Angelo Benvenuto Leonardo Finmeccanica. DMO - TETRA Direct Mode Angelo Benvenuto Leonardo Finmeccanica.

Agenda DMO Modes, Services and facilities DMO and the key differences with TMO Equipment types : Repeaters Gateways Operational example Benefit and Applications Conclusion

What PMR users ask? Fast Reliable Secure lack of network coverage Regardless of lack of network coverage lack of resources any type of network failure

TETRA operation modes TETRA standard provides 2 Operation Modes Direct Mode Operation (DMO) Trunked Mode Operation (TMO) DMO doesn’t require an infrastructure TMO requires a well deployed network infrastructure DMO adds border or out of coverage areas communications TMO provides a wide set of features DMO provides a well defined subset of TMO features

Protocol details DMO protocol stack TMO protocol stack DMO Frame structure

There are 4 basic operational modes of TETRA DMO: DMO operational modes There are 4 basic operational modes of TETRA DMO: “Back-to-back” standard terminal to terminal communications DM Repeater extension of DMO terminal coverage DM Gateway relay between DMO and TMO Dual Watch periodic “scanning” of ‘other’ mode

DMO Characteristics Normal mode Frequency Efficient mode DMO enables 2 communications per carrier (i.e. all 4 slots used, 2 slots used per each call)

TETRA DMO: Repeater Special radio terminal equipment called DMO repeater widen the DMO coverage when needed reaching an MS out of the coverage Based on usual 4 slot structure there are different type of Repeater: DM Repeater 1A For Normal Mode DM Repeater 1B For Normal Mode DM Repeater 2 For Freq Efficient Mode (Obsolete)

DM Repeater Type 1A & 1B Single carrier (1A) DM repeater 1 communications Single frequency DM for Repeater Tx & Rx Higher spectrum efficiency Trunked Mode Air Interface MS RX DM MS TX Type 1A Dual carrier (1B) DM repeater 1 communications Two different frequencies: DM1 for Rx & DM2 for Tx Reduces potential RF interference Trunked Mode Air Interface RP RX DM2 RP TX Type 1B DM1

TETRA Gateway Special radio terminal equipment can operate as a gateway between the two worlds

DM Gateway Trunked Mode Air Interface GW RX DM1 GW TX TM1 TM2 Frequency Usage Enables DMO terminals to communicate with the trunking system & vice versa Gateway uses the ‘normal’ Back2Back DMO mode (single call) One DMO carrier per call

Benefits of DM Gateway Reliability: Trunked communications through adjacent cells partially supported under fault of one radio base station Cost: less strict requirements for coverage in low-traffic areas and “enclosed” areas (incl. buildings, tunnels, underground areas, etc.) Better coverage possibilities during early stages of network roll-out

Type summary DMO type channels calls Back to back 1 Back to back – Frequency efficient 2 Repeater Type 1A Repeater Type 1B Repeater Type 2 Gateway Type 1A Repeater / Gateway Type 1B Repeater / Gateway

Key differences between DMO/TMO (1/2) Individual call (point-to-point) Group call (point-to-multipoint) Circuit mode data transfer Short data service (type 1, 2, 3, 4) Status messages Late entry Emergency and pre-emptive calls OTAR (over the air re-keying)  4 slots (up to 28.8 kbit/s)  (Simplex)  1 slot (up to 7.2 kbit/s)

Key differences between DMO/TMO (2/2) Air interface encryption End to end encryption IP packet data Call authorized by dispatcher Ambience listening Network based features Call forwarding Call recording     (gateway)

Operational Example: An Emergency outside the Network Coverage Needs of a fast network deployment Simple and Fast Wide Coverage Area

DMO Benefits & Applications Operations outside the coverage of Trunking Infrastructure Covert Operations – cannot be monitored by Control Strip-line applications (power, oil and water distribution lines) not requiring trunked network capacity Operations in poor signal strength areas (allows more relaxed coverage requirements and lower the related expenditure) Backup operation when the Trunking Infrastructure system is inoperative

Conclusions TETRA is a multi-mode standard offering trunking & direct communication in-one DMO - a powerful feature thanks to its wide set of sub-modes of operation DMO is a key differentiator between TETRA and other, public and private, cellular technologies

Thank you angelo.benvenuto@leonardocompany.com