蓝牙网络 Piconet 1 Piconet 2 ………………… M Activex Parked slave slave …… Bridge slave
蓝牙网络
无线网状网 Internet with gateway、 Mesh router Mesh'router Mesh router with gateway Wired dients Mesh/ router with gateway/ bridge Wireless dients 口s with ga with gateway bridge Access point Sensor Sink node WI-Fi Sensor networks Base station Base station
无线网状网
Chapter 6 outline 6.1 Introduction Mobility 口65 Principles: Wireless addressing and routing 06.2 Wireless links to mobile users characteristics g6.6 Mobile Ip 6.3IEEE80211 0 6.7 Handling mobility in wireless LANsCwi-fi") cellular networks 0 64 cellular Internet 0 6.8 Mobility and higher access yer proToco ls o architecture o standards (e. g GSM) 0 6.9 Summary 6: Wireless and Mobile Networks 6-13
6: Wireless and Mobile Networks 6-13 Chapter 6 outline 6.1 Introduction Wireless 6.2 Wireless links, characteristics 6.3 IEEE 802.11 wireless LANs (“wi-fi”) 6.4 cellular Internet access architecture standards (e.g., GSM) Mobility 6.5 Principles: addressing and routing to mobile users 6.6 Mobile IP 6.7 Handling mobility in cellular networks 6.8 Mobility and higherlayer protocols 6.9 Summary
无线链路的特性 口信号衰减:信号在传播过程中能量逐渐减少(路 径损耗) 口干扰:受到其它信号源的干扰 口多径传播:由于地面或物体的反射作用,信号沿 多条不同长度的路径到达接收端 口以上特性导致无线链路的传输距离受限、误码 率很高 6: Wireless and Mobile Networks 6-14
6: Wireless and Mobile Networks 6-14 无线链路的特性 信号衰减: 信号在传播过程中能量逐渐减少（路 径损耗） 干扰: 受到其它信号源的干扰 多径传播: 由于地面或物体的反射作用，信号沿 多条不同长度的路径到达接收端 以上特性导致无线链路的传输距离受限、误码 率很高
无线网络的特性 a wants to send to B B wants to send to c but cannot hear that but mistakenly thinks B is busy the transmission will fail Range Range of C's As radio radi A B C A transmitting transmitting (a)隐藏节点 (b)暴露节点 C正在向B发送 口B准备向C发送 口A监听到信道空闲,A向BB监听到信道忙(A在发送 发送 口B不发送,但其实B可以发送( 口A和C的信号在B冲突 A和B的信号不会在C冲突) 6: Wireless and Mobile Networks 6-15
6: Wireless and Mobile Networks 6-15 无线网络的特性 (b) 暴露节点： B准备向C发送 B监听到信道忙（A在发送） B不发送，但其实B可以发送（ A和B的信号不会在C冲突） (a) 隐藏节点: C正在向B发送 A监听到信道空闲，A向B 发送 A和C的信号在B冲突