The choice of 1G in China will be based on technical, economic and political considerations, and the two systems are relatively mainstream.
China's choice of system, there will be technical, economic and political considerations, TACS and AMPS is a relatively mainstream 1G system, the technical level of the two systems and the commercial scale of the difference is not large, the biggest difference between them is the channel spacing is different, the TACS is 25k Hz, while the AMPS is 30k Hz, it is said that the reason for choosing the TACS is because of its channel spacing more than the TACS, which is a good match for the various types of radios used in China. It is said that TACS was chosen because its channel spacing was more compatible with the channel spacing of the various types of radio communication equipment used in China at that time.
But even if the whole country was unified under TACS, there were still AB networks that were not connected to each other, with Motorola equipment dominating in the north, and Ericsson dominating in the south under the A system, and it was not until 1995 that automatic roaming of analog cellular telephones across the country was realized.
At that time, mobile communication was still a luxury for the public, not only did they need to pay the initial installation fee of more than 10,000 yuan, but their cell phones could easily cost tens of thousands of dollars, and there were very few models to choose from. The network capacity was small at the beginning of the network construction, and even if you had the money to buy, you still had to wait a few months.
The bosses in the south like to use their hands to grab their purses and carry cell phones called Big Brother, revealing a long whip antenna, which is a common way to show off their wealth. Mobile communication also brings revolutionary changes to socializing, such as a time when the Secretary, in front of us, answering the cell phone when he said he was on a business trip to Hainan, no time. And so on.
The main reason for the small network capacity is because the network equipment is monopolized by multinational companies, China's domestic industry is seriously backward, so there is a lack of bargaining power, so the price is very expensive, for example, a four-unit directional base station antenna is tens of thousands of dollars, and the Ericsson equipment supporting the material contains more garbage shovels, dust sweeps, cable ladders, and other materials, the foreseeable price of the local material is also more than ten times. Foreign companies are also many times higher than our labor costs, early responsible for the installation of Ericsson personnel to Malaysia, Pakistan-based, there are individuals from Sweden, in the early nineties, the vast majority of the people's annual income of less than 10,000 under the Sweden, a base station installation engineers on the annual salary of four hundred thousand yuan, and business trips can be checked into the best local hotels, see the gross profit of the high, the burden of the Chinese consumer! The company's website has been updated with the latest information on the company's website, including its website.
Reference can be made to Ericsson won the bidding for the British vodafone 100 TACS base station cellular mobile network turnkey project case, the total price of the project 30 million pounds, that is, the average price of a single station equipment plus engineering 300,000 pounds, at least ten times more than the cost of a single station of the current 4G or even 5G, not to mention the cost of a single user. As a comparison, China Mobile in March 2020 has just announced the results of the second phase of its 28 provinces 5G machine base station bidding, to build each 5G base station average price of 180,000 yuan.
The cost of building a network constrains the scale and pace of network construction. Guangdong Province, the TACS **** fourteen expansion, probably in 1998 to completely stop the network expansion, but the final network capacity has only reached more than 1 million households, to solve the larger user capacity, but also need to be the next generation of the system.
1G era, and now the site of the base station is generally difficult to compare, when the local government is begging the mobile company to build base stations, some towns and districts to open the base station will be in the local media publicity, and then most of the base station in the Post Office of the Bureau of Building, even if outside of the leased building is also a lot of public institutions.
02
1G technical shortcomings and network equipment
1G voice using analog modulation, signaling is both analog and digital, but the data rate is very low, such as the TACS is only 8kb/s, so it can not be used as business data.
1G technology decided to support only voice services, a single service, and analog modulation is not good anti-jamming, crosstalk is often encountered problems, so the load-to-dry ratio of C/I requirements higher than the digital system, resulting in low frequency multiplexing efficiency, the same frequency bandwidth can be supported by the user capacity is also low.
Poor confidentiality, easy to be eavesdropped on, when Guangdong Province, the use of Ericsson's RBS 883 base station, in each carrier board can be output on the call audio, then heard a night shift to eavesdrop on the call for fun.
But 1G is even more deadly is the seriousness of the theft, for example, at that time to the Guangzhou Culture Park electronics wholesale market, about 1,000 yuan can be bought to modify the cell phone ROM equipment, as long as you know the legitimate cell phone body IMEI number and phone number, you can network theft of the number of tariffs, and in the network management can not be authentication of the legitimate cell phone, who has a good signal, access to fast access priority;
Of course, it is also quite a bit more than that, but it's not a good idea to use a cell phone. p>
Of course, there is also a significant portion of a number of cell phones with multiple handsets is intentional, for example, there are bosses who intend to change their own cell phone numbers out of multiple handsets for their employees to use, and these handsets are only used for dialing out, but with the pager is not a low-cost mobile communications program. In view of the seriousness of piracy, public security organs around the world have set up special task forces to combat piracy, and even have specialized police officers stationed at the local post and telecommunications bureaus.
The national TACS*** purchased two equipment vendors to build two networks, namely Motorola's A network covering 21 provinces and cities, and Ericsson's B network covering 15 provinces and cities. This was due to the fact that China's vast territory has many provinces, and if only one manufacturer's equipment was used at that time, there would certainly be a lack of timely delivery and a high price, but roaming between the two networks would also need to be manually operated for a long period of time.
The TACS network is dependent on the PSTN network, each mobile switching office is equivalent to an end office of the PSTN, the mobile switching office connection needs to be completed through the PSTN, and the phone number of the mobile subscriber is equivalent to a municipal telephone number, switching office number 90.
Guangdong was using Ericsson's equipment, analog equipment is large in size and power consumption, so the station is equipped with 1 to 2 units. Each station is equipped with 1~2 bulky power cabinets and unusually heavy backup battery packs, when the basic selection of the machine room in the local high-rise, some even in the mountains, you can imagine that if there is no elevator, or even no highway under the handling of these nearly a ton of battery scenarios.
Base station maintenance is not convenient, for example, the battery is not maintenance-free; equipment, due to the receiver and transmitter board out of the voice is still analog, its back to the 2Mbps E1 circuit, so you need to jumper racks, will be 30-way voice convergence to an E1, this very earthy dense jumper racks and mobile communications is indeed a little bit disproportionate to the image of the high profile.
With the now widely used RRU is different, then the base station are indoor equipment, a larger site with more than 32 carriers per sector, the base station indoor area of almost 40 square meters, and the distance from the base station antenna is sometimes as far as hundreds of meters, the high cost of RF cables, high loss, lightning protection is difficult.
As a result of the frequency division multiple access (FDMA) mechanism, the earliest base station in the opening, in addition to the conventional definition of the channel frequency, but also need to be allocated according to the frequency of the RF front-end combiner (also known as the combiner, consisting of different resonant frequencies of the filter) for frequency tuning, network optimization, if it involves the replacement of the frequency, you need to go to the scene of the change, not only cumbersome, but also need to wear an expensive and heavy equipment;
The base station indoor area needs almost 40 square meters, and the distance from the base station antenna sometimes hundreds of meters, high cost of RF cable, loss, lightning protection difficult.
It was only later that Ericsson base stations introduced an auto-tuning combiner that eliminated the need for manual tuning. Combiner will be up to 32 channels into a single antenna, when more than 32 will need to increase the transmission antenna, and at that time also transmit and receive antennas are still independent, so a large number of base stations, each sector requires at least two transmit antennas, two receive antennas used as a diversity reception, for the three-sector site, a total of 12 antennas **** need, and due to the use of unipolarized antennas, antennas have strict minimum distance requirements, so the sky space The minimum distance between antennas is strict due to the use of monopolarized antennas, so the sky space requirements are large.
In general, compared with the current base station, 1G base station equipment works indoors and covers a large area, high energy consumption, more interconnections, large ceiling space requirements, high opening and maintenance costs.
03
1G period of the industry
In the main equipment of mobile communications, China's 1G era is the era of foreign investment represented by Motorola and Ericsson. Unlike Motorola, Ericsson is a switch from the fixed network at the time, see the prospects for the development of the mobile communications market, thus expanding to mobile communications in the early 1980s.
Ericsson in the domestic cultivation for many years, 1G era has been launched localization, through cooperation with the Nanjing Panda and Guangzhou Radio Factory and other production and maintenance of base station equipment, thereby significantly reducing costs and improving competitiveness.
In terms of cell phones, the domestic market is basically monopolized by Motorola, which entered the Chinese market early, and Motorola's 8800/8900 series is synonymous with Big Brother. Following the 8000 series,
Motorola later launched the first flip-type 9900, which protects the keys from being pressed inadvertently, and the size and weight of this cell phone are significantly lower compared to the 8800/8900 series, making it the most famous phone of its generation.
The flip cover of the machine is easy to damage, the earliest repair costs up to thousands, but after all, it is an injection molded parts, so the emergence of a lot of non-genuine parts, repair costs have been significantly reduced. Relative to Motorola's bulky,
Ericsson also launched the EH237 and EH238 as the representative of the cell phone, as well as Nokia's 121, compared to Motorola, these cell phones are more compact and exquisite, giving people a refreshing feeling, has been completely can be put into the pants pocket.
Because the 1G subscriber number is a one-to-one correspondence with each cell phone, so the sale of cell phones is basically contracted by the post and telecommunications sector, the choice of models is very limited, and if the phone is lost, you need to go to the post and telecommunications office to report the loss of the report and to redo the user profile.
Compared to today, cell phone repair was considered a high-level occupation, with high fees and high technical thresholds, and the repair points were basically contracted by the postal and telecommunications sectors, and most of the repairers were undergraduates.
Analog cell phone RF and IF part of the integration is far less than now, the failure rate is also high, such failures if there is no investment in expensive spectrum meter or integrated tester is very difficult to locate, and the general individual store can be equipped with a maximum frequency of a few hundred KHz oscilloscope has been considered a high investment, so it is difficult to repair the business of the postal and telecommunications sector with the rich and powerful competition.
1G era, the domestic industry's participation is very low, the main equipment and cell phones are completely foreign world, when Huawei's main strength is still placed on the digital switch, but only in the rural areas of the small-capacity bureau of the room to see its switching equipment.
China's huge mobile market was asymmetrical to the total lack of national brands, and the situation changed only in 2G and beyond.
In the individual non-core components can be seen sporadically domestic brands, such as Guangdong Jingxin in the low-power repeater, Guangdong Tongyu Communications in the individual repeater antenna and individual omni-directional base station antennas have sporadic supply, as well as similar to the light of the Yu and so on in the latter part of individual sites of the spare battery, and so on. Cell phone on the domestic industry focused on accessories and batteries, also cultivated a number of similar SCUD and other cell phone accessories brand.
The current state of the domestic industry in the 1G era is closely related to China's industrial base at that time, as well as the lack of a global standard for 1G, and the lack of uniformity in the interface of network elements.
The main equipment for mobile communication requires intense and continuous R&D investment, with the ability to integrate the longer industry chain, and at that time, mainstream equipment vendors had their own chip departments, and the key processing chips needed to be self-research.
It can be seen that the main equipment to undertake R & D and manufacturing is bound to be a large company, and China in the 8, 90's on the scale of the enterprise unit basically to the state-owned enterprises and ministries and commissions subordinate to the research unit is mainly on the system, it is difficult to break through in the multinational giants, coupled with a serious lack of China's chip design and manufacturing capacity (although there is a similar tin Huajing chip processing enterprises, but far from being able to satisfy).
So the domestic enterprises first from the low value of non-core supporting parts to do is the inevitable choice, even if this can also get not low profits, but also to cultivate a number of enterprises.
Wireless communications in the late 80's has been a very popular college majors, but the actual after graduation can engage in wireless communications R & D is a minority, the choice to the postal system, or foreign non-core technical positions more; which RF direction of the major more embarrassing, in addition to a small number of radar, aerospace can really play the technical strengths of outside the system is very difficult to find the counterparts of the R & D work, these are side by side to reflect that China is the first time in the world, and the world is the first time in the world. These are all side reflecting that China is seriously lack of main equipment research and development of industry and talent base.
Finally, in terms of localization, it is worth mentioning that earlier than the emergence of 1G one-way mobile communication tool pager, when the account about 1,000 ~ 3,000 yuan, monthly rent is also very low, belonging to the general public at that time affordable range, combined with the street full of public **** phone, can be a large degree of low-cost solution to the mobility of communications. Early paging stations were mainly manual, for example, the most staffed department within a mobile branch is commonly known as the call sister. In the development of automatic paging to the domestic equipment has occupied the main force, is a successful example of the localization of communications equipment in memory.
04
1G's fall
The first generation of the system is technologically backward, only to provide voice services, a single type of business, there is a lack of capacity to meet the large-scale technical access, the system is not uniform, resulting in the inability to cross-network roaming, analog system inherent confidentiality and other issues, but as the first large-scale commercial network, cellular technology, as well as network operation and maintenance. The market potential of huge mobile communication has been tapped and ignited, which formally opened the prelude to the cellular mobile market, so the construction of 2G network was opened soon after the construction of 1G scale.
Developed countries and regions in the mid to late 90's have already started the analog network retirement and conversion, for example, Hong Kong requires that before July 1, 1997, all analog networks must be converted to digital networks.
China's analog network had basically no new subscribers by the end of the 1990s, and stopped expanding the network, and even reduced operating costs through network consolidation, and ultimately withdrew completely from the market by the end of 2001, with some of the equipment being supported in Africa, and the corresponding spectrum also being allocated to China Mobile's GSM network.
China's analog network retired late, which is also China's large geographic differences, the economy and communications industry backwardness and other multiple factors decided.
2G
01
Introduction to the standard
1G Although the mainstream standard technically supports roaming, but in practice, due to the countries alone, the standard is different and can not be implemented, the unified standard has become the urgent need for the next generation of standard, so the standard development also needs a cross-country organization to implement.
In the 2G era, the world is still divided into several standards, including mainstream D-AMPS and narrowband CDMA in the United States, PDC in Japan, and GSM in Europe, but GSM was the only one in the 2G era due to its early startup and support for many countries, and ultimately accounted for as much as 80% of the global share.
Except for CDMA, the other three are based on TDMA multiple access, which was the dominant technology in the 2G era.
In order to achieve a unified European standard, the Group Special Mobile (GSM) under the Technical Committee of the European Telecommunications Standards Institute (ETSI) was established in 1982 to begin the development of the GSM standard.
This is the inherent rhythm of technological evolution, that is, after the previous generation of standards development and commercialization, that is, to start the next generation of evolutionary technology research and standards program.
When GSM set up a standards organization, it had not yet decided to use digital or analog, but for mobile communications 1G hard: the system is not unified spectrum is not unified, as a standard to take into account the needs of global roaming, the first thing is to unify the spectrum of 900M; to the mid-80s, for a variety of multiple access technologies and ultimately choose TDMA. in the strong impetus of the ETSI, the first version of the standard GSM frozen in 1992, and was adopted in 1992. The first version of the GSM standard was frozen in 1992 and was adopted by the industry