Transcript Draft: MoU new organization

TETRA - Direct Mode Operation
Doug Gray
Motorola
AGENDA
• Introduction & explanation of Direct Mode
Operation (DMO)
• Services & Facilities
• Benefits & Applications
• Conclusions
WHY DIRECT MODE IN TRUNKING?
• Trunking offered many
benefits over conventional
communications and was a
great success in the market
• It missed a key feature that
Spectral
Efficiency
?
Automatic
Operation
DMO
Ease of
Data Services
Feature Rich
Service
conventional communications
offered - direct communication
outside network coverage
• TETRA’s multi-mode
capability offers the best of
both worlds - Trunking and
Direct Communications in a
single terminal.
WHAT IS TETRA DIRECT MODE ?
• There are 4 basic operational modes of TETRA DMO, viz.
1
2
3
4
“Back-to-back” (standard DMO terminal coverage)
DMO Repeater (extended DMO terminal coverage)
Dual Watch (periodic “scanning” of ‘other’ mode)
DMO Gateway (continuous relay between modes)
• Communication between Direct Mode terminals
• Communication between trunked and DMO terminals
• Further permutations are possible, e.g. Gateway/Repeater
TETRA DMO - BACK-TO-BACK
C
TRUNKED
TETRA
A1
TETRA
DMO
TETRA
DMO
B1
B2
B3
A2
A3
TETRA DMO REPEATER
A1
C
TRUNKED
TETRA
A3
B1
B2
DMO Repeater
TETRA
DMO
B3
DMO Repeater
TETRA
DMO
A2
TETRA DMO-DUAL WATCH
A1
C
TRUNKED
TETRA
TETRA
DMO
A2
B1
B2
Dual-Watch
B3
Dual-Watch
TETRA
DMO
A3
TETRA DMO - GATEWAY
A1
TRUNKED
TETRA
C
TETRA
DMO
TETRA
DMO
A3
Gateway
B1
Gateway
B3
‘BACK-TO-BACK’ DMO
1
2
3
4
DMO Air
Interface
1
Slot Structure
2
3
4
‘Frequency Efficient’
mode can use these
timeslots for another
call
Pre-emption
Speech Slot
DMO
Master
DMO
Slave
DMO CHARACTERISTICS
• Normal DMO enables 1 conversation per carrier
(i.e. 1 per 4 timeslots)
• Transmitting radio acts as ‘Master’ on a single
timeslot
• Receiving radio is ‘Slave’ on a single timeslot
• In normal mode, two time slots are used, two are
free
• In Frequency Efficient Mode, all four timeslots are
used (2x2) enabling two conversations per carrier
DMO REPEATER TYPE 1A & 1B
• Only one call per repeater
• Uses a 4 slot structure
•2 slot uplink
•2 slot downlink
•Master/slave operation (3 slot delay)
• Single carrier (1A)
TYPE 1A
DM1
MS RX
MS TX
•Simple RF
•1 conversation, 1 DM channel
•Single carrier
• Dual carrier (1B)
•More complex RF
•1 conversation, 2 DM channels
•Supports multiple repeaters
•Reduces potential for RF interference
TYPE 1B
DM1
MS RX
DM2
MS TX
DMO REPEATER TYPE 1A
1
2
3
4
1
2
3
4
DMO Air
Interface
Frequency Usage
1
2
3
4
1
2
3
1
2
3
4
DM1
4
Master Slot
MS RX
Slave Slot
SPEECH
UPSLOT
DMO
Master
SPEECH
DOWNSLOT
Type 1A
Repeater
Pre-Emption
Upslot
DMO
Slave
(Slave slot pattern moved for diagram clarity)
DMO REPEATER TYPE 2
• Two simultaneous calls per repeater
TYPE 2
• Uses a 4 slot structure
•4 slot uplink
DM1
DM2
•4 slot downlink
•Master/slave operation (4 slot delay)
• Dual carrier
•More complex RF but supports multiple repeaters
• Uses power control and addressing
RPT RX
RPT TX
DMO REPEATER TYPE 2
1
2
3
4
1
2
3
4
‘B’ channel can
use other slots
DMO Air
Interface
1
2
3
4
1
2
3
4
1
2
3
4
Uplink Carrier
Downlink Carrier
SPEECH
UPSLOT
Type 2
Repeater
SPEECH
DOWNSLOT
Pre-Emption
Upslot
DMO
Master
DMO
Slave
(Slave slot pattern omitted for diagram clarity)
DUAL WATCH
• Radio is operational in one system mode (Direct or
Trunked) and simultaneously monitors signalling on
the other system.
Mobile Unit whilst engaged in a call in Trunking mode
is alerted of a DMO call/request from a DMO terminal.
DMO GATEWAY
• Enables DMO terminal
to communicate with
'Normal'
the trunking system
& DMO Air
Interface
vice versa
(One simultaneous call)
• Uses ‘normal’ DMO air
interface
(single call)
•
Frequency Usage
TM1
DM1
TM2
Trunked Mode
Air Interface
GW RX
GW TX
Uplink (TM1)
Gateway
Downlink (TM2)
One DMO
carrier per call
DMO User
Trunked Mode
Cell
DMO REPEATER/GATEWAY
• Combines the functionality of a repeater
and a gateway (similar to a VHF-UHF talkthrough repeater)
• Interconnects direct mode to trunked
mode
• Uses ‘normal’ DMO air interface
(single call)
• Can be manned or stand alone (i.e. free
running or manned by an operator)
Frequency Usage
TM1
DM1
TM2
Trunked Mode
Air Interface
GW RX
GW TX
BENEFITS of DMO GATEWAY
• Extends range of Trunking Mode Operation
• Reduces Infrastructure costs
• Enables remote ‘occasional users’ to have
communication at cost effective rates
• Gives Network Operators better coverage
possibilities during early stages of network rollout
MANAGED DIRECT MODE - MDMO
• MDMO terminal is
restricted from
O.K.
transmitting unless
DMO
it receives an authorising
signal
• Generated by authorising device which is in
permanent contact with system, or…..
• …. generated by modified DMO Gateway or
Repeater/Gateway device
• Validity time encoded in authorising signal
BENEFITS OF MDMO
• Network Operators maintain better control of
their network resource/ revenues
• Removes potential for interference
• Manages roaming
DMO SERVICES AND FACILITIES
• Simplex speech - Individual or Group Call
• Circuit mode data up to 7.2 kbps, incl. point-topoint & point-to-multipoint
• Status and short data service (SDS)
• Late Entry
• Emergency call
• Talking Party Identification (TPI) , incl.
concealment
DMO SECURITY (ENCRYPTION)
• Air-interface encryption - TEA1, TEA2 &
TEA3, incl. time stamping
• Implicit authentication
• Key management incl. Over The Air Rekeying
(OTAR)
• “Zapping” (enabling/ disabling) terminals
• End-to-end encryption mechanism
DMO BENEFITS & APPLICATIONS
• Operation outside the coverage of Trunking
Infrastructure
• Gives extra capacity when trunked network is highly
loaded
• Operations in poor signal strength areas
• Fall-back operation when the Trunking Infrastructure
system is inoperative
• Covert Operations - cannot be monitored by Contol
• ‘Stripline’ applications (power, oil, water distribution
lines) not requiring trunked network capacity
CONCLUSIONS
• TETRA is a multi-mode standard offering trunking and
conventional operation in-one
• DMO - a powerful feature in the total TETRA offering, as
it comprises of several sub-modes of operation
• Significant commonality with trunked V+D TETRA
enables for multi-mode terminals (DMO & V+D)
• DMO is a significant differentiator between TETRA and
other cellular services
TETRA - Direct Mode Operation
Thank You
Doug Gray
Motorola