IDLS 2003

INTRODUCTION TO

JTIDS/MIDSLINK 16

IDLS 2003

TERMINOLOGY

JTIDSJoint Tactical Information Distribution

System

MIDSMultifunction

alInformation Distribution

SystemINFORMATION - sensors, navigation, status, commands, vectors, position

DISTRIBUTION - via Link-16

SYSTEM - Platforms joined in a tactical environment

IDLS 2003

TERMINOLOGY

• JTIDS/MIDS refers to the communications equipment necessary to exchange Link 16 messages

• This includes:– Terminal hardware and software– RF equipment– Resulting waveform generated

IDLS 2003

ENVIRONMENTS

• Air• Surface• Subsurface• Land• Space

IDLS 2003

IJMS

• Interim JTIDS Message Standard• Bases on Link 11 M-Series messages• Adapted to utilise basic JTIDS architecture• Class 1 or Bilingual Terminals

IDLS 2003

LINK 16• Message standard (STANAG 5516)• 256 combinations of label and sub-label• Link 16 messages support:

Surveillance Network Management Control EW Voice Free text messaging

IDLS 2003

TECHNICAL CHARACTERISTICS

• L Band UHF

• 51 Frequencies

• 969 to 1206 Mhz @ 3 Mhz Intervals

IDLS 2003

10301030 10901090960 1215

IFF FiltersIFF Filters

14 Frequencies 5 Freq’s 32 Frequencies

TACAN / DME Channels spaced every 1 MHz

Link-16 Frequencies spaced every 3 MHz (51 Frequencies)Link-16 Frequencies spaced every 3 MHz (51 Frequencies)

969 1206

IDLS 2003

ARCHITECTURE

• JTIDS/MIDS Link-16 is a data link that is:– Real Time– Secure– ECM Resistant– High Capacity– Non-Nodal

IDLS 2003

ARCHITECTURE

• Broadcast type system– each unit can receive directly from all

other assigned units

• No critical nodes– if one terminal goes down, the

network is not crippled

IDLS 2003

ARCHITECTURE

• Time Division Multiple Access (TDMA)

• Time is divided into 128 time slots per second

• Each terminal can either transmit or receive

IDLS 2003

DAY (24 Hours)

12.8 mins =EPOCH =

98304Timeslots

EPOCH = 64 FRAMES

1 FRAME =12 Seconds

1Timeslot =7.8125 ms

= 112.5 EPOCHS

FRAME = 1536 Timeslots

IDLS 2003

ARCHITECTURE

• Each time slot is allocated to a specific user for transmission. All other users receive in that time slot.

IDLS 2003

TIMESLOT

• Timeslot equates to 7.8125msec• 1536 timeslots in 12 seconds• Timeslot comprises several

components

IDLS 2003

TIMESLOT

• Number of elements within a timeslot– Jitter– Synchronisation– Time refinement– Message header and data – Propagation

IDLS 2003

TIME SLOT STRUCTURE

Jitter - variable time delay in the start of a transmission of a time slot; standard double pulse and packed-2 single pulse message packing structures

SYNCJITTER HEADER DATA PROPAGATION

7.8125 milliseconds

IDLS 2003

TIME SLOT STRUCTURESynchronization - a pattern of pulses that

allows the receiving terminal to synchronize to the transmission

SYNCJITTER HEADER DATA PROPAGATION

7.8125 milliseconds

IDLS 2003

TIME SLOT STRUCTURE

Time Refinement - used for Class 1 compatibility only

SYNCJITTER HEADER DATA PROPAGATION

7.8125 milliseconds

IDLS 2003

TIME SLOT STRUCTURE

Header - 35 bit word providing information concerning the message(s) transmitted in the time slot

SYNCJITTER HEADER DATA PROPAGATION

7.8125 milliseconds

IDLS 2003

TIME SLOT STRUCTURE

Data - message(s) transmitted in the time slot;3, 6, or 12 TADIL J words, depending on packing structure

SYNCJITTER HEADER DATA PROPAGATION

7.8125 milliseconds

IDLS 2003

TIME SLOT STRUCTURE

Propagation - time period to allow the signal to propagate to 300 or 500 NM prior to start of next time slot

SYNCJITTER HEADER DATA PROPAGATION

7.8125 milliseconds

IDLS 2003

• Header and Data– Link 16 message words taken in groups of:

• 3 words (Std)• 6 Words (P2)• 12 Words (P4)

– Header specifies:• Message Type• Coding• Packing |Structure• Source terminal

TIMESLOT

IDLS 2003

STANDARD PACKING STRUCTURE

S TR H DATA

TIME SLOT

7.8125 MILLISECONDS

3.354 MILLISECONDS 4.4585 MILLISECONDS MINUS JITTER

JITTER

S = SYNCHRONISATIONTR = TIME REFINEMENTH = HEADER

PROPAGATION

IDLS 2003

ACCESS METHODS• Dedicated

– Guaranteed reception– Inflexible

• Contention– Flexible– Reception uncertainty

• Time slot re-allocation– Shared Pool– Unit requests share

IDLS 2003

ECM RESISTANCE

• Double Pulse• Jitter• Frequency Hopping• Crypto variable Encoding• Message Preparation

IDLS 2003

SECURITY

• Message Security (MSEC)• Transmission Security (TSEC)

– Common Variable Mode– Partitioned variable mode

• Auto rollover

IDLS 2003

MESSAGE PREPARATION

• Message Packets• Reed-Solomon encoding

– All J-Series Fixed Format words

• Interleaving• CCSK• Random Noise

IDLS 2003

NETWORK ENTRY

• Network Time Reference (NTR)– First Platform in net

• Transmits Initial Entry Message (IEM) every 12 seconds

IDLS 2003

• Platform other than NTR required to synchronise

NETWORK ENTRY

IDLS 2003

NET ENTRY

Time Slots belonging to Net Entry Time Slot Block A-0-6

Coarse Synchronization will take place using this

time slot

Time error to within propagation

time (clock correction)

Estimate of current system time

Estimate of time of next entry time slot

Time uncertainty

IDLS 2003

FINE SYNCHRONISATION

• Actively or passively– Passively utilising received PPLI’s

• Actively– RTT(A) or RTT(B)

•RTT (A) Dedicated•RTT (B) Contention

IDLS 2003

MULTINETTING

• JTIDS provides the capability to operate simultaneously in up to 127 nets in the same network

• A terminal can operate (transmit or receive) in only one net in any one time slot but can operate in any net in any time slot as determined by assignment

• These nets use independent frequency hopping patterns with the net number a variable in determining the hopping pattern

IDLS 2003

MULTINETTING

NET 127

NET ...

NET 2

NET 1

NET 0

IDLS 2003

NETWORK PARTICIPATION GROUPS

• Previous links, data received and processed if applicable to a platforms role or not

• NPG’s allow for grouping of J-series messages into a functional role

• Aids network design

IDLS 2003

• 13 VOICE GROUP B• 19 NON-C2 TO NON-C2

• 20 NON-C2 TO NON-C2

• 21 BMD • 22 COMPOSITE A• 23 COMPOSITE B• 27 JOINT NET PPLI• 29 RESIDUAL• 30 IJMS POSITION &

STATUS• 31 OTHER IJMS DATA

• 1 INITIAL ENTRY• 2 RTT-A• 3 RTT-B• 4 NETWORK MANAGEMENT• 5 PPLI & STATUS GROUP A• 6 PPLI & STATUS GROUP B• 7 SURVEILLANCE• 8 MISSION MANAGEMENT• 9 CONTROL• 10 ELECTRONIC WARFARE• 12 VOICE GROUP A

NPG’s

IDLS 2003

RELAY

• UHF LOS Only• Paired Slot relay

IDLS 2003

A0 B0 C0 A1 B1 C1 A2 B2 C2 A3 B3 C3 A4 B4 C4 A5

X

Originator Tx in T/S (X)

The relay terminal Rx in (X)

Y

The relay platform will re-Tx in the timeslot controlled by the relay delay (6-31). Y is the re-Tx slot, with a relay delay of 6 timeslots

X

Re-Tx for second Hop by additional relay platform

RELAY

Paired Slots Paired Slots

IDLS 2003

RELAY

• Fixed Format and free text• Capable of relaying to different nets

• No limit to relay hops

IDLS 2003

UK PLATFORMS• In Service

– E3D Tornado F3– Nimrod (R) VC10 &

Tristar– JAPNMS (NMGB) C130– JPC TJF– RN (CVS & T42) RN (JPC)– GRAP (RA & 16 AAB)

• Future– EFA Typhoon ASTOR– MRA (4) T45– GBAD

IDLS 2003

OTHER NATIONS

• USA (USAF, USN, USMC, US Army)• France Germany• Italy Netherlands• Norway Belgium• Denmark Spain• Canada Australia• Switzerland Japan• and others

IDLS 2003

ANY QUESTIONS