HomeWork Report :Homework 10-4-2008
Chinese name :曹志信
English name : Gordon
Student number : 9776611
1. Why 2G is faster than 1G?
Response :
1G Cellular characteristic
A. First ancestor initially of the wireless communication
B. Utilize AMPS technology, cover the frequency of utilization again
C. Transmit in order to imitate the signal
D. High unit price
5. There is few amount of user used
2G Cellular characteristic
A. Few keynote of the amount of user improved
B. Utilize TDMS technology, within different time, can utilize frequency further, make rate of utilization raise
C. Transmit the digit signal
Utilize 2G (TMDA) Advantage
A. Can increase communication users' quantity
B. Security is improved
C. The support of the service is good: Service of adding value such as the pronunciation, data, information, the fax
Utilize using the special bee nest type action communication network finally, is called the ' platform on bases of little cell ' to form cell dose that the form is like the hexagon by a lot of, and can roam world, can be regarded as and reach the real action communication.
The above talks to regard manufacturer's development technology as and consider, general users are by listening to, speak, spread the news in brief, considering finally regard news as the main fact, so the development of science and technology, can let interpersonal interdynamic close.
2.Why cellular is better than broadcast?
Response :
Broadcast rely mainly on the fact that frequency is cut at the technology, in use particular users the frequency cut, as to users amount few 。
TDMA forms the time matrix of frequency with the system, produces a lot of time slots on every frequency at Cellular technology, every these matrix a passway at all, under the circumstances that the base station is controlled and distributes, is it or not business to offer the telephone to an arbitrary movement customer or promote the systematic capacity.
As for development of the communication, just enable more persons to transmit information each other, that novel science and technology can replace the old products, let the mankind enjoy science and technology to come all the time as for the human nature.
Note:
TDMA technology:
It is Time-Division Multiple Access that English is written completely. Regard communicating in sound as the example, as its name suggests, TDMA technology is to stagger the time that each spokesman makes a speech. That is to say can only someone make a speech at the same time, such sound of spokesman can interfere with, and clear janitor. Liken the telephone system of the action to the general meeting occasion. The platform of mobile phone base can be likened to a president, and user likens the mobile phone to the persons who participate in having a meeting. When a lot of people want to make a speech at the same time, presidents can assign order and time that everybody make a speech, and each spokesman makes a speech in accordance with the time assigning, can avoid the noisy situation that have a meeting and often have so. Certainly while using the mobile phone, the user will have no feeling that timesharing makes a speech, the reason is the frequency switched over in this kind of timesharing quickly, and after the sound compresses via the digit, so long as short time can convey on behalf of a certain period of voice signals out very, other time distribute other user.
3. Describe a short history of development of cellular technology from 1G to 3G with a prediction of 4G and beyond.
Response :
Begun research and development by Bell Lab, by the early military use, regard as the portable technology of conveying pronunciation and information, develop the 1st generation of mobile communication equipment during that time,Cutting frequency, giving to users, but the shortcoming is that there are few high unit price and user amount, semiconductor technology fast growing later on, channel mobile communication equipment into, make Cheng,
Reduce cost and construction period effectively, and it is to stagger the time that each spokesman makes a speech to develop TDMA technology. That is to say that there can only be a person's speech at the same time ,Such spokesman's voice will not be interfered with, and the clear janitor. The frequency that timesharing switch over quickly, and after sound compress via the digit, So long as short time can convey on behalf of a certain period of voice signals out very, other time distribute other user. Use a quantity to improve to improve with the rate of utilization of frequency.
Take TDMA and CDMA as the core in the development of 2G, in the technology frequently of exhibition of this introduction CDMA
(Code-Division Multiple Access ) ,But it is initial to begin, its system will need high power and communication distance to interfere with questions such as other users,etc.,
Find out the way to solve here too;
1.Power Control: Cooperate with the distance of the products, automation controls Gain Value.
2.Hand off : Make use of technology of the encoder to improve dead time, increase the systematic capacity.
After finishing introducing the communication system, introduce performing the special of algorithm of it at the same time, there is frequency, time many troughs, regard other information as background noise while conversing.
3G action communication era comes and echoes ' the mobile phone of multimedia will be employed ' the opportunity, multimedia, game, the image is transmitted, digit TV Wait for application, 4G it will whether ' mobile phone network ' add ' the wide-band network ' to two loud combination that employed. Data (data) originally in the network Materials, will apply to the demand of moving ,Combine with the pronunciation (voice) on the original mobile phone Materials, all networks (IP) Melt.
4. Read the article that discussed the future of mobile social networks.
Response :
The present person is because of the relation with busy work, less and true social personnel communicate and share, but make use of MySpace and FaceBook social network to contact other people.
The advantage on the network is at present: Can store any place arbitrarily on the network, then share to other users open, or in order to have a look around the information of the other one, if meet the theme of interest, can exchange information each other, reach the speciality of helping each other.
The development of this network can be used in the mobile phone products at present, transmit or receive the personal communication message with the bluetooth function of the mobile phone, can obtain hotel owner's newer products advantage in the network at the same time. Other application is GPS way, may help you to orientate the function, certainly can set up the blacklist in this network too, avoid meeting the personages that harasses.
social networks: Future trend, the network will carry out amalgamation to enable more users to exchange with other networks, can know more interesting persons, mainstreams of workings, things by reaching network of utilizing.
