The Importance of Communication Standards If every telecom company formulates a communication standard, then interconnection is a big problem. For the communication between devices, it is necessary to have a unified coding rule. The rule that everyone should follow is the "communication standard". Communication standards mainly stipulate two things: coding and decoding standards when sending and receiving information; Coding and decoding methods of transmission content;
A good coding standard can improve information transmission efficiency, reduce loss and reduce bit error rate. 1G is firmly grasped by the United States. 1G was created by Motorola (not formulated) and started as a project of the US military during World War II. In the early stage, this kind of communication equipment weighed about 5 Jin, which required two soldiers to use a transceiver together. The communication range is very small, but it also gives the US military a huge advantage in the communication of World War II.
In the later period, this device has the prototype of our early "mobile phone", and the communication range is still very small, covering about 1KM. In view of its technical advantages in military projects, Motorola's communication equipment began to be commercialized in the 1980s.
Both mobile phones are available. What network is used for transmission? 1978，at & amp； Bell Laboratories of ampT Company pioneered the Advanced Mobile Phone System (AMPS) based on cellular network and analog technology, which is the first generation mobile communication standard (1G). In the same year, the International Radio Conference approved the use of 800/900 MHz frequency band for mobile phones.
Many countries have begun to build the first generation mobile communication system based on frequency division multiplexing (FDMA) technology and analog modulation technology. 1979, Japan introduced the 800MHz car telephone system (HAMTS) and put it into use in Tokyo and Kobe. Nordic countries, Switzerland, the Netherlands, Eastern Europe and Russia invest in NMT; On1980; From 65438 to 0983, the American Advanced Mobile Phone System (AMPS) was first put into use in Chicago.
1984, west Germany built C.
Network, frequency range is 450MHz. From 65438 to 0985, the United Kingdom developed the Total Access Communication System (TACS), which was first put into use in London and then applied to the whole country, with a frequency range of 900MHz. In fact, these networks are all based on the modified version of AMPS in the United States, which are mainly different in frequency band, channel interval, frequency offset and signaling rate, and the others are completely the same. At that time, China used British TACS standard, while China's own mobile communication system was blank, and its fixed-line equipment was all imported.
In the era of 1G, Motorola not only monopolized the global mobile phone market, but also was the equipment supplier of AMPS system (AMPS standard was applied in more than 70 countries around the world). This also means that the United States firmly holds 1G in its hands. 2G is a war between GSM in Europe and CDMA in Qualcomm. Because 1G is an analog standard, its capacity is limited, and it can only transmit voice traffic. There are too many systems, the systems are incompatible, the call quality is poor, the equipment is expensive, it can't roam around the world, and it is easily disturbed by static electricity and noise. Some eavesdroppers can intercept information with special equipment.
Communication industry urgently proposes to use digital signals instead of analog signals to improve the call quality, and to improve the capacity through two schemes: Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). Almost all European and American telecom giants have chosen TDMA, and only the newly established Qualcomm insists on CDMA.
Due to the late maturity of CDMA system standards, the opportunity was missed. Finally, in the 2G era, American CDMA lost to European TDMA. At this time, the European Union jointly established GSM to be responsible for the research of communication standards, and telecom giants such as Ericsson, Nokia, Siemens and Alcatel all joined in, free of patent fees.
GSM is easy to deploy. It adopts a brand-new digital signal coding instead of the original analog signal. In addition to voice, it supports international roaming, provides SIM card for users to store personal data when changing their mobile phones, and can also send short messages with the length of 160 words.
When everyone's attention was still focused on TMDA, Qualcomm built a patent wall around power control, co-frequency multiplexing, soft handover and other technologies, and applied for almost all patents related to CDMA applications. From the beginning, they planned to monopolize profits and stifle downstream companies. Qualcomm has hired an extremely large team of lawyers to apply for patents, negotiate patent prices and prosecute infringements. Through legal battles such as mergers and acquisitions, prosecution of patent infringement of opponents, all CDMA-related patents are taken into the bag, and the core patents are firmly in their own hands.
Then, Qualcomm embedded the CDMA algorithm into the chip and provided a set of System on a chip (system
On the chip,
SoC) solution, baseband, CPU, GPU, sound card, network card, etc. All integrated on one chip. At that time, most mobile phone manufacturers did not have the technical ability of SoC integration, and finally failed to resist the temptation of Qualcomm. They chose the chip from Qualcomm and paid the patent fee for the communication standard.
With the rapid growth of global mobile phone users, the shortcomings of limited capacity of GSM network are constantly exposed. When network users are overloaded, more network facilities must be built. 3G came into being at this time, and its biggest advantage is faster network speed. The download speed of 2G is only about 9600bps-64kbps, while the initial speed of 3G is 300k-2Mbps, which is more than 30 times higher.
199865438+In February, Europe took the lead in establishing 3GPP, dedicated to the transition from GSM to WCDMA, bypassing the Qualcomm patent. America is not to be outdone. 1999, 1 In June, 2006, Qualcomm took the lead in establishing 3GPP2 and devoted itself to realizing its own CDMA2000 technology. 1In June, 1998, the R&D team of Datang Telecom put forward China's own TD-SCDMA standard.
In the 3G era, China's choice gradually began to affect the global communication pattern. Since then, China is no longer subject to others in terms of communication technology standards. 4G China has become one of the makers of the rules of the game. In 2007, the iPhone was born. Steve Jobs redefined the smartphone with the perfect combination of IOS and iPhone. Almost at the same time, Google released Android, and Qualcomm released the first generation of Snapdragon chips.
The far-reaching significance of the iPhone is that the APP Store has driven the blowout of mobile Internet services, entrepreneurs have created rich content and services with apps, and people's demand for network speed improvement has suddenly been detonated. After seven years of bad luck, 3G finally found a home.
In the face of people's growing demand for video chat and making friends, 3G network speed is obviously weak. It coincides with the gradual maturity of 4G core orthogonal frequency division multiplexing (OFDM) technology, the transmission rate is more than ten times that of CDMA, and it also bypasses Qualcomm's CDMA patent.
In 2005, at the 3GPP conference held by China in France, manufacturers in Datang United Kingdom put forward TDD evolution model based on OFDM. In the same year, the 3GPP working group meeting adopted LTE in China, which is the subsequent evolution of TD-SCDMA.
TDD technical scheme. The balance soon fell to Europe. Qualcomm saw that the technical system he built in 3G was destroyed, and UMB was quickly suppressed because no one supported it. The following year, Qualcomm stopped UMB and announced to join the LTE camp of 3GPP. In the 4G era, the United States not only failed to compete with its old rival Europe, but watched the rise of China.
The core patents of LTE include SFR, sOFDM, SC-FDMA, Turbo code and Alam-outicode. Huawei invented the first two items, occupying a leading position in the core patents of LTE. Since then, China, as one of the giants who have mastered the core patents of 4G, has become the most important rival of the United States in the world.
The contest between modern countries is a contest of scientific and technological strength. In this science and technology competition, China's status as a big country has also risen rapidly, and its influence on the whole world pattern has become more and more profound. The above personal views are welcome to criticize and correct. Agree with me, please like to go again, thank you! If you like me, please pay attention to me. Thanks again!