One, one of the main advantages of DMR is through the TDMA enables a single 12.5 kHz channel to support both synchronous and independent call,

According to the standard of DMR, TDMA keep 12.5 kHzi said width, and its main IJ can be divided into two alternate school when A and B, each time slot as A separate communication path, in this kind of layout, half the time of each communication path using 12.5 kHz bandwidth, so each distance using half the bandwidth of 6.25 kHz, 6.25 kHz frequency spectrum has A call way better efficiency, and USES the DMR, the channel as A whole remains the same as the 12.5 kHz analog signal characteristics,

License holder DMR radio can be in the existing 12.5 kHz or 25 kHz channel running, which means that don't need to change the band or to apply for license, at the same time to keep the channel capacity doubled the domestic existing MOTOROLA, the sea can reach, Rio companion brands such as launch DMR handheld walkie-talkie, car terminal, cluster system products, such as TDMA way to increase the calls for a given bandwidth capacity has been system experiment and test, TETRA and GSM cellular mobile, the world's most widely used two kinds of two-way radio communication technology) are the TDMA system, public safety radio in the United States standard P25 is the second phase of its specifications to double time slot TDMA,

Another way to increase the capacity is 12.5 kHz or 25 kHz channel is divided into two or more 6.25 kHz channel, ~ nFDMA, in theory, 6.25 kHzFDMA telephony equipment can be in the old 12.5 kHzi speech way packed into two new channel side by side, but the actual tian F condition isn't so, in many countries, there is no specific 6.25 kHz licenses, and regulations do not allow the permit holder in the existing 12.5 kHz license to run two 6.25 kHz channel,

But usually possible in 12.5 kHz license to run a 6.25 kHz wireless channel, but the user did not increase capacity, in the United States, authorized by 6.25 kHz channel is available, but the permit holder shall not existing 12.5 kHz licensing iiE divided into multiple 6.25 kHz channel, therefore, to increase 6.25 kHzFDMA system of tao, users have to apply for a new other spectrum of 6.25 kHz license, even if in the existing license allows the user to squeeze into two 6.25 kHz road poor countries, it also can create problems,

Base stations use the spectrum of two adjacent channel operation system, it is easy to produce interference risks, for this reason, users are still using 6.25 kHzFDMA solutions to apply to other tao, a new license to increase the capacity of the spectrum, by contrast, due to the two DMR TDMA path is completely suitable for the existing channel structure, installation DMR system, won't produce new interference problems, DMR on the global high end market, Rio companion communication solutions are fully meet the needs of the business of business customers, in the process of analog to digital plays an important role, for hotels, property, large business super, major events such as the user to provide clear and reliable digital communication solution, all in all, digital PMR -/- (FDMA and TDMA system theory used in the agreement have the same spectral efficiency, because they can offer two calls in the 12.5 kHz frequency spectrum path, but DMR USES TDMA method has the advantages of compatible with current regulatory system all over the world, and will not produce a new interference problem,

FDMA6.25 kHz method is a potential benefit, don't need a repeater coordination TDMA time slot to provide two separate calls road basket, which is necessary for the DMR o (DMR system without Repeaters work well, also can reflect the DMR system still many inherent advantages, such as reverse channel signaling, but not every 12.5 kHz frequency spectrum run two completely independent channels), but there were no repeater, FDMA all wireless devices must be within range of each other at any time, in order to realize the expected capacity, therefore, if the system requires repeater now or in the future to cover the scope of the additional or problem areas (such as base stations move or create open new) FDMA this advantage will be discounted,

DMR system's advantage lies in 12.5 kHz signal than 6.25 kHz stronger anti-interference ability, this means that in the noise environment, 12.5 kHz channel attenuation may be boy 6.25 kHz signal, can provide acceptable intercom service for wireless users, therefore I6.25 kHzFDMA system the repeater is limited to increase capacity advantage,

1, only a small base stations, during the service life of the system all wireless users communicate with their objects in contact area;

2, you can achieve the desired frequency 1 because the reasons for regulatory or interference, will be split into multiple existing license 6025 KHZ channel is not reliable;

3, 12.5 the elusive kHzi said licenses;

4, there is no need to compatible with traditional 12.5 kHz simulation system, DMR considering the long-term business needs, at the start of the development without these restrictions,

Second, DMR spectrum backwards compatibility with the traditional simulation system

For the permit holder, retain existing license, to ensure that with their own traditional radio or external agencies (such as in the site contractor) simulation system of backward compatibility is important, DMR leading brand Rio companion has complete product lines and solutions, the leading system integration ability and mature application; For the provision of business users from the terminal to the system, from voice to data, covering led to the multilevel command scheduling solution, the adoption of 12.5 kHz channel DMR, compatibility is built-in frequency I needed for the camp,

Three, the efficient use of infrastructure equipment

DMRTDMA way, is another advantage of using a repeater, an antenna and a simple duplex machine two communication channels, relative to the FDMA solution, double time slot TDMA 6.25 kHz, efficiency can be obtained at the same time minimizing Repeaters and combination of equipment investment, FDMA each channel requires special repeater, plus expensive support multiple frequency share a combination of a base station antenna device, the combination equipment is used for 6.25 kHz signal may be particularly expensive, and was used in this way, often can cause the loss of signal quality and coverage, so you need to use the power amplifier o for oscillator to produce the phenomenon of error, aging FDMA6.25 kHz system of tolerance is low, leading to launch signals deviating from the ideal center frequency, this will lead to the protection of adjacent frequency degree is reduced, the system is easy to be disturbed, special equipment available to offset, known as the high stable oscillator, but will increase the cost, by contrast, when the double | Joan TDMA channel devices with a single letter to achieve stable dual channel equivalent letter, requires no additional repeater or combination equipment (and relay station can reduce consumption of air conditioning and low demand for backup power supply), for DMR users, this means a lower cost and simpler, base station planning in DMR digital market leading brand Rio companion for hotels, property, large business super, major events, and other industries provide customers like the required communication solution, can effectively enhance the efficiency of management and service quality,


Four, longer battery life and greater efficacy

Battery life a animation is one of the biggest challenge for mobile devices, in the past, the choice of the increase of call time on a single charge limited o but, double time slot TDMA provides a good solution, because only a single call to use one of two time slots, so you just need to let half of the transmitter, emitter half time is free, that is, at any time it is unused slots.. Rounds, "

Typical duty ratio is 5%, for example, launch 15% receive 190% spare, launch time accounts for a large proportion of battery, through the effective launch time cut in half, double time slot TDMA compared with analog wireless communication, call time can be as high as 40%. (according to the product information released by the manufacturer, the same radio talk time is 9 hours in simulation mode, digital mode bei IJ: 13 hours), because every time the phone battery total consumption greatly reduced, the use of a charge time extended, DMR digital equipment include stare and power management technology, to further improve the service life of the battery, although many other factors influence the power consumption of individual equipment, large-scale sales will be the market DMR and FDMA digital interphone battery life figures released by the comparison, or it can be seen that TDMA mode is superior to FDMA, use time per hour ITDMA interphone demand for battery capacity ttFDMA model low 19% - 34%.

Besides environmental reasons not wasting energy, choose low energy consumption technology can make us have more flexibility in the future, as the growth of the user communication requirements (such as larger data requirements), need more battery capacity, had better choose essentially more effective technology, in order to have more room to use, as described above, DMR infrastructure also ttFDMA system required by the more simple, which means running a base station needs lower energy TDMMtFDMA, these energy saving features give DMR user leaner, more environmentally friendly wireless network and longer battery life wireless devices,

5, easy to use and create the data application

MR side slanting I) and digital features can easily add GPS message and after measuring application to equipment and system, the standard of DMR also supports wireless IP data transmission, man to develop standard application, along with the modern society more and more dependent on data and voice communication, a wide range of data is added to the system application can bring the maximum return on investment, in fact, adding to the wireless communication system enhanced data services and applications to promote business users to convert one of the main power of digital communication, DMR schemes achieve the channel capacity of multiplication is also important to add data application, in order to maintain the same quality level of most of the existing voice business, must have extra RongJing data transmission, this is of particular importance for applications such as automatic vehicle location; In these applications, the system can: 1: a huge information, to maintain the position of the constantly updated, although this is a very valuable tool for enterprise users, but will most likely need to provide additional capacity, in order to guarantee the voice service is not affected, DMR schemes to simple, clear the way for additional capacity of beans,

Six, the advanced control function

DMR send back channel signaling standard supports the use of the second time slot, namely in the middle of the first channel is used to call, in the second time slot in the form of signal send instruction to wireless devices, this function can be used for priority call control, signal remote control, or give priority to emergency calls, provide accurate control and flexibility for radio system operators, FDMA system cannot provide similar functionality, because they are each frequency channel is only one way of limitation, call

Seven, excellent audio performance

DMR digital technology can offer a better noise suppression, and keep the broader is better than that of analog voice quality, especially on the edge of the transmission range of the oDMR excellence distance characteristics is one of the reasons in formulating the standards, the forward error correction (FEC) and the cyclic redundancy check (CRC) code devoted most effort, the choice of the encoder by analyzing the information of the reception facilities, which can make the insert bit (for receiving device to check whether there is any error), automatic detection and correction transmission errors, DMR standard specifies the 14 different encoders are available, and each encoder to match different types of signal transmission, through the application of the encoder and other technology, digital processing can filter out adjustment, and to reconstruct the signal from the degradation of transmission signal, the user can more clearly hear every call improve the effective scope of wireless solution, and moment l users aware of the situation changes,

Which is the area of digital system can provide the best coverage for some discussion, such as is based on a 12.5 kHz, 6.25 kHz channel system, both advantages and disadvantages, based on a 6.25 kHz system at a disadvantage, because when you put 6.25 kHz channel in multiple high power transmitting into the elbow in the spectrum, will be strict limits on page 5 of each transmission signal modulation signal (the technical term is to reduce the signal deviation) l in order to avoid damage to the next channel in the spectrum of interference, the signal deviation of this restriction means that when the signal is weak, especially at the edge of the system, the receiver can not distinguish it receives is a Ii1 "or 110", in theory, which affect the coverage of 6.25 kHz system,

For hope in a given 12.5 kHz frequency spectrum users running two 6.25 kHz Repeaters, some regulators will kHzFDMA repeater power limit in the system in 6.25 12.5 kHzDMR system 50% of the available power, this is to ensure that the overall power per unit of spectrum, the restrictions may also affect coverage oDMR system also benefited from the above discussed early implementation of the forward error correction technology o but FDMA system indeed benefit from a 6.25 kHzi said the noise of the layer below the wider 12.5 kHz channel,

Eight, by fully open, mature and widely supported standards of supply security

Because the DMR is a completely open widely support supplier public standard, buyers can rest assured supply of sustainability, technology into open standards and the success of many examples, because this standard encourages suppliers widely participation, bring more users to choose more suppliers, more rapid product development and a lower price from the pressure of competition,