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receiver support both analog FM and digital time-division multiple access (TDMA) schemes. Digital transmission is preferred, so when a cellular system has digital capability, the mobile unit is assigned a digital channel first. If no digital channels are available, the cellular system will assign an analog channel. The transmitter converts the audio signal to a radio frequency (RF), and the receiver converts an RF signal to an audio signal. The antenna focuses and converts RF energy for reception and transmission into free space. The control panel serves as an input/output mechanism for the end user; it supports a keypad, a display, a microphone, and a speaker. The coordinator synchronizes the transmission and receives functions of the mobile unit. A dual-mode cellular phone consists of the following:
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dramatically increased battery standby time, several messaging applications, over the air activation and expanded data applications. IS-136 systems needed to support millions of AMPS phones, most of which were designed and manufactured before IS-54 and IS-136 were considered. IS-136 added a number of features to the original IS-54 specification, including text messaging, circuit switched data (CSD), and an improved compression protocol. IS-136 TDMA traffic channels use π/4-DQPSK modulation at a 24.3-
636:(CELP) coders. The speech coding rate of 7.95 kbit/s achieves a reconstructed speech quality similar to that of the analog AMPS system using frequency modulation. The 7.95-kbit/s signal is then passed through a channel coder that loads the bit rate up to 13 kbit/s. The new half-rate coding standard reduces the overall bit rate for each call to 6.5 kbit/s, and should provide comparable quality to the 13-kbit/s rate. This half-rate gives a channel capacity six times that of analog AMPS.
625:
channel or FACCH performs handoffs during the call, with no need for the mobile to go back to the control channel. In case of high noise, FACCH embedded within the digital traffic channel overrides the voice payload, degrading speech quality to convey control information. The purpose is to maintain connectivity. The slow associated control channel or SACCH does not perform handoffs but conveys things like signal strength information to the base station.
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single voice call. Later, each of these full-rate channels was further sub-divided into two half-rate channels, each of which, with the necessary coding and compression, could also support a voice call. Thus, TDMA could provide three to six times the capacity of AMPS traffic channels. TDMA was initially defined by the IS-54 standard and is now specified in the IS-13x series of specifications of the EIA/TIA.
604:
verification color code (DVCC) is the equivalent of the supervisory audio tone used in the AMPS system. There are 256 different 8-bit color codes, which are protected by a (12, 8, 3) Hamming code. Each base station has its own preassigned color code, so any incoming interfering signals from distant cells can be ignored.
544:
AMPS also had many disadvantages, as well. Primarily, it did not have the ability to support the ever-increasing demand for mobile communication usage. Each cell site did not have much capacity for carrying higher numbers of calls. AMPS also had a poor security system which allowed people to steal a
407:
in Canada, have upgraded their existing IS-136 networks to GSM/GPRS. Rogers
Wireless removed all 1900 MHz IS-136 in 2003, and has done the same with its 800 MHz spectrum as the equipment failed. Rogers deactivated its IS-136 network (along with AMPS) on May 31, 2007. AT&T soon followed
620:
Time slots for the mobile-to-base direction are constructed differently from the base-to-mobile direction. They essentially carry the same information but are arranged differently. Notice that the mobile-to-base direction has a 6-bit ramp time to enable its transmitter time to get up to full power,
607:
The modulation scheme for IS-54 is 7C/4 differential quaternary phase shift keying (DQPSK), otherwise known as differential 7t/4 4-PSK or π/4 DQPSK. This technique allows a bit rate of 48.6 kbit/s with 30 kHz channel spacing, to give a bandwidth efficiency of 1.62 bit/s/Hz. This value is
599:
The channel transmission bit rate for digitally modulating the carrier is 48.6 kbit/s. Each frame has six time slots of 6.67-ms duration. Each time slot carries 324 bits of information, of which 260 bits are for the 13-kbit/s full-rate traffic data. The other 64 bits are overhead; 28 of these
595:
The access method used for IS-54 is Time
Division Multiple Access (TDMA), which was the first U.S. digital standard to be developed. It was adopted by the TIA in 1992. TDMA subdivides each of the 30 kHz AMPS channels into three full-rate TDMA channels, each of which is capable of supporting a
591:
The IS-54 standard specifies 84 control channels, 42 of which are shared with AMPS. To maintain compatibility with the existing AMPS cellular telephone system, the primary forward and reverse control channels in IS-54 cellular systems use the same signaling techniques and modulation scheme (binary
699:
platforms in 19 wireless markets, which started on May 30, 2007, with other areas that followed in June and July. The TDMA network in these markets operated on the 1900 MHz frequency and did not coexist with an AMPS network. Service on the remaining 850 MHz TDMA markets was discontinued
670:
By 1993 American cellular was again running out of capacity, despite a wide movement to IS-54. The
American cellular business continued booming. Subscribers grew from one and a half million customers in 1988 to more than thirteen million subscribers in 1993. Room existed for other technologies to
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The discussion of a communication system will not be complete without the explanation of a system example. A dual-mode cellular phone as specified by the IS-54 standard is explained. A dual-mode phone is capable of operating in an analog-only cell or a dual-mode cell. Both the transmitter and the
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A conversation's data bits makes up the DATA field. Six slots make up a complete IS-54 frame. DATA in slots 1 and 4, 2 and 5, and 3 and 6 make up a voice circuit. DVCC stands for digital verification color code, arcane terminology for a unique 8-bit code value assigned to each cell. G means guard
587:
IS-54 employs the same 30 kHz channel spacing and frequency bands (824-849 and 869-894 MHz) as AMPS. Capacity was increased over the preceding analog design by dividing each 30 kHz channel pair into three time slots and digitally compressing the voice data, yielding three times the
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The IS-54 system has different synchronization sequences for each of the six time slots making up the frame, thereby allowing each receiver to synchronize to its own preassigned time slots. An additional 12 bits in every time slot are for the SACCH (i.e. system control information). The digital
624:
Once a call comes in the mobile switches to a different pair of frequencies; a voice radio channel which the system carrier has made analog or digital. This pair carries the call. If an IS-54 signal is detected it gets assigned a digital traffic channel if one is available. The fast associated
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A pragmatic effort was launched to improve IS-54 that eventually added an extra channel to the IS-54 hybrid design. Unlike IS-54, IS-136 utilizes time-division multiplexing for both voice and control channel transmissions. Digital control channel allows residential and in-building coverage,
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The market showed an increasing demand because it had higher capacity and mobility than the then-existing mobile communication standards were capable of handling. For example, the Bell Labs system in the 1970s could carry only 12 calls at a time throughout all of
385:) and digitally compressing the voice data, yielding three times the call capacity in a single cell. A digital system also made calls more secure in the beginning, as analogue scanners could not access digital signals. Calls were encrypted, using
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time, the period between each time slot. RSVD stands for reserved. SYNC represents synchronization, a critical TDMA data field. Each slot in every frame must be synchronized against all others and a master clock for everything to work.
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20% better than GSM. The major disadvantage with this type of linear modulation method is the power inefficiency, which translates into a heavier hand-held portable and, even more inconvenient, a shorter time between battery recharges.
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channels and allows for smooth transition between digital and analog systems in the same area. Capacity was increased over the preceding analog design by dividing each 30 kHz channel pair into three time slots (hence
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are for synchronization, and they contain a specific bit sequence known by all receivers to establish frame alignment. Also, as with GSM, the known sequence acts as a training pattern to initialize an adaptive equalizer.
556:'s Narrowband AMPS or N-AMPS, an analog scheme which increased capacity, by cutting down voice channels from 30 kHz to 10 kHz. IS-54, on the other hand, increased capacity by digital means using
552:, the first American 2G standard. In March 1990, the North American cellular network incorporated the IS-54B standard, the first North American dual mode digital cellular standard. This standard won over
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with analogue cellular and indeed co-existed on the same radio channels as AMPS. No analogue customers were left behind; they simply could not access IS-54's new features. IS-54 also supported
472:). The early systems used throughout Europe were not compatible to each other, meaning the later idea of a common 'European Union' viewpoint/technological standard was absent at this time.
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400:(CSD), and an improved compression protocol. SMS and CSD were both available as part of the GSM protocol, and IS-136 implemented them in a nearly identical fashion.
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protocols. This method separates calls by time, placing parts of individual conversations on the same frequency, one after the next. TDMA tripled call capacity.
695:, the largest US carrier to support D-AMPS (which it refers to as "TDMA"), had turned down its existing network in order to release the spectrum to its GSM and
483:/450 (NMT450) and NMT900 (both in Nordic countries), NMT-F (French version of NMT900), TMA-450 (Spanish version of NMT450), Radiocom 2000 (RC2000) (in France),
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510:' cooperation, European engineering efforts were divided among the various standards, and the Japanese standards did not get much attention. Developed by
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completed their shutdown of their D-AMPS and AMPS networks in
September 2008. The last carrier in the United States to operate a D-AMPS network was
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technique which is used in most 2G standards, including GSM, as well as in IS-54 and IS-136. D-AMPS competed against GSM and systems based on
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and a 6-bit guard band during which nothing is transmitted. These 12 extra bits in the base-to-mobile direction are reserved for future use.
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channel rate and gives an effective 48.6 kbit/s data rate across the six time slots comprising one frame in the 30 kHz channel.
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call capacity in a single cell. A digital system also made calls more secure because analog scanners could not access digital signals.
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band, established in 1994, is for digital operation only.) The success of AMPS kick-started the mobile age in the North
America.
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541:(FDMA) which enabled each cell site to transmit on different frequencies, allowing many cell sites to be built near each other.
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The earliest mobile or wireless technologies implemented were wholly analogue, and are collectively known as 1st
Generation (
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decommissioned its D-AMPS and AMPS networks and moved the remaining customers on these older networks onto its GSM network.
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IS-54 is the first mobile communication system which had provision for security, and the first to employ TDMA technology.
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phone's serial code to use for making illegal calls. All of these triggered the search for a more capable system.
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cater to the growing market. The technologies that followed IS-54 stuck to the digital backbone laid down by it.
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FSK) as AMPS. An AMPS/IS-54 infrastructure can support use of either analog AMPS phones or D-AMPS phones.
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band in the United States and is the most widely distributed analog cellular standard. (The 1900
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along with AMPS service on
February 18, 2008, except for in areas where service was provided by
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IS-136 added a number of features to the original IS-54 specification, including
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since the first commercial network was deployed in 1993. D-AMPS is considered
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Former large IS-136 networks, including AT&T in the United States, and
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Using IS-54, a cellular carrier could convert any of its system's
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704:. The Dobson TDMA and AMPS network was shut down March 1, 2008.
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840:"Cryptanalysis of the Cellular Message Encryption Algorithm"
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422:, shut down its TDMA and AMPS networks in September 2008.
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technology, shut down its TDMA network in
February 2009.
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in
February 2008, shutting down both TDMA and AMPS.
475:The various 1G standards in use in Europe included
57:. Unsourced material may be challenged and removed.
322:, are a further development of the North American
628:The IS-54 speech coder uses the technique called
464:) technologies. In Japan, the 1G standards were:
1915:Telecommunications-related introductions in 1990
1901:
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514:in the 1970s and first used commercially in the
361:The name TDMA is based on the abbreviation for
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479:(in Germany and Austria), Comviq (in Sweden),
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445:began in three different geographic regions:
330:(AMPS). It was once prevalent throughout the
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487:(Total Access Communication System) (in the
418:technology but acquired a TDMA network from
803:The Worldwide History of Telecommunications
468:(NTT) and the high capacity version of it (
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287:
273:
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779:Learn how and when to remove this message
665:
117:Learn how and when to remove this message
742:This article includes a list of general
913:Timeslot structure for IS-136 and IS-54
14:
1902:
1810:Multimedia Broadcast Multicast Service
806:. John Wiley & Sons. p. 533.
688:Sunset for D-AMPS in the US and Canada
503:(AMPS) and Narrow-band AMPS (N-AMPS).
921:
1768:Spectral efficiency comparison table
800:Huurdeman, Anton A. (31 July 2003).
728:
630:vector sum excited linear prediction
389:, which was later found to be weak.
55:adding citations to reliable sources
26:
24:
871:"Digital Wireless Basics: "1990s""
748:it lacks sufficient corresponding
611:
539:Frequency Division Multiple Access
518:in 1983, AMPS operates in the 800
25:
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318:), and most often referred to as
310:) mobile phone systems, known as
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959:List of mobile phone generations
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426:, which now also primarily uses
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42:needs additional citations for
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634:code-excited linear prediction
579:, a help in preventing fraud.
466:Nippon Telegraph and Telephone
13:
1:
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371:code-division multiple access
363:time-division multiple access
142:Wireless network technologies
1880:Telecommunication portal
501:Advanced Mobile Phone System
328:Advanced Mobile Phone System
7:
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1377:CDMA2000 1xEV-DO Release 0
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1259:EDGE/EGPRS - Evolved EDGE
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583:Technology specifications
263:Mobile telecommunications
481:Nordic Mobile Telephones
1715:Comparison of standards
1354:UTRA-TDD LCR / TD-SCDMA
763:more precise citations.
306:are second-generation (
1910:Channel access methods
1720:Channel access methods
1359:UTRA-TDD HCR / TD-CDMA
666:Successor technologies
548:The quest resulted in
334:, particularly in the
1891:Telephones portal
999:MTA - MTB - MTC - MTD
702:Dobson Communications
414:, who primarily used
398:circuit switched data
376:D-AMPS uses existing
1508:iBurst (IEEE 802.20)
1281:CDMA2000 1X Advanced
443:mobile communication
51:improve this article
1394:(3.5G, 3.75G, 3.9G)
1236:(2.5G, 2.75G, 2.9G)
1004:Mobile TeleSeratout
573:backward compatible
1882:
1468:(TIA/EIA/IS-856-B)
1462:(TIA/EIA/IS-856-A)
1460:1xEV-DO Revision A
899:2013-10-19 at the
567:voice channels to
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1700:Cellular networks
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707:On May 31, 2007,
693:AT&T Mobility
441:The evolution of
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16:(Redirected from
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1705:Mobile telephony
1693:Related articles
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1577:LTE Advanced Pro
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1472:EV-DO Revision C
1466:EV-DO Revision B
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1058:AMPS - N-AMPS
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894:Paper on CMEA
892:
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877:on 2006-11-13
876:
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852:on 2013-10-19
848:
841:
837:
833:
829:
828:Wagner, David
823:
815:
813:9780471205050
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719:U.S. Cellular
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658:Control panel
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535:New York City
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447:North America
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383:time division
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68: –
67:
63:
62:Find sources:
56:
52:
46:
45:
40:This article
38:
34:
29:
28:
19:
1820:Push-to-talk
1598:IEEE 802.16m
1567:LTE Advanced
1551:IMT Advanced
1496:IEEE 802.16e
1491:Mobile WiMAX
1452:3GPP2 family
1379:(TIA/IS-856)
1370:3GPP2 family
1268:3GPP2 family
1247:/3GPP family
1183:
1063:TACS - ETACS
879:. Retrieved
875:the original
865:
854:. Retrieved
847:the original
836:Kelsey, John
822:
802:
795:
775:
766:
747:
713:
706:
691:
678:
669:
643:
627:
623:
619:
615:
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598:
594:
590:
586:
562:
549:
547:
543:
537:. AMPS used
531:
506:Despite the
505:
474:
459:
440:
432:
410:
402:
391:
382:
375:
360:
319:
315:
312:Digital AMPS
311:
303:
299:
298:
165:
113:
104:
94:
87:
80:
73:
61:
49:Please help
44:verification
41:
1649:5G-Advanced
1637:3GPP family
1587:IEEE family
1579:(4.5G/4.9G)
1560:3GPP family
1402:3GPP family
1330:3GPP family
1275:CDMA2000 1X
1146:CSD - HSCSD
761:introducing
661:Coordinator
649:Transmitter
424:US Cellular
365:, a common
344:end-of-life
1904:Categories
1503:Flash-OFDM
881:2007-02-02
856:2004-05-21
769:April 2009
744:references
725:References
215:3.9G/3.95G
107:April 2011
77:newspapers
1603:WiMax 2.1
1458:CDMA2000
951:standards
512:Bell Labs
1628:IMT-2020
1532:HiperMAN
1431:DC-HSDPA
1321:IMT-2000
897:Archived
682:kilobaud
655:Receiver
554:Motorola
428:CDMA2000
416:CDMA2000
373:(CDMA).
356:CDMA2000
332:Americas
134:a series
132:Part of
1862:Osmocom
1710:History
1680:DECT-5G
1654:NR-IIoT
1099:DataTAC
1094:Mobitex
757:improve
569:digital
497:Ireland
437:History
225:4G/4.5G
176:Digital
91:scholar
1664:NB-IoT
1630:(2021)
1625:(2018)
1571:E-UTRA
1553:(2013)
1548:(2009)
1525:family
1484:family
1442:E-UTRA
1323:(2001)
1318:(1998)
1177:family
1158:family
1134:family
1120:(1991)
1051:family
1041:(1979)
1024:B-Netz
972:(1946)
810:
746:, but
715:Alltel
675:IS-136
565:analog
477:C-Netz
451:Europe
412:Alltel
340:Canada
316:D-AMPS
304:IS-136
148:Analog
136:on the
93:
86:
79:
72:
64:
18:IS-136
1840:ViLTE
1835:VoLTE
1793:5G NR
1742:STDMA
1730:OFDMA
1673:Other
1659:LTE-M
1644:5G NR
1607:WiBro
1594:WiMAX
1513:WiBro
1426:HSPA+
1419:HSUPA
1414:HSDPA
1297:WiDEN
1290:Other
1193:Other
1156:3GPP2
1089:Hicap
1084:C-450
1072:Other
989:Altai
850:(PDF)
843:(PDF)
550:IS-54
493:Italy
470:Hicap
455:Japan
300:IS-54
243:5.25G
211:3.75G
193:2.75G
98:JSTOR
84:books
1850:ViNR
1845:VoNR
1825:MIMO
1798:CDMA
1783:UMTS
1761:SDMA
1754:CDMA
1749:SSMA
1737:TDMA
1725:FDMA
1523:ETSI
1482:IEEE
1409:HSPA
1347:FOMA
1337:UMTS
1302:DECT
1254:GPRS
1205:iDEN
1200:CDPD
1175:AMPS
1132:3GPP
1049:AMPS
1009:AMTS
984:IMTS
808:ISBN
697:UMTS
558:TDMA
495:and
485:TACS
453:and
387:CMEA
378:AMPS
352:GPRS
338:and
320:TDMA
302:and
247:5.5G
233:4.9G
229:4.5G
207:3.5G
197:2.9G
189:2.5G
166:1.5G
70:news
1830:IMS
1788:LTE
1778:GSM
1438:LTE
1245:GSM
1220:CT2
1215:PHS
1210:PDC
1141:GSM
1128:GSM
1104:CT1
1079:NMT
1029:AMR
1019:ARP
994:OLT
979:MTS
527:PCS
524:MHz
520:MHz
354:or
348:GSM
53:by
1906::
1623:5G
1600:)
1546:4G
1316:3G
1118:2G
1039:1G
967:0G
838:.
834:;
830:;
491:,
462:1G
449:,
396:,
324:1G
308:2G
253:6G
245:,
239:5G
231:,
227:,
221:4G
213:,
209:,
203:3G
195:,
191:,
185:2G
162:1G
157:0G
1596:(
1573:)
1569:(
1444:)
1440:(
1130:/
941:e
934:t
927:v
884:.
859:.
816:.
782:)
776:(
771:)
767:(
753:.
350:/
314:(
288:e
281:t
274:v
249:)
241:(
235:)
223:(
217:)
205:(
199:)
187:(
168:)
164:(
120:)
114:(
109:)
105:(
95:·
88:·
81:·
74:·
47:.
20:)
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