Wireless Communication (ug)

 



Table of Contents

  1. Wireless Communication Technology
  2. Wireless Communications Greenville
  3. Wireless Communications Greenville Sc
  4. Wireless Communications Group
  5. Wireless Communication Guglielmo Marconi 1896
  6. Wireless Communication Goldsmith

In recent days, the wireless communication technology has become an integral part of several types of communication devices as it allows users to communicate even from remote areas. The devices used for wireless communication are cordless telephones, mobiles, GPS units, ZigBee technology, wireless computer parts, and satellite television, etc. There are a number of systems of communication in Uganda, including a system of telephony, radio and television broadcasts, internet, mail, and several newspapers. The use of phones and the internet in Uganda has rapidly increased in the last few years. Wireless communication (or just wireless, when the context allows) is the electromagnetic transfer of information between two or more points that do not use an electrical conductor as a medium by which to perform the transfer. The most common wireless technologies use radio waves.

Wireless Communication -The transmission of information signals without a physical connection, through technologies such as cordless telephones, cellular telephones or microwave is also defined as the transfer of electromagnetic signals from one location to another without cables, often using infrared light or radio waves. Communication that takes place via airwaves as opposed to cables or telephone lines is known as Wireless Communication.
Wireless means transmitting signals over invisible radio waves instead of wires. Garage door openers and television remote controls were the first wireless devices to become a part of everyday life. Now the cordless keyboard & mouse, PDAs and digital, cellular phones’ are commonplace.
The future of wireless lies in faster, more reliable methods of transferring data and to a increased use of voice commands and audio improvements. A laptop is a mobile device if you had a inclination to carry it around with you. A wireless device has some sort of network connectivity. A cell phone is wireless and a laptop or PDA would be wireless if they had a wireless modem. Similarly an application are wireless when they connect and exchange data with a network.

Wireless Communication – Types

Wireless can be divided into following categories:
Fixed Wireless:
The operation of wireless devices or systems in fixed locations, such as homes and offices comes under fixed wireless is known as Fixed Wireless. A example would be equipment connected to the Internet via specialized modems.
Mobile Wireless:
The use of wireless devices or systems in motorized and moving vehicles comes under mobile wireless such as automotive cell phone and personal communication services.
Portable Wireless:
The operation of autonomous, battery powered wireless devices or systems outside the office, home or vehicle comes under portable Wireless. Example: Handheld cell phones.
IR Wireless:
The use of devices that convey data via infrared radiation comes under IR wireless. Example: portable wireless devices that derive their power from batteries.

Evolution – Mobile Generation

Mobile Generation – 1G

1G:

  • 1G is short for first-generation wireless telephone technology, cell phones. These are the analog cellphone standards that were introduced in the 1980s and continued until being replaced by 2G digital cellphones. The main difference between two succeeding mobile telephone systems, 1G and 2G, is that the radio signals that 1G networks use are analog, while 2G networks are digital.
  • Example: AMPS (Advanced Mobile Phone System)

2G:

  • 2G is short for second-generation wireless telephone technology. 2G networks are digital.
  • Using digital signals between the handsets and the towers increases system capacity in two key ways:
  • Digital voice data can be compressed and multiplexed much more effectively than analog voice encodings through the use of various Codec’s, allowing more calls to be packed into the same amount of radio bandwidth.
  • The digital systems were designed to emit less radio power from the handsets. This meant that cells could be smaller, so more cells could be placed in the same amount of space. This was also made possible by cell towers and related equipment getting less expensive.


Advantages:

  • Digital systems were embraced by consumers for several reasons:
  • The lower powered radio signals require less battery power, so phones last much longer between charges, and batteries can be smaller.
  • The digital voice encoding allowed digital error checking which could increase sound quality by reducing dynamic and lowering the noise floor.
  • The lower power emissions helped address health concerns.
  • Going all-digital allowed for the introduction of digital data services, such as SMS and email.


Disadvantages:

  • The downsides of 2G systems, not often well publicized, are:
  • In less populous areas, the weaker digital signal will not be sufficient to reach a cell tower.
  • Analog has a smooth decay curve, digital a jagged steppy one. This can be both an advantage and a disadvantage. Under good conditions, digital will sound better. Under slightly worse conditions, analog will experience static, while digital has occasional dropouts. As conditions worsen, though, digital will start to completely fail, by dropping calls or being unintelligible, while analog slowly gets worse, generally holding a call longer and allowing at least a few words to get through.
  • With analog systems it was possible to have two or more “cloned” handsets that had the same phone number. This was widely abused for fraudulent purposes. It was, however, of great advantage in many legitimate situations. One could have a backup handset in case of damage or loss, a permanently installed handset in a car or remote workshop, and so on. With digital systems, this is no longer possible, unless the two handsets are never turned on simultaneously.
  • While digital calls tend to be free of static and background noise, the lossy compression used by the CODECs takes a toll; the range of sound that they convey is reduced. You’ll hear less of the tonality of someone’s voice talking on a digital cellphone, but you will hear it more clearly.
  • Example: GSM (Global System for Mobile communications)

3G :

  • 3G is the third generation of mobile phone standards and technology, superseding 2G. The most significant feature of 3G mobile technology is that it supports greater numbers of voice and data customers — especially in urban areas — and higher data rates at lower incremental cost than 2G. It also allows the transmission of 384 kbit/s for mobile systems and 2 Mb/s for stationary systems. As of 2005, the evolution of the 3G networks was on its way for a couple of years, due to the limited capacity of the existing 2G networks. 2G networks were built mainly for voice data and slow transmission. Due to rapid changes in user expectation, they do not meet today’s wireless needs.
  • 2.5 G are technologies such as i-mode data services, camera phones, high-speed circuit-switched data (HSCSD) and General packet radio service (GPRS) were created to provide some functionality domains like 3G networks, but without the full transition to 3G network. They were built to introduce the possibilities of wireless application technology to the end consumers, and so increase demand for 3G services.
  • Example: UMTS (Universal Mobile Telecommunications System)


4G :

  • 4G is the fourth generation of mobile phone mobile communications standards. It is a successor of the third generation (3G) standards. A 4G system provides mobile ultra-broadband Internet access, for example to laptops with USB wireless modems, to smartphones, and to other mobile devices. Conceivable applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing and 3D television.

Table of Contents of this Web Site

Welcome to this website on the fundamentals of Wireless Communication. The contents are arranged according to subject:

  • Analog electronics and RF front ends
  • Further reading
  • Audio, streaming, podcasts

This web site has been created by Jean-Paul Linnartz.

The tutorial on wireless communication systems, as presented on this web site is now available as open source. Previously, the contents have been developed for lectures and short various courses, mostly in the period 1995-2001. I apologize for some material that may have become a bit outdated in this rapidly developing field. Nonetheless I hope that the material can be useful for your studies. I would greatly appreciate it if you can personally help me in updating and extending this web site. In particular, I encourage PhD students to submit portions of their introductory, overview chapters and literature surveys for inclusion as new web pages. All copyrights reside with the respective authors of the pages.

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Network Concepts and Standards

  • Overview and discussion of Wireless (Data) Systems in Germany,
  • Evolution of systems, spectrum allocations for mobile services. Security
  • Telephony
    • Cellular Telephony
      • GSM: Radio standard (Basic principles explained as a fairy tale), Business aspects, Network
      • U.S. cellular telephony: analogue AMPS, digital IS 54 and IS 95. PCS
      • Japan: PDC
      • IMT 2000 (FLPMTS), UMTS
    • Cordless telephony
      • Digital Enhanced Cordless Telephone (DECT)
  • Broadcast Systems
    • broadcast standards,
      • Radio Data System (RDS/RBDS)
    • Digital Audio Broadcasting (DAB), Digital Radio Mondiale (DRM)
    • Digital Video Broadcasting
      • DVB / DTTB
      • copyright protection and conditional access: General description of pay TVPay TV and storage devices - Copy(right) protectionHardware for cryptographic protectionOverview of existing conditional access video broadcast systems
    • MVDS Microwave distribution, 'wireless cable'
  • Data and Multi-Media Systems
    • Wireless LANs and ISM bands, IEEE 802.11, IEEE 1394, HIPERLAN, Bluetooth, Zigbee, Windflex
    • Broadband Wireless Multimedia Systems, U.C. Berkeley Infopad (broadband CDMA design)
    • Mobile (macro-cellular) data networks
      • CDPD: Network Architecture, Protocol issues for Mobile Station, Base Station, Intermediate System: Channel Sniffing, Handover, Roaming.
    • Wireless Computing, software downloading, software radios
  • Satellite Systems: geo stationary, IRIDIUM and Very Small Aperture Terminal (VSAT) systems
  • Road Transportation Informatics, Communication for IVHS and AVCS, Digital Short Range Communication DSRC

Analog electronics and RF front ends (under preparation at CWT/e)

  • RF front end components
    • Antenna filters
    • Low noise amplifiers
    • Mixers
    • Local oscillators
    • Bandpass filters
    • Analog to Digital convertors
    • Power amplifiers
  • Front-end architectures
    • Zero IF
    • Super heterodyne
  • Performance of RF frontends
    • Noise figure
    • Linearity and IP3
    • IQ imbalance
    • Power optimization of a cascade
  • Digital compensation of RF imperfections
  • Antennas

Wireless Propagation Channels

  • Large scale and small scale propagation mechanisms
    • Path loss propagation models
      • Plane earth loss, ground reflections, Propagation for AM broadcast radio
    • Shadowing, joint effect of multiple interferers.
    • MultipathFading
      • Wide Sense Stationary Uncorrelated Scattering (WSSUC)
      • Scatter function, SRCM model
      • Rayleigh fading
        • PDF of amplitude and power
        • Doppler spectrum, rate of fading, random FM
        • Threshold crossing rate TCR and average fade duration AFD
        • Delay spread and coherence bandwidth
        • Samples of typical Rayleigh channels
        • Channel simulation methods, Java phasor animation
      • Rician fading
        • PDF of amplitude and power, Bessel Function
        • How to measure K-factor?
      • Nakagami fading
        • PDF of power,
        • Using a Nakagami model to approximate Rician fading
  • Channel Models
    • Macro cellular channel
    • Micro-Cellular channel
    • Indoor channel at 2.4 GHz, 5 GHz, 17 GHz, 60 GHz, infrared
    • Indoor Radio wave Propagation Measurements and Stochastic Channel modelling
    • vehicle-to-vehicle channel
  • Reciprocity of uplink and downlink.

Cellular Telephone Networks

Communication
  • Systems and Standards: see above.
  • Radio Resource Management
    • Cellular frequency reuse, cell sizes, practical aspects of cell planning
    • Multiple access: FDMA, TDMA, CDMA, SDMA
    • Cell sectorization, reuse partitioning, dynamic channel assignment (DCA)
    • Digital Speech Interpolation (DSI)
  • Link Quality Performance Evaluation and Network Performance Analysis
    • Protection ratio, Outage probability, useful expressions, computer methods.
    • Man-made noise and link-budget
    • Cumulation of interference: Nakagami fading, method by Schwartz & Yeh
    • Call blocking, speech clipping, subjective speech quality, ErlangB and C formulas
    • Spectrum efficiency versus performance
  • Network Aspects
    • Handover, soft handover

Wireless Communication Technology

Analog and Digital Transmission

  • Modulation methods. BPSK, DQPSK, FSK, GMSK, QAM
  • Effects of fading and dispersion (for analog and digital)
  • Noise: AWGN and matched filters
  • Bit error rates
    • BER in very slowly fading channel, BER in cellular network
  • Multicarrier modulation and OFDM;
    • Intuitive and mathematical description
    • frequency domain channel simulation
  • Spread spectrum
    • Direct sequence transmission
      • Selection of spreading codes
      • Synchronization acquisition and tracking
      • RAKE receiver, Multiuser detection, Antenna array processing
      • CDMA for packet data: Performance
    • Frequency hopping
    • Orthogonal Multi-Carrier CDMA, CDMA/OFDM
      • Receiver aspects: subcarrier weighing
    • Hybrid DS/FH Spreading CDMA
      • design aspects of WISSCE: A Hybrid DS/FH CDMA Communication System
    • Wideband channel models: resolvable paths, multipath self-interference,
  • Reeiver techniques
    • Basic principles of GSM explained as a fairy tale: The Story of Big Solitude and Mostly Silent
    • Diversity techniques
      • Selection diversity, Equal Gain Combining, Maximum Ratio Combining
      • Interference Rejection Combining (Smart antennas), CDMA Array Processing
    • Coding
      • Viterbi decoder, Animation

Wireless Data Networks

  • Wireless data networking. How does it differ from digital telephony?
  • Data systems and concepts: see Systems and Concepts.
  • Queuing delay in cellular data networks
  • Random access
    • Methods and principles
      • ALOHA
        • Drift of Backlog, Stability, Dynamic Frame Length
        • Cellular ALOHA Networks, Frequency Reuse and ALOHA
      • CSMA
      • ISMA (busy tone feedback)
      • Collision resolution schemes:
        • Adaptive retransmission backoff
        • Stack algorithm, Tree algorithm
        • Dynamic Frame Length ALOHA
      • Access reservation schemes: PRMA, STRMA
    • Performance Analysis
      • Throughput versus Offered Traffic
      • Receiver capture, vulnerability to interference
    • Diversity in random access networks

Business and Regulatory Aspects

  • The technical issues in wireless communication, the problem of user mobility
  • History; Evolution of systems towards PCS
  • Economics of wireless access:
    • The last mile,
    • The cost of cellular phones and business models of operators.
    • The market value of the radio spectrum
    • Example of tariffing in GSM
  • Success factors for innovations in information services

Capita Selecta

  • Glossary and Acronyms
    • on wireless communication (The buzz words)
    • on video and television
  • List of main mathematical symbols
  • Companies active in Wireless and Cellular
  • Organizations and Standards
    • ISO
      • ISO layers
    • Conférence Européenne des Postes et des Télécommunications CEPT; ETSI: European Telecommunications Standards Organisation
    • ITU: International Telecommunications Union
    • DVB: Digital Video Broadcasting
    • FCC: Federal Communications Commission, USA
  • Research directions in Propagation; Wireless Computing
  • Electronic Watermarking (an application of spread spectrum in image processing)

Courses, Presentations

educational tools and exercises.

Have a look at the wireless communication quizzes or the radio link design exercise.

The glossary helps you to rapidly acquire the buzz words of this field.

See an animated SMIL overview or a word of welcome plus a selection of audio fragments from interviews featured.

Playlists provide a selection of longer audio clips, talks and interviews.

Acrobat Course Slides

  • System Concepts and Standards
    • History of wireless.
  • Transmission Aspects
    • Microscopic Propagation Mechanisms (Multipath)
    • Modulation methods
  • Research Projects;

    Powerpoint® slides

  • UMTS by Raul Bruzzone HTML pointer
  • Propagation: Basics, Intermediate, Advanced
  • Bluetooth (HTML)
  • History (HTML)
  • RF front/end tutorials : design basics, imperfections

Exercises and educational tools

  • Radio link design exercise.
  • Aloha collision resolution exercise
  • Channel assignment game

Further reading

Postscript® and Acrobat PDF® printable documents

Wireless Communications Greenville

  • Overview of large-scale propagation models (PS; PDF)
  • Statistical Propagation models (PS; PDF)
  • Rician and Rayleigh fading
    • Statistical behavior of Inphase and Quadrature components (PS; PDF)
    • Statistical behavior of amplitude (PS; PDF)
  • Outage Probabilities (PDF)
  • Delay in Cellular Networks (PDF)
  • Direct sequence CDMA
    • General Discussion (PS; PDF)
    • Performance of synchronous DS-CDMA downlink (PS; PDF)
  • Multi-Carrier CDMA: discussion (PS/PDF) and slides (PDF)
  • Turbo coding and OFDM (PDF 1, 2, 3)
  • Road Traffic Informatics
    • Vehicle-to-vehicle channel model: theory and measurements
    • Base-to-vehicle communication

Recommended Books and Papers

  • Overview of text books
  • Evolution of Wireless Systems
  • Wireless Services
    • Pricing (and economic models used in system control)
  • Cellular Systems
  • Transmission aspects
  • Packet Data
    • Random Access: ALOHA, CSMA
    • Wireless Internet (IP) Protocol
  • Networks
    • Tele-Traffic Models

Computer Programs

Wireless Communications Greenville Sc

  • Programmers Guidelines and Hints

    • Hints for program to compute Outage Probability in cellular network with Rayleigh fading, shadowing and path loss. (see also Javascript)

  • MS DOS and Windows® EXE files

    • PROMOT Planning Tool for gathering telemetric data (DOS Executable).
    • STRMA Space - Time Reservation Multiple Access (PC Windows Executable)
    • Watermark correlation detector for digital images. (Description, executables)

  • Java® Applets

    • Phasor diagrams for Rayleigh fading.
    • Phasor diagrams for AM, NBPM and FM modulation.
    • Calculator in design exercise.
    • Dynamic Channel Assignment (DCA), BDCL

  • JavaScript® Embedded Calculators, Spreadsheets

    • Time constants of Rayleigh fading, average fade duration, Doppler spread, level crossing rate
    • Path loss, incl. Egli, Hata
    • Indoor path loss
    • Single knife edge diffraction loss
    • Outage probability:
      • Comprehensive: Rayleigh fading, shadowing
    • Gold sequences: crosscorrelation
    • PDF of Power sum of multiple lognormal signal
    • Effective throughput, packet length
    • Bit Error Rate
      • BER for BPSK, QPSK, MSK and FSK with Rician fading,
        SER for QAM in Rayleigh fading
      • BER for DS-CDMA with rake receiver
      • BER for OFDM with Doppler

  • Matlab® Code

    • Effect of Doppler on OFDM, MC-CDMA
    • Frequency-domain (OFDM, MC-CDMA) channel modelling
    • BER and SER for OFDM: ser.mfunc.m and summ.m
    • BER of a hybrid FH/DS CDMA system in flat Rician Fading

Disclaimer: Executable software programs are provided with no guarantee whatsoever.
Some browsers do not support Java applets or JavaScript 1.2. See License.

Wireless Communications Group


Editor: Jean-Paul Linnartz
Other authors, contributors, artists

Wireless Communication Guglielmo Marconi 1896

Wireless Communication
© 1993, 1995, 1997, 1999, 2001, 2006.

Wireless Communication Goldsmith

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