Category Archives: hobby

　　The most basic usage of GPRS DTU is: put a SIM card with GPRS function in DTU, after DTU is powered on, first register to GPRS network, and then establish connection with data processing center through GPRS network. After the GPRS DTU is powered on, first read the working parameters saved in the internal FLASH (including GPRS dialing parameters, serial baud rate, IP address of data center, etc., which have been configured in advance).The industry believes that, radio Module The development of our company marks the rapid and steady progress of the whole industry. https://www.hkulike.com/

　　

　　GPRS DTU logs into GSM network, and then dials GPRS PPP. After successful dialing, GPRS DTU will get an internal IP address randomly assigned by Mobile. That is to say, GPRS DTU is in the mobile intranet, and its intranet IP address is usually not fixed and changes with each dial. We can understand that GPRS DTU is a mobile device in the internal LAN, and it communicates with the external Internet public network through the mobile gateway. This is similar to the way that computers in a local area network access external networks through gateways.

　　

　　GPRS DTU actively initiates communication connection with data center, and keeps communication connection always existing. Because GPRS DTU is in the mobile intranet and the IP address is not fixed. Therefore, only GPRS DTU can actively connect to the data center, but not the data center. This requires the data center to have a fixed public IP address or a fixed domain name. The public IP address or fixed domain name of the data center is stored as a parameter in the GPRS DTU, so that once the GPRS DTU is powered on and dialed successfully, it can actively connect to the data center.

　　

　　Specifically, GPRS DTU sends TCP or UDP communication requests to the data center through the IP address and port number of the data center. After receiving the response from the center, GPRS DTU thinks that the handshake with the center is successful, and then keeps this communication connection. If the communication connection is interrupted, GPRS DTU will immediately shake hands with the center again.

　　

　　Since the TCP/UDP communication connection has been established, two-way data communication can be carried out.

　　

　　For DTU, as long as the two-way communication with the data center is established, it is relatively simple to complete the conversion between user serial data and GPRS network data packets. Once receiving the user’s serial data, DTU immediately encapsulates the serial data in a TCP/UDP packet and sends it to the data center. Conversely, when DTU receives the TCP/UDP packet from the data center, it takes out the data content and immediately sends it to the user equipment through the serial port.

　　

　　Through the wired data acquisition center, it communicates with many GPRS DTU in two directions at the same time. This is the most commonly used way in GPRS DTU application system at present.

　　As we all know, wireless modules have two common performances. The following small series with outstanding skills will introduce the comparison of the two performances.In the eyes of peers, radio Module It has good qualities that people covet, and it also has many loyal fans that people envy. https://www.hkulike.com/

　　

　　Firstly, the instantaneous frequency of the FM carrier transmitted by the FM transmitter is that the FM wave that changes with the modulation signal is an equal amplitude wave, and its maximum power is equal to the average power; The amplitude modulation transmitter emits an amplitude signal, and the maximum transmission power is equal to 4 times the average power. If the last stages of AM transmitter and FM transmitter use the same type of power tubes, and both are estimated according to the maximum power, the power emitted by FM transmitter is four times the average power emitted by FM transmitter.

　　

　　The main feature of FM is its strong anti-jamming performance. The so-called strong anti-jamming performance mainly means that the signal-to-noise ratio at the output of FM receiver is greater than the signal-to-noise ratio at the output of FM receiver under the same input signal-to-noise ratio.

　　

　　The reason why FM has stronger anti-jamming ability than AM can be analyzed from the power of the transmitted signals of the two systems. The power of the side frequency component of FM wave is divided from the carrier power. Its sidebands are not only numerous, but also increase in amplitude, which means that the proportion of power converted into sidebands in carrier rate is large, and the maximum power of sidebands of amplitude-modulated waves is equal to that of carrier power. Therefore, FM has more side frequency power than AM, which means it is more capable of overcoming the noise and interference in the channel or the machine.

　　

　　Secondly, we can make a comparative analysis from the mediation of receiving signals. Because the information of amplitude modulation signal is contained in the amplitude of the amplitude modulated signal, the demodulated envelope detector can’t suppress the parasitic amplitude modulation interference, while the information of FM signal contains the frequency change at the moment of high frequency oscillation, so the parasitic amplitude modulation caused by interference can be removed by limiter.

　　

　　Therefore, the anti-interference performance of FM system is better than that of AM system, regardless of the sideband power of the transmitted signal or the demodulation of the received signal.

　　JZX891 data transmission module is a high-integration micro-power half-duplex wireless data transmission module, which adopts “SI” high-performance RF chip and high-speed single chip microcomputer. The module provides 8 channels, adopts national measurement frequency points, and is equipped with professional setting software for users to change parameters. The module adopts transparent transmission mode, and can transmit data of any size without the need for users to write setting and transmission programs. The module is small in size, wide in operating voltage and convenient to use.Without exception, RF Module Our customers are willing to purchase their products, because high quality is the concept of their products. https://www.hkulike.com/

　　

　　Functional features:

　　

　　* Working frequency is 470-510MHz.

　　

　　* Transmission distance is 1500m (1200bps).

　　

　　* GFSK modulation method

　　

　　* transparent transmission mode

　　

　　* Built-in watchdog to ensure long-term reliable operation.

　　

　　* UART/TTL, RS232 and RS485 interfaces

　　

　　* Convenient and flexible software programming

　　

　　* Large 512bytes data buffer.

　　

　　* Suitable for built-in installation

　　

　　Scope of application:

　　

　　* Automatic meter reading and charging system for water, electricity, gas and heating;

　　

　　* intelligent wireless PDA terminal;

　　

　　* Wireless queuing equipment;

　　

　　* burglar alarm;

　　

　　:: Smart cards;

　　

　　* Automatic control of medical and electronic instruments;

　　

　　* Intelligent teaching equipment;

　　

　　* Intelligent control of household appliances and lighting;

　　

　　* wireless hanging scale, electronic scale for wireless transmission;

　　JZX891 data transmission module is a high-integration micro-power half-duplex wireless data transmission module, which adopts “SI” high-performance RF chip and high-speed single chip microcomputer. The module provides 8 channels, adopts national measurement frequency points, and is equipped with professional setting software for users to change parameters. The module adopts transparent transmission mode, and can transmit data of any size without the need for users to write setting and transmission programs. The module is small in size, wide in operating voltage and convenient to use.in other words Wireless Module It is possible to develop in a good direction, and there are still many places worth looking forward to in the future. https://www.hkulike.com/

　　

　　Functional features:

　　

　　* Working frequency is 470-510MHz.

　　

　　* Transmission distance is 1500m (1200bps).

　　

　　* GFSK modulation method

　　

　　* transparent transmission mode

　　

　　* Built-in watchdog to ensure long-term reliable operation.

　　

　　* UART/TTL, RS232 and RS485 interfaces

　　

　　* Convenient and flexible software programming

　　

　　* Large 512bytes data buffer.

　　

　　* Suitable for built-in installation

　　

　　Scope of application:

　　

　　* Automatic meter reading and charging system for water, electricity, gas and heating;

　　

　　* intelligent wireless PDA terminal;

　　

　　* Wireless queuing equipment;

　　

　　* burglar alarm;

　　

　　:: Smart cards;

　　

　　* Automatic control of medical and electronic instruments;

　　

　　* Intelligent teaching equipment;

　　

　　* Intelligent control of household appliances and lighting;

　　

　　* wireless hanging scale, electronic scale for wireless transmission;

　　The wireless transceiver module is mainly used for signal transmission to achieve multi-functional purposes such as communication and wireless control. General wireless modules are used in a variety of occasions, and the following mainly introduces three kinds.In view of the actual needs of society, radio Module We need to change some original problems to better serve the society and benefit people. https://www.hkulike.com/

　　

　　First, used for channel control

　　

　　What is channel control? Channel control is divided into parallel and multi-channel. This kind of control is generally applied to the control of complex remote-controlled robots, and the safety protection control of some places can be controlled and driven by the receiving and sending signals of wireless modules.

　　

　　Second, for the development of wireless communication networks

　　

　　For professionals, the link of wireless communication network needs the application of topological structure, and only with this structure can the application value be realized by using the transceiver system of wireless module. On the one hand, this kind of transmitting and receiving module is cheap, and the cost of forming a star topology is relatively low; On the other hand, the transmitting and receiving module can adopt modular design, which is small in size, convenient to use and easy to integrate. This transmitting and receiving module is very practical for wireless networks with low communication speed and close distance.

　　

　　Third, used for serial data transmission

　　

　　Usually, many control instruments and devices use serial port, and communication with these devices must meet the requirements of serial port, and the transmission rate and electrical characteristics must meet the serial port standard. Some special places, industrial control sites. When it is necessary to use wireless transmission mode, the transmitting and receiving module mentioned in this paper can be naturally selected. However, it must be explained here that in order to adopt this communication method, the corresponding software must be compiled at the transmitter and receiver to realize the file format conversion, so as to achieve the purpose of wireless communication.

　　If the mobile phone uses GPRS DTU on the Internet, data can be sent and received in groups, which means that users are always online and charged according to traffic, which quickly reduces the service cost. If CSD bearer is changed to GPRS, it means that dozens of people will bear the cost of the original one. Therefore, many unnecessary expenses will be greatly reduced.In order to grow rapidly, radio Module Do not hesitate to change the strategy and rearrange the products, so as to obtain unexpected results. https://www.hkulike.com/

　　

　　The advantage of GPRS DTU is that its data transmission speed is not comparable to that of GSM. At present, the transmission speed of GSM mobile communication network is 9.6K kilobytes per second, and the transmission speed of GPRS mobile phone has reached 56Kbps when it was launched at the beginning of this year, and now it has reached 115Kbps. Packet is to package Data into many independent packets, and then send these packets one by one, which is somewhat similar to sending a package. The advantage of packet switching is that it only takes up bandwidth when there is data to be sent, and it can be priced according to the amount of data transmitted, which is a more reasonable charging method for users, because most of the time and bandwidth of data transmission like the Internet are intermittent.

　　

　　GPRS DTU can provide four different coding methods, which also provide different error protection capabilities. Using four different coding methods, each time slot can provide different transmission rates. Each user can use up to eight time slots at the same time. So GPRS DTU is called high transmission rate.

　　If the mobile phone uses GPRS DTU on the Internet, data can be sent and received in groups, which means that users are always online and charged according to traffic, which quickly reduces the service cost. If CSD bearer is changed to GPRS, it means that dozens of people will bear the cost of the original one. Therefore, many unnecessary expenses will be greatly reduced.Through bit by bit efforts, let RF Module Our market share is getting higher and higher, and the return on investment is also rising steadily. https://www.hkulike.com/

　　

　　The advantage of GPRS DTU is that its data transmission speed is not comparable to that of GSM. At present, the transmission speed of GSM mobile communication network is 9.6K kilobytes per second, and the transmission speed of GPRS mobile phone has reached 56Kbps when it was launched at the beginning of this year, and now it has reached 115Kbps. Packet is to package Data into many independent packets, and then send these packets one by one, which is somewhat similar to sending a package. The advantage of packet switching is that it only takes up bandwidth when there is data to be sent, and it can be priced according to the amount of data transmitted, which is a more reasonable charging method for users, because most of the time and bandwidth of data transmission like the Internet are intermittent.

　　

　　GPRS DTU can provide four different coding methods, which also provide different error protection capabilities. Using four different coding methods, each time slot can provide different transmission rates. Each user can use up to eight time slots at the same time. So GPRS DTU is called high transmission rate.

　　There are various types of fiber optic cables available on the market, differing in size, shape, color, structure, and material. Choosing the right fiber optic cable can be challenging, but this article offers some tips to help you make the best decision.more importantly, fiber optic cables Made a fighter in the product, not afraid of any competitor’s attack. https://kechengdg.com/

　　

　　optical cable

　　

　　What is Fiber Optic Cable?

　　

　　Fiber optic cables transmit data in the form of light pulses through flexible, optically pure glass. These cables consist of five main components: the core, cladding, coating, strength members, and outer jacket.

　　

　　- Core: Made of high-purity silica (SiO2) with a small amount of dopants, the core is responsible for transmitting light pulses generated by lasers or light-emitting diodes (LEDs).

　　

　　- Cladding: This thin layer of glass surrounds the core and has a different refractive index to reflect light back into the core, allowing the signal to propagate.

　　

　　- Coating: Designed to absorb shock, prevent excessive bending, and protect the core.

　　

　　- Strength Members: These components shield the core from excessive tension and compression, particularly during installation.

　　

　　- Outer Jacket: Provides protection from external factors like shock, moisture, and other environmental influences.

　　

　　optical cable

　　

　　Tips for Choosing the Right Fiber Optic Cable

　　

　　1. Cable Type

　　

　　First, determine whether you need single-mode (SM) or multimode (MM) fiber optic cable based on your network application and specifications. Generally, SM fiber is ideal for long-distance and outdoor applications, while MM fiber is suited for short-distance and indoor use.

　　

　　2. Fiber Core Count

　　

　　After selecting the fiber type, calculate the number of fibers needed for your network. This depends on the scale of your FTTX (Fiber to the x) and ODN (Optical Distribution Network) projects and the type of fiber optic cable you plan to use. Backbone cables typically range from 24 to 288 cores, while distribution cables require fewer cores. FTTH home cables usually have 1 or 2 cores.

　　

　　3. Deployment Environment

　　

　　Consider the structure and material of the fiber optic cable based on its deployment location:

　　

　　- Outdoor:

　　

　　For direct burial, loose tube layer-stranded armored fiber optic cables offer the best protection. In overhead environments, self-supporting cables that can bear their own weight, such as figure-8 or ADSS cables, are ideal.

　　

　　- Indoor:

　　

　　Flame-retardant, low-smoke, halogen-free (LSZH) cables are essential for indoor use. In duct environments, choose cables with flame-retardant and LSZH properties. For exposed indoor environments, the same LSZH cables are required. Tight-buffered optical fibers, known for their small bending diameter, softness, and easy stripping, are well-suited for indoor applications.

　　

　　- Buildings:

　　

　　When laying cables vertically or horizontally within a building, tight-buffered, bundled (D-type), or branched (B-type) optical cables are recommended.

　　

　　4. Connectors

　　

　　Connectors are crucial for establishing a secure fiber optic network. Common types include ST, FC, SC, LC, and MTP/MPO connectors.

　　

　　- ST: Popular in telecommunication networks, spring-loaded for easy connection and removal.

　　

　　- FC: Threaded body, ideal for high-vibration environments, polarized fiber, and SM fiber.

　　

　　- SC: Snap-on connector, commonly used in SM fiber, duplex networks, CATV, media converters, and FTTX.

　　

　　- LC: A standard ceramic ferrule connector, half the size of SC, used in SM fiber, data centers, LANs, FTTH, and CATV.

　　

　　- MTP/MPO: High-performance multi-core connectors for data centers.

　　

　　optical cable

　　

　　Summary

　　

　　When selecting a fiber optic cable, consider the cable type, fiber core count, deployment environment, and connectors. By evaluating these factors, you can confidently choose the most suitable fiber optic cable for your needs.

　　Smart advertising machines have long been widely used in the healthcare field. Now let¨s turn our attention to smart advertising machines in clinics. Although clinics are not as busy as hospitals, there is still a lot of information to be conveyed. Smart advertising machines can help clinics provide better services to customers in many ways.from led outdoor display Looking at the development prospects, the future will always bring positive effects. https://chestnuter.com/

　　

　　smart advertising machines

　　

　　Ways to Serve Customers

　　

　　1. Daily Health Tips

　　

　　Set up an easily visible screen in the waiting area or consultation room to display daily health tips, including nutrition, chronic disease management, etc. You can also share some interesting content so that customers can gain health knowledge in a relaxed atmosphere.

　　

　　2. Seasonal health alerts

　　

　　Provide corresponding health advice according to different seasons, such as allergy protection in spring, sun protection and moisturizing in summer, and disease prevention in winter.

　　

　　3. Product and service promotion

　　

　　Introduce the products and services provided by the clinic, including basic medicines, new products, etc. By making attractive slides, show the characteristics, efficacy and usage of the products.

　　

　　4. General Medication Information and Guidelines

　　

　　Inform customers of general medication guidelines, such as when to take medication, whether to take with food, and what to do if you forget to take medication or take an overdose. For new or prescribed medications, provide more detailed information, including instructions for use, potential side effects and interactions, etc.

　　

　　5. Scheduling Appointments

　　

　　If the clinic offers additional services, such as health checks, vaccinations, etc., list these services on the smart advertising machine so that customers can learn about them and make appointments.

　　

　　6. Prescription preparation notification

　　

　　Use the screen to notify customers of the prescription preparation status and reduce the waiting time of customers. At the same time, promote online booking services to facilitate customers to start consultations at home and reduce waiting time in the clinic.

　　

　　Notes

　　

　　1. Evaluate customer needs

　　

　　Understand customer interests and needs, display relevant content in a targeted manner, and improve customer engagement and satisfaction.

　　

　　2. Be concise and clear

　　

　　The content should be concise and easy to understand, avoiding overly professional terms and complex sentence structures.

　　

　　3. Update in a timely manner

　　

　　Update the content of the smart advertising machine in a timely manner according to changes in seasons, products and services to keep the information fresh and accurate.

　　

　　4. Interactivity

　　

　　Add interactive elements, such as touch screens, QR codes, etc., so that customers can obtain more information independently.

　　

　　In short, the clinic smart advertising machine is an effective information dissemination tool that can help the clinic improve service quality and enhance customer satisfaction and loyalty. By making reasonable use of smart advertising machines, clinics can provide customers with more personalized, convenient and considerate services.

　　1. List of questions and alliance answers for operators to deploy NB-IoTDoing these simple things can also make RF Module Sowing high-quality genes will eventually grow into towering trees and become the leader in the industry. https://www.hkulike.com/

　　

　　How is the network architecture of NB-IoT composed?

　　

　　Building vertical industry application of Internet of Things based on NB-IoT technology will tend to be simpler and the division of labor will be clearer.

　　

　　How do domestic and foreign operators divide the frequency bands of NB-IoT?

　　

　　Most operators in the world use the 900MHz frequency band to deploy NB-IoT, and some operators deploy it in the 800MHz frequency band. China Unicom’s NB-IoT is deployed in 900MHz and 1800MHz frequency bands, and only 900MHz can be tested at present. In order to build the NB-IoT Internet of Things, China Mobile will obtain the FDD license and allow the existing 900MHz and 1800MHz frequency bands to be re-cultivated. China Telecom’s NB-IoT is deployed in the 800MHz band, with a frequency of only 5MHz.

　　

　　NB-IoT network deployment schedule?

　　

　　In 2016, China Unicom launched NB-IoT field-scale networking tests based on 900MHz and 1800MHz in seven cities (Beijing, Shanghai, Guangzhou, Shenzhen, Fuzhou, Changsha and Yinchuan), as well as more than six business application demonstrations. In 2018, the commercial deployment of NB-IoT will be fully promoted nationwide. China Mobile plans to start the commercialization of NB-IoT in 2017. China Telecom plans to deploy NB-IoT network in the first half of 2017. Huawei and six operators (China Unicom, China Mobile, Vodafone, Emirates Telecom, Telefonica and Italia Telecom) set up six NB-IoT open laboratories around the world, focusing on NB-IoT business innovation, industry development, interoperability testing and product compatibility verification. ZTE and China Mobile completed the technical verification demonstration of NB-IoT protocol in the laboratory of China Mobile’s 5G Joint Innovation Center.

　　

　　Can non-operators deploy NB-IoT networks?

　　

　　The answer is no.

　　

　　Does NB-IoT need real-name registration system?

　　

　　All needs, tracked to the responsible subject.

　　

　　Does NB-IoT all adopt eSIM?

　　

　　The product features of NB-IoT are that it can work without installation and configuration, and it can be directly connected to the network by booting, and it supports functions such as automatic equipment registration and air upgrade. SIM card and eSIM will coexist for a long time, and operators refuse the soft SIM mode.

　　

　　What is the operator’s plan to quit the 2G/3G network?

　　

　　China Unicom may gradually close its 2G network in 2018, and in some places it may close its 3G network. Japan’s mobile operators have all shut down 2G networks, and AT&T in the United States, Telstra and Optus in Australia have announced plans to shut down 2G networks. Telenor plans to close its 3G network in Norway in 2020, followed by its 2G network in 2025. Some operators consider that there are more than 100 million GPRS IOT terminals and low-end GSM mobile phones for a long time, and the cost of GSM is lower than that of LTE for a long time because of its low complexity and no patent fees. Therefore, most operators will maintain the GSM frequency band to continue their operations for a long time.

　　

　　Do operators support NB-IoT roaming?

　　

　　The answer is no.

　　

　　How can operators ensure the stability of NB-IoT network?

　　

　　NB-IoT is directly deployed in GSM, UMTS or LTE networks, which can be reused with existing network base stations to reduce deployment costs and achieve smooth upgrade. However, the use of a separate 180KHz frequency band does not occupy the voice and data bandwidth of existing networks, ensuring that traditional services and future Internet of Things services can be carried out stably and reliably at the same time.

　　

　　The control and bearer of NB-IoT are separated, with signaling on the control plane and data on the bearer plane. If it is a low-rate service, it goes directly to the control plane, and no dedicated bearer is established, which omits the signaling process of establishing a link between NAS and the core network and shortens the wake-up recovery delay. NB-IoT is an operational telecommunications network. This is the key to distinguish NB-IoT from GPRS, LoRa, SigFox and other technologies.

　　

　　How can operators make use of NB-IoT network to make profits?

　　

　　Operators’ existing areas such as QoS service quality assurance, network security, telecom-level billing and big data services continue to maintain their industry advantages. NB-IoT network allows operators to strengthen their business service capabilities in the field of Internet of Things, including cloud service provision, mass customer management, real-name authentication of Internet of Things, system general contracting integration, and high-end customized services for large customers.

　　

　　Price issues related to NB-IoT?

　　

　　Operator’s charges: one is based on flow and the other is based on message, and the trend will be lower than the price of GPRS cost chip: lower than the price of 2G main chip, with a reasonable expected price of $1. Module price: lower than the price of GPRS module, with a reasonable expected price of $2. Terminal price: pricing maintenance cost according to actual function: far lower than the existing network maintenance cost subsidy policy: operators will provide larger operating subsidies in the early stage.

　　

　　2. List of questions and answers about NB-IoT technology.

　　

　　Will NB-IoT standard support TDD LTE?

　　

　　At present, FDD LTE system supports NB-IoT technology, while TDD LTE system does not support NB-IoT technology. The physical layer design of NB-IoT mostly follows LTE system technology, such as SC-FDMA for uplink and OFDM for downlink. The design of high-level protocol follows LTE protocol, and its function is enhanced according to its small data packet, low power consumption and large connection characteristics. The core network is connected based on S1 interface, which supports independent deployment and upgrade deployment.

　　

　　Does NB-IoT support base station positioning?

　　

　　R13 does not support base station location, but the operator network can do private solutions, such as location based on cell ID, which will not affect the terminal, and only need the network to increase the location server and contact with the base station. R14 plans to enhance positioning, supporting E-CID, UTDOA or OTDOA, and the operator’s desired positioning accuracy target is within 50 meters.

　　

　　Considering the terminal complexity, UTDOA is better, because it has little influence on the terminal, and in the case of enhanced coverage (basement 164dB), UTDOA (uplink) power consumption is lower; If coverage enhancement is not needed in most scenarios, OTDOA (downlink) will be better from the perspective of network capacity.

　　

　　What are the deployment methods of NB-IoT?

　　

　　NB-IoT supports three different deployment modes, namely independent deployment, guard band deployment and in-band deployment. Independent deployment: A separate frequency band can be used, which is suitable for re-cultivation in GSM frequency band. Guard band deployment: The marginal useless frequency band in LTE system can be utilized. In-band deployment: Any resource block in the middle of LTE carrier can be utilized.

　　

　　What modulation and demodulation technology does NB-IoT use?

　　

　　OFDMA is used for downlink, and the subcarrier spacing is 15kHz. The uplink adopts SC-FDMA, single-tone: 3.75kHz/15kHz, and multi-tone: 15kHz. Only need to support half duplex, with a separate synchronization signal. The terminal supports the indication of Single-tone and Multi-tone capabilities. The MAC/RLC/PDCP/RRC layer processing is based on the existing LTE processes and protocols, and the physical layer is optimized.

　　

　　What are the number of connected users and active users of NB-IoT base station?

　　

　　NB-IoT has 50-100 times the uplink capacity improvement compared with 2G/3G/4G, and NB-IoT can provide 50-100 times the access number compared with the existing wireless technology under the same base station. Under the frequency of 200KHz, according to the simulation test data, a single base station cell can support 50,000 NB-IoT terminals to access.

　　

　　What is the coverage of NB-IoT base station?

　　

　　NB-IoT has a gain of 20dB higher than that of LTE and GPRS base stations, and it is expected to cover underground garages, basements, underground pipelines and other places where signals are difficult to reach. According to the simulation test data, in the independent deployment mode, the coverage capacity of NB-IoT can reach 164dB, and the in-band deployment and guard band deployment need to be simulated and tested.

　　

　　What is the uplink and downlink transmission rate of NB-IoT?

　　

　　NB-IoT RF bandwidth is 200kHz. Downlink rate: greater than 160kbps and less than 250kbps. Uplink rate: greater than 160kbps and less than 250 kbps (multi-tone)/200 kbps (single-tone).

　　

　　Does NB-IoT support retransmission mechanism?

　　

　　NB-IoT adopts retransmission (up to 200 times) and low-order modulation to enhance coverage.

　　

　　Does NB-IoT support voice?

　　

　　NB-IoT supports Push to Talk without coverage enhancement. In the scenario of enhanced coverage of 20dB, only similar voicemails can be supported. NB-IoT does not support VoLTE, which requires too high delay, and the high-level protocol stack needs QoS guarantee, which will increase the cost.

　　

　　Why does the chip of NB-IoT consume low power?

　　

　　The energy consumed by a device is related to the amount or rate of data, and the size of data packets sent per unit time determines the size of power consumption. NB-IoT introduces eDRX power saving technology and PSM power saving mode, which further reduces power consumption and prolongs battery life. NB-IoT can keep devices online all the time, but it can save power by reducing unnecessary signaling and not accepting paging information when in PSM state.

　　

　　In PSM mode, the terminal is still registered in the network, but the signaling is unreachable, which makes the terminal stay in deep sleep for a longer time to save electricity. EDRX power saving technology further prolongs the sleep period of the terminal in idle mode, reduces unnecessary startup of the receiving unit, and greatly improves the downlink accessibility compared with PSM.

　　

　　Does NB-IoT sleep wake-up mode affect battery life?

　　

　　At present, the working time given by NB-IoT is based on simulation data, without considering the battery itself and environmental factors, such as self-discharge and aging of the battery, high and low temperature environmental impact, etc. In actual use, it is necessary to comprehensively evaluate the power supply time of the battery according to the actual situation. NB-IoT adopts the power-saving scheme of sleep wake-up. When the battery is awakened during sleep, it will receive instantaneous strong current, which will greatly affect the battery life. The application of meter reading usually adopts lithium thionyl chloride (Li/SOCl2) battery and super capacitor. Consumer electronics and others should be powered by li-polymer.

　　

　　Why are NB-IoT chips cheap?

　　

　　Low speed, low power consumption and low bandwidth bring low cost advantages. Low speed: it means that no large cache is needed, so the cache can be small and the DSP configuration is low; Low power consumption: it means that RF design requirements are low, and small PA can be realized; Low bandwidth: It means that there is no need for complicated equalization algorithm … These factors make the NB-IoT chip small, so the cost will be reduced.

　　

　　Taking a certain chip as an example, NB-IoT chip integrates BB, AP, Flash and battery management, and reserves the function of sensor set. The AP includes three ARM-M0 cores, and each M0 core is responsible for the application, security and communication functions respectively, which facilitates the function management and reduces the cost and power consumption.

　　

　　What is the range of NB-IoT to the device movement rate?

　　

　　NB-IoT is suitable for application scenarios with weak mobility support (such as intelligent meter reading, intelligent parking, etc.), while simplifying the complexity of the terminal and reducing the power consumption of the terminal. NB-IoT does not support mobility management in connected state, including related measurement, measurement report, handover, etc.

　　

　　What is the network delay of NB-IoT?

　　

　　NB-IoT allows a delay of about 10s, but it can support a lower delay, such as about 6s, in the environment of maximum coupling loss.

　　

　　3. Deployment of NB-IoT technology in various vertical application fields of the Internet of Things.

　　

　　What is the deployment cost of NB-IoT vertical application?

　　

　　The deployment cost of NB-IoT vertical application field includes hardware cost, network cost, installation cost and service cost. If we want to realize the scale of application field, we must reduce the deployment cost.

　　

　　What is the focus of NB-IoT in vertical application field?

　　

　　NB-IoT technology can meet the requirements of low-rate services with low power consumption, long standby, deep coverage and large capacity, and is more suitable for static services, low sensitivity to time delay, discontinuous movement and real-time data transmission. 1. Autonomous anomaly reporting business types: such as smoke alarm detectors, abnormal equipment operation, etc. The uplink data volume is extremely small (on the order of ten bytes), and the cycle is mostly in years and months. 2. Business types of autonomous periodic reporting: such as remote meter reading of public utilities and environmental monitoring, etc. The uplink data volume is small (on the order of 100 bytes), and the cycle is mostly in days and hours. 3. Service type of remote control instruction:

　　

　　For example, if the equipment is turned on/off remotely, and the equipment triggers to send an uplink report, the downlink data amount is very small (on the order of ten bytes), and the cycle is mostly in days and hours. 4. Software remote update service type: such as software patch/update, and the uplink and downlink need a large amount of data (kilobyte level), and the cycle is mostly in days and hours.