Hi IEEE 802.11 Key Concepts Let’s get started with the IEEE 802.11 Journey synopsis. Standards are defined at physical and mac-sub layer(data-link). We are referring to different ways of transmitting data over the air. Also how our communication signal would deliver information. One of the original ones we’ve come across is FHSS (Frequency Hopping Spread…
Category: Wireless
What is 802.11ax
Well we first thought there are lot of acronyms in CPU naming schemes but wireless nomenclature may be even more confusing. Started with 802.11 and then got on to 802.11b/g/n/ac/ac wave 2 and then the recent one 802.11ax. Speed – Max theoretical speed for 1 stream on AC is 866 Mb/s, AX promises speeds around…
QAM and Modulation
Abbreviations Galore and Column Legend MCS – Modulation and Coding Scheme QAM – Quadrature Amplitude Modulation BPSK – Binary Phase Shift Keying GI – Guard Interval HT – High Throughput VHT – Very HT RSSI – Received Signal Strength Indicator BPSK – Change the Phase by 180 degrees 1 becomes 0 2 Bit Modulation Symbol…
Wave Length and Frequency Basics
Wave Length – is the distance between 2 successive crests (peaks). Commonly, lower frequency signal will travel farther than higher frequency. 2.4GHz – 4.82 inches (12.24 cms), 5GHz – 2.04 inches (5.19 cms) Frequency – Peaks of signal, seen over a period of time. Defined in Hertz. 1 Hz = 1 cycle p/s 1 KHz…
Wireless Site Survey Notes
Keep in mind about? Floor plan? Dimensions? Get from google earth if no info or double check Number of serving clients Ceiling Height Door (Entrance/Exit doors if apply) Material of doors/walls/obstructions etc. Location? Balanced – Capacity(numbers), Coverage Cisco Access Points : 60:1 ratio, other vendors 30:1 Use DWG for Simulated design Layers on the floor…
CWNA : New Things Learnt today
Cinemas jamming mobile phone signals #cinemajammers The US’s National Association of Theater Owners wants the FCC’s permission to block mobile reception inside cinemas. To be honest I thought this already happened in some places… maybe I’d mentally linked it to office buildings with Faraday cage wall structures to prevent eavesdropping on wireless data transfer; I…
4 Way Handshake
In my own simple words 4-way handshake between a client and an access point Acronyms used: PMK – pairwise master key PRF = Pseudo Random Function AA = Authenticator Address, SA = Supplicant Address PTK = PRF(PMK | ANonce | SNonce | AA | SA) MIC = Message integrity code GTK = Group…
Skycity Level 48
Been to Auckland Skycity level 48 a while ago! The floor is an array of antenna and micro wave radios pointing in all the directions. Skycity tower is remarkably the tallest tower in southern hemisphere. Ideally it will one of the best locations to install your radio/antenna. Was quite a fascination to see the disk…
Wireless : Antenna
Types of Antenna Omni Directional – Design to radiate RF signal in all directional. Default type of antenna in the APs. Semi Directional – Used for short to medium distance communications. Patch, Panel and Yagi come under the category of semi directional. Patch Antenna – used for outdoor point to point communication. Looks flat, usually…
Azimuth and Elevation Concept
The azimuth is the angle between a celestial body (sun, moon) and the North, measured clockwise around the observer’s horizon. In WI-FI, radiation patterns can be defined by Azimuth and Elevation charts. To determine the signal strength relative to where the antenna is. In either chart, the antenna is placed at the center of the…