First, ancient times
In order to convey the information of the enemy's attack in time, soldiers on the border of ancient China lit "fuel" on the beacon tower. The smoke is so heavy that you can see it from a distance. In this way, the beacon towers were lit one by one, and the news of the enemy's attack quickly spread out. Among them, there are many ways of communication, such as flying pigeon passing books and post-horse mail. ?
Second, modern times
/kloc-After the middle of the 0/9th century, with the development of telegraph and telephone and the discovery of electromagnetic waves, great changes have taken place in the field of human communication, realizing the transmission of information by metal wires and even wireless communication by electromagnetic waves.
1837, American Samuel Morris successfully developed the world's first electromagnetic telegraph. He used his own code to convert the information into a series of long or short electric pulses, which were transmitted to the destination and then converted into the original information.
1875, alexander bell invented the world's first telephone, and applied for an invention patent in 1876. 1878, the first long-distance telephone experiment was conducted between Boston and new york, which are 300 kilometers apart, and it was successful.
1888, physicist heinrich hertz proved Maxwell's electromagnetic theory with experiments, which led to the birth of radio and the development of electronic technology.
British electrical engineer Fleming invented the diode in 1904. American physicist Fessenden successfully developed radio broadcasting in 1906.
Third, modernity.
From telegraph to telephone, a new era in the communication world has begun. Now, the third technological revolution, with computers and the Internet as its main content, has once again brought about human communication.
1, 0G, era of wireless communication technology 1950s. Get rid of the connection shackles of PSTN, and mobile communication technology was born. It has reached a brand-new level, mainly manifested in the progress of mobile communication technology from 0G to 5 G.
2. 1G, era of cellular communication technology 1980s. From PSTN value-added services to independent mobile communication services.
3,2g, the era of digital communication technology 1990s. Technology determines ecology, and ecology determines business scale.
4. In the pre-3G era, standards will be unified. Communication standards will inevitably be unified, but this is a gradual process of balancing interests.
5, 3G, broadband communication technology era in the 2000s. The fierce competition of communication standards and the redefinition of communication world
6, 4G, the era of unified communication technology standards is 20 10s. Looking at the communication industry, the world is in dispute and will eventually be unified.
7, 5G, the era of software-defined network technology in the 2020s.
Key technologies 1: large-scale antenna array and beamforming. The flexibility of 5G network lies in its ability to control communication elements.
Key technology 2: Millimeter wave communication, which is the most far-reaching technological evolution of 5G.
Key Technology 3: Software Defined Network (SDN) and Network Function Virtualization (NFV)