Wireless Communication Networks PDF

CCCN 422 Wireless Communication Networks Dr. Mohammed Balfaqih Assistant Professor [email protected] @modditto Lecture Outline ▪ Introduction to Wireless Communication Networks • • • • Wireless Vision and Technical Issues Current Wireless Systems The Wireless Spectrum History and Evolution of...

CCCN 422 Wireless Communication Networks Dr. Mohammed Balfaqih Assistant Professor [email protected] @modditto Lecture Outline ▪ Introduction to Wireless Communication Networks • • • • Wireless Vision and Technical Issues Current Wireless Systems The Wireless Spectrum History and Evolution of Wireless Communications Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Introduction to Wireless Communications Networks Next-Gen Cellular/WiFi Smart Homes/Spaces Autonomous Cars Smart Cities Body-Area Networks Internet of Things All this and more … Introduction to Wireless Communications Networks • • Wireless communication: Transmitting voice and data using electromagnetic waves in open space. Electromagnetic waves - Frequency and wavelength =𝑐×𝑓 - • wavelength , speed of light c  3 × 108 m/s, frequency f Higher frequency means higher energy photons The higher the energy photon has worse penetrating capability. Wireless channel - Line-of-sight is best but not required - Signals can still be received: Transmission through objects, Reflections of objects, Scattering of signals, and Diffraction around edges of objects Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Introduction to Wireless Communications Networks • The demand for mobile communication created already decades ago the need for integration of wireless networks into existing fixed networks: - wide area networks: e.g., internetworking of GSM and ISDN, and VoIP over WLAN. local area networks: standardization of IEEE 802.11. Internet: Mobile IP extension of the internet protocol IP. Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Introduction to Wireless Communications Networks Wireless networks in comparison to fixed networks • Higher loss-rates due to interference - emissions of, e.g., engines, lightning • Restrictive regulations of frequencies - frequencies have to be coordinated; useful frequencies are almost all occupied • Lower transmission rates - local some Mbit/s, regional sometimes only, e.g., 53kbit/s with GSM/GPRS or about 150 kbit/s using EDGE – some Mbit/s with LTE (shared!) – compare countryside vs. downtown • Higher delays, higher jitter - connection setup time with GSM in the second range, several hundred milliseconds for other wireless systems – in ms range with LTE • Lower security, simpler active attacking - radio interface accessible for everyone, base station can be simulated, thus attracting calls from mobile phones Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Wireless Vision and Technical Issues • • • • • • Profound. Shrinks the world. Always on. Always connected. Changes the way people communicate Converged global wireless network. Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Wireless Vision and Technical Issues • • Wireless is convenient and less expensive, but not perfect Limitations and technical difficulties inhibit wireless technologies 5-6G AdHoc Short-Range - Wireless Network/Radio Challenges - Gbps data rates with “no” errors Energy efficiency Scarce/bifurcated spectrum Reliability and coverage Heterogeneous networks Seamless internetwork handoff - Device/System of Chip (SoC) Challenges - Performance Complexity Size, Power, Cost, Energy High frequencies/mmWave Multiple Antennas Multi-radio Integration Co-existance Dr. Mohammed Balfaqih BT Cellular Radio GPS Cog Mem WiFi CPU mmW CCCN 422: Wireless Communication Networks Current Wireless Systems • Wireless Technology Landscape Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Current Wireless Systems ▪ Effect of mobility on protocol stack • Application - new applications and adaptations service location, multimedia • Transport - congestion and flow control quality of service • Network - addressing and routing device location, hand-over Application Application Transport Transport Network Network • Link Data Link Data Link Data Link Data Link - Physical Physical Physical Physical media access and security • Physical - transmission errors and interference Dr. Mohammed Balfaqih Radio Network Network Medium CCCN 422: Wireless Communication Networks Current Wireless Systems Spectral Reuse: Due to its scarcity, spectrum is reused In licensed bands and unlicensed bands BS Cellular Wifi, BT, UWB,… Reuse introduces interference Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Current Wireless Systems • Cellular Systems: Reuse channels to maximize capacity - Geographic region divided into cells - Freq./timeslots/codes/space reused in different cells (reuse 1 common). - Interference between cells using same channel: interference mitigation key - Base stations/MTSOs coordinate handoff and control functions - Shrinking cell size increases capacity, as well as complexity, handoff, … BASE STATION Dr. Mohammed Balfaqih MTSO CCCN 422: Wireless Communication Networks Current Wireless Systems ▪ 4G/LTE-Advanced Cellular System • Much higher data rates than 3G (50-100 Mbps “LTE”) and (500Mbps-1Gbps “LTEAdvanced”) - 3G systems has 384 Kbps peak rates • Greater spectral efficiency (bits/s/Hz) - More bandwidth, adaptive OFDM-MIMO, reduced interference • Flexible use of up to 100 MHz of spectrum • 10-20 MHz spectrum allocation common • Low packet latency (<5ms). • Reduced cost-per-bit (not clear to customers) • All IP network Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Current Wireless Systems ▪ 5G Cellular System Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Current Wireless Systems ▪ Wi-Fi Systems 802.11ac Dr. Mohammed Balfaqih • Streaming video • Gbps data rates • High reliability • Coverage inside and out Wireless HDTV and Gaming CCCN 422: Wireless Communication Networks Current Wireless Systems Wireless LAN Standards • 802.11b (Old – 1990s) - Standard for 2.4GHz ISM band (80 MHz) Direct sequence spread spectrum (DSSS) Speeds of 11 Mbps, approx. 500 ft range • 802.11a/g (Middle Age– mid-late 1990s) - Standard for 5GHz band (300 MHz)/also 2.4GHz OFDM in 20 MHz with adaptive rate/codes Speeds of 54 Mbps, approx. 100-200 ft range Many WLAN cards have many generations • 802.11n/ac/ax or Wi-Fi 6 (current gen) - Standard in 2.4 GHz and 5 GHz band Adaptive OFDM /MIMO in 20/40/80/160 MHz Antennas: 2-4, up to 8 Speeds up to 1 Gbps (10 Gbps for ax), approx. 200 ft range Other advances in packetization, antenna use, multiuser MIMO Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Current Wireless Systems ▪ Why does WiFi performance suck? Carrier Sense Multiple Access: if another WiFi signal detected, random backoff Collision Detection: if collision detected, resend • The WiFi standard lacks good mechanisms to mitigate interference, especially in dense AP deployments - Multiple access protocol (CSMA/CD) from 1970s - Static channel assignment, power levels, and sensing thresholds - In such deployments WiFi systems exhibit poor spectrum reuse and significant contention among APs and clients Result is low throughput and a poor user experience - Multiuser MIMO will help each AP, but not interfering APs Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks The Wireless Spectrum • • • • Radio frequencies range from 9KHz to 400GHZ (ITU) Microwave frequency range - 1 GHz to 40 GHz Directional beams possible, Suitable for point-to-point transmission Used for satellite communications Radio frequency range - 30 MHz to 1 GHz Suitable for omnidirectional applications VLF = Very Low Frequency Infrared frequency range - LF = Low Frequency Roughly, 3x1011 to 2x1014 Hz Useful in local point-to-point multipoint applications within confined areas twisted pair coax cable optical transmission MF = Medium Frequency HF = High Frequency VHF = Very High Frequency UHF = Ultra High Frequency 1 Mm 300 Hz Dr. Mohammed Balfaqih 10 km 30 kHz VLF 100 m 3 MHz LF MF HF 1m 300 MHz 10 mm 30 GHz VHF SHF UHF EHF 100 m 3 THz infrared 1 m 300 THz visible light UV SHF = Super High Frequency EHF = Extra High Frequency UV = Ultraviolet Light The Wireless Spectrum • VHF-/UHF-ranges for mobile radio - • SHF and higher for directed radio links, satellite communication - • simple, small antenna for cars deterministic propagation characteristics, reliable connections small antenna, beam forming large bandwidth available Wireless LANs use frequencies in UHF to SHF range - some systems planned up to EHF limitations due to absorption by, e.g., water (dielectric heating, see microwave oven) weather dependent fading, signal loss caused by heavy rainfall etc. twisted pair coax cable optical transmission VLF = Very Low Frequency LF = Low Frequency MF = Medium Frequency HF = High Frequency VHF = Very High Frequency UHF = Ultra High Frequency 1 Mm 300 Hz Dr. Mohammed Balfaqih 10 km 30 kHz VLF 100 m 3 MHz LF MF HF 1m 300 MHz 10 mm 30 GHz VHF SHF UHF EHF 100 m 3 THz infrared 1 m 300 THz visible light UV SHF = Super High Frequency EHF = Extra High Frequency UV = Ultraviolet Light The Wireless Spectrum • • • • • Frequencies from 9KHz to 300 MHZ in high demand (especially VHF: 30-300MHZ) Two unlicensed bands - Industrial, Science, and Medicine (ISM): 2.4 GHz Unlicensed National Information Infrastructure (UNII): 5.2 GHz Different agencies license and regulate - www.fcc.gov - US www.etsi.org - Europe www.wpc.dot.gov.in - India www.itu.org - International co-ordination VLF = Very Low Frequency LF = Low Frequency Regional, national, and international issues Procedures for military, emergency, air traffic control, etc twisted pair coax cable MF = Medium Frequency HF = High Frequency optical transmission VHF = Very High Frequency UHF = Ultra High Frequency 1 Mm 300 Hz Dr. Mohammed Balfaqih 10 km 30 kHz VLF 100 m 3 MHz LF MF HF 1m 300 MHz 10 mm 30 GHz VHF SHF UHF EHF 100 m 3 THz infrared 1 m 300 THz visible light UV SHF = Super High Frequency EHF = Extra High Frequency UV = Ultraviolet Light Thank you Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Review Questions 1) The advantage of using frequency reuse is a. Increase capacity b. Limited spectrum is required c. Same spectrum may be allocated to other networks d. All of the above 2) The radio communication spectrum is divided into bands based on ___________. a. Frequency b. Cost and hardware c. Transmission media d. Amplitude Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Review Questions 3) _____________ is used for satellite communications a. Microwave frequency range b. Radio frequency range c. Infrared frequency range d. VHF-/UHF-range 4) The 2.4 GHz Industrial, Science, and Medicine (ISM) and the 5.2 GHz Unlicensed National Information Infrastructure (UNII) are considered ____________ a. Licensed bands b. Unlicensed bands c. None of the above d. All the above Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks Review Questions 5) What are the advantages of Wireless networks compared to fixed networks? 6) Give any four examples of wireless communication systems. 7) List five ranges of wireless spectrum and their utilization. Dr. Mohammed Balfaqih CCCN 422: Wireless Communication Networks