(gprs, edge, umts, lte and…)
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DESCRIPTIONGSM. (GPRS, EDGE, UMTS, LTE and…). Global System for Mobile communications. GSM History. GSM world coverage map. Differences Between First and Second Generation Systems. Digital traffic channels – first-generation systems are almost purely analog; second-generation systems are digital - PowerPoint PPT Presentation
(GPRS, EDGE, UMTS, LTE and…)
Global System for Mobile communications
GSM HistoryYear Events
1982CEPT establishes a GSM group in order to develop the standards for a pan-European
cellular mobile system
1985 Adoption of a list of recommendations to be generated by the group
1986Field tests were performed in order to test the different radio techniques proposed for
the air interface
1987TDMA is chosen as access method (in fact, it will be used with FDMA) Initial
Memorandum of Understanding (MoU) signed by telecommunication operators (representing 12 countries)
1988 Validation of the GSM system
1989 The responsibility of the GSM specifications is passed to the ETSI
1990 Appearance of the phase 1 of the GSM specifications
1991 Commercial launch of the GSM service
1992Enlargement of the countries that signed the GSM- MoU> Coverage of larger
1993 Coverage of main roads GSM services start outside Europe
1995 Phase 2 of the GSM specifications Coverage of rural areas
GSM world coverage map
Differences Between First and Second Generation Systems
• Digital traffic channels – first-generation systems are almost purely analog; second-generation systems are digital
• Encryption – all second generation systems provide encryption to prevent eavesdropping
• Error detection and correction – second-generation digital traffic allows for detection and correction, giving clear voice reception
• Channel access – second-generation systems allow channels to be dynamically shared by a number of users
The GSM network can be divided into four subsystems: • The Mobile Station (MS). • The Base Station Subsystem (BSS). • The Network and Switching Subsystem (NSS). • The Operation and Support Subsystem (OSS).
GSM Network Architecture
Mobile Station• Mobile station communicates across Um interface (air
interface) with base station transceiver in same cell as mobile unit
• Mobile equipment (ME) – physical terminal, such as a telephone or PCS– ME includes radio transceiver, digital signal
processors and subscriber identity module (SIM)• GSM subscriber units are generic until SIM is inserted
– SIMs roam, not necessarily the subscriber devices
Base Station Subsystem (BSS)• BSS consists of base station controller and one or more base
transceiver stations (BTS)• Each BTS defines a single cell
– Includes radio antenna, radio transceiver and a link to a base station controller (BSC)
• BSC reserves radio frequencies, manages handoff of mobile unit from one cell to another within BSS, and controls paging
• The BSC (Base Station Controller) controls a group of BTS and manages their radio ressources. A BSC is principally in charge of handovers, frequency hopping, exchange functions and control of the radio frequency power levels of the BTSs.
Network Subsystem (NS)• NS provides link between cellular network and public
switched telecommunications networks– Controls handoffs between cells in different BSSs– Authenticates users and validates accounts– Enables worldwide roaming of mobile users
• Central element of NS is the mobile switching center (MSC)
Mobile Switching Center (MSC) Databases
• Home location register (HLR) database – stores information about each subscriber that belongs to it
• Visitor location register (VLR) database – maintains information about subscribers currently physically in the region
• Authentication center database (AuC) – used for authentication activities, holds encryption keys
• Equipment identity register database (EIR) – keeps track of the type of equipment that exists at the mobile station
The Operation and Support Subsystem (OSS)
• The OSS is connected to the different components of the NSS and to the BSC, in order to control and monitor the GSM system. It is also in charge of controlling the traffic load of the BSS.
• However, the increasing number of base stations, due to the development of cellular radio networks, has provoked that some of the maintenance tasks are transferred to the BTS. This transfer decreases considerably the costs of the maintenance of the system.
GSM Channel Types• Traffic channels (TCHs)
carry digitally encoded user speech or user data and have identical functions and formats on both the forward and reverse link.
• Control channels (CCHs)
carry signaling and synchronizing commands between the base station and the mobile station. Certain types of control channels are defined for just the forward or reverse link.
How a Cellular Telephone Call is Made• All base stations continuously send out identification
signals (ID) of equal, fixed strength. When a mobile unit is picked up and goes off-hook, it senses these identification signals and identifies the strongest. This tells the phone which cell it is in and should he associated with. The phone then signals to that cell's base station with its ID code, and the base station passes this to the MSC, which keeps track of this phone and its present cell in its database. The phone is told what channel to use for talking, is given a dial tone, and the call activity proceeds just like a regular call. All the nontalking activity is done on a setup channel with digital codes.
• Mobile unit initialisation• Mobile-originated call• Paging• Call accepted• Ongoing call• Handoff
GSM Radio interface • Frequency allocation • Two frequency bands, of 25 Mhz each one, have been
allocated for the GSM system: • The band 890-915 Mhz has been allocated for the uplink
direction (transmitting from the mobile station to the base station).
• The band 935-960 Mhz has been allocated for the downlink direction (transmitting from the base station to the mobile station).
Multiple access scheme • In GSM, a 25 MHz frequency band is divided, using a
FDMA, into 124 carrier frequencies spaced one from each other by a 200 kHz frequency band.
• Each carrier frequency is then divided in time using a TDMA. This scheme splits the radio channel into 8 bursts.
• A burst is the unit of time in a TDMA system, and it lasts approximately 0.577 ms.
• A TDMA frame is formed with 8 bursts and lasts, consequently, 4.615 ms.
• Each of the eight bursts, that form a TDMA frame, are then assigned to a single user.
Maximum number of simultaneous calls = [(124) × 8] / N = 330 (if N=3)
GSM frame format
Trail bits: synchronisation between mobile and BS.
Encrypted bits: data is encrypted in blocks, Two 57-bit fields
Stealing bit: indicate data or stolen for urgent control signaling
Training sequence: a known sequence that differs for different adjacent cells. It indicates the received signal is from the correct transmitter and not a strong interfering transmitter. It is also used for multipath equalisation. 26 bits.
Guide bits: avoid overlapping, 8.25 bits
Data rate• channel data rate in GSM
(1/120 ms) × 26 × 8 × 156.25 = 270.8 33Kbps • User data rate
Each user channel receives one slot per frame
iframeslots/mult 24bits/slot 114
iframeslots/mult 24bits/slot data65
With error control
full rate channels offer a data rate of 22.8 kBit/s:• speech data: used as 13 kBit/s voice data plus FEC data• packet data: used as 12, 6, or 3.6 kBit/s plus FEC data
half rate channels offer 11.4 kBit/s:• speech data: improved codecs have rates of 6.5 kBit/s,
plus FEC• packet data: can be transmitted at 3 or 6 kBit/s
Two half rate channels can share one physical channel Consequence: to achieve higher packet data rates, multiple logical channels have to be allocated =) this is what GPRS does
Speech codingThere are 260 bits coming out of a voice coder every 20 ms. 260 bits/20ms = 13 kbpsThese 260 bits are divided into three classes:
• Class Ia having 50 bits and are most sensitive to errors
3-bit CRC error detection code 53, then protected by a Convolutional (2,1,5) error correcting code.
• Class Ib contains 132 bits which are reasonably sensitive to bit errors--protected by a Convolutional (2,1,5) error correcting code.
• Class II contains 78 bits which are slightly affected by bit errors– unprotected
• After channel coding: 260 bits 456bits
Channel coding: block coding Then Convolutional coding
Evolution from 2G
IS-95 IS-136 & PDCGSM-
• Newer versions of the standard were backward-compatible with the original GSM phones.
• Release ‘97 of the standard added packet data capabilities, by means of General Packet Radio Service (GPRS). GPRS provides data transfer rates from 56 up to 114 kbit/s.
• Release ‘99 introduced higher speed data transmission using Enhanced Data Rates for GSM Evolution (EDGE), Enhanced GPRS (EGPRS), IMT Single Carrier (IMT-SC), four times as much traffic as standard GPRS. accepted by the ITU as part of the IMT-2000 family of 3G standards
• Evolved EDGE standard providing reduced latency and more than doubled performance e.g. to complement High-Speed Packet Access (HSPA). Peak bit-rates of up to 1Mbit/s and typical bit-rates of 400kbit/s can be expected.
• the Base Station Subsystem (the base stations and their controllers).
• the Network and Switching Subsystem (the part of the network most similar to a fixed network). This is sometimes also just called the core network.
• the GPRS Core Network (the optional part which allows packet based Internet connections).all of the elements in the system combine to produce many GSM services such as voice calls and SMS.
ITU’s View of Third-Generation Capabilities• Voice quality comparable to the public switched telephone
network• High data rate. 144 kbps data rate available to users in high-
speed motor vehicles over large areas; 384 kbps available to pedestrians standing or moving slowly over small areas; Support for 2.048 Mbps for office use
• Symmetrical / asymmetrical data transmission rates• Support for both packet switched and circuit switched data
services• An adaptive interface to the Internet to reflect efficiently the
common asymmetry between inbound and outbound traffic• More efficient use of the available spectrum in general• Support for a wide variety of mobile equipment• Flexibility to allow the introduction of new services and
Third Generation Systems (3G)
The dream of 3G is to unify the world's mobile computing devices through a single, worldwide radio transmission standard. However,
3 main air interface standards:
W-CDMA(UMTS) for Europe
CDMA2000 for North America
TD-SCDMA for China (the biggest market)
UMTS (Universal Mobile Telecommunications System ) Services
UMTS offers teleservices (like speech or SMS) and bearer services, which provide the capability for information transfer between access points. It is possible to negotiate and renegotiate the characteristics of a bearer service at session or connection establishment and during ongoing session or connection. Both connection oriented and connectionless services are offered for Point-to-Point and Point-to-Multipoint communication.Bearer services have different QoS parameters for maximum transfer delay, delay variation and bit error rate. Offered data rate targets are:
144 kbits/s satellite and rural outdoor384 kbits/s urban outdoor2048 kbits/s indoor and low range outdoor
The Core Network is divided in circuit switched and packet switched domains. Some of the circuit switched elements are Mobile services Switching Centre (MSC), Visitor location register (VLR) and Gateway MSC. Packet switched elements are Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN). Some network elements, like EIR, HLR, VLR and AUC are shared by both domains.
The Asynchronous Transfer Mode (ATM) is defined for UMTS core transmission. ATM Adaptation Layer type 2 (AAL2) handles circuit switched connection and packet connection protocol AAL5 is designed for data delivery.
Summary of UMTS frequencies:
• 1920-1980 and 2110-2170 MHz Frequency Division Duplex (FDD, W-CDMA) Paired uplink and downlink, channel spacing is 5 MHz and raster is 200 kHz. An Operator needs 3 - 4 channels (2x15 MHz or 2x20 MHz) to be able to build a high-speed, high-capacity network.1900-1920 and 2010-2025 MHz Time Division Duplex (TDD, TD/CDMA) Unpaired, channel spacing is 5 MHz and raster is 200 kHz. Tx and Rx are not separated in frequency.1980-2010 and 2170-2200 MHz Satellite uplink and downlink.
Universal Mobile Telephone System (UMTS)
OFCOM: The Office of Communications www.ofcom.org.uk
Global Wireless Frequency Bands
Base station finder: http://www.sitefinder.ofcom.org.uk/
Frequency Spectrum in UK(Sep 2007)
900MHz 1800MHz 2100MHz ( 3G ) Vodafone Vodafone Vodafone
O2 O2 O2 Restricted to 2G
services only T-Mobile T-Mobile
Orange Orange Three
Restricted to 3G
GSM frequency allocations
Mobile phone transmit frequency MHz
Base station transmit frequency MHz
Vodafone GSM 900 890 - 894.6 -23 chs 935 - 939.6
O2 (BT) GMS 900 894.8 - 902 939.8 - 947
Vodafone GSM 900 902 - 910 947 - 955
O2 (BT) GMS 900 910 - 915 955 - 960
Vodafone GSM 1800 & O2 GSM 1800:
1710 - 1721.5 1805 - 1816.5
T Mobile GSM 1800 1721.5 - 1751.5 1816.5 - 1846.5
Orange GSM 1800: 1751.5 - 1781.5 1846.5 - 1876.5
The UMTS/3G frequency allocationsFrequency (MHz) Bandwidth (MHz) licence holder1900 - 1900.3 Guard band
1900.3 - 1905.2 4.9 licence D T-Mobile
1905.2 - 1910.1 4.9 licence E Orange
1910.1 - 1915.0 4.9 licence C O2
1915.0 - 1919.9 4.9 licence A 3
1919.9 - 1920.3 Guard band
1920.3 - 1934.9 14.6 licence A 3
1934.9 - 1944.9 10 licence C O2
1944.9 - 1959.7 14.8 licence B Vodafone
1959.7 - 1969.7 10 licence D T-Mobile
1969.7 - 1979.7 10 licence E Orange
2110 - 2110.3 Guard band
2110.3 - 2124.9 14.6 licence A 3
2124.9 - 2134.9 10 licence C O2
2134.9 - 2149.7 14.8 licence B Vodafone
2149.7 - 2159.7 10 licence D T-Mobile
2159.7 - 2169 10 licence E Orange
2169.7 - 2170 Guard band
3G downlink Signal level measured at T701
3 VodafoneO2 T-Mobile Orange
3G download Signal level measured at T714
3G Uplink signal level
Uplink signal monitoring without 3G calls
Uplink signal monitoring with an Vodafone 3G call
A mobile virtual network operator (MVNO) is a mobile phone operator that provides services directly to their own customers but does not own key network assets such as a licensed frequency allocation of radio spectrum and the cell tower infrastructure.
The UK mobile market has 5 main mobile network operators and has a total of more than 20 MVNOs (virgin, tesco, asda, lyca…).
International Mobile Telecommunications (IMT) Advanced
Key features of ´IMT-Advanced´• a high degree of commonality of functionality worldwide while
retaining the flexibility to support a wide range of services and applications in a cost efficient manner;
• compatibility of services within IMT and with fixed networks; • capability of interworking with other radio access systems; • high quality mobile services; • user equipment suitable for worldwide use; • user-friendly applications, services and equipment; • worldwide roaming capability; and, • enhanced peak data rates to support advanced services and
applications (100 Mbit/s for high and 1 Gbit/s for low mobility were established as targets for research)*.
High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing WCDMA protocols
3.5G introduces many new features that will enhance the UMTS technology in future. 1xEV-DV already supports most of the features that will be provided in 3.5G. These include:
- Adaptive Modulation and Coding
- Fast Scheduling
- Backward compatibility with 3G
- Enhanced Air Interface
What is 4G
4th Generation of Mobile communicationsFirst Gen Analog, AMPS2G, Digital, IncreaseVoice Capacity- TDMA, GSM & 1xRTT3G High Speed Data; EVDO, UMTS, HSPAITU defines 4G as 100 Mbps mobile, 1 Gbps stationaryLTE-Advanced & WiMax 2.0 4G certified, theoretically capableRealistic? Nokia lab demo w/ 8 antennas, 60 MHz & 1 userMarket 4G defined as ~10X 3G or 5-10+ MbpsCurrent gen WiMax, LTE & HSPA+
4G (LTE)• LTE stands for Long Term Evolution• Promises data transfer rates of 100 Mbps• Based on UMTS 3G technology• Optimized for All-IP traffic
LTE Link Budget ComparisonUplink Budget Comparison
LTE Link Budget Comparison
Downlink Budget Comparison
Mapping of Path Losses to Cell Sizes
Advantages of LTE
Comparison of LTE Speed
Major LTE Radio Technogies• Uses Orthogonal Frequency Division Multiplexing (OFDM) for
downlink• Uses Single Carrier Frequency Division Multiple Access (SC-
FDMA) for uplink• Uses Multi-input Multi-output(MIMO) for enhanced throughput• Reduced power consumption• Higher RF power amplifier efficiency (less battery power used by
LTE Physical Channels
Physical Channels used in Long Term Evolution (LTE) downlink and in uplink Downlink Channels：
Physical Downlink Control Channel (PDCCH) Physical Downlink Shared Channel (PDSCH) Common Control Physical Channel (CCPCH)
Uplink Channels： Physical Uplink Shared Channel (PUSCH) Physical Uplink Control Channel (PUCCH)
Commercial LTE Speed evolution
Peak rate ~50 Mbps ~150 Mbps ~1000 Mbps
Typical user rate downlink 5-30 Mbps 10-100 Mbps Operator dependent
Typical user rate uplink
Bandwidths1-10 Mbps 5-50 Mbps Operator dependent
LTE AdvancedRadio Systems
>20 MHz20 MHz10 MHz5-50 Mbps
10-100 Mbps~150 Mbps
3-10 Mbps8-30 Mbps~50 Mbps
Operator dependentOperator dependent
50 Mbps150 Mbps
LTE brings excellent user and network experience
Release 7 HSPA+ (MIMO, etc.)
Release 8 LTE
ITU-R M.1457IMT-2000 Recommendation
ITU-R M.2012 [IMT.RSPEC]
Release schedule & RAN features
3GPP work is structured in releases (REL) of 1-3 years durationeach release consists of several work items (WI) and study items (SI)even if a REL is completed corrections are possible laterexisting features of one REL can be enhanced in a future REL
Further LTE enhancements
2001 2003 2005 2007 2009 2011 2013
3GPP aligned to ITU-R IMT process3GPP Releases evolve to meet:
• Future Requirements for IMT• Future operator and end-user
only mainRAN WI
Dr. Joern Krause
Main Features in LTE-A Release 10
Support of wider bandwidth (Carrier Aggregation)• Use of multiple component carriers (CC) to extend bandwidth up to 100 MHz• Common L1 parameters between component carrier and LTE Rel-8 carrier Improvement of peak data rate, backward compatibility with LTE Rel-8
Advanced MIMO techniques• Extension to up to 8-layer transmission in downlink (REL-8: 4-layer in downlink)• Introduction of single-user MIMO with up to 4-layer transmission in uplink• Enhancements of multi-user MIMO Improvement of peak data rate and capacity
Heterogeneous network and eICIC (enhanced Inter-Cell Interference Coordination)
• Interference coordination for overlay deployment of cells with different Tx power Improvement of cell-edge throughput and coverage
Relay• Relay Node supports radio backhaul and creates a separate cell and appears
as Rel. 8 LTE eNB to Rel. 8 LTE UEs Improvement of coverage and flexibility of service area extension
Minimization of Drive Tests• replacing drive tests for network optimization by collected UE measurements Reduced network planning/optimization costs
Relay NodeDonor eNB
Dr. Joern Krause
LTE/LTE-A REL-11 features
• Coordinated Multi-Point Operation (DL/UL) (CoMP):– cooperative MIMO of multiple cells to improve spectral efficiency, esp. at cell edge
• Enhanced physical downlink control channel (E-PDCCH): new Ctrl channelwith higher capacity
• Further enhancements for– Minimization of Drive Tests (MDT): QoS measurements (throughput, data volume)– Self Optimizing Networks (SON): inter RAT Mobility Robustness Optimisation (MRO)– Carrier Aggregation (CA): multiple timing advance in UL, UL/DL config. in inter-band CA TDD– Machine-Type Communications (MTC): EAB mechanism against overload due to MTC– Multimedia Broadcast Multicast Service (MBMS): Service continuity in mobility case– Network Energy Saving for E-UTRAN: savings for interworking with UTRAN/GERAN– Inter-cell interference coordination (ICIC): assistance to UE for CRS interference reduction– Location Services (LCS): Network-based positioning (U-TDOA)– Home eNode B (HeNB): mobility enhancements, X2 Gateway
• RAN Enhancements for Diverse Data Applications (eDDA):– Power Preference Indicator (PPI): informs NW of mobile’s power saving preference
• Interference avoidance for in-device coexistence (IDC):– FDM/DRX ideas to improved coexistence of LTE, WiFi, Bluetooth transceivers, GNSS receivers in
UE• High Power (+33dBm) vehicular UE for 700MHz band for America for Public Safety• Additional special subframe configuration for LTE TDD: for TD-SCDMA interworking• In addition: larger number of spectrum related work items: new bands/band combinations
Dr. Joern Krause
Generations ofMobile Communication Systems
• 1G: analogue systems from 1980s(e.g. NMT, AMPS, TACS, C-Netz)
• 2G: first digital systems of 1990s(e.g. GSM, CDMAone, PDC, D-AMPS)
• 3G: IMT-2000 family defined by ITU-R(e.g. UMTS, CDMA2000)
• 4G: fulfilling requirements ofIMT-Advanced defined by ITU-R(e.g. LTE-A, WiMAX)
• 5G: ?– too early to be a topic in standardization,
further 4G enhancements expected before– driven by requirements from customers &
network operators– restricted by spectrum limitations– often influenced by new
Dr. Joern Krause
Ofcom (The Office of Communications) awards 4G licences in £2.34 billion auction Feb 2013
Everything Everywhere, Hutchison 3G UK, Telefonica (O2), Vodafone (VOD) and BT (BT.A)'s Niche Spectrum Ventures secured the 4G licences. Vodafone was the highest bidder at £791 million, securing five chunks of 4G spectrum.When mobile operator EE, a joint venture between T-Mobile and Orange, became the first to launch a 4G service in October 2012 in a brief monopoly, it struggled to attract users. It was forced to cut its prices in January, lowering its entry price to £31 from £36 a month.
Ofcom: Independent regulator and competition authorityfor the UK communications industries.
Ofcom announces winners of the 4G mobile auctionFebruary 20, 2013 http://consumers.ofcom.org.uk/4g-auction/
Spectrum won Base price
Everything Everywhere Ltd
2 x 5 MHz of 800 MHz (796-801; 837-842MHz) and2 x 35 MHz of 2.6 GHz (2535-2570; 2655-2690MHz) £588,876,000
Hutchison 3G UK Ltd 2 x 5 MHz of 800 MHz (791-796; 832-837MHz) £225,000,000
Niche Spectrum Ventures Ltd (a subsidiary of BT Group plc)
2 x 15 MHz of 2.6 GHz (2520-2535; 2640-2655MHz) and1 x 25 MHz of 2.6 GHz (unpaired) (2595-2620MHz) £186,476,000
Telefónica UK Ltd (O2)
2 x 10 MHz of 800 MHz (811-821; 852-862MHz)(coverage obligation lot) £550,000,000
2 x 10 MHz of 800 MHz, (801-811; 842-852MHz)2 x 20 MHz of 2.6 GHz (2500-2520; 2620-2640MHz) and1 x 25 MHz of 2.6 GHz (unpaired) (2570-2595MHz)
Frequencies are in use for LTE in the UK
Three different frequency bands are used for 4G LTE in the UK. • 800MHz, • 1.8GHz , • 2.6GHz band.
Measured signal strength of LTE in 800MHz in T718 LSBU
Measured signal strength of LTE in 2.6 GHz in T718 LSBU
Vodafone Vodafone Vodafone BT
4G coverage in UK, 2014
EE, 4G coverage in the UK, March 2015
The State of LTE (February 2013)
What is the difference between LTE and 4G?4G: 100Mbp/s while on moving transport and 1Gbp/s when stationary. While LTE is much faster than 3G, it has yet to reach the International Telecoms Union's (ITU) technical definition of 4G. LTE does represent a generational shift in cellular network speeds, but is labelled 'evolution' to show that the process is yet to be fully completed.
The Global Rollout
76 Countries with LTE18 LTE scheduled
Australia (24.5Mbps) Fastest Country With LTEClaro Brazil (27.8Mbps) Fastest Network With LTEJapan (66% LTE improvement) Most Improved country for LTE SpeedTele2 Sweden (93% coverage) Network With Best CoverageSouth Korea (91% average coverage) Country with Best Coverage
Feb 2013; http://opensignal.com/reports/state-of-lte/
Feb 2014; http://opensignal.com/reports/state-of-lte-q1-2014/
On average LTE is the fastest wireless technology worldwide, representing a real increase in speed on both 3G and HSPA+. 4G LTE is over 5x faster than 3G and over twice as fast as HSPA+ and represents a major leap forward in wireless technology.
References• Dr. Joern Krause, ”Future 3GPP RAN standardization
activities for LTE” ppt, Oct 2012.• http://www.ofcom.org.uk/• http://www.4g.co.uk/4g-lte-advanced/