I. Introduction

Wireless infrared communications refers to the use of free-space propagation of light waves in the near infrared band as a transmission medium for communication(1-3), as shown in Figure 1. The communication can be between one portable communication device and another or between a portable device and a tethered device, called an access point or base station. Typical portable devices include laptop computers, personal digital assistants, and portable telephones, while the base stations are usually connected to a computer with other networked connections. Although infrared light is usually used other regions of the optical spectrum can be used (so the term wireless optical communications" instead of wireless infrared communications" is sometimes used).
Wireless infrared communication systems can be characterized by the application for which they are designed or by the link type, as described below.


I.導(dǎo)言

無線紅外通信指的是使用近紅外波段的光作為通信傳輸介質(zhì)的一種通訊方式（1-3），如圖1所示。通信可于一個便攜式設(shè)備和另一個便攜式設(shè)備或系留設(shè)備之間進行，這樣的設(shè)備稱之為接入點或基站。典型的便攜設(shè)備包括筆記本電腦，個人數(shù)字助理，便攜式電話，而基站通常與網(wǎng)絡(luò)內(nèi)的其他計算機相連來工作。雖然通常采用紅外光，光頻譜的其他地區(qū)可以使用（所以說，我們一般稱為無線光通信，而不是無線紅外通信）。
無線紅外通信系統(tǒng)可以以他們所設(shè)計的應(yīng)用程序或由鏈路類型為特征，特點如下所述。

A． 應(yīng)用
主要的商業(yè)應(yīng)用如下：
1．短期無電纜連接的兩個用戶之間的信息交流（名片，日程安排，文件共享）。主要的例子是紅外線系統(tǒng)（見第4節(jié)）。
2．無線局域網(wǎng)（WLAN）提供建筑物內(nèi)的網(wǎng)絡(luò)連接工作。這可以是對現(xiàn)有的局域網(wǎng)的延伸，或在沒有網(wǎng)絡(luò)的地方建立網(wǎng)絡(luò)。主要的例子是IEEE802.11標準（見第4節(jié)）。
3．為城域網(wǎng)或校園區(qū)網(wǎng)絡(luò)內(nèi)的建筑物提供高速網(wǎng)絡(luò)連接。
4．無線輸入和控制設(shè)備，如無線鼠標，遙控器，無線游戲控制器，遠程電子鑰匙。