From the point of technical standards, according to the definition of the International Telecommunication Union (ITU), the static transmission rate reaches 1 Gbps, and the high-speed mobile state can reach 100 Mbps, which can be used as one of the 4G technologies.
At present, there are two major international 4G standards: First, the WiMAX (Global Interoperability for Microwave Access) standard led by Intel in the United States. The 4G technology with the longest transmission distance is also the fastest growing technology in the mobile communication environment. The maximum downlink and uplink rates can reach 75Mbps and 75Mbps respectively. The new generation of IEEE 802.16m (WiMAX 2) allows mobile receiving downlink and uplink maximum speeds up to 300Mbps, and stationary fixed-point reception up to 1Gbps.
Second, LTE Advanced - The standard is an enhancement of LTE, fully backward compatible with LTE, usually through software upgrade on LTE, and the upgrade process is similar to upgrading from WCDMA to HSPA. Peak rate: 1Gbps downstream and 500Mbps upstream.
Since the original purpose of researching 4G communication is to increase the rate of wireless access to the Internet by cellular phones and other mobile devices, the most impressive feature of 4G communication is its faster wireless communication speed. Compared with the data transmission rate of the mobile communication system, the first generation analog only provides voice service; the second generation digital mobile communication system has a transmission rate of only 9.6 Kbps, up to 32 Kbps, such as PHS; and the third generation mobile communication system, the data transfer rate can reach 2Mbps.
Experts estimate that the fourth-generation mobile communication system can reach 10Mbps to 20Mbps, and even up to 100Mbps per second to transmit wireless information, which is equivalent to about 10,000 times the transmission speed of the latest mobile phones in 2009.
In order to achieve 4 Mbps transmission of 4 Mbps communication, communication operators must carry out substantial transformation and research on the basis of 3G communication network, so that the communication bandwidth of 4G network is much higher than that of 3G network cellular system. According to AT&T executives who research 4G communications, it is estimated that each 4G channel will occupy 100MHz of spectrum, which is equivalent to 20 times that of W- CDMA 3G networks.
Particularly, the function of 4G mobile phones cannot be simply classified as a "telephone". After all, the transmission of voice data is only one of the functions of 4G mobile phones, so the future 4G mobile phone should be regarded as a small one. The computer, and 4G mobile phone from the appearance and style, there will be more amazing breakthroughs, people can imagine, glasses, watches, cosmetic boxes, travel shoes, on the premise of convenience and personality, any item that can be seen It is possible to become a 4G terminal, but people still don't know what to call it.
The future 4G communication enables people not only to communicate anywhere, anytime, but also to download data, pictures, and images. Of course, they can play online games with strangers who have never met before. There may be distress that the online positioning system is always locked in nowhere, but compared to the convenience and security brought by the maps it provides, this is negligible.
The fourth generation of mobile communication is more intelligent, not only the design and operation of terminal devices that are represented by 4G communication are intelligent, for example, the dependence on menus and scrolling operations is greatly reduced, and more important 4G mobile phones can realize many unimaginable The function.
For example, a 4G mobile phone can promptly remind the owner of the mobile phone of what to do at this time according to the environment, time and other setting factors, or should not do anything. The 4G mobile phone can directly download the cinema box office information onto the PDA. These materials can clearly show the ticketing situation and the seating situation. You can use this information to purchase your own movie tickets online. The 4G mobile phone can be regarded as a portable TV. It can be used to watch sports games and the like. Various live broadcasts.
In order to make 4G communication accepted as soon as possible, not only its powerful function, but also the basis of existing communication, so that more existing communication users can easily transition with the least investment. To 4G communication. Therefore, from this perspective, the future fourth-generation mobile communication system should have global roaming, open interfaces, interconnection with multiple networks, diversification of terminals and smooth transition from the second generation.
4G communication is not evolved from the simple upgrade of 3G communication. Their core construction technology is fundamentally different. 3G mobile communication system mainly uses CDMA as the core technology, while 4G mobile communication system technology is positive. Cross -task crossover technology (OFDM) is the most popular. With this technology, wireless communication proliferation services such as wireless area loop (WLL) and digital audio broadcasting (DAB) can be realized.
However, considering the transitional nature of 3G communication, the fourth generation mobile communication system will not only adopt one technology of OFDM in the future. CDMA technology will cooperate with OFDM technology in the fourth generation mobile communication system to play a larger role. The role of even the future fourth-generation mobile communication system will also have new integration technologies such as OFDM/CDMA generation. The digital audio broadcasting mentioned above, in fact, the technology it actually uses is the integration technology of OFDM/FDMA, the same is Take advantage of the combination of the two technologies. Therefore, the fourth generation of mobile communication systems with OFDM as the core technology will combine the advantages of the two technologies, and some will be extended technologies of CDMA.
Although the third generation mobile communication system can achieve a variety of multimedia communication, but the future of 4G communications to meet the third generation mobile communication can not reach in the coverage, communication quality, cost to support high-speed data and high -resolution multimedia services The need for the fourth generation of mobile communication systems to provide wireless multimedia communication services, including voice, data, video and other information transmitted through the broadband channel, for the future fourth-generation mobile communication system is also known as "multimedia mobile communication" .
The fourth generation of mobile communication is not only to cope with the increase in the number of users, but more importantly, it must respond to the transmission requirements of multimedia, and of course the requirements of communication quality. To sum up, we must first be able to accommodate a large number of users in the market, improve the quality of existing communications, and meet the requirements of high-speed data transmission.
Compared with the third generation mobile communication technology, the fourth generation mobile communication technology uses and introduces many powerful breakthrough technologies in the development process. For example, some optical fiber communication products companies have introduced to further improve the bandwidth bandwidth of the wireless Internet. Switching level technology, this technology can cover different types of communication interfaces at the same time, that is to say, the fourth generation mainly uses routing technology (Routing)-based network architecture.
The use of radio frequencies is much more efficient than the second and third generation systems due to the use of several different technologies. According to the most optimistic situation, this effectiveness allows more people to do more with the same amount of wireless spectrum as before, and these things are quite fast. The researchers say the download rate is likely to reach 5Mbps to 10Mbps.
Since 4G communication not only solves the compatibility problem with 3G communication, but also allows more existing communication users to easily upgrade to 4G communication, and 4G communication introduces many sophisticated communication technologies, which ensure that 4G communication can provide one. A very flexible system operation, so 4G communication is much easier to deploy than other technologies.
At the same time, when constructing a 4G communication network system, communication operators will consider adopting a step-by-step method directly on the infrastructure of the 3G communication network, so that the cost of operators and users can be effectively reduced. According to researchers, some services such as wireless instant connections for 4G communications will be cheaper than 3G communications.
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