Mobile Communications: From 2G to 4G
Dennis Roberson
Motorola Senior VP, CTO & CIO

While the incredibly rapid growth of the Internet is generally understood, it is less well known that wireless telephony and in particular wireless Internet capability are also growing at unprecedented rates. By the end of 2002, it is expected that wireless voice subscribers will exceed wired (conventional telephone) subscribers. Even more surprising is the fact that wireless Internet subscribers will surpass wired (that is, by computer) Internet subscribers by the same date. This results from the fact that in the near future, most cellular phones will have Internet access capability. To fully realize the potential of wireless Internet access requires three factors- a wireless data rate which roughly matches current wired internet data rates, an aggregate wireless capacity (total bits) which roughly matches current wired Internet capacity, and a novel user interface which allows for the limitations and advantages of a handheld device.

Current wired Internet access varies from 56Kbps (dial-up) to 10Mbps or even 100Mbps (Ethernet), while wireless access is generally below 14.4Kbps. Wireless speeds will increase to as much as 115Kbps with the GPRS (General Packet Radio Service) overlay to 2nd generation GSM cellular technology and to as much as 384Kbps with EDGE modulation enhancements (at least for stationary users). Third generation (3G) will increase this to between 144Kbps for mobile users to 384Kbps for pedestrian speeds, to as much as 2Mbps for stationary users. The Fourth Generation (4G) systems, which may be commercialized by 2010, will increase this to 80 Mbps or even more for mobile users.

To fully utilize such data rates, novel user interfaces must be developed. Motorola is currently experimenting with the full range of multimedia data types including video, image, data, music and voice technologies which will enable entirely new forms of human interaction, including techniques for immersing one person in the environment perceived by another.

移动通信: 从第二代到第四代

因特网的迅猛增长已广为人知，但较少人知道的是，无线电话，尤其是无线因特网的用量也以空前的速率增长着。预计到2002年底，无线语音用户将超过有线(传统电话) 用户。更令人惊奇的是，无线因特网接入用户量同时将超出有线因特网(通过计算机)接入用户量。这种预测的根据是，多数手机在不久的将来会具备因特网的接入能力。有三个关键因素影响着无线因特网接入潜能的充分展现，一是无线数据传输率要和目前有线因特网数据率大致相当，二是无线传输总容量要和目前有线因特网数据容量大致相当，再是需要一种能对手持设备扬长避短的新颖的用户界面。 目前有线因特网的接入速率覆盖于56Kbps (拨号) 到 10Mbps 甚至于 100Mbps (以太网)，而无线接入速率一般都低于14.4Kbps。无线速率将通过建立在第二代GSM技术基础上的GPRS (广义无线分组交换服务) 系统增至115Kbps，并且通过具有改进调制功能的EDGE（增强数据率的GSM）系统增加到 384Kbps（至少对静止用户而言）。第三代系统将把无线速率从对移动用户的144Kbps，提高到步行速度下使用的 384Kbps，以及静止用户使用的 2Mbps。 第四代系统 (4G)可望于 2010年投入商用，将为移动用户提供80 Mbps甚至更高的无线速率。

为了充分利用这样的速率，我们需要开发新颖的用户界面。摩托罗拉目前正在全面地试验各种不同类型的多媒体数据技术， 包括视频、图象、数据、音乐和语音等技术。这些技术可以提供全新的人机交互方式，包括把人融入其他人可以感知到的环境中的技术。