Yes, some of us have been around here a while. There used to be one list back when I made my first post in December of 1999. That was when Jason Simons of Midcoast in Maine was the sage of WISPs. And I remember being there at Mike's first WISPCON when Scriv showed up all wide eyed and chomping at the bit. Now he is out there bidding for licensed spectrum and wearing the leadership mantle along with a number of you. Marlon was of course around -- always has been and probably always will!
Patrick -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Hammett Sent: Wednesday, August 29, 2007 6:28 AM To: WISPA General List Subject: Re: [WISPA] Glossary, updated from 6 years ago post Wow, 6.5 years ago... I don't think I was even looking at becoming a WISP then. ;-) --Mike ----- Original Message ----- From: "Patrick Leary" <[EMAIL PROTECTED]> To: "WISPA General List" <wireless@wispa.org> Sent: Monday, August 27, 2007 3:21 PM Subject: [WISPA] Glossary, updated from 6 years ago post So I was looking through some old material when I came across this glossary of wireless business related acronyms that WISPs should be familiar with in this space. For the new person, it can be daunting to keep track. I sent to this list 6 1/2 years ago. I though it merited a re-send, with some additions. Deeper concepts are further below. Hope it is helpful and if I missed any key ones, please add. Patrick Leary AVP, Market Development Alvarion, Inc. o: 650.314.2628 c: 760.580.0080 [EMAIL PROTECTED] -----Original Message----- From: Patrick Leary [mailto:[EMAIL PROTECTED] Sent: Thursday, January 18, 2001 8:29 PM To: [EMAIL PROTECTED] Subject: Glossary Common abbreviations and/or acronyms... 477: (Form 477) FCC's mandatory broadband reporting form for commercial operators AAA server: authentication authorization accounting server APD: automatic protocol detection AES OCB: usually just called "AES," advanced encryption standard offset code book AIFS: arbitration inter-frame spacing AP: access point ARK: automatic retransmission queing ARS: automatic rate switching ASN-GW: access service network gateway ATPC: automatic transmit power control AU: access unit (same as above) BE: best effort BER: bit error rate BRS: Broadband Radio Service (commercial side of the 2.5 GHz allocation in the US) BSS: basic service set BST: base station (referred more often this way in licensed networks) BWA: broadband wireless access BWIA: broadband wireless Internet access (Steve Stroh's preferred acronym) CBR: constant bit rate CC: convolutional coding CDL: cell distance learning (refers to an automatic process within RF devices) CDMA: code division multiple access CG (or UGS): constant grant or unsolicited grant service CIR: committed information rate CoS: class of service CPE: customer premises equipment C/I: carrier to interference ratio CSMA/CA: carrier sense multiple access/collision avoidance EBS: Educational Broadband Spectrum (2.5 GHz allocated to non-profits, may be sublet), formerly ITFS (Instructional Fixed Television Service) DFS: dynamic frequency selection DFS2 or DFS+: second generation DFS (mandated for all new 5.3 and all 5.4 GHz) DIFS: distributed coordination function inter-frame spacing) DS (or DSSS): direct sequence spread spectrum EIRP: effective isotropic radiated power (expressed in dB) EMI: electromagnetic interference ESSID: extended service set ID FCC: Federal Communications Commission FDD: frequency division duplex FEQ: forward error correction FFT: fast fourier transform mathematical algorithm FH (or FHSS): frequency hopping spread spectrum FIPS: federal information processing standards GFSK: Gausian frequency shift keying HIPPA: Healthcare Insurance Portability and Accountability Act IC: Industry Canada (Canadian peer to FCC) IDU: indoor unit IF: intermediate frequency ISM: Industrial, Scientific, and Medical LOS: Line of sight LQI: link quality indicator MAC: media access control MAN: metropolitan area network MIB: management information bit(s) MIR: maximum information rate NLOS: Near/non LOS NMS: network management system NPU: network processing unit OA&M: operation, administration & maintenance ODU: outdoor unit OET: Office of Engineering and Technology (FCC division responsible for equipment authorization and rules enforcement) OFDM: orthogonal frequency division multiplexing OFDMA: orthogonal frequency division multiple access OBE or OOBE: out-of-band emissions PAN: personal area network Part 15: refers to FCC regulations in Part 15.247 of the Federal Code governing certain UL bands PIU: power interface unit PoE: power over Ethernet PtMP or PmP: point-to-multipoint PtP: Point-to-point QAM: quadrature amplitude modulation QinQ: VLAN type that allows customer to have own VLAN inside the operator's VLAN QoS: quality of service RAN: radio access network RFI: radio frequency interference RSSI: receive(r) signal strength index/indication rtPS: real time polling services RTS/CTS: request to send, clear to send Rx: receive RTCP: real time control protocol RTP: real time protocol SCADA: supervisory control and data acquisition SDR: software defined radio SIF: short inter-frame spacing SIP: session initiation protocol SNR: signal to noise ratio SOFDMA: scalable orthogonal frequency division multiple access STC: space time coding TDD: time division duplex TDMA: time division multiple access TVoIP: TV over IP Tx: transmit UL: offen used to abbreviate "unlicensed," but also could mean "uplink" UNII: Universal Information Infrastructure VLAN: virtual LAN VoIP: voice over IP VPN: virtual private network VOFDM: vector OFDM WCS: Wireless Communications Service (2.3 GHz licensed band) WEP: wired equivalent privacy WiMAX: wireless interoperability, microwave access WLAN: wireless LAN WLL: wireless local loop Some terms... dB The dB convention is an abbreviation for decibels. It is a mathematical expression showing the relationship between two values. RF Power Level RF power level at either transmitter output or receiver input is expressed in Watts. It can also be expressed in dBm. The relation between dBm and Watts can be expressed as follows: PdBm = 10 x Log Pmw For example: 1 Watt = 1000 mW; PdBm = 10 x Log 1000 = 30 dBm 100 mW; PdBm = 10 x Log 100 = 20 dBm For link budget calculations, the dBm convention is more convenient than the Watts convention. Attenuation Loss of power, expressed in dB Attenuation is expressed in dB as follows:PdB = 10 x Log (Pout/Pin) For example: If, due to attenuation, half the power is lost (Pout/Pin = 2), attenuation in dB is 10 x Log (2) = 3dB Path Loss Path loss is the loss of power of an RF signal travelling (propagating) through space. It is expressed in dB. Path loss depends on: 1. The distance between transmitting and receiving antennas. 2. Line of sight clearance between the receiving and transmitting antennas. 3. Antenna height. Free Space Loss Attenuation of the electromagnetic wave while propagating through space. This attenuation is calculated using the following formula: Free space loss = 32.4 + 20xLog F(MHz) + 20xLog R(Km) F is the RF frequency expressed in MHz. R is the distance between the transmitting and receiving antennas. At 2.4 Ghz, this formula is: 100+20xLog R(Km) Isotropic Antenna A hypothetical, lossless antenna having equal radiation intensity in all directions. Used as a zero dB gain reference in directivity calculation (gain). The sun is often given as an example of an isotropic radiator. Gain Antenna gain is a measure of directivity. It is defined as the ratio of the radiation intensity in a given direction to the radiation intensity that would be obtained if the power accepted by the antenna was radiated equally in all directions (isotropically). Antenna gain is expressed in dBi. Radiation Pattern The radiation pattern is a graphical representation in either polar or rectangular coordinates of the spatial energy distribution of an antenna. Side Lobes The radiation lobes in any direction other than that of the main lobe. Omni-directional Antenna This antenna radiates and receives equally in all directions in azimuth. Directional Antenna This antenna radiates and receives most of the signal power in one direction. Antenna Beamwidth The directiveness of a directional antenna. Defined as the angle between two half-power (-3 dB) points on either side of the main lobe of radiation. Receiver Sensitivity The minimum RF signal power level required at the input of a receiver for certain performance (e.g. BER). EIRP (Effective Isotropic Radiated Power) The antenna transmitted power. Equal to the transmitted output power minus cable loss plus the transmitting antenna gain. EIRP = Pout - Ct + Gt Pout = Output power of transmitted in dBm Ct = Transmitter cable attenuation in dB Gt = Transmitting antenna gain in dBi Gr = Receiving antenna gain in dBi Pl = Path loss in dB Cr = Receiver cable attenuation is dB Si = Received power level at receiver input in dBm Ps = Receiver sensitivity is dBm Si = Pout - Ct + Gt - Pl + Gr - Cr Example: Link Parameters: Frequency: 2.4 Ghz Pout = 4 dBm (2.5 mW) Tx and Rx cable length (Ct and Cr) = 10 m. cable type RG214 (0.6 dB/meter) Tx and Rx antenna gain (Gt and Gr) = 18 dBi Distance between sites = 3 Km Receiver sensitivity (Ps) = -84 dBm Link Budget Calculation EIRP = Pout - Ct + Gt = 16 dBm Pl = 32.4 + 20xLog F(MHz) + 20xLog R(Km) @ 110 dB Si = EIRP - Pl + Gr - Cr = -82 dBm In conclusion, the received signal power is above the sensitivity threshold, so the link should work. The problem is that there is only a 2 dB difference between received signal power and sensitivity. Normally, a higher margin is desirable due to fluctuation in received power as a result of signal fading. Signal Fading Fading of the RF signal is caused by several factors: 1. Multipath The transmitted signal arrives at the receiver from different directions, with different path lengths, attenuation and delays. The summed signal at the receiver may result in an attenuated signal. 2. Bad Line of Sight An optical line of sight exists if an imaginary straight line can connect the antennas on either side of the link. Radio wave clear line of sight exists if a certain area around the optical line of sight (Fresnel zone) is clear of obstacles. A bad line of sight exists if the first Fresnel zone is obscured. 3. Link Budget Calculations 4. Weather conditions (Rain, wind, etc.) At high rain intensity (150 mm/hr), the fading of an RF signal at 2.4 Ghz may reach a maximum of 0.02 dB/Km. Wind may cause fading due to antenna motion. 5. Interference Interference may be caused by another system on the same frequency range, external noise, or some other co-located system. The Line of Sight Concept An optical line of sight exists if an imaginary straight line can be drawn connecting the antennas on either side of the link. Clear Line of Sight A clear line of sight exists when no physical objects obstruct viewing one antenna from the location of the other antenna. A radio wave clear line of sight exists if a defined area around the optical line of sight (Fresnel Zone)is clear of obstacles. Fresnel Zone (pronounced: fruh nell) The Fresnel zone is the area of a circle around the line of sight. The Fresnel Zone is defined as follows: R1 = ½ square root of (lxD) R: radius of the first fresnel zone l: wavelength D: distance between sites Fairness Factor The Fairness Factor enables to define the level of fairness in providing services to different SUs. When set to 100%, all SUs have the same probability of getting services when competing for bandwidth. If set to X%, then SUs located up to X% of the maximum distance from the AU will have an advantage in getting services over SUs located farther than this distance. Patrick Leary District Manager, Southeast U.S. (FL, SC, NC, GA, TN, AL, MS) BreezeCOM Wireless The global leader in broadband wireless access solutions. pcs 770.331.5849 home office 352.592.5409 efax 509.479.2374 [EMAIL PROTECTED] www.breezecom.com Pete Gonzales Inside Account Manager, Southeast U.S. 760.517.3139 fax 760.517.3200 [EMAIL PROTECTED] Archives: http://isp-lists.isp-planet.com/isp-wireless/archives/ ___________ * The ISP-WIRELESS Discussion List * ___________ To Join: mailto:[EMAIL PROTECTED] To Remove: mailto:[EMAIL PROTECTED] Archives: http://isp-lists.isp-planet.com/isp-wireless/archives/ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(84). ************************************************************************************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses. ************************************************************************************ -------------------------------------------------------------------------------- ** Join us at the WISPA Reception at 6:30 PM on October the 16th 2007 at ISPCON ** ** ISPCON Fall 2007 - October 16-18 - San Jose, CA www.ispcon.com ** ** THE INTERNET INDUSTRY EVENT ** ** FREE Exhibits and Events Pass available until August 31 ** ** Use Customer Code WSEMF7 when you register online at http://www.ispcon.com/register.php ** -------------------------------------------------------------------------------- WISPA Wants You! 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