Optimization of DATA Transmission for Transport Sector User case, TMB David Lumbreras Project Area Manager

In this presentation: User requirements High efficiency in AVL Systems –Comparing methods An example: TMB case

Fleet Manager Requirements: Ü Traffic Bus Regulation. Ü Frequency Improvement. Ü Customer Service. Ü Investment Optimization. Ü Passengers Safety

How to do it? Ü Voice Communications with the Control Centre. Ü Half-duplex and duplex voice calls. Ü Status and short data transmission. Ü Vehicle sensors transmission. Ü MMI integrated on driver’s dashboard. Ü Interaction with passenger information system. Ü GPS-based location system.

How often is needed? Ü Data User Requirements: Ü Continuous Actualization of Data in Control Centre. Ü 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 unit DISPLAY data Ambience listening microphone Hands-free audio kit Handset TETRA MS

Bus on-board equipment Example: INSTALLATION DETAILS Passenger information system Micro speaker & hands-free mic TETRA radio Driver’s MMI console Control unit Bus system interface

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) Type of service Random PD Polling PD Random SDSPolling SDS MCCH Occupation 25% 50% 75% 100% 49% Scenario example buses seconds of latency for all buses bytes of information size. 4 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 ACK 1/2 slot downlink SwMi acknowledge Status REQUEST+ slot granting (1). D_STATUS_REQ 1/2 slot downlink Ack to Status + SDS data (160 bits) ACK + SDS_DATA 1 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) Type of service Random PD Polling PD Random SDSPolling SDS MCCH Occupation 25% 50% 75% 100% 49% Optimised Polling SDS The best one Scenario example buses seconds of latency for all buses bytes of information size. 4 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 buses seconds of latency for all buses bytes of information size. 4 8 coverage sites (SBS). High efficiency in AVL, Comparing Methods

Synchronising the polling means obtaining following figures: 4 8 SBS x 4 CCHs = 24 CCHs to request the bus position 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. 4 So for this reason Infrastructure manufacturers have to give the synchronism solution. 4 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: 4 AVL-ADD-ISSI 4 AVL-DEL-ISSI 4 AVL-START-POLLING 4 AVL-STOP-POLLING 4 AVL-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. 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

è Conclusions: 4 This solution can save around 60% of the channels in the network, with respect to the other alternatives 4 Only synchronized polling generated by the SwMi can manage with success this amount of data traffic 4 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 Sector User case, TMB Thank you for your attention David Lumbreras Project Area Manager