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MOTOTRBO Digital Radio Technology

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MOTOTRBO Digital Radio TechnologyOverview

The technologies that enable MOTOTRBO to deliver benefits like greater usable range, integrated voice and data, spectrum efficiency, and increased battery life will be explored on the next 4 slides:

1: Analog to Digital Conversion2: Vocoding and Forward Error Correction3. Framing4. TDMA Transmission

Inputs: Voice orIP data

Output: 2-slot TDMA

MOTOTRBO Digital Processes

1 2 3 4

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MOTOTRBO Digital Radio TechnologyOverview: Step 1 - Analog to Digital Conversion

Analogous to how a written message is converted to a data stream by a fax machine, Analog to Digital Conversion translates the user’s voice (microphone input) to a digital bitstream.

1

The digital bitstream contains a LOT of bits - far too many to transmit over a radio channel. So some form of compression is required…..

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MOTOTRBO Digital Radio TechnologyOverview: Step 2 - Vocoding & Forward Error Correction

2

Vocoding (Voice encoding) compresses speech by breaking it into its most important parts and encoding them with a small number of bits. Because it focuses on human speech, it greatly reduces background noise.

Forward Error Correction (FEC) enables the receiving radio to correct bit errors that occur due to RF channel impairments - enabling more consistent audio performance throughout the coverage area.

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MOTOTRBO Digital Radio TechnologyOverview: Step 3 - Framing

3

Compressed digital voiceOrIP Data Digital Packets

Framing organizes digital voice (or data) into digital packets: the voice or data becomes payload (like a letter in an envelope) while the header describes the type of call, source and destination address, etc. (like the addressing information on the envelope). This enables one radio to provide integrated voice and data.

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MOTOTRBO Digital Radio TechnologyOverview: Step 4 - TDMA Transmission

Transmission encoding completes the encoding process (like adding the machine-readable sorting information on the envelope) and finally “mails the letter.”

TDMA (Time Division Multiple Access) organizes a channel into 2 time slots: a given radio’s transmitter is active only for short bursts, which provides longer battery life. And by transmitting only on their alternating time slots, two calls can share the same channel at the same time, thereby doubling spectrum efficiency.….

4

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MOTOTRBO Digital Radio Technology Spectrum Efficiency

frequency

time

12.5kHz Channel

Regulatory emissions mask

12.5kHz TDMA• Divides existing channel into two timeslots• Delivers twice the capacity through repeater• Performance is same or better than 12.5kHz FDMA• 1 repeater does work of 2• Reduces need for combining equipment• Enables 40% increase in radio battery life

12.5kHz Analog• 1 voice for each 12.5kHz channel• 1 repeater for each channel

Today’s Analog

frequency

12.5kHz Channel

Slot 1

Slot 1

Slot 1

Slot 2

Slot 2

Slot 2

MOTOTRBOTM

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MOTOTRBO Digital Radio Technology 2 Slot TDMA

Voice Call 1 (or Data)

timeslot 1 timeslot 2 timeslot 1 timeslot 2 timeslot 1 timeslot 2

Voice Call 2 (or Data)

1. Radio gives priority to voice (e.g.: if its time for radio to send in its GPS update and the user happens to press PTT, the data will wait).

2. Radio cannot transmit and receive at the same time.

3. Radio transmits in only one slot at a time (e.g.: radio cannot transmit voice on slot one while also transmitting data on slot two).

4. Calls are not dynamically allocated to slots, they are statically assigned to a frequency and slot in CPS.

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MOTOTRBO Digital Radio Technology Reduces Infrastructure Equipment

MOTOTRBO 2-Channel System

Analog 2-Channel System

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MOTOTRBO Digital Radio Technology Digital Audio Coverage

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MOTOTRBO Digital Radio Technology Digital Audio Coverage (Cont.)

• What end user will experience with Digital Audio:- Consistent performance throughout coverage area with no gradual fade at

the fringes.- Digital sounds different.- Background noise reduction.

• What end user will NOT experience with Digital Audio:- Digital radio ‘CD quality’.- Digital cannot solve historic problems.

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MOTOTRBO Digital Radio Technology System Coverage Planning

Coverage Considerations

• DAQ measures the intelligibility and quality of voice conveyed through a communications system.

• Audio quality is measured on a 5-point scale, with the DAQ rating of 3 as the minimal acceptable audio quality level for public safety applications.

• The definition of DAQ 3 is: ‘Speech understandable with slight effort. Occasional repetition required due to Noise/Distortion’.

One accepted method is known as Delivered Audio Quality (DAQ).

Before coverage (usable audio range) can be defined.

Identify the minimum acceptable audio quality.

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MOTOTRBO Digital Radio Technology System Coverage Planning (Cont.)

Coverage Considerations –Greater Usable Range

• The figure illustrates the regions of coverage that have comparable audio quality for a MOTOTRBO site compared to an equivalent analog site.

• For a DAQ 3, which is the minimum acceptable audio quality level for public safety applications, MOTOTRBO provides a greater useable range than analog when all other factors are considered equal (e.g. transmit power level, antenna height, terrain, etc.)

• In general, plan as you would for an analog system at the same power level and enjoy the better performance.

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MOTOTRBO Digital Radio TechnologyFrequency Licensing

• The licensing process varies from region to region.

• Emission Designators: Includes several pieces of vital information, such as modulation, signal, type of information and size of the channel.

• This determines the channel width your system will occupy. For MOTOTRBO systems, the Emissions Designators are

– Data only: 7K60FXD– Voice and Data: 7K60FXE

• If you have a 12.5kHz license, you will need to update your emissions designator.

• If you have a 25kHz license, you will need to update your emissions designator. You will generally not be allowed to break it into two – 12.5kHz channels.

• For regulators who currently assign CTCSS/DCS tones to analogue PMR channel licenses, for MOTOTRBO they will need to assign Color Codes instead.

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