After nearly two weeks of study, we have learned a lot from sensibility, which has a far-reaching impact on our future study and research direction. Through this internship, I enriched my theoretical knowledge, enhanced my observation ability, and gave me a qualitative understanding of my future work, which really made me gain a lot. Now this internship will be summarized from three aspects: visiting the internship content, gaining new knowledge, and the direction and feelings of my own efforts in the future.
First, visit the internship content
1. Director Li of Hunan Telecom Group gave a wonderful speech.
On July 9th, I attended the cognitive practice mobilization meeting. At the meeting, Professor Wang, the teacher who led the team, explained the matters needing attention during the internship and encouraged everyone to ask questions to technicians frequently during the internship. Later, Director Li of Hunan Telecom gave me a wonderful lecture, which was divided into three parts: 1) national information strategy, 2) path dependence and technological innovation, and 3) telecommunication network reliability. Director Li earnestly hopes that we will study hard, take the strategic deployment of national informatization development as an opportunity, be brave in innovation, understand the influence of path dependence on a person, and seek advantages and avoid disadvantages. At the same time, it is pointed out that there is a relative lack of research on telecommunication network reliability in China at present, and students should seize the opportunity and strive for early success.
2. Visit the Communication Service Center of Railway College of Central South University to maintain the base station.
On July 10, we visited the Communication Service Center of Railway College of Central South University, which is mainly responsible for providing Tietong call service for more than 5,000 users in the railway campus. In the computer room, the staff mainly told us the main flow of Tietong communication, the items provided by some main equipment and the role it played in the communication network. Has been dedicated to explain to us the work of program-controlled switches (this computer room uses Huawei C&C08 model machine): C&C08 switches can provide rich pstn and isdn services and provide personalized industrial solutions for group users. Has served XX groups of users in provincial capitals and major cities across the country. Adopting C & C08 switch is beneficial for operators to win users and competition. C&C08 switch 128 module is a large-capacity integrated network system, which consists of central switching network (cnet), central processing module (cmp), synchronous timing system (cks), communication control module (ccm), service processing module (spm), * * * resource sharing module (srm) and line interface module (lim). The system provides enough standard physical interfaces and large-scale network connection matrix, and allocates network resources and signaling protocols through software loading, thus forming various large-capacity switching systems.
3. Visit the program-controlled exchange laboratory of TV station and electronic building of Railway College of Central South University.
On July 1 1, we visited the TV station of Railway College of Central South University and the program-controlled exchange laboratory of electronic building of Railway College of Central South University. At the TV station, the staff explained the current situation of TV signals to us, and pointed out that digital signals are booming now, and it will replace analog signals just around the corner. The frequency band of this TV station is 550mhz. Generally, every TV channel is 8mhz, so the capacity of this TV station is 550 divided by 8, which is about 68 channels. Come to think of it, we usually watch more than 50 TVs. The signals of TV stations are mainly provided by merchants, and some of them are directly received from satellites. The received signals are usually transmitted through optical cables. At this time, there is an optical receiver at the receiving end, which converts the optical signal into an analog electrical signal, which is amplified and demodulated by the amplifier and then output to the end user.
Then 10, we came to the program-controlled exchange laboratory of the electronic building. The teacher mainly explained the working process and maintenance measures of the program-controlled switch, and introduced the functions of each component of the switch to us. It really benefited us a lot.
4. Visit the emergency communication vehicle of Changsha Unicom Co., Ltd.
On July 12, our class went to the emergency base station of Changsha Unicom Co., Ltd. in the suburbs by bus. There, we visited the emergency communication car, mainly to prevent the loss of users in some areas due to the lack of signals in emergencies, and to provide sufficient communication capacity for the local area when holding large-scale activities on some occasions. Fortunately, I visited the cdma communication system. On the bus, the staff introduced the current situation and main technical characteristics of cdma technology in detail, and gave us an emphasis on the emergency communication vehicle. It is pointed out that the value created by mobile communication has far exceeded that of fixed-line users before, so for communicators, grasping the mobile market is basically equivalent to grasping the mainstream in the real society. Therefore, we should strive to develop in the direction of wireless communication.
5. Investigation and research on communication products.
On July 13, our task is to do a survey of communication products. The topic I choose is: mobile phone product survey. I mainly investigated the brand, price and monthly cost of mobile phones by current consumers, aiming at providing reference for mobile phone consumers. The survey shows that consumers are optimistic about foreign-made mobile phones such as Nokia, sumsing, Sony and motorlola, but domestic mobile phone Lenovo is also the first reference model for buyers. In addition, students' consumption groups are mainly concentrated in the low-end mobile phones with RMB 600 ~ 10000. The average normal distribution of monthly telephone charges is RMB in 40 yuan.
6. Guo, a technician of China Netcom Hunan Company, and Li Xuechang, a technician of China Unicom, jointly taught.
On July 16, our college friends Guo, technician of China Netcom Hunan Company, and Li Xuechang, technician of China Unicom, gave us lectures, focusing on the current situation and development trend of mobile communication technology, and the development and application of Netcom network architecture pstn and ngn. After the meeting, we asked two seniors questions about communication, and they all gave us detailed answers. What impressed me the most is that as a communication operator, the most basic requirement for staff is their attitude.
7. Social communication talents survey
On July 17, we made a survey on the demand for communication talents in the social talent market. We are very pleased that the communication industry belongs to the it industry, among which there is a shortage of high-tech talents, including 500,000 domestic mobile phone software engineers. Facing the current domestic 3g business is about to start, and 3g licenses will be issued in a few months, so the employment situation of our graduates is very promising.
8. Visit Zhuzhou Branch of Hunan Tietong Group Co., Ltd.
On July 18, we visited Zhuzhou Branch of Hunan Tietong Group Co., Ltd. On the spot, we visited the power supply part, the link layer part and the user layer part successively. The staff told us the networking theory of Tietong, and pointed out that China's telephone communication network is divided into long-distance telephone network and local telephone network. The long-distance telephone network adopts dc 1 and dc2 two-level structure. Dc 1 is a first-class exchange center, located in provincial capitals, autonomous regions and municipalities directly under the Central Government. Its main function is to connect the inter-provincial, intra-provincial, international and domestic long-distance incoming calls, outgoing calls, forward calls and long-distance terminal (landing) traffic of the local network where dc 1 is located. Dc2 is the secondary switching center and terminal long-distance switching center of long-distance network. Located in the central city of local networks in various provinces, its main function is to collect the international and domestic long-distance incoming and outgoing traffic, the long-distance call transfer traffic between local networks in various provinces (cities) and the long-distance terminal traffic in the central city where dc2 is located.
9. Speech by the Director of China Telecom Changsha Branch
On the morning of July 19, we listened to a lecture given to us by the director of Changsha Branch of China Telecom. He mainly introduced to us the development of basic telecom network and intelligent network services. Intelligent network (in) is a network structure added on the basis of the original communication network. Its purpose is to quickly introduce new services in a multi-vendor environment and safely load them into the existing telecommunications network for operation. Basic idea: separating exchange from business control. That is, the original switch only completes the basic connection function, and some new functional nodes are set in the original network, such as service switching point (ssp), service control point (scp), intelligent peripheral (ip), service management system (sms) and so on. Intelligent services are completed by these functional nodes in cooperation with the original switch. We have gained a lot.
Second, acquire new knowledge.
1. Digital mobile communication: Digital communication includes gsm, cdma, etc. At present, the third generation mobile communication (3g) mainly has two technical directions. One of them is the cdmaXX technology evolved from the second generation cdmaone, which has been widely used in North America, South Korea, Hong Kong and other places. In May of XX, China Unicom adopted enhanced cdmaone technology to build a mobile communication network in China. CdmaXX and cdmaone have the same chip rate in the air channel, and the cdmaone system in backwards compatibility can be upgraded smoothly from cdmaone. Its evolution route is cdmaone-cdmax1x-cdmax1xev. Another mainstream third-generation communication technology is wcdma, which is developed from the second-generation gsm standard. Because gsm adopts tdma (Time Division Multiple Access) modulation, wcdma adopts cdma (Code Division Multiple Access) modulation, and their air channels are incompatible, so we use multimode mobile phones and backwards compatibility gsm system by stacking stations. Its evolution route is gsm-gprs-edge-wcdma. There are time division multiple access (tdma) and code division multiple access (cdma). Both of them can realize high-speed packet 3g data services, but there are essential differences between them in terms of air channel modulation, core access network and end users. Gsm is the first cellular system in the world that specifies digital modulation, network layer structure and services. Gsm was developed to solve the fragmentation problem of the first generation cellular system in Europe.
2. Optical fiber communication: using transparent optical fiber to transmit light waves. Efficiency and speed are far superior to wired communication. Synchronous digital hierarchy (sdh) is a digital communication system in optical fiber communication system. This is a new set of international standards. Sdh is not only a networking principle, but also a set of multiplexing methods. In order to overcome the shortcomings of pdh, Sdh came into being. It has a clear goal, then standardizes, and then develops equipment. In this way, the systems and equipment needed for the future communication network can be set up in the most perfect way. Sdh was officially recommended by ccitt in 1988, also called synchronous digital hierarchy. Sdh is a very important standard, which is not only suitable for optical fiber communication, but also suitable for microwave and satellite communication in principle.
3. Unicom base station structure: bts includes the following main functional units: transceiver radio interface (tri) and transceiver subsystem (trs). Trs includes transceiver unit (tg) and local maintenance.
Tri has switching function, which makes the connection between bsc and tg very flexible; Trs includes all wireless devices of the base station; Tg includes all wireless devices connected to one transmitting antenna; Lmt is a user interface for operation and maintenance functions, which can be directly connected to the transceiver. The transmitter subsystem includes all wireless devices of the base station, mainly including the transceiver unit (tg) and the local maintenance terminal (lmt). The transceiver unit consists of multiple transceivers (trx) connected to the same transmitting antenna.
4. Configuration and classification of Unicom bts: 1. Bts configuration shall meet the following requirements: indoor bts shall support the following capacities: omni-directional bts shall support the following configurations: 1-4 trx and 4 2mbit ports. Sector bts shall support the following configurations: two-sector bts, 1+ 1 trx to 2+2 trx, and four 2mbit ports. Three-sector bts, 1+ 1+ 1 trx to 4+4+4 trx and four 2mbit ports. The outdoor bts shall support the following capacities: the omni-directional bts shall support the following configurations: 1-3 trx and two 2mbit ports. Sector bts shall support the following configurations: two-sector bts, 1+ 1 trx to 2+2 trx and two 2mbit ports. Three-sector bts, 1+ 1+ 1 trx to 2+2+2 trx and two 2mbit ports. Outdoor small bts shall support the following capacities: omni-directional bts shall support the following configurations: 1-2 trx and 1 2mb/s ports. For the above configuration, when the operator needs it, it should also be able to expand to a larger configuration and expand bts on the spot while reducing the impact on actual operation. 2. Antenna: Any type of antenna should be able to withstand the wind load with the wind speed of 150km/h, and the joint of the antenna should generally be under the antenna. The antenna should have anti-icing performance.
5.ADSL (Asymmetric Digital Subscriber Line) is an asymmetric digital subscriber line. This technology adopts more advanced digital coding technology and modulation and demodulation technology to transmit broadband signals on the user's conventional copper twisted pair. Specifically, it is realized by a pair of modems, one of which is placed in the isp and the other is placed at the user's end. Adsl is designed for downlink (downlink, that is, from the local office to the client) transmission, and its bandwidth is wider than that of uplink (uplink, that is, from the user end to the local office). Its downlink rate ranges from1.5mbit/s to 8mbit/s, while its uplink rate ranges from1.6kbit/s to 640kbit/s. The transmission distance on a pair of copper twisted pair can reach about 5km. Because adsl technology does not occupy all the bandwidth of twisted pair, it still leaves room for voice channel. Users who use adsl modems to connect to the Internet can still talk on the same pair of lines. In this way, adsl users do not need to rewire, but only need to use ready-made phones to achieve high-speed internet access. In addition, adsl with inconsistent transmission speed is very suitable for users to surf the Internet, so adsl is the main way to surf the Internet in Changsha now.
Of course, there are too many gains. The above is just a summary. But I believe this internship left a deep impression on me, and its harvest will definitely guide my future study.
Third, the direction of my own efforts in the future and my feelings about this internship.
Through this practice, I learned the basic knowledge of communication specialty, broadened my horizons, increased my knowledge, learned some simple principles of communication equipment, and learned the latest development of the current industry. I applied the knowledge in books to practice and gained a lot of valuable knowledge wealth. On the other hand, I also see my own shortcomings. Still have to study hard, understand relevant knowledge, enrich experience, consult teachers and relevant personnel, and learn through various channels.
Through various forms, I understand the development status and bright future of the communication industry. Feel the wonderful life brought by information technology today. Of course, I will devote myself to the communication industry in the future, focusing on the research of new mobile communication technologies. Therefore, when you choose to continue your graduate studies next year, you should strive to engage in the research of mobile communication and let yourself grow up as soon as possible.
9. Speech by the Director of China Telecom Changsha Branch
On the morning of July 19, we listened to a lecture given to us by the director of Changsha Branch of China Telecom. He mainly introduced to us the development of basic telecom network and intelligent network services. Intelligent network (in) is a network structure added on the basis of the original communication network. Its purpose is to quickly introduce new services in a multi-vendor environment and safely load them into the existing telecommunications network for operation. Basic idea: separating exchange from business control. That is, the original switch only completes the basic connection function, and some new functional nodes are set in the original network, such as service switching point (ssp), service control point (scp), intelligent peripheral (ip), service management system (sms) and so on. Intelligent services are completed by these functional nodes in cooperation with the original switch. We have gained a lot.
Second, acquire new knowledge.
1. Digital mobile communication: Digital communication includes gsm, cdma, etc. At present, the third generation mobile communication (3g) mainly has two technical directions. One of them is the cdmaXX technology evolved from the second generation cdmaone, which has been widely used in North America, South Korea, Hong Kong and other places. In May of XX, China Unicom adopted enhanced cdmaone technology to build a mobile communication network in China. CdmaXX and cdmaone have the same chip rate in the air channel, and the cdmaone system in backwards compatibility can be upgraded smoothly from cdmaone. Its evolution route is cdmaone-cdmax1x-cdmax1xev. Another mainstream third-generation communication technology is wcdma, which is developed from the second-generation gsm standard. Because gsm adopts tdma (Time Division Multiple Access) modulation, wcdma adopts cdma (Code Division Multiple Access) modulation, and their air channels are incompatible, so we use multimode mobile phones and backwards compatibility gsm system by stacking stations. Its evolution route is gsm-gprs-edge-wcdma. There are time division multiple access (tdma) and code division multiple access (cdma). Both of them can realize high-speed packet 3g data services, but there are essential differences between them in terms of air channel modulation, core access network and end users. Gsm is the first cellular system in the world that specifies digital modulation, network layer structure and services. Gsm was developed to solve the fragmentation problem of the first generation cellular system in Europe.
2. Optical fiber communication: using transparent optical fiber to transmit light waves. Efficiency and speed are far superior to wired communication. Synchronous digital hierarchy (sdh) is a digital communication system in optical fiber communication system. This is a new set of international standards. Sdh is not only a networking principle, but also a set of multiplexing methods. In order to overcome the shortcomings of pdh, Sdh came into being. It has a clear goal, then standardizes, and then develops equipment. In this way, the systems and equipment needed for the future communication network can be set up in the most perfect way. Sdh was officially recommended by ccitt in 1988, also called synchronous digital hierarchy. Sdh is a very important standard, which is not only suitable for optical fiber communication, but also suitable for microwave and satellite communication in principle.
3. Unicom base station structure: bts includes the following main functional units: transceiver radio interface (tri) and transceiver subsystem (trs). Trs includes transceiver unit (tg) and local maintenance.
Tri has switching function, which makes the connection between bsc and tg very flexible; Trs includes all wireless devices of the base station; Tg includes all wireless devices connected to one transmitting antenna; Lmt is a user interface for operation and maintenance functions, which can be directly connected to the transceiver. The transmitter subsystem includes all wireless devices of the base station, mainly including the transceiver unit (tg) and the local maintenance terminal (lmt). The transceiver unit consists of multiple transceivers (trx) connected to the same transmitting antenna.
4. Configuration and classification of Unicom bts: 1. Bts configuration shall meet the following requirements: indoor bts shall support the following capacities: omni-directional bts shall support the following configurations: 1-4 trx and 4 2mbit ports. Sector bts shall support the following configurations: two-sector bts, 1+ 1 trx to 2+2 trx, and four 2mbit ports. Three-sector bts, 1+ 1+ 1 trx to 4+4+4 trx and four 2mbit ports. The outdoor bts shall support the following capacities: the omni-directional bts shall support the following configurations: 1-3 trx and two 2mbit ports. Sector bts shall support the following configurations: two-sector bts, 1+ 1 trx to 2+2 trx and two 2mbit ports. Three-sector bts, 1+ 1+ 1 trx to 2+2+2 trx and two 2mbit ports. Outdoor small bts shall support the following capacities: omni-directional bts shall support the following configurations: 1-2 trx and 1 2mb/s ports. For the above configuration, when the operator needs it, it should also be able to expand to a larger configuration and expand bts on the spot while reducing the impact on actual operation. 2. Antenna: Any type of antenna should be able to withstand the wind load with the wind speed of 150km/h, and the joint of the antenna should generally be under the antenna. The antenna should have anti-icing performance.
5.ADSL (Asymmetric Digital Subscriber Line) is an asymmetric digital subscriber line. This technology adopts more advanced digital coding technology and modulation and demodulation technology to transmit broadband signals on the user's conventional copper twisted pair. Specifically, it is realized by a pair of modems, one of which is placed in the isp and the other is placed at the user's end. Adsl is designed for downlink (downlink, that is, from the local office to the client) transmission, and its bandwidth is wider than that of uplink (uplink, that is, from the user end to the local office). Its downlink rate ranges from1.5mbit/s to 8mbit/s, while its uplink rate ranges from1.6kbit/s to 640kbit/s. The transmission distance on a pair of copper twisted pair can reach about 5km. Because adsl technology does not occupy all the bandwidth of twisted pair, it still leaves room for voice channel. Users who use adsl modems to connect to the Internet can still talk on the same pair of lines. In this way, adsl users do not need to rewire, but only need to use ready-made phones to achieve high-speed internet access. In addition, adsl with inconsistent transmission speed is very suitable for users to surf the Internet, so adsl is the main way to surf the Internet in Changsha now.
Of course, there are too many gains. The above is just a summary. But I believe this internship left a deep impression on me, and its harvest will definitely guide my future study.
Third, the direction of my own efforts in the future and my feelings about this internship.
Through this practice, I learned the basic knowledge of communication specialty, broadened my horizons, increased my knowledge, learned some simple principles of communication equipment, and learned the latest development of the current industry. I applied the knowledge in books to practice and gained a lot of valuable knowledge wealth. On the other hand, I also see my own shortcomings. Still have to study hard, understand relevant knowledge, enrich experience, consult teachers and relevant personnel, and learn through various channels.
Through various forms, I understand the development status and bright future of the communication industry. Feel the wonderful life brought by information technology today. Of course, I will devote myself to the communication industry in the future, focusing on the research of new mobile communication technologies. Therefore, when you choose to continue your graduate studies next year, you should work hard on the research of mobile communication so that you can grow up as soon as possible.