Virtual MMI for TETRA radio terminals
Any given TETRA radio terminal using Java (Java ME/CLDC) based technology, provides the end user with the communication rights necessary to fulfil his or her work role on any short duration assignment.
For dexterity, flexibility, and evolution ability, the public transportation radio engineering department, have chosen to use the open sources, Java language specification administered by Sun and the associated work groups in order to produce a transport application tool kit.
Service acquisition admits different authorised agents to establish communication channels between different services by calling the service identity, and without possessing the complete knowledge of the ISSI, GSSI, or any other TETRA related communication establishment numbering plan. Service acquisition is administered through a communication rights centralised service or roll allocation server, interfaced into the TETRA core network.
In summary, the TETRA MMI aims are to:
- Allow any given agent while in exercise, to exploit any given radio terminal without materiel constraint.
- Provide specific transportation application software to the end-user agents (service acquisition, fraud, and aggression control).
This transport application tool-kit has been produced successfully and with TETRA communication technology and assures for the public transport application requirements for the future mentioned hereafter.
The home (main) menu presents the end user with three possibilities:
- Service acquisition,
- Status SDS,
- End-user parameters.
Service acquisition provides a means of virtually personalising the end user to any given radio terminal and onto TETRA network for the duration the end user conserves the terminal under his possession.
Status SDS provides the end user with a mechanism for generating a 440 Hz repeating tone that signals a fraud occurrence to members within the same (dynamic or static) Group Short Subscriber Identity (GSSI) or to a specific Individual Short Subscriber Identity (ISSI) for the duration of the assignment (an hour, a morning patrol or a given short period allocated to the assignment). The advantage being that each of the end users may attach themselves to any given terminal, and group for short durations without requiring any major reconfiguration by means of radio software programming tools. Similarly, the aggression feature functions, but with a higher tone frequency (880 Hz), and with a quicker repetitious nature, so to highlight the urgency of the alert.
The parameters tab provides an essential means to the terminal end-user allowing them to pre-configure the target (preprogrammed ISSI or GSSI ) destination communication number. With this pre-programmed destination number, the end-user shall liaise with the destination radio terminal or roll allocation server, and may communicate, in the group, or into a dedicated server to which the service acquisition requests are received, preprocessed, and ultimately dispatched though the TETRA core network. This simplifies the reconfiguration or recycling configuration process allowing flexibility on short assignments.
The parameters tab also provides a means of choosing between preselected tones to match the work group requirements for the purposes of fraud and aggression alerts. A possibility of selecting any given key available from the keypad to serve as an aggression or fraud quick key is also made possible though the transport application software tool kit. It is recommend to use the asterisk and the hash keys for the fraud and aggression quick keys respectively. For the fraud and aggression tones, it is also recommend to use 440 Hz slow repeating tone (blank space 500 milli-seconds) and 880 Hz fast repeating tone (blank space 250 milliseconds) respectively. The tone options are as follows: 440 Hz, 620 Hz, 880 Hz, and 1060 Hz.
The parameters page provides an aid or help menu and the last tab within parameters describes briefly the tool kit the version and the history of the transport application tool kit to date.
Tetra Enhanced Data Service (TEDS)
The TETRA Association, working with ETSI, developed the TEDS standard, a wideband data solution, which enhances TETRA with a much higher capacity and throughput for data. In addition to those provided by TETRA, TEDS uses a range of adaptive modulation schemes and a number of different carrier sizes from 25 kHz to 150 kHz. Initial implementations of TEDS will be in the existing TETRA radio spectrum, and will likely employ 50 kHz channel bandwidths as this enables an equivalent coverage footprint for voice and TEDS services. TEDS performance is optimised for wideband data rates, wide area coverage and spectrum efficiency.
Advances in DSP technology have led to the introduction of multi-carrier transmission standards employing QAM modulation. WiMAX, Wi-Fi and TEDS standards are part of this family.
Refer also to:
- Mobile Information Device Profile, JSR-37;
- Wireless Messaging API, JSR120;
- Connected Limited Device Configuration, JSR-139; and
- Technology for the Wireless Industry, JTWI-185.