Optimization of DATA Transmission for Transport SectorUser case, TMB

David LumbrerasProject Area Manager

In this presentation:

• User requirements• High efficiency in AVL Systems

– Comparing methods

• An example: TMB case

Fleet Manager Requirements:

Traffic Bus Regulation. Frequency Improvement. Customer Service. Investment Optimization. Passengers Safety

How to do it?

Voice Communications with the Control Centre. Half-duplex and duplex voice calls.

Status and short data transmission. Vehicle sensors transmission. MMI integrated on driver’s dashboard. Interaction with passenger information system. GPS-based location system.

How often is needed?

Data User Requirements: Continuous Actualization of Data in Control

Centre. Normally 20/ 30 second each Terminal.

User Requirements

Bus on-board equipment

Example: CONFIGURATION STRUCTURE

- PTT- Emergency button

- Call request

Passenger information

system

Audio interface

Bus driver’s audio system

Bus driver’s

MMI

control

PEI Telemetry sensors

Billing system

Other peripherals

engine, speed, doors...

Control unitControl unit

DISPLAYDISPLAY

data

Ambience listening

microphone

Hands-free audio kit

Handset

TETRA MSTETRA MS

Bus on-board equipment

Example: INSTALLATION DETAILS

Passenger Passenger information information

systemsystem

Micro speaker & Micro speaker & hands-free michands-free mic

TETRA TETRA radioradio

Driver’s MMI consoleDriver’s MMI console

Control unitControl unitBus system Bus system

interfaceinterface

Looking for the most efficient way for

DATA TRANSMISSION with TETRA

technology

• In this type of scenario it is necessary to analyse carefully the geographic positioning as the stronger requirement.

• Short Data Messages (SDS) comparing to Packet Data Protocol (PDP), the conclusions are:

With these conclusions, we are going to work with SDS polling to obtain the geographic positioning.

Nº slots

1 (MCCH)

2

3

4

Type of service

Ran

dom

PD

Polli

ng P

D

Ran

dom

SD

S

Polli

ng S

DS

MCCH Occupation

25%

50%

75%

100%

49%Scenario example

500 buses. 30 seconds of latency for all buses.20 bytes of information size.3 coverage sites (SBS).

High efficiency in AVL, Comparing Methods

• With the standard SDS procedure the requirement for the network is still strong.

• So now, it is necessary to think beyond the TETRA technology.

• New option improving the efficiency.

• Packets used in MCCH to transmit 20 bytes of data.

SwMiMobile in MCCH

ACK1/2 slot downlink SwMi acknowledge

Status REQUEST+ slot granting (1).D_STATUS_REQ1/2 slot downlink

Ack to Status + SDS data (160 bits)ACK + SDS_DATA1 slot uplink

System considerations.

Terminal considerations.

High efficiency in AVL, Comparing Methods

• New optimised polling SDS is the best solution to this type of application.

Nº slots

1 (MCCH)

2

3

4

Type of service

Ran

dom

PD

Polli

ng P

D

Ran

dom

SD

S

Polli

ng S

DS

MCCH Occupation

25%

50%

75%

100%

49%

Opt

imis

edPo

lling

SD

S

The

bes

t o

ne

Scenario example

500 buses. 30 seconds of latency for all buses.20 bytes of information size.3 coverage sites (SBS).

High efficiency in AVL, Comparing Methods

TMB User case

8 SBS´s

1300 buses

• With the best service selected…

Now it is necessary to think how we are going to synchronize the different CCHs.

Here using 1MCCH and 3 SCCH per SBS:• 15% of the control channel is used for geographic positioning.

To obtain this percentage it is necessary to synchronise all CCHs

Real scenario example

1300 buses. 20 seconds of latency for all buses.20 bytes of information size.8 coverage sites (SBS).

High efficiency in AVL, Comparing Methods

Synchronising the polling means...

...obtaining following figures:8 SBS x 4 CCHs = 24 CCHs to request the bus position

1300 buses / ( 20 seconds x 24 CCHs ) = 3 buses per second per CCH

Doing this polling is possible to obtain success with the application.

TMB user case, High efficiency in AVL

Synchronising the polling means...

The problem is:

External Application has not the capability to know where is located every bus in every second.

So for this reason Infrastructure manufacturers have to give the synchronism solution.

In that case the SwMi has to give to the applications provider several commands to introduce the buses to be polling, then…

..... polling answer will come from the SwMi Automatically.

TMB user case, High efficiency in AVL

Commands used by the application provider:

NEBULA

OUTPUT

COMMANDS User Application

List of commands needed to manage this application:

AVL-ADD-ISSIAVL-DEL-ISSIAVL-START-POLLINGAVL-STOP-POLLINGAVL-GET-POSITION

TMB user case, High efficiency in AVL

How the SwMi uses the ISSI list to poll at same time every CCH?

Real time operative system.

SwMi knows where all buses are placed so it can request them as same time with an internal table.

SBS1MCCH

SBS1SCCH1

SBS1SCCH2

SBS1SCCH3

SBS2MCCH …..

SBS8MCCH

SBS8SCCH1

SBS8SCCH2

SBS8SCCH3

70030 89903 34990 32122 08578 ….. 32890 38767 9009 348798439 33432 88998 83439 34343 ….. 34788 43433 34988 493834897 34676 34657 34686 34577 ….. 43789 43763 34876 34767

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .43677 34768 34566 34777 76667 ….. 36776 47767 3476 33344467 34553 33763 33 ….. 46673

33878 78898 3433 6676 ….. 4676634786 67763 ….. 6666787555 ….. 5346667657 ….. 53443

….. 34674

This three ISSI lines will be sent to poll the buses in one second

In 20 seconds all ISSIs on the table have to be sent to the

base stations to poll the complete buses fleet

TMB user case, High efficiency in AVL

Conclusions:

This solution can save around 60% of the channels in the network, with respect to the other alternatives

Only synchronized polling generated by the SwMi can manage with success this amount of data traffic

Thinking beyond the TETRA technology manufacturers can give to the customers the final solution

TMB user case, High efficiency in AVL

Optimization of DATA Transmission for Transport SectorUser case, TMB

Thank you for your attention

David LumbrerasProject Area Manager