTE-TDD, along with other companies like Datang Telecom and Huawei , which worked to deploy LTE-TDD networks, and later developed technology allowing LTE-TDD equipment to operate in white spaces —frequency spectra between broadcast TV stations. Intel also participated in

304-618: A combined LTE-TDD and LTE-FDD network in Poland, and by April 2012, ZTE Corporation had worked to deploy trial or commercial LTE-TDD networks for 33 operators in 19 countries. In late 2012, Qualcomm worked extensively to deploy a commercial LTE-TDD network in India, and partnered with Bharti Airtel and Huawei to develop the first multi-mode LTE-TDD smartphone for India. In Japan , SoftBank Mobile launched LTE-TDD services in February 2012 under

380-504: A given TETRA radio cell becomes improvable . The serving cell becomes improvable when the following occurs: the C1 of the serving cell is below the value defined in the radio network parameter cell reselection parameters, slow reselect threshold for a period of 5 seconds, and the C1 or C2 of a neighbour cell exceeds the C1 of the serving cell by the value defined in the radio network parameter cell reselection parameters, slow reselect hysteresis for

456-575: A mechanism for generating a 440 Hz repeating tone that signals a fraud occurrence to members within the same (dynamic or static) Group Short Subscriber Identity (GSSI) or to a specific Individual Short Subscriber Identity ( ISSI ) for the duration of the assignment (an hour, a morning patrol or a given short period allocated to the assignment). The advantage being that each of the end users may attach themselves to any given terminal, and group for short durations without requiring any major reconfiguration by means of radio software programming tools. Similarly,

532-485: A number of carriers promoting VoLGA (Voice over LTE Generic Access) as an interim solution. The idea was to use the same principles as GAN (Generic Access Network, also known as UMA or Unlicensed Mobile Access), which defines the protocols through which a mobile handset can perform voice calls over a customer's private Internet connection, usually over wireless LAN. VoLGA however never gained much support, because VoLTE ( IMS ) promises much more flexible services, albeit at

608-399: A period of 5 seconds, and the C1 or C2 of a neighbour cell exceeds the C1 of the serving cell by the value defined in the radio network parameter cell reselection parameters, fast reselect hysteresis, for a period of 5 seconds. No successful cell reselection shall have taken place within the previous 15 seconds unless Mobility Management (MM) requests a cell reselection. The MS-MLE shall check

684-402: A period of 5 seconds. The next diagram illustrates where a given TETRA radio cell becomes usable . A neighbour cell becomes radio usable when the cell has a downlink radio connection of sufficient quality. The following conditions must be met in order to declare a neighbour cell radio usable: The neighbour cell has a path loss parameter C1 or C2 that is, for a period of 5 seconds, greater than

760-480: A sequence of one or more TETRA terminals as relays. This functionality is called DMO gateway (from DMO to TMO) or DMO repeater (from DMO to DMO). In emergency situations this feature allows direct communications underground or in areas of bad coverage. In addition to voice and dispatch services, the TETRA system supports several types of data communication. Status messages and short data services (SDS) are provided over

836-509: A series of tests of voice over LTE ( VoLTE) calls on China Mobile's TD-LTE network. The next month, Nokia Solutions and Networks and Sprint announced that they had demonstrated throughput speeds of 2.6 gigabits per second using a LTE-TDD network, surpassing the previous record of 1.6 gigabits per second. Much of the LTE standard addresses the upgrading of 3G UMTS to what will eventually be 4G mobile communications technology. A large amount of

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912-608: A sharp filter so that unnecessary spectrum is not used up. This results in an amplitude modulation and is why TETRA requires linear amplifiers. The resulting ratio of peak to mean (RMS) power is 3.65 dB. If non-linear (or not-linear enough) amplifiers are used, the sidebands re-appear and cause interference on adjacent channels. Commonly used techniques for achieving the necessary linearity include Cartesian loops, and adaptive predistortion. The base stations normally transmit continuously and (simultaneously) receive continuously from various mobiles on different carrier frequencies; hence

988-693: A technology utilized by only a few countries, including China and India, by 2011 international interest in LTE-TDD had expanded, especially in Asia, in part due to LTE-TDD's lower cost of deployment compared to LTE-FDD. By the middle of that year, 26 networks around the world were conducting trials of the technology. The Global LTve (GTI) was also started in 2011, with founding partners China Mobile, Bharti Airtel , SoftBank Mobile , Vodafone , Clearwire , Aero2 and E-Plus . In September 2011, Huawei announced it would partner with Polish mobile provider Aero2 to develop

1064-508: A transfer latency of less than 5  ms in the radio access network . LTE has the ability to manage fast-moving mobiles and supports multi-cast and broadcast streams. LTE supports scalable carrier bandwidths , from 1.4  MHz to 20 MHz and supports both frequency division duplexing (FDD) and time-division duplexing (TDD). The IP-based network architecture, called the Evolved Packet Core (EPC) designed to replace

1140-481: A voice call on a non-VoLTE-enabled network or device, LTE handsets will fall back to old 2G or 3G networks for the duration of the call. To ensure compatibility, 3GPP demands at least AMR-NB codec (narrow band), but the recommended speech codec for VoLTE is Adaptive Multi-Rate Wideband , also known as HD Voice . This codec is mandated in 3GPP networks that support 16 kHz sampling. Fraunhofer IIS has proposed and demonstrated "Full-HD Voice", an implementation of

1216-422: Is 1.02 seconds) consists of 18 frames. Hyperframes also exist, but are mostly used for providing synchronisation to encryption algorithms. The downlink (i.e., the output of the base station) is normally a continuous transmission consisting of either specific communications with mobile(s), synchronisation or other general broadcasts. All slots are usually filled with a burst even if idle (continuous mode). Although

1292-407: Is 18,000 symbols per second, and each symbol maps to 2 bits, thus resulting in 36,000 bit/s gross. As a form of phase shift keying is used to transmit data during each burst, it would seem reasonable to expect the transmit power to be constant. However it is not. This is because the sidebands , which are essentially a repetition of the data in the main carrier's modulation, are filtered off with

1368-622: Is a list of top 10 countries/territories by 4G LTE coverage as measured by OpenSignal.com in February/March 2019. For the complete list of all the countries/territories, see list of countries by 4G LTE penetration . Long-Term Evolution Time-Division Duplex ( LTE-TDD ), also referred to as TDD LTE , is a 4G telecommunications technology and standard co-developed by an international coalition of companies, including China Mobile , Datang Telecom , Huawei , ZTE , Nokia Solutions and Networks , Qualcomm , Samsung , and ST-Ericsson . It

1444-408: Is a stream cipher with 80-bit keys. The algorithms were later reversed and it appeared that TEA1 reduces its key strength to 32 bits. TEA1 and TEA4 provide basic level security, and are meant for commercial use. The TEA2 cipher is restricted to European public safety organisations. The TEA3 cipher is for situations where TEA2 is suitable but not available. This first representation demonstrates where

1520-400: Is also included in the standard though at a low data rate. TETRA Mobile Stations (MS) can communicate direct-mode operation (DMO) or using trunked -mode operation (TMO) using switching and management infrastructure (SwMI) made of TETRA base stations (TBS). As well as allowing direct communications in situations where network coverage is not available, DMO also includes the possibility of using

1596-399: Is also recommend to use 440 Hz slow repeating tone (blank space 500 milli-seconds) and 880 Hz fast repeating tone (blank space 250 milliseconds) respectively. The tone options are as follows: 440 Hz, 620 Hz, 880 Hz, and 1060 Hz. The parameters page provides an aid or help menu and the last tab within parameters describes briefly the tool kit the version and

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1672-566: Is an independent, not-for-profit, standardization organization operating in the field of information and communications . ETSI supports the development and testing of global technical standards for ICT-enabled systems, applications and services. ETSI was set up in 1988 by the European Conference of Postal and Telecommunications Administrations ( CEPT ) following a proposal from the European Commission (EC). ETSI

1748-499: Is developed by the 3GPP (3rd Generation Partnership Project) and is specified in its Release 8 document series, with minor enhancements described in Release 9. LTE is also called 3.95G and has been marketed as 4G LTE and Advanced 4G ; but the original version did not meet the technical criteria of a 4G wireless service, as specified in the 3GPP Release 8 and 9 document series for LTE Advanced . The requirements were set forth by

1824-521: Is diverse and includes all the key stakeholders of the ICT sector: private companies, research entities, academia, government and public bodies as well as societal stakeholders. Small and Medium Enterprises (SMEs) and Micro-Enterprises (MEs) represent more than a quarter of ETSI's total membership. The list of current members can be found on the ETSI website. Membership contributions are calculated depending on

1900-425: Is error-protection encoded before transmission to allow correct decoding even in noisy (erroneous) channels. The data rate after coding is 7.2 kbit/s. The capacity of a single traffic slot when used 17/18 frames. A single slot consists of 255 usable symbols, the remaining time is used up with synchronisation sequences and turning on/off, etc. A single frame consists of 4 slots, and a multiframe (whose duration

1976-708: Is generally cheaper to access, and has less traffic. Further, the bands for LTE-TDD overlap with those used for WiMAX , which can easily be upgraded to support LTE-TDD. Despite the differences in how the two types of LTE handle data transmission, LTE-TDD and LTE-FDD share 90 percent of their core technology, making it possible for the same chipsets and networks to use both versions of LTE. A number of companies produce dual-mode chips or mobile devices, including Samsung and Qualcomm , while operators CMHK and Hi3G Access have developed dual-mode networks in Hong Kong and Sweden, respectively. The creation of LTE-TDD involved

2052-495: Is one of the two mobile data transmission technologies of the Long-Term Evolution (LTE) technology standard, the other being Long-Term Evolution Frequency-Division Duplex ( LTE-FDD ). While some companies refer to LTE-TDD as "TD-LTE" for familiarity with TD-SCDMA , there is no reference to that abbreviation anywhere in the 3GPP specifications. There are two major differences between LTE-TDD and LTE-FDD: how data

2128-594: Is the officially recognized body with a responsibility for the standardization of information and communication technologies (ICT). It is one of the three bodies officially recognized by the European Union as a European Standards Organisation (ESO), the others being CEN and CENELEC . The role of the ESOs is to support EU regulation and policies through the production of harmonised European Standards (ENs) and other deliverables. The standards developed by ESOs are

2204-703: Is uploaded and downloaded, and what frequency spectra the networks are deployed in. While LTE-FDD uses paired frequencies to upload and download data, LTE-TDD uses a single frequency, alternating between uploading and downloading data through time. The ratio between uploads and downloads on a LTE-TDD network can be changed dynamically, depending on whether more data needs to be sent or received. LTE-TDD and LTE-FDD also operate on different frequency bands, with LTE-TDD working better at higher frequencies, and LTE-FDD working better at lower frequencies. Frequencies used for LTE-TDD range from 1850 MHz to 3800 MHz, with several different bands being used. The LTE-TDD spectrum

2280-459: The AAC-ELD (Advanced Audio Coding – Enhanced Low Delay) codec for LTE handsets. Where previous cell phone voice codecs only supported frequencies up to 3.5 kHz and upcoming wideband audio services branded as HD Voice up to 7 kHz, Full-HD Voice supports the entire bandwidth range from 20 Hz to 20 kHz. For end-to-end Full-HD Voice calls to succeed, however, both

2356-598: The COFDM radio access technique to replace the CDMA and studying its Terrestrial use in the L band at 1428 MHz (TE) In 2004 by Japan's NTT Docomo , with studies on the standard officially commenced in 2005. In May 2007, the LTE/ SAE Trial Initiative (LSTI) alliance was founded as a global collaboration between vendors and operators with the goal of verifying and promoting the new standard in order to ensure

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2432-586: The GPRS Core Network , supports seamless handovers for both voice and data to cell towers with older network technology such as GSM , UMTS and CDMA2000 . The simpler architecture results in lower operating costs (for example, each E-UTRA cell will support up to four times the data and voice capacity supported by HSPA ). Most carriers supporting GSM or HSUPA networks can be expected to upgrade their networks to LTE at some stage. A complete list of commercial contracts can be found at: The following

2508-462: The GSM / EDGE and UMTS / HSPA standards. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. Because LTE frequencies and bands differ from country to country, only multi-band phones can use LTE in all countries where it is supported. The standard

2584-681: The ITU-R organisation in the IMT Advanced specification; but, because of market pressure and the significant advances that WiMAX , Evolved High Speed Packet Access , and LTE bring to the original 3G technologies, ITU-R later decided that LTE and the aforementioned technologies can be called 4G technologies. The LTE Advanced standard formally satisfies the ITU-R requirements for being considered IMT-Advanced. To differentiate LTE Advanced and WiMAX-Advanced from current 4G technologies, ITU has defined

2660-566: The TETRA Association (formerly TETRA MoU) and the standards can be downloaded for free from ETSI . Its main disadvantages are: Up to 7.2 kbit/s per timeslot, in the case of point-to-point connections, and 3.5 kbit/s per timeslot in case of IP encapsulation. Both options permit the use of between one and four timeslots. Different implementations include one of the previous connectivity capabilities, both, or none, and one timeslot or more. These rates are ostensibly faster than

2736-468: The trusted execution environment on a TETRA-enabled radio. The team points to a list of previously broken cryptographic systems relying on obscurity and argues that the Kerckhoffs's principle should have been followed: the system would have been safer when its structure is publicly known. The main advantages of TETRA over other technologies (such as GSM ) are: Further information is available from

2812-455: The MS to rate the neighbour cell to have higher service level than the current serving cell: The next diagram illustrates where a given TETRA radio cell becomes relinquishable ( abandonable ). The serving cell becomes relinquishable when the following occurs: the C1 of the serving cell is below the value defined in the radio network parameter cell reselection parameters, fast reselect threshold, for

2888-547: The Midnight Blue team spots a "peculiarity regarding the TEA3 S-box ", but has yet to determine whether it constitutes a weakness. These vulnerabilities remained publicly unknown for 28 years after TETRA's publication because TETRA does not make definitions of its cryptographic algorithms public, an example of security through obscurity . The Midnight Blue team gained access to TETRA's cryptographic code by attacking

2964-426: The TETRA system is a frequency-division duplex (FDD) system. TETRA also uses FDMA/TDMA (see above) like GSM. The mobiles normally only transmit on 1 slot/4 and receive on 1 slot/4 (instead of 1 slot/8 for GSM). Speech signals in TETRA are sampled at 8 kHz and then compressed with a vocoder using algebraic code-excited linear prediction (ACELP). This creates a data stream of 4.567 kbit/s. This data stream

3040-865: The United States, Bell and Telus in Canada, au by KDDI in Japan, SK Telecom in South Korea and China Telecom / China Unicom in China) have announced instead they intend to migrate to LTE. The next version of LTE is LTE Advanced , which was standardized in March 2011. Services commenced in 2013. Additional evolution known as LTE Advanced Pro have been approved in year 2015. The LTE specification provides downlink peak rates of 300 Mbit/s, uplink peak rates of 75 Mbit/s and QoS provisions permitting

3116-494: The adoption of LTE, carriers will have to re-engineer their voice call network. Four different approaches sprang up: One additional approach which is not initiated by operators is the usage of over-the-top content (OTT) services, using applications like Skype and Google Talk to provide LTE voice service. Most major backers of LTE preferred and promoted VoLTE from the beginning. The lack of software support in initial LTE devices, as well as core network devices, however led to

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3192-426: The aggression feature functions, but with a higher tone frequency (880 Hz), and with a quicker repetitious nature, so to highlight the urgency of the alert. The parameters tab provides an essential means to the terminal end-user allowing them to pre-configure the target (preprogrammed ISSI or GSSI ) destination communication number. With this pre-programmed destination number, the end-user shall liaise with

3268-405: The block cipher Tiny Encryption Algorithm . The TEA ciphers have different availability due to export and use restrictions. Few details are published concerning these proprietary ciphers. Riess mentions in early TETRA design documents that encryption should be done with a stream cipher , due to the property of not propagating transmission errors. Parkinson later confirms this and explains that TEA

3344-678: The caller and recipient's handsets, as well as networks, have to support the feature. The LTE standard covers a range of many different bands, each of which is designated by both a frequency and a band number: As a result, phones from one country may not work in other countries. Users will need a multi-band capable phone for roaming internationally. According to the European Telecommunications Standards Institute 's (ETSI) intellectual property rights (IPR) database, about 50 companies have declared, as of March 2012, holding essential patents covering

3420-715: The carrier began using these frequencies for LTE service on networks built by Samsung , Alcatel-Lucent , and Nokia . As of March 2013, 156 commercial 4G LTE networks existed, including 142 LTE-FDD networks and 14 LTE-TDD networks. As of November 2013, the South Korean government planned to allow a fourth wireless carrier in 2014, which would provide LTE-TDD services, and in December 2013, LTE-TDD licenses were granted to China's three mobile operators, allowing commercial deployment of 4G LTE services. In January 2014, Nokia Solutions and Networks indicated that it had completed

3496-508: The cell reselection procedures occur on time and assure communication continuity for on-going communication calls. The next diagram illustrates where a given TETRA radio cell initial selection. The initial cell selection is performed by procedures located in the MLE and in the MAC. When the cell selection is made, and possible registration is performed, the mobile station (MS) is said to be attached to

3572-499: The cell. The mobile is allowed to initially select any suitable cell that has a positive C1 value; i.e., the received signal level is greater than the minimum receive level for access parameter. The initial cell selection procedure shall ensure that the MS selects a cell in which it can reliably decode downlink data (i.e., on a main control channel/MCCH), and which has a high probability of uplink communication. The minimum conditions that shall have to be met are that C1 > 0. Access to

3648-538: The competing technologies DMR, dPMR, and P25 are capable of. Latest version of standard supports 115.2 kbit/s in 25 kHz or up to 691.2 kbit/s in an expanded 150 kHz channel. To overcome the limitations many software vendors have begun to consider hybrid solutions where TETRA is used for critical signalling while large data synchronization and transfer of images and video is done over 3G / LTE . For its modulation TETRA, uses π ⁄ 4 differential quadrature phase-shift keying . The symbol (baud) rate

3724-413: The cost of having to upgrade the entire voice call infrastructure. VoLTE may require Single Radio Voice Call Continuity (SRVCC) in order to be able to smoothly perform a handover to a 2G or 3G network in case of poor LTE signal quality. While the industry has standardized on VoLTE, early LTE deployments required carriers to introduce circuit-switched fallback as a stopgap measure. When placing or receiving

3800-520: The criterion for serving cell relinquishment as often as one neighbour cell is scanned or monitored. When the FRT threshold is breached, the MS is in a situation where it is essential to relinquish (or abandon) the serving cell and obtain another of at least usable quality. That is to say, the mobile station is aware that the radio signal is decaying rapidly, and must cell reselect rapidly, before communications are terminated because of radio link failure. When

3876-452: The destination radio terminal or roll allocation server , and may communicate, in the group, or into a dedicated server to which the service acquisition requests are received, preprocessed, and ultimately dispatched though the TETRA core network. This simplifies the reconfiguration or recycling configuration process allowing flexibility on short assignments. The parameters tab also provides a means of choosing between preselected tones to match

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3952-482: The development, setting up a LTE-TDD interoperability lab with Huawei in China, as well as ST-Ericsson , Nokia, and Nokia Siemens (now Nokia Solutions and Networks ), which developed LTE-TDD base stations that increased capacity by 80 percent and coverage by 40 percent. Qualcomm also participated, developing the world's first multi-mode chip, combining both LTE-TDD and LTE-FDD, along with HSPA and EV-DO. Accelleran,

4028-548: The different ETSI technical groups (Technical Committee (TC), ETSI Project (EP), ETSI Partnership Project (EPP), Industry Specification Group (ISG), and Special Committee (SC). ETSI's Cloud Group aims to consider standardisation within cloud computing and conformity with interoperability standards in this field. In October 2023, ETSI reported a data breach. Hackers stole a database containing information on ETSI’s online users. ETSI has more than 900 member organizations worldwide from 65 countries and five continents. Its community

4104-529: The end user with the communication rights necessary to fulfil his or her work role on any short duration assignment. For dexterity, flexibility, and evolution ability, the public transportation radio engineering department, have chosen to use the open sources, Java language specification administered by Sun and the associated work groups in order to produce a transport application tool kit . Service acquisition admits different authorised agents to establish communication channels between different services by calling

4180-639: The existing TETRA radio spectrum, and will likely employ 50 kHz channel bandwidths as this enables an equivalent coverage footprint for voice and TEDS services. TEDS performance is optimised for wideband data rates, wide area coverage and spectrum efficiency . Advances in DSP technology have led to the introduction of multi-carrier transmission standards employing QAM modulation. WiMAX, Wi-Fi and TEDS standards are part of this family. Refer also to: European Telecommunications Standards Institute The European Telecommunications Standards Institute ( ETSI )

4256-442: The fast reselect threshold plus the fast reselect threshold, and the service level provided by the neighbour cell is higher than that of the serving cell. No successful cell reselection shall have taken place within the previous 15 seconds unless MM requests a cell reselection. The MS-MLE shall check the criterion for serving cell relinquishment as often as one neighbour cell is scanned or monitored. The following conditions will cause

4332-605: The global introduction of the technology as quickly as possible. The LTE standard was finalized in December 2008, and the first publicly available LTE service was launched by TeliaSonera in Oslo and Stockholm on December 14, 2009, as a data connection with a USB modem. The LTE services were launched by major North American carriers as well, with the Samsung SCH-r900 being the world's first LTE Mobile phone starting on September 21, 2010, and Samsung Galaxy Indulge being

4408-488: The history of the transport application tool kit to date. The TETRA Association, working with ETSI, developed the TEDS standard, a wideband data solution, which enhances TETRA with a much higher capacity and throughput for data. In addition to those provided by TETRA, TEDS uses a range of adaptive modulation schemes and a number of different carrier sizes from 25 kHz to 150 kHz. Initial implementations of TEDS will be in

4484-568: The latter as "True 4G". LTE stands for Long-Term Evolution and is a registered trademark owned by ETSI (European Telecommunications Standards Institute) for the wireless data communications technology and a development of the GSM/UMTS standards. However, other nations and companies do play an active role in the LTE project. The goal of LTE was to increase the capacity and speed of wireless data networks using new DSP (digital signal processing) techniques and modulations that were developed around

4560-511: The mobile station radio-signal breaches the minimum receive level, the radio is no longer in a position to maintain acceptable communications for the user, and the radio link is broken. Radio link failure: (C1 < 0). Using the suggested values, this would be satisfied with the serving cell level below −105 dBm. Cell reselection procedures are then activated in order to find a suitable radio base station. Any given TETRA radio terminal using Java ( Java ME / CLDC ) based technology, provides

4636-497: The name Advanced eXtended Global Platform (AXGP), and marketed as SoftBank 4G ( ja ). The AXGP band was previously used for Willcom 's PHS service, and after PHS was discontinued in 2010 the PHS band was re-purposed for AXGP service. In the U.S., Clearwire planned to implement LTE-TDD, with chip-maker Qualcomm agreeing to support Clearwire's frequencies on its multi-mode LTE chipsets. With Sprint's acquisition of Clearwire in 2013,

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4712-515: The network shall be conditional on the successful selection of a cell. At mobile switch on, the mobile makes its initial cell selection of one of the base stations, which indicates the initial exchanges at activation. The minimum receive access level information element shall indicate the minimum received signal level required at the SwMI in a cell, either the serving cell or a neighbour cell as defined in table 18.24. The next diagram illustrates where

4788-428: The only ones that can be recognized as ENs. ETSI develops standards in key global technologies such as: GSM , TETRA , 3G , 4G , 5G , DECT . ETSI’s standardization activities are organized around sectors: Home & Office, Better Living with ICT, Content Delivery, Networks, Wireless Systems , Transportation, Connecting Things, Interoperability, Public Safety and Security. Technical activities are carried out in

4864-404: The public transport application requirements for the future mentioned hereafter. The home ( main ) menu presents the end user with three possibilities: Service acquisition provides a means of virtually personalising the end user to any given radio terminal and onto TETRA network for the duration the end user conserves the terminal under his possession. Status SDS provides the end user with

4940-579: The remaining three slots to switch frequency to receive a burst from the base station two slots later and then return to their transmit frequency ( TDMA ). To provide confidentiality the TETRA air interface is encrypted using one of the TETRA Encryption Algorithm (TEA) ciphers. The encryption provides confidentiality (protect against eavesdropping) as well as protection of signalling. Currently 4 different ciphers are defined, TEA1 up to TEA4. These TEA ciphers should not be confused with

5016-592: The service identity, and without possessing the complete knowledge of the ISSI, GSSI, or any other TETRA related communication establishment numbering plan. Service acquisition is administered through a communication rights centralised service or roll allocation server , interfaced into the TETRA core network. In summary, the TETRA MMI aims are to: This transport application tool-kit has been produced successfully and with TETRA communication technology and assures for

5092-442: The slow reselect threshold (SRT), the fast reselect threshold (FRT), and propagation delay exceed parameters are most likely to be. These are represented in association with the decaying radio carrier as the distance increases from the TETRA base station . From this illustration, these SRT and FRT triggering points are associated to the decaying radio signal strength of the respective cell carriers. The thresholds are situated so that

5168-528: The system uses 18 frames per second only 17 of these are used for traffic channels, with the 18th frame reserved for signalling, Short Data Service messages (like SMS in GSM) or synchronisation. The frame structure in TETRA (17.65 frames per second), consists of 18,000 symbols/s; 255 symbols/slot; 4 slots/frame, and is the cause of the perceived "amplitude modulation" at 17 Hz and is especially apparent in mobiles/portables which only transmit on one slot/4. They use

5244-431: The system's main control channel, while packet-switched data or circuit-switched data communication uses specifically assigned channels. TETRA provides for authentication of terminals towards infrastructure and vice versa. For protection against eavesdropping, air interface encryption and end-to-end encryption is available. The common mode of operation is in a group calling mode in which a single button push will connect

5320-407: The turn of the millennium. A further goal was the redesign and simplification of the network architecture to an IP -based system with significantly reduced transfer latency compared with the 3G architecture. The LTE wireless interface is incompatible with 2G and 3G networks, so that it must be operated on a separate radio spectrum . The idea of LTE was first proposed in 1998, with the use of

5396-499: The type of membership. Members' and associate members' contributions are calculated by class which is derived from the member company's annual ECRT band. The organisation is located in Sophia-Antipolis , in the south of France . LTE (telecommunication) In telecommunications , long-term evolution ( LTE ) is a standard for wireless broadband communication for mobile devices and data terminals, based on

5472-460: The user to the users in a selected call group and/or a dispatcher . It is also possible for the terminal to act as a one-to-one walkie talkie but without the normal range limitation since the call still uses the network. TETRA terminals can act as mobile phones ( cell phones ), with a full-duplex direct connection to other TETRA Users or the PSTN . Emergency buttons, provided on the terminals, enable

5548-532: The users to transmit emergency signals, to the dispatcher , overriding any other activity taking place at the same time. An in-depth review published in July 2023 by the company Midnight Blue of the TETRA standard and encryption algorithms, the first made public in the last 20 years, has found multiple security flaws, collectively referred to as TETRA:BURST. A total of 5 flaws were filed to the CVE database: In addition,

5624-413: The work group requirements for the purposes of fraud and aggression alerts. A possibility of selecting any given key available from the keypad to serve as an aggression or fraud quick key is also made possible though the transport application software tool kit. It is recommend to use the asterisk and the hash keys for the fraud and aggression quick keys respectively. For the fraud and aggression tones, it

5700-450: The work is aimed at simplifying the architecture of the system, as it transitions from the existing UMTS circuit + packet switching combined network, to an all-IP flat architecture system. E-UTRA is the air interface of LTE. Its main features are: The LTE standard supports only packet switching with its all-IP network. Voice calls in GSM, UMTS and CDMA2000 are circuit switched , so with

5776-772: The world's first LTE smartphone starting on February 10, 2011, both offered by MetroPCS , and the HTC ThunderBolt offered by Verizon starting on March 17 being the second LTE smartphone to be sold commercially. In Canada, Rogers Wireless was the first to launch LTE network on July 7, 2011, offering the Sierra Wireless AirCard 313U USB mobile broadband modem, known as the "LTE Rocket stick" then followed closely by mobile devices from both HTC and Samsung. Initially, CDMA operators planned to upgrade to rival standards called UMB and WiMAX , but major CDMA operators (such as Verizon , Sprint and MetroPCS in

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