Customer center

We are a boutique essay service, not a mass production custom writing factory. Let us create a perfect paper for you today!

Example research essay topic: Division Multiple Access Spread Spectrum - 4,863 words

NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service.
One click instant price quote

Wireless Technology applied to Computer ProcessinAbstrac Wireless technology can provide many benefits to computing including faster response to queries, reduced time spent on paperwork, increased online time for users, just-in-time and real time control, tighter communications between clients and hosts. Wireless Computing is governed by two general forces: Technology, which provides a set of basic building blocks and User Applications, which determine a set of operations that must be carried out efficiently on demand. This paper summarizes technological changes that are underway and describes their impact on wireless computing development and implementation. It also describes the applications that influence the development and implementation of wireless computing and shows what current systems offer 1 IntroductioWireless computing is the topic of much conversation today.

The concept has been around for some time now but has been mainly utilizing communication protocols that exist for voice based communication. It is not intended to replace wired data communication but instead to be utilized in areas that it would be otherwise impossible to communicate using wires. Only recently has the industry been taking steps to formulate a standard that is more suitable to data transmission. Some the problems to be overcome are Data Integrity relatively error free transmission Speed as close as possible to the speed of current wired networks Protection making sure that the data now airborne is encoded and cannot be tapped b unwelcome receivers (4) Compatibility ensuring that the many protocols that sure to be created subscribe to a standard to allow inter-operability (5) Environmentally safe strengths of electromagnetic radiation must be kept within normal levels In our study of the theories and implementation concerns of wireless computing, we found that it irving treated in an object oriented fashion.

Scientists and development crews, including the IEEE, adding their best to implement wireless connectivity without changing the existing computer hardware As a result, a lot of focus is on using existing computer hardware and software to convert data t format compatible with the new hardware which will be added to the computer using ports or PCMCIconnections that already exist. This means that wireless communication will be transparent to the use and when wireless computing is utilized on a wide scale Wireless computing applications covers three broad areas of computing today. Replacement of norma wired LAN? s need to retain the speed and reliability found in wired LAN? s. Creation of semipermanenLAN?

s for quick and easy setup without the need for running wires. This would be necessary for event such as earthquakes. The last category is that of mobile computing. With advent of PCMCIA cards, notebook computers are being substituted for regular desktop machines with complete connectivity of the desktop machine. However, you lose the connectivity when out of the office unless you have a wireless means of communicating On the compatibility issue, the ability to mix wireless brands on a single network is not likely to common.

The IEEE Standards Committee is working on a wireless LAN standard 802. 11, which is a extension of the Ethernet protocol. Because the field of wireless communication is so broad, the IEE was not able to set a standard by the time private researchers were ready to test their theories hoping tset the standard for others to follow 2 Method There are a few methods of wireless communication being theorized and tested Radio: This is the method that makes use of standard radio waves in the 902 MHz to 928 MH frequency range. Although these frequencies are well used, methods have been developed tenure data integrity. Spread spectrum transmission of data is a method where the transmittewill send information simultaneously out over many frequencies in the range increasing th change that all data will eventually reach the receiver. Frequency hopping is an additionameasure that also enables data security. The 26 MHz range of frequencies is further divided ito channels.

The transmitter then sends out data hopping from one channel to the next i certain pattern known to the receiver. Within each channel, spread spectrum transmission cabe used to maintain interference avoidance. Some of this transmission manipulation can b avoided by transmitting at a frequency that is less used. Some developers have trie transmitting in the gigahertz range. The disadvantages here are: 1) Higher frequencies mea shorter wavelengths and shorter wavelengths do not penetrate solid objects like walls and floors The same transmission strength employed by lower wavelength transmitters yields a shorter range at higher frequencies. This means that transmission strength will need to be boosted something hard to accomplish using portable tools and potentially dangerous to humans; 3) Transmission frequencies of 3 GHz and higher are licensed by the Federal Communications Commission.

Developers in the range have the additional hassle of obtaining a license every time an installation is done (2) Laser: Laser-based communication is the fastest way to communicate without wires Information travels at the speed of light. The drawbacks however far outweigh the speed advantage and prevent this method from becoming the standard. The major drawback is that communication is restricted to line of sight. Also, very thick fog or blizzard conditions will diffuse the laser beam and causing interference and reducing data integrity (3) Infrared: This method is similar to Laser.

High speed communications are easy to achieve using this method. However, it suffers from the same problems that plague laser communications. It requires line of sight transmission and can be disrupted by strong ambient light. Infrared wireless computing exists more commonly in the form of peripheral connections in a small area (4) Cellular connections although expensive to use now is the area of much development by privat companies. Cellular computing can be likened to the current wire-based internet network. Dat is packaged in to units, size of the unit is dependent on the actual hardware, and is sent to th nearest participating cell.

That cell then forwards the packet to the next cell and so forth until the packet reaches its destination (5) Microwave: This method of communication has been utilized for quite some time now However this method has makes little provision for data aware transmission. It used extensively in Europe where wired transmission of any type including voice is poor. For data transmission, a lot of technology is utilized in packaging the data into a form that is compatible to voice communication. On the receiving end, the process is reversed. The advantage of this method however is that communication can be accomplished using existing satellite connections making worldwide connectivity possibleStandardThe IEEE 802. 11 committee has voted to create a minimum requirement for wireless computing connections. In their consideration Use the frequencies 2. 4 to 2. 5 GHz.

This is in the low end of the high frequency spectrum an is currently not licensed by the FCC (2) Use spread spectrum technology. Compared to the current bandwidth 26 MHz, 902 MHz t 928 MHz, the range 2. 4 to 2. 5 GHz yields a bandwidth of 100 MHZ. Spread spectrum transmission now gives 385 % percent increase in data reliability (3) Many more sub-channels can be formed in a bandwidth of 100 MHZ. This increases th capability of frequency hopping which in turn yields greater data security (4) Utilize Gaussian Frequency Shift-Keying. Frequency shift-keying is a form of frequency modulation in which binary signaling is accomplished by using two frequencies separated become Df Hz.

The frequency duration is small compared with the carrier frequency, fc. A signa received at frequency fc, would represent a digital low and signals received at frequency fc + Df would represent a digital high. Note that this does not interfere with spread spectrum or frequency hopping capabilities since those function on frequencies separated by 1 MHz or more As part of setting a wireless standard some modifications of the standard set by the IEEE 80 committee have been adopted. The most significant of these is the modification to the carrier sens multiple access / collision detection, or CSMA/CD, protocol used in wired networks today. This i method whereby any machine at any time, wishing to send a message on the net, will first send a takeout to ensure that a carrier exists (network ready). After establishing this, the message will be sent Because any machine may send at any time, collisions of information will occur.

If any machine detect collision, it will send out a jamming signal to all the others. All machines will then wait on a rando interval timer after which they will try to send again For wireless networks however, since a machine is not in constant communication with the rest of th LAN, detecting a collision and notifying all other machines on the net is impossible. A modification the way of the collision handling had to be made. A method known as collision avoidance implored to create th CSMA/CA standard.

I collision avoidance strategy, the estimates the average time collisions and sen jamming signal at that time wireless transceiver will noon sense a carrier but will als listen out for the jammin signal. When all is clear it then send its message. This collision avoidance method has two drawbacks 1) It cannot completely filter all collisions since it operates on estimated times of collisions; 2) and iit did, it slows the network significantly by sending jamming signals whether or not a collision actualloccurs 4 Physical LayeMuch of the focus of wireless computing development is centered on the physical and media acces control layers of a system. It is on this level of the LAN protocol of which wireless products lik modems and transceiver On the physical layer issue, the 802. 11 is focusing on the one proposed by Apple Computer Corporation The Apple physical-layer protocol appears the most robust of any considered to date in 802. 11.

Apple? system is a full-duplex, slow frequency-hopping protocol. By using a frequency-hop spread-spectrum radio, the system fits with the spread-spectrum methods of virtually all 802. 11 specifications Apple splits the data-transport protocol into two layers? The RF Adoption Layer is similar in some respects to cell-based data protocols, such as Asynchronous Transfer Mode and IEEE 802. 6 Switched Multi megabit Data Services; like ATM and 802. 6, the RF Adoption Layer includes segmentation / reassembly functions and Protocol Data Unit generation functions, and it also includes Forward Error Correction (FEC) generation and verificatiofunctions which substantially increase packet integrity in wireless environments but adds FEC overhead? The RF Hopping Protocol Physical Layer consists of a transmission convergence sub layer including header generation, RF framing, and RF hopping protocol functions and the physical- medium-dependent sub layer, in which the actual characteristics of the RF channel are handled In the RF Adoption Layer, a Protocol Data Unit is split into three segments, and two error-correctindata units are added.

The RF Hopping segments, and two error-correcting data units are added. The RHopping Physical Layer builds special Burst Protocol Data Units out of the data and FEC units and use carrier-sense methods borrowed from Ethernet to determine whether an RF Hop Group is clear fo transmission. Each hop group consists of five separate radio channels. The controller scans hop group via state-machine operation with four states: scan, receive, carrier-sense, and transmit. In early tests a Apple, the hop system showed 80 -microsecond hop times, 57 -microsecond clock recovery, an 5 -microsecond lapse between the time an empty channel is sensed and transmission begins. Since eac cluster of wireless LANs can use different hop groups, multiple LANs could operate in the same are without interference.

One concern is whether the overhead for error correction for each packet, wiccan be as much as 50 % is too high to give the proposal a chance The safety of those operating new equipment now plays a larger role in determining the direction of technological growth now more that ever. Factors under consideration are the effect of infrared and strong electromagnetic radiation that would pervade the workplace on the workers. This limits the strength of and communication device that would be used in accomplishing transmission For the Personal Computer. The adapters have a small attached antenna through which they send an receive network traffic as radio signals. Some wireless products are small boxes that attach to your PC? parallel port.

In either case, the signals may travel from PC to PC, forming a wireless peer-to-peer network, or they may travel to a network server equipped with both wireless and standard Ethernet adapters, providing notebook users a portable connection to the corporate network. In either case, wireless LANs can either replace or extend wired networks Standards are lacking. Wireless networking is still a technology looking for a standard, which is where few wireless products can work with one another. Each vendor uses a different protocol, radi frequency, or signaling technology. If wired networks still operated like wireless, you would have the the same brand of network interface card throughout your network. Right now you are, for the mozart, tied to whichever brand of wireless LAN you pick.

Most of the products in this comparison liste their wireless protocol as Ethernet carrier sense multiple access / collision avoidance (CSMA/CA), a variation of standard Ethernet. Unfortunately, each vendor has put its own spin on CSMA/CA, which means even their protocols are incompatible 5 Wireless service As technology progresses toward smaller, lighter, faster, lower power hardware components, mor computers will become more and more mobile. For space concerns this paper will exclude any furthediscussion of the hardware developments toward mobility except for devices directly related to wireles connectivity such as modems wireless computer is not connected via a wireline and thus has mobility and convenience. A wireles LAN provides the convenience of eliminating the wires, yet is not necessarily mobile (What is mobility? Mobility is a characteristic where the wireless computer may connect, loose the physica communication (possibly due to interference) and reconnect (possibly to another sub-network) and retain its virtual connections and continue to operate its applications. Th network protocols will be discussed later (Then, what is portable?

Portable is defined that the wireless computer may connect, loose the connection and then re-connect, as well. However, the mobile unit will have to restart if it is reconnected to another sub-network, requiring that running processes be shut-down and windows closed Mobility may be limited by the wireless service subscribed. Four basic service zones are described Global/National service zone: Ubiquitous radio coverage throughout a region, country or then tire globe, low user densities, and minimal bandwidth requirements. Typically satellite systems Mobile service zone: Radio coverage in urban, suburban and populated rural areas medium to high user densities, low to medium bandwidtrequirements (tens of Kbps), and high vehicular speed. Cellular (AMPS) system is a good example Local / micro service zone: Radio coverage in densely populated urban areas, shoppinmalls, and transportation centers. High endured densities medium bandwidth requirements, hand-held portable terminals low-speed mobility Indoor / pica service zone: in-building radio coverage, low to high user densities, medium high bandwidth requirements (Mbps), very low mobility Prior to the cellular phone network, base station radio covering a single cell geographic area with a fixe number of channels was the only service available The cellular phone service divides the service area into cells and assigns a subset of the availablchannels to any given cell.

This way the channels can be reused and interference from neighboring cells reduced. The system tracks the active mobile unit, delivers calls, and maintains connections as unit move between cells (Hand-off: a realtime transfer of a call between radio channels in different cells). This system is called Advanced Mobile Phone Service (AMPS). Current cellular systems use analog FM technology. However, implementation of digital radio technology is being deployed now. These systems utilize Time Division Multiple Access (TDMA) or Code Division Multiple Access (CDMAto increase throughput up to ten times the previous analog system.

Additionally, end users will acces wider range of telecommunications as the implementation of integrated services digital networ (ISDN) principles are utilized. Personal Communication Services, similar to the current cellular system will soon be available from the larger telecommunication services, but with reduced price and wider availabilityWirelesAdvantageLimitationTraditional Cellular no restrictions on length type of dattransmissionational coveragbill by minutpotential lininterruptionscongestions in urbaarealimited throughpuCDP enhanced technolog for data over cellulabill by message siz integrated voice andatpacket switching erro correction technique lack of applicationdevelopmennot fully develope Dedicated packet switchemobile network integrated application and communications call setup tim inherent reliability an security of packeswitchincoverage not fulnationwidlimited packet siz require specializemodemdata onl Specialized mobile radi voice and dat vehicle base limited coveragSatellite-enabled network geographic reac expensive equipmenand service cost The application of the wireless computing system determines the type of wireless medium system to b employed. Circuit switched or packet switched, both are available through wireless technology an provide connectivity. Circuit switched systems provide a continuous connection established to th destination by the switching system. The most popular examples are the wireline public switchetelephone network (PSTN) and cellular telephones systems. This method of communication can b relatively expensive.

If the phone systems offers voice grade bandwidth, then a standard modem ca provide speed of 14. 4 Kbps (at the time of this writing). However, if a digital line is provided the higher communication rates can be achieved with more specialized equipment Packet switched systems provide a delivery system of information packets. The packet contains the data an address to the destination. Packet switching is far less expensive than circuit switching. Examples would be RAM, ARDIS, and Internet networks. Packet radio networks have been the target of many studies since the military has a vested interest in the communication medium.

Concerns such as reliability, throughput optimization and re-routing of packets have been recent topics Packet SwitcheSystemARDIRAM MobilDatCircuit Cellula CDP NetworCapacit 1, 300 bas stations i approx. 32 metro servic area (MSA 840 base station 210 MSA 8, 000 cell site 734 metrareapotentially entircellular networ Coverage (citibank towns 10, 70 6, 30 NN Transmissiospee 4. 8 Kbps 19. 2 Kbp upgrade in manometry area 8 Kbp 38. 4 Kbps t 56 Kbp 19. 2 Kbp Messagcapacit 256 byte 512 byte N 114 byte Nationaroamincompleted bid Sept 9 yen In-buildincoveragyetop 20 MSAs b June 199 limitelimiteCellular Digital Packet Data technology (CDPDutilizes the space between the voice segments o cellular (AMPS) network channels and insert data packet. The user pays only for the packesent as opposed to a cellular circuit switcheconnection. CDPD cellular communication systems such as the Ubiquity 1000 from PCSIoffer packet burst rate of 19. 2 Kbps with ful duplex. This CDPD modem offers the option the circuit switched cellular, wireline PSTN advice support. However, in a large urban are with thousands of stations using any packeswitching service at current speeds, delay may b unacceptable Satellite can be used as long distance links withiwireless networks. Three major projects haven proposed.

The Teledesic system, composed 840 low orbit satellites, was proposed by Bil Gates (Microsoft) and Craig McCaw (McCaCellular). Second, the Pentagon, solicitesystem, using 1, 000 smaller satellites, from TRW and Martin Marietta. Both the Teledesic and th Pentagon systems cost around $ 9 billion. The third system, called Iridium, from Motorola, will use 6 satellites to offer mobile phone service all over the globe.

This project will begin this year and the resin place by 199 6 Softwar Software concerns in a wireless computing environment can be broken into two areas, system and application 7 System Softwar Network operating systems must be able to handle the uniqueness of a wireless computer. Advance operating systems utilizing distributed technology must be adapted to the specific communicatiomedia. The advancement of technology has provided that even mobile computer systems the size o notebooks are capable of internetworking as a host in global networks. Mobile host protocol compatible with TPC/IP have been developed to allow continuous network connectivity where ever those may be. Due to the unpredictable nature of wireless connections, even operating systems may have be written to provide support services for mobile network. The WIN OS, a micro kernel for a wireless-compatible operating system, was developed to support concurrent and comparable objects and coordinated communication among groups of objects through a process of agreements 8 Application Softwar Application software concerns in the wireless computing environment vary depending on the type o application and wireless medium used.

For example, E-mail software must know how to communicatwith the packet switched network as compared to the traditional cellular network. Software develope kits (SDK) and application programmers interfaces (API) are usually available by the service provider Remote access software allows the remote user to connect to a host workstation to view the screen an control the keyboard as if the user was there. The data does not have to be communicated to the remoter and thus allows processing locally. Carbon copy and PC anywhere are among the programs which provide remote access for microcomputers.

High baud rate is needed especially when a graphical user interface (GUI) is used 9 Wireless Local Area Networks (WLANWLAN offers the same features as a wireline LAN but without the wires. Coverage can range from a room to a building to a campus (wide-spread, multi-building). Both stationary desktop systems and mobile notebook computers can connect using specialized wireless LAN adapter cards. Another configuration allows wireless additions to current networks. Wireless Hubs have been developed which bridge the wireless units into the wireline network As mentioned before, during the recent natura disasters in California, the Federal EmergencManagement Agency (FEMA) set up field office with WLAN very quickly.

Here is a great example how WLAN can be used: An ETHERNEconnection over a radio link provided data follow-power PC in a buoy to a PC on a ship. Th system provided a megabyte / sec data rate for fridays while guaranteeing error-free delivery omaha. Even more incredible is the MBARacoustic LAN. Since under water, radio wave travel only a few feet but sound waves can traveler miles, the acoustic LAN uses the better carried wireless data signals.

The acoustic LAN hat 5 Kbps data channels and two slow-spee command channels. The LAN is used t communicate with tilt meters and buoys Personal Data Assistants (PDA) are the new handheld computers which also have wireless options. Using a pen-based GUI operating system, the applications are accessed from local storage. Fax, data and voice can be transferred to and from the PDA via cellular phone system. The AT&# 038; T EO can run a program called Gnosis which when also loaded on a remote server host will allow the user to search for documents and have them downloaded in minutes including graphics Even though all these nifty devices such as radi modems and PDAs are developed and marketed recent study of mobile professionals shows tha currently relatively few spend time far from thei desks. In fact, only 13 percent of mobile user spend time outside their metro area and jus percent outside the country.

As the technolog becomes more common place, more users willing themselves moving further out of their wire areas and into the wireless field 10 Security Security becomes essential in wireles computing. Especially since the data i broadcast to the receiving unit. Internationa Standards Organization (ISO) has publishesecurity services which provide for secure data computer systems on standard wirelinnetworks. However, these must be modified t meet the needs of mobile users and systems.

Data encryption and Two possible solutions include exchanging security information between a small number of entities, or even more complex involving an information center Infrared offers the least problem of security due fact that stations must be in the line-of-sight and th limited area of coverage, usually one room. Spread spectrum RF transmissions spread the data orange of frequencies making interception extremely difficult. Also, low power limits the coverage area although the signal will penetrate walls. Cellular phone networks offer no security of their own.

Eve though listening to these transmissions has been made unlawful, the signals can be overheard by a radi scanner. Data encryption is left up to the connecting unit. Packet radio offers inherent data security b scrambling the data packets Clipper chip will replace the digital encryption standard (DES). The Clipper chip boasts to be 1 million times stronger with 80 -bits as compared to the old DES, which has a 56 -bit binary key. Thich ip will be used in many communication products, especially wireless. The Department of Justice anAT&# 038; T will be installing them in their telephone products.

The controversy about these chips stems frothy fact that they are programmed with a back door. The government can, with a court order, access the chip and monitor the communication 11 Conclusio In the relatively short time of the Information Revolution, the world has seen several technologies, firs introduced as convenient, become essential the basic structure of the modern lifestyle. Th automobile, telephone, and the refrigerator are easy examples to cite. The wireless revolution wil transform another convenience to a necessity. Emerging wireless systems will provide the technology allow people and machines to communicate anytime, anywhere, using voice, data an messaging services through telecommunications. The wireless revolution began with the introduction the cellular phone networks.

This coupled along with the reduction in size of the microcomputer anan increase in the applicable technologies After surveying the many aspects of wireless computing, several areas stand-out and apparently requirfurther research and development. Among those are mobile internetworking protocols, which woulallow a mobile host to connect to any part of the network. Mobile aware operating systems woulfurther allow more features catering to mobile users. Features such as built-in APIs in the OS kerne available for specific applications which would provide services pertaining to suspend / resume and storage forward operations. Standardized mobile networking protocol will allow interoperability betweeopen wireless systems. Advanced signal processing and speech coding techniques will allow mor efficient use of bandwidth and data transfer speed.

Security research at all levels will continue to remain issue and must stay one step ahead of the criminal elements. All of these areas will help to brin about the wireless computing revolution 12 About the author Christopher xxxx Christopher xxx is a first year Computer Science graduate student of Florida International University. He is also an operations systems analyst for xxxx xxxx xxxx xxxx xxxxxxxxxxx xxx of Florida where he participates in the implementation of a DB 2 /Client-Server operating system. He graduated with a Bachelors in Computer Science from FIU in 1992. His current interests in research include mobile computing and visual object oriented programming David R. Xxxxxxxx David R.

xxxxxxxxx is currently a Master? s degree candidate at Florida International University where he originally graduated with a Bachelors degree in Computer Science in 1986. He also designed curriculum and taught lower and upper division computer classes for the School of Computer Science at FIU. For six years he has been employed at xxx xxxx xxx as Accounting/Informations systems manager. He is an avid user of mobile computers and advanced technology 13 Reference CDPD The future of cellular data communications, PCSI, Inc. , San Diego, CA, November 199 Infrastructure in the sky, The Economist, March 26, 199 Money Goin?

Out, The Economist, March 5, 199 Wireless standards firm up at IEEE meeting, The Local Netter, Vol 13, No 9, 199 Badrinath, Acharya, Imielinski, Impact of Mobility on Distributed Computations, ACM Operating Systems Review, Vol 27, No. 2, April 199 Bank, D. , and Bauchot, F, Wireless LAN Design Alternatives, IEEE Network, Vol 8, No 2, March/April 199 Bhattacharjya, P. , A micro kernal for mobile networks, Wireless Communications, April 199 Buchholz, D. , Wireless in-building network architecture and protocols, Supercomm/ICC? 92, Chicago, Il, June 199 Cohen, Raines, Movie users are not as far away as you might think, study shows, Mac Week, Vol 8, No 3, January 199 Code, T. , Cutting the Cord, Infoworld, Vol 15, No 40, October 199 Directions in Mobile/Wireless Computing, September 199 Directions in Mobile/Wireless Computing, July 199 Hagen, R. , Security requirements and their realization in mobile networks. , International Switching Symposium 1992 Proceedings, Yokohama, Japan, October 199 Hu, L. , Topology Control for Multi hop Packet Radio Networks, IEEE Transactions on Communications, Vol 41, No 10, October 199 Inglis, A. , Electronic Communication Handbook, McGraw Hill, NY, 199 McMullen, Melanie, The amazing aqua LAN, LAN Magazine, V 9, No 2, February 199 Mobile Office, April 199 Myles, A. and Seller, D. , Comparing four IP based mobile host protocols, Computer Networks and ISDN Systems, Vol 26, No. 3, November 199 Park, D. , and Un, C. , Performance of the prioritized random token protocol for high speed radio networks, IEEE Transactions on Communications, Vol 41, No 6, June 199 Perkins, C. , Providing continuous network access to mobile hosts using TCP/IP, Computer Networks and ISDN Systems, Vol 26, No. 3, November 199 Polling, G. and Haas, Z, E-BAMA vs. RAMA, IEEE Network, Vol 8, No 2, March/April 199 Steenstrup, M. , Editorial, IEEE Network, Vol 8, No 2, March/April 199 Tanenbaum, A, Computer Networks, Prentice-Hall, N. J. , 198 von der Head, K. , Kemp, J. , Barents Sea shallow water tomography, Sea Technology, Vol 34, No 8, August 199 Wang, J, Maximum Number of Independent Paths and Radio Connectivity, IEEE Transactions on Communications, Vol 41, No 10, October 19914 Endnotes


Free research essays on topics related to: electromagnetic radiation, circuit switched, division multiple access, frequency hopping, spread spectrum

Research essay sample on Division Multiple Access Spread Spectrum

Writing service prices per page

  • $18.85 - in 14 days
  • $19.95 - in 3 days
  • $23.95 - within 48 hours
  • $26.95 - within 24 hours
  • $29.95 - within 12 hours
  • $34.95 - within 6 hours
  • $39.95 - within 3 hours
  • Calculate total price

Our guarantee

  • 100% money back guarantee
  • plagiarism-free authentic works
  • completely confidential service
  • timely revisions until completely satisfied
  • 24/7 customer support
  • payments protected by PayPal

Secure payment

With EssayChief you get

  • Strict plagiarism detection regulations
  • 300+ words per page
  • Times New Roman font 12 pts, double-spaced
  • FREE abstract, outline, bibliography
  • Money back guarantee for missed deadline
  • Round-the-clock customer support
  • Complete anonymity of all our clients
  • Custom essays
  • Writing service

EssayChief can handle your

  • essays, term papers
  • book and movie reports
  • Power Point presentations
  • annotated bibliographies
  • theses, dissertations
  • exam preparations
  • editing and proofreading of your texts
  • academic ghostwriting of any kind

Free essay samples

Browse essays by topic:

Stay with EssayChief! We offer 10% discount to all our return customers. Once you place your order you will receive an email with the password. You can use this password for unlimited period and you can share it with your friends!

Academic ghostwriting

About us

© 2002-2024 EssayChief.com