北大火星人从1G走到4G

   近日，我们接连发表博客科普短文，提及世界 互联网发展、演

的时间表。

    那么。什么是1G、2G、3G和4G呢？怎么划分互联网的“G”？请看本文附件。

注：1995年5月26日，北大方正盗窃火星人远程通信软件源代码，其中包含互联网“滑动窗口”协议模块的程序实现。

袁萌  陈启清  5月27日

附件：

What is 5G?

Evolution beyond mobile internet

From analogue through to LTE, each generation of mobile technology has been motivated by the need to meet a requirement identified between that technology and its predecessor (see Table 1). For example, the transition from 2G to 3G was expected to enable mobile internet on consumer devices, but whilst it did add data connectivity, it was not until 3.5G that a giant leap in terms of consumer experience occurred, as the combination of mobile broadband networks and smartphones brought about a significantly enhanced mobile internet experience which has eventually led to the app-centric interface we see today. From email and social media through music and video streaming to controlling your home appliances from anywhere in the world, mobile broadband has brought enormous benefits and has fundamentally changed the lives of many people through services provided both by operators and third party players.

Generation Primary services Key differentiator

Weakness (addressed by subsequent generation)

1G Analogue phone calls Mobility Poor spectral efficiency, major security issues

2G Digital phone calls and messaging

Secure, mass adoption

Limited data rates – difficult to support demand for internet/e-mail

3G Phone calls, messaging, data Better internet experience

Real performance failed to match hype, failure of WAP for internet access

3.5G Phone calls, messaging, broadband data

Broadband internet, applications

Tied to legacy, mobile

 specific architecture and protocols

4G All-IP services (including voice, messaging)

Faster broadband internet, lower latency

?

Table 1: Evolution of technology generations in terms of services and performance Source: GSMA Intelligence

More recently, the transition from 3.5G to 4G services has offered users access to considerably faster data speeds and lower latency rates, and therefore the way that people access and use the internet on mobile devices continues to change dramatically. Across the world operators are typically reporting that 4G customers consume around double the monthly amount of data of non-4G users, and in some cases three times as much. An increased level of video streaming by customers on 4G networks is often cited by operators as a major contributing factor to this.

The Internet of Things (IoT) has also been discussed as a key differentiator for 4G, but in reality the challenge of providing low power, low frequency networks to meet the demand for widespread M2M deployment is not specific to 4G or indeed 5G.