Transcript discus - Home | Ofcom

.
(((dmr)))
A Presentation for the DATA
OVER PMR GROUP -
WHAT IS DMR
What is ((dmr))
A LOW COST LOW COMPLEXITY
DIGITAL RADIO PROTOCOL
Using a polite protocol?
PMR BUSINESS MODEL
PMR Business Model
WHAT IS DMR(2)
What is ((dmr))
4
4
4
(2)
Repeater
4
4
Peer to peer
4
4
4
4
4
4
Trunked
SWISS
Short Messages
Short Messages
ETSI & TEAM
((dmr)) – THE TEAM
WHAT IS DMR
What is ((dmr))
• A Digital PMR Standard serving Existing PMR markets.
Licenced and licence exempt
• Fits in existing PMR Spectrum
– MB, VHF & UHF
• Conventional ETS 12.5Khz channel (1 carrier/Ch)
– plus 2 channels/carrier and channel sharing
• Range as good as F.M
• Simple LOW COST or fully featured radio’s (including databricks)
• Peer to peer OR infrastructure modes SO –
• Fully Scalable from two radio’s to large trunked networks
FEATURES CIRCLE
Security
TRANSMITTER
RangeA–12.5kHz
Equal
HAS
to FM
ANALOGUE
MASK
Scalable from
two radio’s to
wide area fleets
Plug and Play
Data
Repeaters
2ch/carrier
(((dmr)))
Low cost
Terminal
Manufacture
Works out of
the box
Good quality Speech
Battery Life
DIFFERENTIATOR FROM FM
Differentiator (from FM)
•
•
•
•
•
•
•
“Free” protection from eavesdropping
“Free” Voice Storage
“Free” Pager
“Free” Simultaneous speech and SMS
“Built-in” Data.
Spectrum Sharing
Two channels/carrier
STARTING WITH 2 UNITS BACK 2 BACK
The
It Works
Marketing
Out of the
is
inBox
the Box
4
4
Starting with two DMR units working backto-back in licence exempt spectrum
BRICKS
These may be Databricks
WORKING THROUGH A REPEATER
4
Working through a
Repeater
4
SUPPORTS TWO SIMULTANEOUS CALLS
4
4
One Channel supports
two independent
simultaneous calls
4
4
SHARING A CHANNEL
4
4
4
4
4
4
4
4
Independent Repeaters sharing a single
channel (in licence exempt spectrum?)
TRUNKED
Repeaters may be
linked
or sites may have
multiple channels
4
4
4
4
DATA
Data
I am a
Modem
Access Interface
Application
• MAP27
• Custom
• ………………
TEKKI STUFF(1)
Tekki Stuff
•
•
•
•
Modulation – 4 level FM. Transmitter Mask EN300-113
Symbol Rate 6kb/s. Bit Rate 12kb/s
20mS slots each of 240 bits unprotected
18 slots/frame. 4 frames/superframe
20mS
Slot requiring a
response from (B)
STIMULUS (A)
(B) will not
decode this
Slot 1
(B) will not
decode this
Slot 2
Slot 3
(B) will not
decode this
(B) will not
decode this
Slot 4
Slot 5
(B) will
decode this
Slot 6
RESPONSE (B)
5mS
PLL
5mS SYNC tuning and timing
CPU Processing
20mS VCO 5mS TX
Switch
Ramp
20mS
5mS TX
Ramp
20mS VCO
Switch
TEKKI STUFF(2)
Tekki Stuff(2)
360mS
POWER SAVE
Press PTT here
Release PTT here
PLL(12)+SYNC(60)+SYS(22)+Recipient Address(18)
SYNC(60)+SYS(22)+RecipientAddress(18)+WAKEUPOPCODE(8)+WakupSlotNumber(4)
Pilot(14)+SenderAddress(18)+VOCODERHEADEROPCODE(8)+VocoderNegotiation(8)
Pilot(14)+TelegramType(2)+Vocoder Data
Pilot(14)+CALLMAINTENANCEOPCODE(8)+PTT ReleaseType
DIVINITY
DATA and divinity
http://www.mod.uk/issues/pcomms/physics.htm
Capacity = Bandwidth x Log2 {1 + Signal to Noise Ratio}
TEXT BOOK
SIMULATIONS
Simulations for DMR
7.2 Kbit/s
4.8 Kbit/s
MER=10
%
MER=1%
MER=10
%
MER=1%
450 MHz 150 Km/h
15.8
18.4
12
14.2
450 MHz 50 Km/h
16.8
20.5
12.8
16
150 MHz 50 Km/h
18.0
23.8
14.2
19.3
66 MHz - 5
Km/h
17.8
28.3
16.1
26.2
Static
Conditions
7.8
8.4
6.6
7
THROUGHPUT
Throughput
7
Mobile
Coverage
Portable
Coverage
Tetra 7.2kb/s
DMR 7.2kb/s
Throughput (kb/s)
6
5
Tetra 4.8kb/s
DMR 4.8kb/s
4
3
Tetra 2.4kb/s
2
1
-119 -117 -115 -113 -111 -109 -107 -105 -103 -101
-99
-97
-95
-93
-91
-89
-87
-85
Signal strength (dbm)
RA
(((dmr)))
Licensed Exempt
PMR446 - equivalent
CEPT dedicated harmonised simplex channels
in UHF1 (currently considering the PMR446
channels and if market demands further
channels in the range 440-450MHz)
Licensed PMR & PAMR
3W erp Handheld (max)
10W erp Mobile (max)
25W erp Base/Repeater (max)
.
More Informations
More Information
LPRA+URL’s
LPRA
There is an opportunity for the DATA OVER
PMR GROUP to influence what DMR becomes.
WHAT DO YOU WANT?
URL’s
MOD web site
http://www.mod.uk/issues/pcomms/physics.htm
Shannon Article
http://www.fyldemicro.com/dmr/shannon.doc
DMR Article
http://www.fyldemicro.com/dmr/what_is_dmr.doc
This Powerpoint Presentation
http://www.fyldemicro.com/dmr/pmr-dmr.ppt