http___www.tetra-komunikacije.com_sto-je-tetra__1.xml
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What is TETRA? TETRA is an open standard developed by the European Telecommunications Standards Institute (ETSI). The main purpose of the TETRA standard was to define a series of open interfaces, as well as services and facilities, in sufficient detail to enable independent manufacturers to develop infrastructure and terminal products that would fully interoperate with each other as well as meet the needs of traditional PMR user organisations. The initial responsibility of ETSI Project TETRA (now known as ETSI Technical Committee (TC) TETRA) was to deliver as set of standards, under a mandate from the European Commission, for a Digital Trunked PMR communications system that could be deployed in Western Europe. As well as producing these mandatory ETSI deliverables (now completed), TC TETRA’s responsibility was, and still is, to make sure that the portfolio of standards continue to be developed in accordance with user needs and priorities. The technology solutions chosen to meet user requirements contained in the TETRA standards have been, and continue to be, developed primarily by well know and respected manufacturers who have been serving the PMR market with products and services for several decades. This combined “Know How” ensures that optimum technology solutions are chosen to meet user requirements. Details of manufacturers can be viewed on the member’s page of the TETRA Association by clicking on the left hand menu under core products. Although the prime responsibility of ETSI is to develop standards for Europe, many of its standards are also adopted world-wide, as evidenced by the uptake of GSM, the first wireless technology standard to be developed by ETSI. Similarly, TETRA has already been deployed in many regions and nations outside Europe, resulting in TETRA becoming a truly global standard. There is no doubt that a proprietary technology solution can be brought to market in less time than a solution conforming to a recognised open standard. However, large user organisations, especially those in the public sector, have recognised that some proprietary solutions can meet their needs but the ‘tie in’ to a single supplier can have significant disadvantages. Even though there are some disadvantages, the main advantages and benefits of adopting an open standard are: •Economies of scale provided by a large harmonised market served by several independent manufacturers and suppliers competing for the same business resulting in competitively priced solutions •Second source security if existing suppliers exit the market •Evolution (instead of revolution) of the technology standard ensuring longevity and good return on investment for both users and suppliers •Choice of manufacturers for new products keeping prices down •Greater choice of products for specialised applications •Greater responsiveness to future needs by existing suppliers because of competition Because there are several independent manufacturers of both TETRA network infrastructure and radio terminals all the benefits of standardisation listed also apply to the TETRA market. Evolution & Longevity The ETSI TETRA standard will continue to evolve beyond Release 1 and Release 2 to provide additional enhancements as driven by user needs, technology innovations and other parallel standard developments. As a consequence, ETSI has no plans to develop a new technology standard for use by large traditional PMR user organisations. Similarly, other technology standards being developed and/or available outside Europe offer little or no benefit over what TETRA already provides. This planned evolution of TETRA can be appreciated when considering that traditional PMR user organisations will always require private PMR networks because public networks cannot adequately provide the required RF coverage, Grade of Service (GoS) during busy periods and high levels of reliability. Besides these basic needs, public networks will not be able to provide the specialised voice services such as wide area fast call-set up all informed nets (group calls), Direct Mode Operation (DMO) and high levels of secure encryption for voice and data. In summary, TETRA will evolve in a similar way to GSM, which evolved from providing a basic V+D “one to one” telephony service (via GSM II+, GPRS, EDGE, etc.) to UMTS/3G supporting powerful multimedia applications and High Speed Data. Also, the focus and technology solution for Next Generation Networks (NGN) will primarily be for public networks. Taking these previous factors into consideration and the fact that analogue MPT 1327 trunking networks are still being deployed across the world more than 28 years after the technology was first developed, TETRA networks are expected to be available for at least another 25 years, thereby ensuring a very good return on investment for user organisations as well as manufacturers and suppliers.
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Što je TETRA? TETRA je otvoreni standard koji je razvio ETSI (European Telecommunications Standards Institute). Glavna namjena TETRA standarda je definiranje otvorenog sučelja, kao i usluga i opreme, na dovoljno detaljan način da se omogući nezavisnim proizvođačima da razviju infrastrukturu i uređaje koji su međusobno interoperabilni, i koji zadovoljavaju potrebe uobičajenih PMR (Professional Mobile Radio) korisnika i organizacija. Inicijalno je ETSI projekt TETRA (novo ime je ETSI Technical Committee TETRA) bio zadužen (od strane Europske Komisije) za izradu standarda za digitalni ‘trunked’ radio sustav koji bi bio korište u zapadnoj Europi. Osim inicijalne izrade i definicije samog standarda TC TETRA je zadužen i za daljnji razvoj i unaprijeđivanje standarda u skladu sa zahtjevima i potrebama korisnika sustava. Tehnologije i rješenja koja su izabrana u TETRA standardu bili su i još uvijek su prvenstveno rješenja poznatih i cijenjenih proizvođača koji su na PMR tržištu već više desetljeća. Tako kombinirani ‘know-how’ osigurava optimalna tehnološka rješenja za ispunjavanje korisničkih zahtjeva. Iako su ETSI standardi primarno namijenjeni za područje Europe, mnogi su prihvaćeni i širom svijeta (kao npr. GSM – prvi bežični standard kojeg je definirao ETSI). Slično je i sa TETROM koja je prihvaćena u mnogim regijama izvan Europe, pa je tako sada već postala globalni standard. Bez dvojbe je da se tzv. ‘proprietary’ (privatni, zatvoreni) standardi mogu implementirati u znatno kraćem vremenu od otvorenih i opće poznatih standarda, no velike organizacije, posebno one u javnom sektoru su uvidjele nedostatke korištenja ‘proprietary’ privatnih rješenja, prvenstveno zbog ovisnisti prema samo jednom dobavljaču. Glavne prednosti korištenja otvorenih standarda su: - sudjelovanje više nezavisnih proizvođača i ponuđača koji se natječju na istom području rezultira u konkurentnom formiranju cijena - sigurnost postojanja drugog u slučaju da neki od ponuđača odustane - veći izbor proizvođača snizuje cijene - veći izbor specijaliziranih proizvoda, prilagođenih potrebama i traženju korisnika - bolja i brža reakcija ponuđača na buduće potrebe korisnika zbog postojanja konkurencije Razvoj i dugovječnost ETSI TETRA standard nastavlja sa razvojem i nakon Release 1 i Release 2 kako bi potaknut korisničkim potrebama omogućio dodatna poboljšanja, tehnološke inovacije i drugo. Zbog toga ETSI još uvijek nema planova za razvoj nove tehnologije koja bi služila tradicionalnim PMR korisničkim organizacijama. Isto tako druge tehnologije i standradi koji se razvijaju i koriste izvan Europe i dalje nude vrlo malo ili nimalo poboljšanja u odnosu na TETRU. Ovakav razvoj TETRA standarda je razumljiv budući da uobičajeni PMR korisnici zahtijevaju (i navikli su) da imaju svoju privatnu mrežu koja zadovoljava teritorijalnom pokrivenošću i razinom usluge i za vrijeme vrlo velikih opterećenja (broja korisnika i govornih kanala/grupa). Osim osnovnih potreba, javne mreže ne mogu pružiti specifične glasovne usluge kao što su brza uspostava grupnih poziva na velikom području, enkripcija glasovnih i podatkovnih usluga i DMO direktni način rada. Daljnji razvoj TETRE će biti sličan GSMu koji se razvio od ponude jednostavnih i osnovnih V+D (voice + data) jedan na jedan telefonskih usluga (GSM II+, GPRS, EDGE, itd.) do UMTS/#G thenologije koja podržava multimedijske aplikacije i razmjenu podataka velikim brzinama. Fokus i tehnološka rješenja za mreže novih generacija (NGN – Next Generation Networks) biti će primarno na javnim a ne privatnim mrežama. Zbog svega navedenog kao i činjenice da se analogni trunking sustavi (MPT 1327) još uvijek instaliraju i koriste iako su razvijeni prije 28 godina, za očekivati je da će se TETRA mreže koristiti barem još sljedećih 25 godina, osiguravajući tako vrlo dobar ROI – povrat investicije kako za organizacije koje je korista tako i za proizvođače i dobavljače. [TRUNKING - možda najtočniji prijevod ove riječi bi bio 'dinamička dodjela resursa prema potrebama'. Kod radio trunking sustava misli se na automatsku dinamičku dodjelu raspoloživih kanala. Kanali mogu biti klasični radijski kanali tipa jedna frekvencija jedan kanal, no mogu biti i TDM kao kod TETRA sustava gdje na jednoj frekvenciji mogu biti 4 kanala - timeslota.]