Archive for the ‘Wireless’ Category

The Power of 802.11

The goal of this paper is to educate the reader on the power of 802.11 wireless LANs. The power to which I refer is literal power, measured in wattage. This paper will guide you through understanding how that power is expressed and explain decibel mathematics. You will learn how to add power or “gain” either passively or actively as well as how power can be lost. The various types of antennae available and their uses will be also addressed. Lastly, we will close by discussing FCC regulations governing the maximum EIRP (a term you will learn through reading) and the special requirement imposed by the IEEE.
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Establishing long distance 802.11 links

My original title for this paper was “Quantum Electrodynamics, diffraction, the Huygens-Fresnel Principle, earth bulge and their effects on the Fresnel Zone,” but I thought that was a bit much. Plus I was afraid it might scare some people away. This paper does assume some RF competence on the part of the reader, and at least a basic understanding of algebra. As my original title indicates the actual scope of this article is much more refined than the revised title would lead one to believe. I will not be discussing the finer points of establishing long distance connections from start to finish. This paper’s main focus is on the Fresnel Zone (Pronounced Fra-nel btw).
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Spread Spectrum and Modulation/Encoding Techniques used in 802.11 Wireless

The goal of this paper is to educate those curious on how information is sent in wireless LANs. This paper is about the physical way the signal is sent, that is to say we will not be preforming a dissection of the 802.11 protocols but rather the manner in which the ones and zeros make their way through the air. We will be covering the various spread spectrum technologies used such as FHSS, DSSS and OFDM. Beyond the spread spectrum technologies we will also be discussing Barker Codes, CCK, DB/QFSM and other fun stuff, so sit back and enjoy the ride.
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