Linksys WUSB300N manual What is ISM band?, What is Spread Spectrum?, What is WEP?

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Wireless-N USB Network Adapter

simultaneously requires a dynamic RF networking technology that links access points and nodes. In such a system, the user’s end node undertakes a search for the best possible access to the system. First, it evaluates such factors as signal strength and quality, as well as the message load currently being carried by each access point and the distance of each access point to the wired backbone. Based on that information, the node next selects the right access point and registers its address. Communications between end node and host computer can then be transmitted up and down the backbone.

As the user moves on, the end node’s RF transmitter regularly checks the system to determine whether it is in touch with the original access point or whether it should seek a new one. When a node no longer receives acknowledgment from its original access point, it undertakes a new search. Upon finding a new access point, it then re-registers, and the communication process continues.

What is ISM band?

The FCC and their counterparts outside of the U.S. have set aside bandwidth for unlicensed use in the ISM (Industrial, Scientific and Medical) band. Spectrum in the vicinity of 2.4 GHz, in particular, is being made available worldwide. This presents a truly revolutionary opportunity to place convenient high-speed wireless capabilities in the hands of users around the globe.

What is Spread Spectrum?

Spread Spectrum technology is a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communications systems. It is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the trade-off produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread-spectrum signal looks like background noise. There are two main alternatives, Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).

What is DSSS? What is FHSS? And what are their differences?

Frequency-Hopping Spread-Spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise. Direct-Sequence Spread- Spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered. Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers.

What is WEP?

WEP is Wired Equivalent Privacy, a data privacy mechanism based on a shared key algorithm, as described in the 802.11 standard.

Appendix A: Troubleshooting

35

Frequently Asked Questions

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Contents GHz Word definition Copyright and TrademarksTable of Contents Wireless-N USB Network Adapter Front Panel List of Figures10 Creating a Profile Welcome IntroductionWhat’s in this User Guide? Adapter a device that adds network functionality to your PCIntroduction What’s in this User Guide? Network Topology Planning your Wireless NetworkRoaming Topology the physical layout of a networkNetwork Layout LED Indicators Getting to Know the Wireless-N USB Network AdapterUSB Extension Base USB Extension BaseStarting the Setup Setting up and Connecting the Wireless-N USB Network AdapterSetting up the Adapter Connecting the AdapterWEP Key Needed for Connection PSK2 Needed for Connection Advanced Setup WEP PSK PSK+RADIUS PSK2+RADIUS Radius 22 Confirm New Settings Accessing the Wireless Network Monitor Using the Wireless Network MonitorWireless Network Status screen Link InformationWireless Network Status Wireless Network Statistics Site Information ConnectProfile Information Profiles10 Creating a Profile Create a New Profile12 PSK Needed for Connection 15 Available Wireless Networks 17 Wireless Mode 19 Wireless Security WEP 20 Wireless Security PSK 23 Wireless Security PSK+RADIUS Peap Peap 26 Wireless Security Radius EAP-TLS 28 Confirm New Settings Common Problems and Solutions Appendix a TroubleshootingFrequently Asked Questions What is the 802.11b standard?What 802.11b features are supported? What is the Ieee 802.11g standard?What Ieee 802.11g features are supported? What is ad-hoc mode?What is Spread Spectrum? What is ISM band?What is DSSS? What is FHSS? And what are their differences? What is WEP?What is RADIUS? What is WPA?What is WPA2? Windows XP Wireless Zero Configuration Appendix B Windows XP Wireless Zero ConfigurationFigure B-4 Available Wireless Network Figure B-6 Network Connection Wireless Security Security Threats Facing Wireless Networks Appendix C Wireless SecuritySecurity Precautions Appendix C Wireless Security Wireless-N USB Network Adapter TCP/IP Appendix D Windows HelpAppendix E Glossary Wireless-N USB Network Adapter Wireless-N USB Network Adapter Wireless-N USB Network Adapter Wireless-N USB Network Adapter USB Appendix F SpecificationsStorage Temp Limited Warranty Appendix G Warranty InformationFCC Statement Appendix H Regulatory InformationImportant Note Wireless-N USB Network Adapter Wireless-N USB Network Adapter Wireless-N USB Network Adapter Wireless-N USB Network Adapter Wireless-N Notebook Adapter Appendix I Contact Information
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