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1327 (and dPMR) over TDMA-based systems such as TETRA and DMR, which cannot pool traffic channels so efficiently (if at all). The disadvantage of using a time-shared CCH is that it slows down registration and calls and requires some customization of the registration process, so is only useful if the network has a patient user community!
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For the duration of his call a subscriber is exclusively allocated a traffic channel from the available pool. If all channels are occupied, the call will be queued. If the control channel has become a traffic channel, like in the case of a non-dedicated control channel, the call will be queued in the
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Some MPT 1327 networks can also time-share control channels, which can be useful if the network has limited frequency availability, as it frees up channels for use as traffic channels, which can also be pooled across sites so the network capacity follows the traffic. This is another advantage of MPT
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A non-dedicated control channel can be used as a traffic channel when all the other traffic channels are busy. This can be useful if the site is part of a multi-site network and has a very low traffic profile as the site could have a single channel rather than at least two freeing up one channel for
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A spectrum efficiency advantage over a 4-slot TDMA system like TETRA is in areas where low-bandwidth channels are required. The absolute minimum TETRA installation would require a 25 kHz bandwidth in order to carry a control slot and three traffic slots. The absolute minimum MPT1327 assignment is a
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respectively. The Tier 3 standard for these systems defines a trunking protocol very similar to MPT1327 and is intended as a potential migration path for existing and perhaps future trunking customers. Tier 3 equipment is (late 2011) now becoming available, so the impact on TETRA and MPT 1327 is yet
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uses the first two digits of the Ident as the fleet number, and the last two digits as the unit number. Idents in the 6,000–6,999 range are typically used to establish group calls. After it has been entered the call number will be converted in the mobile to a 20-bit address. The numbering rules are
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The advantage of MPT 1327 over TETRA is the increased availability, lower cost of equipment, the ease of installation, the familiarity with the equipment, and many believe that MPT 1327 is superior to TETRA, due to its uncompressed FM audio, and greater receiver sensitivity. MPT1327 control channel
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It is worth noting that whilst many comparisons are made between
Digital and Analog radio technologies, when it comes to applying these arguments to MPT1327, many of the distinctions become blurred, since MPT1327 with its digital control channel, already offers most of the features being offered by
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Systems based on MPT 1327 only require one, but usually use two or more radio channels per site. Channels can be 12.5 or 25 kHz bandwidth, and can be any variety of channel spacings, with 6.25 kHz or 12.5 kHz being typical. At least one of these channels is defined as the control channel (CCH) and
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call", known as "non-prescribed data" can be established, whereby free-form 1,200 baud data can be exchanged on a traffic channel without tying up the control channel. With the use of special modems, the speed can be 19,200 bit/s. This, along with Short Data
Messaging and Status Messaging via the
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A typical installation will have around 6–10 channels. A 7-channel trunk, correctly engineered, is capable of handling in excess of 3,000 mobile units. The capacity of the system increases dramatically with the number of traffic channels. For example, 1 traffic channel with queuing can not handle
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Broadcast calls can be used to make announcements to the entire customer base on a trunked system. For example, if work is to be carried out on the trunked system, the owner of the system can initiate a
Broadcast Call which calls every mobile on the system. However, the mobiles may not have talk
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Each subscriber in an MPT-1327 trunked radio network has a unique call number. This call number (address) is a compound number consisting of a prefix (three digits), the fleet number and the subscriber's call number within the fleet. Different numbering schemes work differently, for example
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use elsewhere. The disadvantage is loss of queuing, and data cannot be sent on the control channel whilst it is in traffic mode. A non-dedicated CCH should not be used as a "reserve tank" for a busy site as the lack of signalling will seriously affect the operation of the site.
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Whilst MPT 1327 systems, unlike DMR or dPMR, do not employ digital speech compression to gain any
Spectral Efficiency (voice channels per 6.25 kHz), there are several methods used that increase the Spectrum Efficiency (Erlangs per square kilometre, per 6.25 kHz).
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to be seen, but may well be significant. However, it is unlikely that in terms of cost that the complicated new DMR/dPMR equipment will be able to compete with the simpler MPT1327 equipment for some time, if ever.
156:. Many countries had their own version of numbering/user interface, including MPT1343 in the UK, Chekker (Regionet 43) in Germany, 3RP (CNET2424) in France, Multiax in Australia, and Gong An in China.
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audio quality", can become misleading, since the squelch levels tend to be set rather high on MPT1327 systems, such that weak/noisy signals do not generally open the mute.
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radio, although radio queuing loses the first come, first served effect, so if there are seven units queuing, the last unit to queue may get a traffic channel first.
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with 20 mobiles. In effect this would be a CBS with queuing. However, a 7 channel trunked system can handle 40 minicabs with 20 mobiles with ease. The
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entitlement, so the PTT may not work. By this means the owner can announce to all customers a short period of inoperation due to maintenance.
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Furthermore, most MPT1327 systems are engineered to a far higher standard than conventional FM systems, partially due to the lack of
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networks, the advantage being that the network can be used for this sort of application whilst still carrying voice traffic.
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292:. Data messages between mobiles and the network are exchanged on the control channel at 1,200 bits per second using
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175:(ETSI), as a digital alternative to analogue trunked systems. However, TETRA, with its enhanced
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scheme that requires a far higher Signal to Noise ratio to function than 1,200 bit/s
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The different types of communications on an MPT-1327 network and their definitions
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single non-dedicated control channel, utilising 12.5 kHz, in most cases.
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signalling is more resilient, since the TETRA protocol uses a complex
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all other channels are traffic channels (TCs) used for speech calls.
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clarified and expanded by supplementary standards such as MPT-1343.
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Short data messages on the control channel (186-bit data length)
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within the standard. As such arguments with regards to "noisy
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Transparent data transmission on the TC (data communication).
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formulas are typically used for calculating system capacity.
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control channel makes an MPT1327 network ideal for managing
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Status messages on the control channel (5-bit data length)
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Group calls without talk entitlement (broadcast calls)
46:. Unsourced material may be challenged and removed.
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272:Time-shared control channels and channel pooling
173:European Telecommunications Standards Institute
128:First published in January 1988 by the British
179:capability, has developed into a higher tier (
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171:trunked radio standard was developed by the
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106:Learn how and when to remove this message
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123:trunked radio communications networks
44:adding citations to reliable sources
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702:Mobile telecommunications standards
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401:Group calls with talk entitlement
207:the DMR/dPMR/TETRA counterparts.
348:Mobile-mobile in different cells
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222:MPT1327 advantages and features
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31:needs additional citations for
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623:General Electric Mobile Radio
362:station via landline or radio
351:Mobile-line access unit via
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192:digital private mobile radio
121:is an industry standard for
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296:signalling, or a specific "
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518:Type II SmartZone OmniLink
398:Point to point connections
243:many customers, perhaps 2
130:Radiocommunications Agency
658:LTR Standard and Passport
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303:AVL for asset management
345:Mobile-mobile in a cell
697:Trunked radio systems
471:Trunked radio systems
432:. 16 September 2016.
427:"Regulator archives"
290:frequency modulation
188:digital mobile radio
163:Digital alternatives
40:improve this article
640:Logic Trunked Radio
616:distributed control
255:Spectrum efficiency
482:Central controller
377:Data communication
285:Speech is sent as
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51:Find sources:
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29:This article
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663:LTR MultiNet
653:LTR Passport
648:LTR Standard
614:Scan-based /
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142:South Africa
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38:Please help
33:verification
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150:New Zealand
691:Categories
360:dispatcher
287:narrowband
229:modulation
177:encryption
96:March 2014
66:newspapers
55:"MPT-1327"
630:GE Marc V
369:, Mobile-
317:Numbering
146:Australia
597:Tier III
574:TETRAPOL
559:MPT-1327
355:or radio
353:landline
245:minicabs
119:MPT 1327
668:LTR-Net
564:OpenSky
503:Type II
365:Mobile-
358:Mobile-
80:scholar
586:Mode 3
498:Type I
324:Zetron
249:Erlang
138:Europe
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569:TETRA
549:EDACS
532:Other
430:(PDF)
413:Notes
393:Calls
311:SCADA
298:modem
212:CTCSS
186:DMR (
169:TETRA
154:China
87:JSTOR
73:books
590:NXDN
584:dPMR
579:GoTa
523:iDEN
371:PSTN
367:PABX
309:and
294:FFSK
233:FFSK
200:FDMA
198:and
196:TDMA
167:The
152:and
59:news
601:PDT
595:DMR
42:by
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305:,
216:FM
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