2008-10-4 Homework

1. Why 2G is faster than 1G?
2G is faster than 1G , because new technology, like digital signle and TDMA, are used for 2G system. More capacity are available when use TDMA technology. Another, the data can be compressed and transfered by signle.


2. Why cellular is better than broadcast?
The cellular is better than broadcast, because the more services can be got from cellular. The broadcast like a single channel. We always listen the radio from broadcast, and do not communicate with others. But, we can get and provide information by cellular system, it is like the dual way. There are many access points in the cellular system. Our data can be transfered by access point in cellular system. So, we can share data and communicate with others in this system.

3. Describe a short history of development of cellular technology from 1G to 3G with a prediction of 4G and beyond.
There is long story from 1G to 3G. Shortly, the 1G system is AMPS and it's analog system. I remember that the system was used in America military first. Due to the convenient communication, the capacity is not enough to used for 1G system. As a result, the 2G system was set up. The digital signal and TDMA technology are used in the system. The full name is Global System for Mobile Communication, and we also call "GSM system". The GSM can provide more capacity and fast speed. Another, the GPRS is 2.5G system. The concept of packet switch is used in the mobile phone. Recently, many ISP provide 3G system to use. The CDMA and packet switch technology are used. So, the the mobile network throughput become fast and wide. We can get more services for 3G system, like video phone. In the future, the 4G system will be set up. We can get information easily.