Generally, 3G is called 3rd-generation in wireless technology, the representative character of 3G technology is to provide of high speed data transmission, it could provide mobile broadband access of several Mbit per second to mobile phone which have higher computing ability and connectivity and mobile modems in laptops. And then, the development of the high-speed voice and data transmission is the major difference between 3G and 2G.With high speed internet access, 3G services could simultaneously provide users to do phone calls, data transmissions (fax transmissions, e-mails transmission, etc), data downloading (movies, images, music, etc.) and so on. In order to provide these kinds of services, the wireless internet must support different speeds for different data transmission. It means that the least allowed transmission speed could change according to the different environment. For example, it must support 2Mbps transmission speed in home environment, 384kbps transmission speed in outdoor environment and 144kbpstransmission speed in driving environment at least. And then, the standard of 3rdgeneration is fulfilled by the International Mobile Telecommunications-2000 specifications by the international telecommunication union.
3G transmission method
As mention to 3G mobile phone, it is necessary to understand duplex which could allow handset to transfer two data streams. It means cell phone could simultaneous send and receive signals, customers could both downlink signal from base station to mobile device and uplink signal from mobile device to the base station. And then, there are two technologies could make the mobile device to achieve this simultaneous two-way transfer communication. The first one is frequency division duplex (FDD), this kind of technology designed two separate frequency bands to ensure customers uplink by using a frequency band, and downlink for the other frequency band, so that it could satisfy users to simultaneous transfer two data streams. The second one is named time division duplex (TDD), and this kind of technology could send uplink and downlink signal in one frequency. However, these operations would be switched rapidly. For this reason, if the channel is sending uplink signal and the switch could perform extremely quickly, the channel would be sending downlink signal very soon. As a result, these two operations could be acting as they could perform at the same time. And then, TDD mode is a high efficient transmission method in the small propagation delay environment.
According to the mobile phone transmission technology this essay introduced in the previous paragraph, it could understand the transmission method in general. And then, this essay would introduce the multiple access which could allow many users to be multiplexed into the same channel without disturbance from other users, and this technology is used in the 3G mobile phone. In general, there are two kinds of technologies which could support multiple access, these are Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). Firstly, the technology of TDMA is to separate a radio frequency into many time slots, and each user of TDMA could have a exclusive time slot to transfer data streams between 3G mobile devices and base station. However, the users of CDMA could get a unique code and all signals of users could spread in a wide frequency wide. And then, according this unique code for each customer, receiver could distinguish the exact signal of each user no matter what the frequency.
3G mobile phone
3G mobile phone is a terminal device which could be based on mobile internet technology, and it is not only involving the telecommunication industry but also has relationship with computer industry. To compare with mobile phone which uses the previous technology, it has large amounts of developments. Generally, 3G mobile phone has its large color screen, and users could touch this kind of screen to control the mobile phone. However, beside high-tech daily phone　calls, it could also help people communicate with each other by using multimedia. Users could write messages, draw pictures through the screen of the 3G mobile phone, and sent these kinds of information to another mobile or computer during less time. And then, it is possible for users to directly search　internet by using 3G mobile phone, it could provide users to download information, send email and so on. Moreover, users could have computer　meetings through mobile phone.
According to the practicability and conveniency of 3G mobile phone, it could become an essential part of people's life. It is just the same as moving device which could well send and receive the wireless signals. In order to handle large amounts of wireless data, it is designed as a separate signal which could work at the same time. For this reason, it would not take up the space of GSM bandwidth.
And then, this article could introduce several basic technologies for 3G mobile phone:
Video calls
This feature of 3G handset could allow users to video chat with the one who is called, and it is similar to video chat on the computer. However, through currently technology, the quality of video may be not as good as computer.
GPS technology
According to the GPS support, 3G mobile phone could also be designed as a navigation device. And it is convenient for users could find the exactly locations which they want to reach (such as restaurant, hotel, office, etc).
Internet service
With the development of 3G mobile phone, several web designers have already designed large amounts of mini sites which is convenient for customers to search internet and get useful information.
There are also several useful services of 3G handset, and according to the requirements of markets, designers could also develop the features of 3G mobile phone to satisfy the requirements of customers. And then, the price of 3G handset is also a problem for the market, there are large amounts of wireless providers could offer for the 3G mobile phone, but some of these are too expensive, so that it is necessary to make it cheaper enough to satisfy the requirements of population.
The advantage of 3G technology
With the development of 3G technology, a growing number of customers to use 3G mobile phone, so that it become an essential technology in people's daily life. And in this part, this article could introduce several advantages of 3G technology and several benefits of 3G technologies for our life.
Firstly, to compare with 2G internet access, 3G is a much higher internet access which could allow user to transmit data efficiently (e.g. e-mail sending, surfing website, fast downloading data, fax transmission, etc.).The reason of the higher internet access is 3G technology has higher bandwidth than the previous technology. The high bandwidth allow users to access online shopping, update networking pages, watch online video, check e-mail efficiently through the 3G moving devices. Additionally, several people could be their 3G handset to have a business meeting as a computer. It means the 3G technology make these kinds of 3G devices are the same as a small scale computer by using high speed wireless network while the users are on the move. And then, according to the silicon press, the 3G moving have different device bandwidths in the different speed situations. For a 3G device which is moving fast, the maximum bandwidth could be 128KB; for a 3G device which is moving at a slowly speed, the maximum bandwidth could become 384KB; and the maximum bandwidth of immobile 3G devices is up to 2.05MB. Generally, to compare with 2G devices, 3G technology could be nearly 10 times faster than it, moreover it also several times faster than the ADSL bandwidth which is used for the computer in the home.
And then, according to 3G technology, several users of 3G mobile phone could have large amounts of special personal selections to satisfy requirements of every customer. Users could prefer their favorite applications in their 3G handset such as electronic diaries, automatic reminders, contact lists.
Moreover, according to packet-based internet protocol connectivity, 3G handset could be designed as always-online device. However, the pay of the 3G internet service is only depend on whether users sending and receiving data packages or not. Furthermore, customer also could prefer to the access internet by using free to access Wi-Fi signal, so that it could make users surf the internet by using their 3G devices free.
The disadvantage of 3G technology
With the development of 3G technology, 3G internet is widely used in several countries. And according to large amounts of advantages of 3G technology, it is convenient for customer to use their 3G moving devices to fast access surf internet, transfer data efficiently, chat with video and so on. However, there are also several disadvantages for 3G technology.
Firstly, there are lots of customers have to buy new special cell phone which could support 3G internet to replace their previous 2G handset. And it is necessary for customers to user new card for their new 3G technology mobile phone. And then, 3G cell phone has larger amounts of tasks (such as video chat, fast data transfer, high-speed access internet) to perform, it is necessary for 3G cell phone to have larger screen and larger battery which could store more power. For this reason, to compare with 2G cell phone, the majority of 3G handsets have larger and heavier shape. So it is not convenient for users to carry.
Secondly, 3G devices which could support this kind of 3G technology are expensive for the most of customers. Actually, 3G internet could allow users to video chat, check email, high-speed surf internet. However, in order to support this kind of technology, customers have to buy more advanced and higher quality 3G devices. Moreover, several features of 3G technology are too expensive for customers. For example, the price of video chat is too high to users obviously; and then, if users surf on the internet through their 3G devices, it could cost much network flow; and according to provisions of many mobile phone service providers,customers should to pay some additional fee beside their monthly service fee in order to have some special data streaming access and internet access features.
Thirdly, for the 3G internet, it exist different kinds of disturbances in different environments. If there are several strong disturbances around customers, the speed of 3G internet could be strongly affected, even it could cause the wireless signal be break off. For this reason, high speed internet access for 3G internet could be only achieved in some special situations. It is impossible to satisfy customer use high speed internet access all the time. Actually, it is not necessary to spend too much money to build a base station every few meters. The place real has strong signal and high bandwidth is the location which has high density of people. It means that customers could only use high speed to access internet in the place which has large numbers of people such as office building and Business Street. However, if users walk in the clear road, it may not have high speed to surf on the internet. As a result, if customers need stable and high speed access wireless signal, they should stay in the place which has high density of people.
And then, according to several researches in Europe, a lot of parents would be worried about the effect of 3G technology to their children. They thought the 3G handset could have the same open-door internet access as the internet, but it may not pre-install the software which could filter out the content not suitable for younger people.
To conclude, it mainly introduces the 3G technology and some 3G applications such as 3G mobile phone in this essay. And then, it is also could get the knowledge of the advantages and disadvantages of 3G technology and its devices from this essay. To compare with 2G internet, the most developments of 3G technology are high-speed internet access and the high-quality of voice transmission. Moreover, according to high-speed wireless internet access, it could also allow customers to surf internet, have meetings by using 3G video calls, check e-mail and so on. And with the development of telecommunication, 3G technology would be advanced and attract billions of users in the few years.
