Radio SpectrumAbstractOutlineWhat radio bands may be used?The License Free Radio Bands - Industry Scientific and Medical (ISM)- Unlicensed National Informational Infrastructure (UNII)- Unallocated bandsSo what does this all mean?What are these bands and their behaviors?Behavior, continueSlide 11Slide 12What activities are in those bands?What problems exist today?Current Problems, continueSlide 16Slide 17Slide 18Current Problems, continue:Slide 20Slide 21Slide 22PowerPoint PresentationSlide 24Slide 25Slide 26Slide 27What problems may happen tomorrow?Future Problems, continuedSlide 30Is there an answer?Answer, continuedSlide 33What now? The end or the beginning.Questions? Comments? Feedback?Added materialRadio SpectrumThe Achilles’ Heel of Wireless ComputingFred L. StricklandCOMP 7970 Persuasive ComputingFall 2002Directed by Dr Richard Chapman Auburn University, Auburn AlabamaAbstractWireless devices are everywhere.Communicate while movingWork outside of the deskAre there any draw backs?OutlineWhat radio bands may be used?What are the behaviors of these bands?What are in those bands?What problems exist today?What problems may happen tomorrow?Is there an answer?What radio bands may be used?Wireless devices are really radios.The License Free Radio Bands - Industry Scientific and Medical (ISM)6,765-7,000 kHz (HF)13,410-13,570 kHz (HF)26,950-27,410 kHz (HF)40-40.98 MHz (VHF)902-928 MHz (UHF)2.450-2.500 GHz (UHF)5.650-5.925 GHz (SHF)24.000-24.250 GHz (SHF)59.00-64.00 GHz (EHF)120.02-126.00 GHz (EHF)241.00-248.00 GHz (EHF)- Unlicensed National Informational Infrastructure (UNII)5.1250-5.2500 GHz (SHF)5.2500-5.3500 GHz (SHF)5.5250-5.8250 GHz (SHF)- Unallocated bandsBelow 9 kHzAbove 400 GHz (EHF)So what does this all mean?–What are these bands and their behaviors?ELF(Extremely Low Frequency): 30 to 300 Hz300 to 3,000 HzVLF (Very Low frequency): 3,000 Hz or 3 kHz to 30 kHz)LF (Low Frequency): 30 to 300 kHzBehavior, continueMF (Medium Frequency)300 to 3,000 kHzHF (High Frequency)3,000 kHz to 30,000 kHz Or3 to 30 MHzBehavior, continueVHF (Very High Frequency)30 to 300 MHzFM Broadcast band (88 to 108) FM Broadcast bandAir Traffic Control (108 to 138)Television (begins here)UHF (Ultra High Frequency)300 to 3,000 MHzSame as above, plus radar.Behavior, continueSHF (Super High Frequency)3,000 to 30,000 MHzOR3 to 30 GHzEHF (Extremely High Frequency)30 to 300 GHzWhat activities are in those bands?What problems exist today?In generalWhat will the FCC do?Between a licensed user and a non-licensed user: The non-licensed user must Reduce powerChange operationsShut downBetween two or more non-licensed usersFor the most part, the FCC does not oversee the conflict.Current Problems, continueDo systems co-exist peacefully?Current Problems, continueRadars and the Dedicated Short-Range Communication (DSRC) SystemThe DSRC could live near a radar with 1 meter separation and the right combination of frequency usage and antennas.If the DSRC was on the same frequency with a regular antenna, then it would need 7.1 kilometers of separation!Guess what band these systems operate in?Guess what is the placement of these systems?Current Problems, continueCordless telephonesOperate in900 MHz2.4 GHz5.8 GHzCurrent Problems, continueCordless telephones do cause interference to other wireless devices:To baby monitorsTo headphonesTo audio productsTo video productsCordless telephones do receive interference from other devices, such asMicrowave ovensWireless computer networksAnd other devices operating in the 2.4 GHz bandCurrent Problems, continue: In the context of wireless computer users, how well do these wireless computer devices work?Bandwidth or data rateTransmission rangeStill need wires to somewhereLimited support to wireless usersPerformanceSecurityCurrent Problems, continueBandwidth or data rateIEEE 802.11a6 to 54 Megabits per second in the 5 GHz bandIEEE 802.11b2 to 11 Megabits per second in the 2.8 GHz bandCurrent Problems, continueTransmission rangeIEEE 801.11a15 feet for 54 Megabits per secondLower the rate and the distance increasesIEEE 801.11bRoughly 300 feetThick concrete walls will cut down the range even more or stop it completely.Current Problems, continueThe cord cannot be completed cut.Access points are needed.Wires must run from each access point device to a network hub, bridge, or router.Running wires has it challenges too.Roughly, how many access points does Dartmouth College use to cover the campus?Over 500 access points!Current Problems, continueHow many users?IEEE 802.11a can support 8 channelsIEEE 802.11b can support 3 channelsHard to tellHow many users can a single access point support?How many access points can you have in a large lecture hall?Current Problems, continueAnother weakness is the area of performance.Wireless connections will never approach the reliability and performance of wired networks.Wireless connections are subject to noise, weak signals, and other communications problems.The current best data rate is below the best telephone modem rate of 56 kilobits per second.Current Problems, continueThe point is security.Not on par with wired security systems.Some system administrators turn it off.Dartmouth College did this so that any one on campus could access the network.Once a signal is in the air, anyone can listen to it.What problems may happen tomorrow?The demands for more radio spectrum keeps growing. A 1995 study* determined that 204 MHz of bandwidth (radio spectrum) is needed for new...Cellular usersPersonal communications servicesMobile satellitesIntelligent transportation system sectors*NTIA Report 98-349: A Technological Rational to Use Higher Wireless Frequencies, February 1998Future Problems, continuedSome want to increase the 5 GHz band.Some want 5.470-5.725 GHz.This band is important to the Department of Defense.High power radars and low power wireless computer devices cannot live togetherFuture Problems, continuedAs more devices appear in an area, then the overall throughput will decrease.IEEE 802.11a and IEEE 802.11b are still evolvingSome companies (Intel and