Wireless systems overview

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Gabriella Chrystal Cox
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1 Wireless systems overview Evolution of systems from 1G to 4G 1G, 4G major features Specifications comparison 5G communication systems Summary Wireless Systems 2016 Evolution of cellular networks WiMAX WCDMA 1G 2G 2.5G 3G 4G 2 1

2 Cellular networks comparison 3 1G Mobile Communication Analog Telecommunication Standard FDMA Transmission Technique Hand-off and frequency reuse Only voice transmission First commercially automated cellular network in 1979 Standards: AMPS, NMT, TACS, JTACS, C-450, Radiocom 2000 and RMTI Drawbacks Poor security due to lack of encryption Many different standards being used in different places Limited capacity 4 2

3 2G Mobile Communication Purely digital technology TDMA, CDMA operator technologies Conversations digitally encrypted Introduced data services for mobile, starting with SMS Commercially launched on the GSM standard in Finland in 1991 Circuit-switched data services (HSCSD) Greatly reduced fraud and discouraged cloned handsets Frequency 800/900 or 1800/1900 MHz with BW = khz Drawbacks Weak digital signal may not be sufficient especially at higher frequencies Increased dropouts Very slow data transmission 5 2.5G Mobile Communication Packet-switched domain in addition to the circuit-switched domain GPRS: The first major step in the evolution of GSM networks to 3G Improved connection to Internet Other: EDGE, CDMA Increased data rates up to 100 kbps 6 3

4 3G Mobile Communication Digital broadband packet access UTMS(WCDMA), CDMA2000 1xEV-DO operator technologies Voice telephone, mobile Internet, video calls and mobile TV in a mobile. Offers greater security than 2G Supports up to 3.1Mbps peak but general speed is kbps Uses different frequency bands than 2G Operates at MHz and bandwidth of MHz (with 3-4 channels of 5 MHz) Drawbacks No proper backward compatibility Need to replace BS hardware No formal definition carriers used their own technologies to implement 3G network Expensive hardware and maintenance 7 3.5G Mobile Communication HSPA (has many versions) Improved performance of existing UTMS protocols Fairly high peak data downlink rates up to 3.6/ 7.2/ 14.4 Mbps Fairly high peak data uplink rates up to 5.76 Mbps Average speeds 1-3 Mbps Reducing the production cost per bit Easy update to existing 3G networks. Preferred over WiMAX, which requires a dedicated network infrastructure 8 4

5 Key techniques for 3G/3.5G Systems Increase of chip rate (limited unless moving to higher frequencies that is also problematic) Variable spreading gain CDMA (higher bit rate with lower spreading factor) Multicode CDMA (groups of bits chip-encoded with different orthogonal codes, then added and sent on one carrier) MIMO technology OFDM used in WLAN systems 9 Evolution of WCDMA (UMTS) 10 5

6 4G Mobile Communication All IP based secured packet switched network Voice also transmitted over IP Supports IPv6 Access schemes OFDMA, SC-FDMA, MC-CDMA Supports up to 100 Mbps downlink and 50 Mbps uplink. Using MIMO, speed can be increased. Technologies LTE, WiMAX, Wi-Fi metro, HSPA+. No formal specification Operators making their own choices. 11 4G Technologies LTE Advanced (E-UTRAN) Proposed by 3GPP based on UMTS/HSPA. OFDMA for uplink and downlink Improved spectral efficiency by scalable bandwidth Can be constructed using existing 3G network. Backward compatible. Downlink up to 100 Mbps and uplink up to 50 Mbps. Natural upgrade to GSM/UMTS networks, can be also used by CDMA networks. WiMAX Advanced Proposed by IEEE based on WiMAX OFDMA for downlink and SC- FDMA for uplink. Requires completely different network. Backward compatible. Bit rates up to 40 Mbps. 12 6

7 Frequency band (MHz) Specifications comparison GSM IS-95 WCDMA LTE (F) (R) (F) (R) (F) (R) various for TDD Several bands 700 MHz 2600 MHZ Channel BW 200 khz 1.25 MHz 5 MHz 1.4 MHz 20 MHz Modulation GMSK BPSK QPSK QPSK 64 QAM Data rates 270 kbps kbps 2 Mbps 300 Mbps (DL) 75 Mbps (UL) Access technology FDMA/TDMA/FH FDMA/CDMA FDMA/CDMA/FDD (TDD) OFDMA (DL) SC FDMA (UL) FDD/TDD Forward error correction Variable, rate-½ convolutional Variable, rate- 1/2-1/3 convolutional Variable, rate-1/2-1/3 convolutional Concatenated codes Frame size 4.61 ms 20 ms 10 ms 10 ms (5 ms) Voice encoding RELP 13kbps CELP 9.6 kbps Adaptive CELP kbps AMR-WB 24kbps (clean voice) Traffic channels 8 63 Depends on data rate Depends on setup Diversity Freq. hopped Spread spectrum + RAKE Rx Space-time block coding MIMO 13 Specifications comparison summary Similar frequency bands FDMA underlying strategy in combination with TDMA, CDMA Multi-carrier in WLAN and 4G systems, older system one-carrier Channel BW depends on multiple access technique Modulation techniques vary but tend to be simple Data rates are low in older generations Forward error correction commonly used Frame size small and motivated by vocoders Various diversity techniques are used, Rx-antenna diversity at BS common 14 7

5G communication Providing ubiquitous super-fast connectivity and seamless service delivery in all circumstances Time horizon 2020+ Major objectives - huge capacity /massive number of users, -

8 5G communication Providing ubiquitous super-fast connectivity and seamless service delivery in all circumstances Time horizon Major objectives - huge capacity /massive number of users, - accessibility with low blocking probability, - low response times, - very low latency, - flexible use of infrastructure elements, - support of various levels of mobility, - very high data rates, - energy efficiency, - overall high QoE/QoS - economic efficiency, - environment friendliness 15 5G concepts Coexistence of multiple Radio Access Technologies (RATs) Compatibility with 4G, 3G, 2G Various cell networks/cell sizes incl. Device-to-device / Machine-to-machine Dynamic spectrum management (DSM) including mm-waves; RATs share spectrum, different forms of spectrum licensing Cloud and non-cloud architectures, dynamic assignment to physical elements Improving of resources utilization - possible network sharing by various operators - possible software-defined networking /SDN layers: infrastructure, control, applications 16 8

9 Summary We are on the way to wireless world covering all kinds of personal and data communication 17 9

Mobile Broadband Comparison. CDMA Development Group March 2008

Mobile Broadband Comparison. CDMA Development Group March 2008 Mobile Broadband Comparison CDMA Development Group March 2008 Assumptions and Notes for the Technology Comparison This document compares the performance of existing and future mobile communications systems