{"id":367,"date":"2013-11-14T17:32:20","date_gmt":"2013-11-14T17:32:20","guid":{"rendered":"http:\/\/www.kodcafe.com\/?p=367"},"modified":"2013-11-14T17:32:20","modified_gmt":"2013-11-14T17:32:20","slug":"1gden-4gye-mobil-iletisim-teknolojileri","status":"publish","type":"post","link":"http:\/\/www.kodcafe.com\/?p=367","title":{"rendered":"1G’den 4G’ye Mobil ileti\u015fim teknolojileri"},"content":{"rendered":"

Bu makalede, g\u00fcn\u00fcm\u00fcze kadar cep telefonu ve kablosuz ileti\u015fim a\u011f\u0131 teknolojilerinin de\u011fi\u015fimini inceleyece\u011fiz. Yaz\u0131ya genel terimlerden ba\u015flay\u0131p 1G, 2G gibi standartlarla devam edece\u011fiz, \u015fu tarihlerde s\u0131k\u00e7a bahsedilen 3G\u2019de biraz durduktan sonra gelecek teknolojilerden de bahsedip yaz\u0131y\u0131 sonland\u0131raca\u011f\u0131z. Umar\u0131m kafan\u0131zda soru i\u015fareti b\u0131rakmayacak, a\u00e7\u0131klay\u0131c\u0131 bir yaz\u0131 olur. S\u00f6z\u00fc fazla uzatmadan genel ge\u00e7er terimler ile ba\u015flayal\u0131m.<\/p>\n

Analog Veri(Analogue data, Analogue Signal)<\/p>\n

Sinyalin form\u00fclize edilebilir elektriksel i\u015flemlerden ge\u00e7mesiyle elde edilen veri. Giri\u015f sinyali ve \u00e7\u0131k\u0131\u015f sinyali aras\u0131ndaki ge\u00e7i\u015f, matematiksel olarak rahatl\u0131kla ifade edilebilir, bu durum veri g\u00fcvenli\u011fini ciddi bi\u00e7imde d\u00fc\u015f\u00fcrmektedir. 1G’de kullan\u0131lan veri ileti\u015fimi analog veri ileti\u015fimidir.
\n
\nH\u00fccreler Aras\u0131 Ge\u00e7i\u015f<\/p>\n

\u015eebekelerin sahip oldu\u011fu her h\u00fccrenin belli bir kapsama alan\u0131 vard\u0131r. Konu\u015fman\u0131n kesilmemesi i\u00e7in ise cep telefonunun s\u00fcrekli kapsama alan\u0131 i\u00e7erisinde kalmas\u0131 gerekir. Bir h\u00fccrenin kapsama alan\u0131ndan di\u011ferine ge\u00e7ti\u011finizde konu\u015fman\u0131z\u0131n kesilmesini istemezsiniz. Bunun i\u00e7in ba\u011flant\u0131n\u0131n sorunsuz bir \u015fekilde bir baz istasyonundan di\u011ferine aktar\u0131lmas\u0131 gerekir. 1G\u2019den beri hizmet sa\u011flay\u0131c\u0131lar bu deste\u011fi vermektedir.<\/p>\n

Aktar\u0131m ise \u015fu \u015fekilde ger\u00e7ekle\u015fir: \u00d6nce telefondan h\u00fccre de\u011fi\u015ftirme iste\u011fi ba\u011flant\u0131 sa\u011flamak istedi\u011fi h\u00fccreye (baz istasyonu) g\u00f6nderilir. Bu baz istasyonu taraf\u0131ndan kullan\u0131c\u0131n\u0131n o anda ba\u011fl\u0131 oldu\u011fu baz istasyonuna ge\u00e7i\u015f iste\u011fi g\u00f6nderilir. Baz istasyonlar\u0131 aras\u0131nda ileti\u015fim sa\u011fland\u0131ktan sonra telefona h\u00fccre de\u011fi\u015ftirme onay sinyali gelir, ve g\u00f6r\u00fc\u015fme yeni baz istasyonundan devam eder. Bu a\u015famalar s\u0131ras\u0131nda g\u00f6r\u00fc\u015fme normal bir \u015fekilde sa\u011flan\u0131r.<\/p>\n

Y\u00fck Da\u011f\u0131t\u0131m\u0131(Load Balance)
\n<\/strong><\/p>\n

\u00c7ok \u00e7ekirdekli bilgisayar i\u015flemcilerindeki sistem gibi d\u00fc\u015f\u00fcnebilirsiniz. Fazla y\u00fck geldi\u011finde, y\u00fck b\u00f6l\u00fcnerek azalt\u0131lmaya \u00e7al\u0131\u015f\u0131l\u0131r. Ayn\u0131 alan\u0131 kapsayan birden fazla baz istasyonu varsa istasyonlar\u0131n y\u00fck durumuna g\u00f6re ba\u011fl\u0131 kullan\u0131c\u0131lar dengelenir.<\/p>\n

 <\/p>\n

Dola\u015f\u0131m<\/strong><\/p>\n

Roaming olarak da duymu\u015f olabilirsiniz. Temelinde bir abonenin, ayn\u0131 \u00f6zelliklere sahip ba\u015fka bir a\u011fdan hizmet alabilmesidir. \u015eebekeler aras\u0131nda kar\u015f\u0131l\u0131kl\u0131 anla\u015fmalarla bu hizmet verilebilir. Sistemin getirisi b\u00fcy\u00fckt\u00fcr. Numaran\u0131z\u0131 ve SIM kart\u0131n\u0131z\u0131 herhangi bir \u015fekilde de\u011fi\u015ftirme gere\u011fi duymadan uluslar aras\u0131 gezinebilir, ya da e\u011fer anla\u015fma sa\u011fland\u0131ysa bir \u015febekenin \u00e7ekmedi\u011fi yerde di\u011ferinin kapsama alan\u0131ndaysan\u0131z onu kullanabilirsiniz.<\/p>\n

Yeni kurulan hizmet sa\u011flay\u0131c\u0131lar\u0131, daha \u00f6nce kurulmu\u015f olan ve kapsama alan\u0131 y\u00fcksek a\u011flar\u0131 para kar\u015f\u0131l\u0131\u011f\u0131 kendi yap\u0131lanmas\u0131n\u0131 sa\u011flay\u0131ncaya kadar dola\u015f\u0131m amac\u0131yla kullanmaktad\u0131rlar. T\u00fcrkiye\u2019de Turkcell ve Vodafone Avea\u2019ya bu hizmeti vermeyi reddetmi\u015ftir.<\/p>\n

GSM<\/strong><\/p>\n

Global System for Mobile Communications, kablosuz(mobil, ta\u015f\u0131nabilir) a\u011flar i\u00e7in evrensel sistem. 2G ile ortaya \u00e7\u0131kan en yayg\u0131n standartt\u0131r, o b\u00f6l\u00fcmde daha fazla bahsedece\u011fiz.<\/p>\n

 <\/p>\n

 <\/p>\n

GPRS<\/strong><\/p>\n

General Packet Radio Service, genel paket yay\u0131n servisi. \u00dclkemizde \u015fu anda etkin olan t\u00fcm \u015febekelerin destekledi\u011fi 2G standard\u0131, anahtarlamal\u0131 olarak paket yay\u0131n\u0131 yap\u0131lmas\u0131na olanak tan\u0131r. Pratikte 30-50 kbps civar\u0131 veri aktar\u0131m\u0131n\u0131 desteklemektedir. Bas Konu\u015f\u2019un geli\u015ftirilmesine imkan sa\u011flam\u0131\u015ft\u0131r.<\/p>\n

Bas Konu\u015f<\/strong><\/p>\n

PTT, PushToTalk. Cep telefonlar\u0131n\u0131n telsiz \u015feklinde kullan\u0131m\u0131na imkan tan\u0131r. \u00dcst\u00fcn veri s\u0131k\u0131\u015ft\u0131rma teknolojileri ile GPRS \u00fczerinden \u00e7ok ucuza g\u00f6r\u00fc\u015fme yap\u0131labilmektedir. \u00dclkemizde ChatIn ya da Bas Konu\u015f gibi isimlerle bu hizmet sa\u011flanmaktad\u0131r.<\/p>\n

EDGE<\/strong><\/p>\n

Enhanced Data rates for GSM Evolution, GSM geli\u015fimi i\u00e7in artt\u0131r\u0131lm\u0131\u015f veri h\u0131z\u0131. \u00dc\u00e7\u00fcnc\u00fc nesil ileti\u015fim teknolojisi 3G\u2019nin \u00f6ncesindeki son ad\u0131md\u0131r. 380 kbps\u2019ye kadar veri aktar\u0131m\u0131na olanak tan\u0131r. 2G\u2019de \u00fczerinde daha fazla duraca\u011f\u0131z.<\/p>\n

CDMA<\/strong><\/p>\n

3G\u2019nin bir getirisi olan UMTS klasik frekans b\u00f6lmeli \u00e7oklu ileti\u015fim (frequence division multiple access) veya zaman b\u00f6lmeli \u00e7oklu ileti\u015fim (time division multiple access)\u00a0 tekniklerinden prensip olarak \u00e7ok farkl\u0131 olan CDMA (Code Division Multiple Access) teknolojisini kullan\u0131r. Bir \u00e7e\u015fit da\u011f\u0131n\u0131k frekans (spread spectrum) tekni\u011fi olan bu teknolojide kullan\u0131c\u0131lar 5MHz geni\u015fligindeki ayn\u0131 banttan haberle\u015firler. Her vericinin sinyali \u00f6zg\u00fcn bir yonga koduyla \u00e7arp\u0131larak (bu kodun h\u0131z\u0131 3.84Mchips\/s) 5MHz geni\u015fli\u011findeki spektruma yay\u0131l\u0131r. Al\u0131c\u0131 da bu spektruma yay\u0131lm\u0131\u015f sinyali ayn\u0131 yonga koduyla \u00e7arparak veriyi elde eder.(wikipedia.org)<\/p>\n

W-CDMA(UMTS)<\/strong><\/p>\n

Wideband Code Division Multiple Access, Geni\u015fbant Kod B\u00f6lmeli \u00c7oklu Eri\u015fim. Mobil ileti\u015fim sistemi kavram\u0131 olarak UMTS’nin (Universal Mobile Telecommunication System) kar\u015f\u0131l\u0131\u011f\u0131d\u0131r. 3G standartlar\u0131nan bir tanesidir.<\/p>\n

 <\/p>\n

HSDPA<\/strong><\/p>\n

High Speed Downlink Packet Access, Y\u00fcksek H\u0131zl\u0131 Veri Paketi \u0130ndirme \u0130mkan\u0131. Teoride 14.4 Mbit h\u0131z\u0131 sa\u011flasa da pratikte 1Mbit ile s\u0131n\u0131rl\u0131 kalm\u0131\u015ft\u0131r. WCDMA \u00fczerinde paket eri\u015fimi ba\u015fta olmak \u00fczere yap\u0131lan iyile\u015ftirmeler sonucu indirme h\u0131z\u0131n\u0131n y\u00fckseltilmesine dayanmaktad\u0131r. Hizmet sa\u011flay\u0131c\u0131lar\u0131n h\u00fccre kapasitelerinin \u00fcst\u00fcnde kullan\u0131c\u0131y\u0131 kay\u0131t etmeleri sonucu \u00fcst s\u0131n\u0131r epeyce azalmaktad\u0131r.<\/p>\n

HSUPA<\/strong><\/p>\n

High Speed Uplink Packet Access, Y\u00fcksek h\u0131zl\u0131 Veri Paketi G\u00f6nderme \u0130mkan\u0131. HSDPA\u2019daki gibi teoride 14.4Mbit h\u0131z\u0131 destekler, ancak pratikte 1Mbit ile s\u0131n\u0131rl\u0131 kal\u0131r. HSDPA’da oldu\u011fu gibi WCDMA \u00fczerinde paket eri\u015fimi ba\u015fta olmak \u00fczere yap\u0131lan iyile\u015ftirmeler sonucu indirme h\u0131z\u0131n\u0131n y\u00fckseltilmesine dayanmaktad\u0131r. Hizmet sa\u011flay\u0131c\u0131lar\u0131n h\u00fccre kapasitelerinin \u00fcst\u00fcnde kullan\u0131c\u0131y\u0131 kay\u0131t etmeleri sonucu \u00fcst s\u0131n\u0131r epeyce azalmaktad\u0131r.<\/p>\n

 <\/p>\n

\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Bu makalede, g\u00fcn\u00fcm\u00fcze kadar cep telefonu ve kablosuz ileti\u015fim a\u011f\u0131 teknolojilerinin de\u011fi\u015fimini inceleyece\u011fiz. Yaz\u0131ya genel terimlerden ba\u015flay\u0131p 1G, 2G gibi standartlarla devam edece\u011fiz, \u015fu tarihlerde s\u0131k\u00e7a bahsedilen 3G\u2019de biraz durduktan sonra gelecek teknolojilerden de bahsedip yaz\u0131y\u0131 sonland\u0131raca\u011f\u0131z. Umar\u0131m kafan\u0131zda soru i\u015fareti b\u0131rakmayacak, a\u00e7\u0131klay\u0131c\u0131 bir yaz\u0131 olur. S\u00f6z\u00fc fazla uzatmadan genel ge\u00e7er terimler ile ba\u015flayal\u0131m. Analog […]<\/p>\n","protected":false},"author":1,"featured_media":1080,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-367","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-genel"],"_links":{"self":[{"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=\/wp\/v2\/posts\/367","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=367"}],"version-history":[{"count":0,"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=\/wp\/v2\/posts\/367\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=\/"}],"wp:attachment":[{"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=367"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=367"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.kodcafe.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}