3g- module

Course Objectives

At the end of this course, you will be able to:-

Understand evolution of mobile communications

Master 3G frequency allocation

Master 3G mode comparison

AGENDA

What is 3G? 3G Standards and capabilities

UMTS Network Architecture

Channel types and Radio Resource Management

Broadband propagation channel and WCDMA basic concept

Spreading, scrambling and modulation

Power control in UMTS

Handover Types

What is 3G Mobile?

Third Generation VisionCommon spectrum worldwide

1920-1980 MHz and 2110-2170 MHz

Wide range of new services

Data centric (e g. Internet) and multimedia oriented

Data bit rates up to 2 Mb/s

Seamless global roaming

Improved security and performance

Support a variety of terminal (from PDA to desktop)

Intensive use of Intelligent Network (IN) technology

IMT – 2000: The Mobile Internet

The IMT-2000 third generation mobile standard enables mobile users to harness the full power of the Internet through efficient high-speed radio transmission, optimized for multimedia communications..

Evolution towards 3G

3G Capabilities High-speed data transmissions

Symmetrical and asymmetrical data transmission support

Improved voice quality

Greater capacity

Multiple simultaneous services

Global roaming across networks

Improved security

Service flexibility

The 3G Performance Advantage

Time to download a 1 MB file:

Fixed line modem: 3 minutes

GSM cell phone: 15 minutes

Enhanced GSM phone: 1-5 minutes

3G phone (outdoor): 21 seconds

3G phone (indoor): 4 seconds

Wireless Internet

Audio on demand

Electronic postcards

Video conferencing

Secure mobile commerce transactions

Traffic and traveling information - location specific

3G Applications

Types of mobile Internet connectivity

Global systems for mobile communication (GSM)

High speed circuit switched data (HSCSD)

General packet radio services (GPRS)

Third generation (3G) mobile

Enhanced data GSM environment (EDGE)

Public access WLAN

Linked public access WLANs

3G Subscribers

Why 3G?

Limitations of 2G:-

Voice centric Designed mainly for telephony application Circuit-switched High BER (Bit Error Rate) Low data bit rate (< 14.4kbps)

Too many standards globally GSM, CDMA, PDC, PHS etc.

Isolated networks MAP based IS-41 based Difficult to roam between these networks

Why lower subscribers

Pricing.

Lack of awareness of it’s benefits.

The lower subscriber numbers are a testimonial to the fact that private players should be allotted spectrum at the earliest - after all, government is losing money by delaying 3G auction and the ones who have been allotted spectrum aren’t able to market/position it to consumers

All said and done, government owned companies need serious (and aggressive) competition from private players – otherwise, expect a suboptimal and mediocre 3G story.

Why delayed?

3G services were delayed because of the spectrum issues, licensing issues and auction process. There is still not enough clarity on the policy front and there are lot of questions to be answered.

Will price-sensitive Indian consumers shift in large enough numbers to a 3G system? While there's no doubt the market is low-value with each customer yielding just Rs 400 a month to the mobile phone companies (after deducting the licensing revenue share), around 5 to 10 per cent of customers pay monthly bills of more than Rs 1,000 per month.

Standards of 3G

The 3G standard was created by the International Telecommunication Union (ITU) and is called IMT-2000. The aim of IMT-2000 is to harmonize worldwide 3G systems to provide global roaming. As a result, what we have been left with is five different standards grouped together under the IMT-2000 label:

W-CDMA

CDMA2000

TD-CDMA/TD-SCDMA

DECT

UWC-136

UMTS NETWORK ARCHITECTURE

UMTS NETWORK Architecture

The UMTS network includes not only the air interface of an UMTS network but also the fixed network part with its connection to the core networks (packet and circuit switched) .All main elements of an UMTS network and the connection to the external networks are shown in figure-1

UMTS NETWORK Architecture

1)UE (User Equipment) The UE consists of two parts :-

The mobile equipment (ME) is the radio terminal used for radio communication over the Uu interface

The UMTS Subscriber Identity Module (USIM) is the equivalent smartcard to the SIM in GSM. It holds

the subscriber identity, performs authentication algorithms, stores authentication and encryption keys, etc.

2) UTRAN (UMTS Radio Access Network)

The UTRAN consists of one or several Radio Network Subsystems (RNS) each containing one RNC and one or several Node B:- Node BThe Node B is the correspondent element to the BTS in GSM. Within Alcatel this part of the network is called the Multi-standard Base Station (MBS), as it is possible to integrate GSM modules as well (not in the early versions!) RNCThe Radio Network Controller (RNC) owns and controls the radio resources of theconnected Node Bs. The RNC can have three different logical roles: CRNC, SRNC,DRNC.

3) CN (Core network)HLRThe Home Location Register is a database located in the user’s home system that stores the master copy of the user’s service profile.MSC/VLRThe Mobile Services Switching Center and Visitor Location Register are the switch (MSC) and database (VLR) serving the UE in its current location for circuit switched services.GMSCThe Gateway MSC (GMSC) is the MSC at the point where the UMTS PLMN is connected to external circuit switched networks.SGSNThe Serving GPRS Support Node (SGSN) is the counterpart of the MSC/VLR for the packet switched part of the network.

GGSNThe Gateway GPRS Support Node (GGSN) is the counterpart of the GMSC in the packet switched domain.

4) External networks:-

The UMTS network is connected to two kinds of external networks:

Circuit switchedExamples for CS networks are: Existing telephone service, ISDN, PSTN

Packet switchedBest example today for a packet switched network is the Internet

5) InterfacesIt is important to know, that all external UMTS interfaces are open interfaces. This means that theoretically equipment of different vendors can be mixed if it fulfills the standards.

Cu interfaceThe Cu interface is a standard interface for smartcards. In the UE it is the connection between the USIM and the UE.

Uu interfaceThe Uu interface is the WCDMA radio interface within UMTS. It is the interface through which the UE accesses the fixed part of the network. This interface is the most important one to understand for RNP issues.

Iu interfaceThe Iu interface connects the UTRAN to the core network and is split in two parts. The Iu-CS is the interface between the RNC and the circuit switched part of the core network.The Iu-PS is the interface between the RNC and the packet switched part of the core network.Iur interfaceThis RNC-RNC interface was initially designed in order to provide inter RNC soft HO, but more features were added during the development. Four distinct functions are provided now:1.Basic inter-RNC mobility2.Dedicated channel traffic3.Common channel traffic4.Global resource management

Iub interfaceThe Iub interface connects the Node B and the RNC. Contrarily to GSM, this interface is fully open in UMTS and thus more competition is expected.

6) Logical roles of the RNC

CRNCFor each Node B the RNC to which the Node B is connected is the Controlling RNC (CRNC).

SRNC & DRNC

The Serving RNC (SRNC) for a certain connection is the RNC providing the Iu connection to the core network. When the UE is in inter-RNC soft HO, more than one Iub and at least one Iur connection is established. Only one of the RNCs (the SRNC) is providing the Iu interface to the core network, allother ones are just routing information between Iub and Iur interface. These RNCs are called Drift RNC (DRNC). Figure 2 illustrates the logical role of SRNC and DRNC.

Mapping between GSM and UMTS

Standards and used frequency spectrumThe ITU-R has produced high-level documents covering the performance, service type, and inter- working requirements for IMT-2000. Various international standards bodies such as the European Telecommunications Standards Institute (ETSI) are responsible for the detailed technical specifications of the equipment required to provide an IMT-2000 compatible service. A number of different standards are likely to emerge; but they are expected to have sufficient inter-working capability to allow an integrated IMT-2000 service for subscribers. IMT-2000 networks will supportfive interface standards:IMT-DSUMTS Frequency Division Duplex (FDD)IMT-MCUS CDMA 2000 standardIMT-TCUMTS Time Division Duplex (TDD)IMT-SCGSM EDGE (IS-136) standardIMT-FTDECT standard

For this part, the following band is reserved:-

UL:-1920 – 1980 MHzDL:-2110 – 2170 MHzAs the UMTS carrier spacing is 5 MHz, the available bandwidth for the FDD part provides 12 different channels. Depending on the country these 12 available licenses are given to different operators. An operator gets typically 2 or 3 licenses for paired (UL and DL) frequency bands. This small amount of frequencies is due to the frequency reuse of 1 applied within a UMTS system.The nominal channel spacing is 5 MHz, but this can be adjusted to optimize performance in a particular deployment scenario. The channel raster is 200kHz, which means that the center frequency must be an integer multiple of 200 kHz. The carrier frequency is designated by the UTRA Absolute Radio Frequency Channel Number (UARFCN).

Mobile classes:-

For the terrestrial UTRAN system, the following mobile power classes are defined. They define the maximum output power of the UE

CHANNEL TYPES AND RADIO RESOurce management

CHANNEL TYPES AND RADIO RESOURCE MANAGEMENT

The UTRA radio interface is layered into three protocol layers :-

Physical layer (L1)Data link layer (L2)Network layer (L3)

Layer 2 is split into following sub-layers: Medium Access Control (MAC), Radio Link Control (RLC),Packet Data Convergence Protocol (PDCP) and Broadcast/Multicast Control (BMC).

Layer 3 is partitioned into sub-layers where the lowest sub-layer, denoted as Radio Resource Control (RRC), interfaces with layer 2 and terminates in the UTRAN. The next sub-layer provides 'Duplication avoidance' functionality.

The higher layer signaling such as Mobility Management (MM) and Call Control (CC) follows a protocol architecture, which is similar to the current ITU-R protocol architecture, ITU-R M.1035.

Overview of the radio interface protocol architecture

Overview on channel types and names

In UMTS three different channel types for data transmission and signaling are defined:-

Physical channels (Layer 1)Transport channels(Interface between layer 1 and 2)Logical channels (Interface between layer 2 and 3)Each of these channel types and the mapping between them will be described in more detail hereafter.

Physical channels:-Physical channels are channels really transmitted over the air. They are carrying transport channels within their frames and time slots.

Transport channels

Transport channels are used as interface between Layer 1 and Layer 2 of the radio network architecture. They are divided into

Common transport channels (all except DCH)Dedicated transport channels (only DCH)Coded Composite Traffic Channels (CCTrCH)

The CCTrCH is used to multiplex several transport channels into one new transport channel. This CCTrCH is than mapped to one or several physical channels depending on the required bit rate. A CCTrCH must fulfil the following criteria:

A maximum of 5 transport channels can be multiplexed to one CCTrCHOnly transport channels with the same active set can be mapped to one CCTrCHDifferent CCTrCHs can not be mapped onto the same physical channelDedicated and common transport channels can not be multiplexed into the same CCTrCHFor the common transport channels, only the FACH and PCH may belong to the same CCTrCH.

There are hence two types of CCTrCH:-

CCTrCH of dedicated type, corresponding to the result of coding and multiplexing of one or several DCHs.CCTrCH of common type, corresponding to the result of the coding and multiplexing of a common channel, RACH in the uplink, DSCH ,BCH, or FACH/PCH for the downlink.

The reason for using CCTrCHs is to provide a more efficient usage of resources. Due to multiplexing of several channels into one channel and splitting of this new channel into pieces with the right size for fitting into a physical channel, the physical channel are used more efficient.

Common and dedicated transport channels

RACH-Random Access Control Channel

CPCH-Common Packet Channel

The Common Packet Channel (CPCH) is an uplink transport channel and is a extension to the RACH. The CPCH is associated with a downlink DPCCH with special slot format (for fast power control commands transmission and CPCH signaling). Before transmission on CPCH starts, the FACH in downlink is used to provide power control and CPCH control commands. In the physical layer the main differences from the RACH are the use of fast power control (inner loop power control), a physical layer based collision detection mechanism and a CPCH status monitoring procedure.

FACH- Forward Access Channel

The Forward Access Channel (FACH) is a downlink transport channel. The first FACH is transmitted over the entire cell with low data rate. Additional FACHs in the cell can be transmitted over only a part of the cell (e.g. beam forming antennas) using higher data rates.The FACH is not allowed to use fast PC (inner loop PC). It can be used to transmit packet data to the UE.

DSCH- Downlink Shared Channel

The Downlink Shared Channel (DSCH) is a transport channel intended to carry dedicated user data and/or control information; it can be shared by several users. In many aspects it is similar to the FACH, but DSCH supports the fast power control as well as variable bit rate open a frame-by-frame basis. The DSCH can be transmitted only over a part of the cell. It can employ the different transmit diversity modes used by the associated downlink DCH. The DSCH is always associated with a downlink DCH.

BCH- Broadcast Channel

The Broadcast Channel (BCH) is a downlink transport channel that is used to broadcast system- and cell-specific information. The BCH is always transmitted over the entire cell and has a single transport format. The broadcast channel carries information like random access codes and access slots in the cell, or types of used transmit diversity. As it is mandatory to receive the BCH transport channel to register to the corresponding cell, the BCH must be transmitted with relatively high power.

PCH- Paging Channel

The Paging Channel (PCH) is a downlink transport channel. The PCH is always transmitted over the entire cell to be able to initiated a communication with the UE. The PCH is sent by all cells within the location area of the mobile. The transmission of the PCH is associated with the transmission of physical-layer generated Paging Indicators, to support efficient sleep-mode procedures.

DCH- Dedicated Channel

The Dedicated Channel is a downlink or uplink transport channel. The DCH is transmitted over the entire cell or over only a part of the cell using e.g. beam-forming antennas. The contents of the DCH transport channel are not visible to the physical layer, thus the DCH can carry user data and control information as well. The UTRAN will set the physical layer parameters depending on DCH carrying control or user data. The DCH supports

Fast power controlFast data rate change on a frame-by-frame basisSoft HO

Logical channels

Logical channels are used as interface between Layer 2 and Layer 3 of the radio network architecture.

BCCH- Broadcast Control Channel (DL)System control information is broadcasted on the BCCH

PCCH- Paging Control Channel (DL)Paging information is broadcasted on the PCH channel.

CCCH-Common Control Channel (DL & UL)A bi-directional channel for transmitting control information between the network and UEs.The logical CCCH channel is always mapped onto RACH/FACH transport channels.

DCCH- Dedicated Control Channel (DL&UL)

The DCCH is a bi-directional channel, that transmits dedicated control information between UE and UTRAN. The DCCH is established during RRC connection establishment procedure.

Logical Traffic channels:-

DTCH- Dedicated Traffic Channel (DL&UL)The DTCH carries user data. It can exist in UL & DL.

CTCH- Common Traffic Channel (UL)A common downlink traffic channel to transfer dedicated user information to all or a group of UEs.

Mapping between different channel types

The physical channelsIn this the physical channels will be explained. They are separated into UL and DL channels

The physical channels in Uplink:-

PRACH- Physical Random Access ChannelThe PRACH is used to carry the RACH transport channel.

PCPCH- Physical Common Packet ChannelThe PCPCH is used to carry the CPCH transport channel.

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DPCH (DPCCH/DPDCH) - Dedicated Physical Channel

The DPCH is a summary of the two physical channels DPDCH and DPCCH. The DPCCH carries user dedicated control information and the DPDCH carries user dedicated data.

The physical channels in DL:-

Physical downlink channels

DPCH (DPDCH & DPCCH) -Dedicated Physical Channel

Dedicated Physical Data Channel (DPDCH) and Dedicated Physical Control Channel (DPCCH) are time multiplexed on the same DPCH.

DL-DPCCH for CPCHDL- Dedicated Physical Control Channel

This special DPCCH is always associated with a CPCH for PC and signaling of the CPCH.

CPICH (P-CPICH & S-CPICH) -Common Pilot ChannelThe CPICH consists of two sub-channels, the primary CPICH (P-CPICH) and the secondary CPICH (S-CPICH).

PCCPCH- Primary Common Control Physical ChannelIt is used to carry the BCH transport channel.

SCCPCH- Secondary Common Control Physical Channel It is used to carry to FACH and PCH.

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SCH- Synchronization channelThe SCH is needed for the cell search of the mobile and consists of a Primary SCH and a Secondary SCH, which are sent in parallel. They are time multiplexed with the PCCPCH.

PDSCH- Physical Downlink Shared channelThe PDSCH is used to carry the DSCH. A certain code for channelization is given to the PDSCH for one frame. During this frame all slots are allocated to one UE. The UE can change every frame. Different UEs can be code multiplexed, using codes from the same OVSF root during one frame. A UE knows when it has to decode the PDSCH by the DPCH which is necessarily associated with a PDSCH connection of each UE

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AICH - Acquisition Indication Channel:

The AICH is used to sent an acknowledgement to the UE after correct reception of the RACH. The AICH is not visible to higher layers, thus directly controlled by the physical layer. It has a spreading factor of 256 and consists of 15 repeated consecutive access slots of 5120 chips duration (20 ms frame). 4096 chips are used by the AICH and for the other 1024 chips the transmission is either off, or they are used by the CSICH or other possiblefuture physical channels.

PICH- Page Indication Channel

The Paging Indicator Channel (PICH) is a fixed rate (SF=256) physical channel used to carry the paging indicators. The PICH is always associated with an S-CCPCH to which a PCH transport channel is mapped.Once a PI message has been detected on the PICH, the UE decodes the next PCH frame transmitted on the SCCPCH whether there is a paging message intended for it.

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AP-AICH- CPCH Access Preamble Acquisition Indicator Channel

CD/CA-ICH- CPCH Collision Detection/Channel Assignment Indicator Channel

CSICH- CPCH Status Indication Channel

These physical channels have been specified for the CPCH access procedure. They carry no transport channels, but only information needed in the CPCH access procedure.

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Broadband propagation channel and WCDMA basic concept

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Broadband propagation channel and WCDMA basic concept

Multiple Access TechniquesIn a mobile radio system, the radio channel has to be accessed by a great number of users. A multiple access method has to be used in order to avoid interference in the receiver. The current principles are

TDMA (Time Division Multiple Access)FDMA (Frequency Division Multiple Access)CDMA (Code Division Multiple Access)

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 The data signals are modulated with user specific carrier signals. The orthogonality1 of the multiple access carrier signals represents the prerequisite for correctly detecting the data of all users.

FDMA uses bandpass carrier signals which are non-overlapping in the frequency domain and therefore orthogonal at any time.TDMA impulse carrier signals are non-overlapping in the time domain and orthogonal at sampling time.CDMA signature waveforms are generated from orthogonal code sequences (e.g. Walsh sequences) or from quasi-orthogonal pseudo-noise (PN) sequences (e.g. Gold Sequences). By modulating the data with the user specific CDMA carrier signals, the original signal is spread over the whole available frequency band.

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Orthogonality of two functions g(t) and s(t) is given in the case, that their cross-correlation function is equal to zero

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Broadband signal and Coherence bandwidth

A signal is called broadband, if its coherence bandwidth is smaller than the signal bandwidth. Coherence bandwidth of a channel is defined as the range of frequency components which experience similar fading conditions. The coherence bandwidth of the channel depends on the local scattering environment. For most practical mobile channels 5MHz is much larger than the coherence bandwidth. Narrow band transmission (<200 kHz) the channel bandwidth is less than the coherence bandwidth. Fading characteristics at different frequency components are identical. Forwide band transmission (>1 MHz) fading characteristics of spectral components tend to be uncorrelated

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In narrow band transmission, when the receiver experiences a deep fade, signal quality is severely degraded High BERHowever in wide band systems because of uncorrelated fading of the spectral components deep fades affects only a portion of the spectrumBetter signal qualityLow BERBetter robustness to fading

The differentiation between broadband and narrow band signals can also be made in the time domain. If the delay spread of a signal is that big, that the received multipath signals of the next transmitted symbol interfere with the previous symbol, the channel is called a narrow band channel.

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Multipath propagation and RAKE receiver

One big advantage of the UMTS system is its capability to benefit from a multipath environment. In the upper part of Figure we can see the delay spread of a broadband channel as used in UMTS. The received energy from the different multipaths of one signal overlaps much less than in thenarrow band case. Thus, the different multipaths can be combined by a special receiver technique, called RAKE receiver, to one improved signal. A RAKE receiver has several input paths (called RAKE fingers), where the signal can be delayed by an adjustable time. Selecting the delay time on each finger in that way, that the different multipaths entering the receiver at the same time, the signals can be combined and thus an improved summary signal can be generated. The delay time on each RAKE finger is determined automatically. The number of RAKE fingers is not fix and depends on the considered product.

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Spreading, scrambling and modulation

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Spreading, scrambling and modulation

Spreading

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Despreading

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CODES USED

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Codes used

The spreading of the data signal onto physical channels is done in two steps:

1.Channelization

2.Scrambling

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Spreading, scrambling and modulation

As demodulation is the reciprocal of modulation, only the modulation is explained in more detail here.The UTRA system uses QPSK modulation. This means, that one transmitted symbol consists of two bits, one is transmitted with 0° phase shift (I branch, or real part) and the other one with 90° phase shift (Q branch or imaginary part).

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Uplink part

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Downlink part

POWER CONTROL IN UMTS

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Power Control in UMTS FDDFind detailed information on power control in [25.214]. Summary in [WFI] or [INTRO]. This chapter is in accordance with [SysDesign]. This chapter is divided into 3 parts:-

General Power Control

Uplink PC

Downlink PC

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General Power Control:-

Outer Loop Power Control

Inner Loop Power Control for dedicated channels

Open Loop Power Control

Site selection diversity transmit power control

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. HANDOVER TYPES

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HO types & events

Definition: The list of cells involved in the soft/softer HO is called “Active Set”. The maximum size of the active set can be defined.

1) Hard handover:-

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Cell 1 Cell 2

Handover is a process by which the control/communication of a Mobile is transferred from one cell to another

HANDOVER

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2) Soft handover

Soft HO means, that the mobile receives the same signal from more than one Node B and its transmitted signal is processed by more than one Node B. 3)Softer handoverA softer HO is a soft HO between cells of the same Node B, thus sectors of the same site. As this is not improving the multipath conditions as much as soft HO does, the diversity gain is smaller.

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3) Power control in soft(e r) handoverIn SHO, the UE has established more than one radio link. This requires special power control functionality to identify the correct power control command.3.1) Downlink PC in SHOThis is leading to the reception of more than one Power Control command in downlink (one from each Node B in the active set). If at least one of the Node Bs in the active set is sending a power down command, the UE will reduce its output power. It is enough, if one of the Node Bs is receivedcorrectly.

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3) Power control in soft(e r) handover

In SHO, the UE has established more than one radio link. This requires special power control functionality to identify the correct power control command.

3.1) Downlink PC in SHO

3.2) Uplink PC in SHO

3.2.1) Power drifting

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Reporting events for Soft Handover and measurement reports

To find out the best cell or cells within UMTS, the UE measures the CPICH of all received neighbor cells. The UE is told by UTRAN witch reporting events shall force the mobile to generate a measurement report and sent it to the SRNC. This is different from GSM, where a measurementreport was generated at fixed time intervals (480 ms). So by using less reporting events within the handover algorithms is leading to less measurement reports sent over the air interface.In this chapter al HO events defined in 3GPP for intra-frequency measurements are listed. The HO algorithms using this events are not standardized, but have to use reporting events out of the poolgiven by 3GPP .

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Intra frequency reporting events:-

1A

1B

1C

1D

1E

1F

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90 Million 3G Subscribers In India By 2013?

According to a study by industry association Federation of Indian Chambers of Commerce and Industry (FICCI) and telecom consulting firm BDA, 3G revenues in India will reach $15.8 billion or 46% of the total wireless revenue, by 2013.

The 3G subscriber base is expected to reach 90 million in five years, accounting for 12% of the total telecom subscriber base of 746 million

Issues related to 3G

Expensive input fees for the 3G service licenses & agreements

Lack of member state support for financially troubled operators

Expense of 3G phones

Lack of coverage, because it is still a new service

Current lack of user need for 3G voice and data services in a hand-held device

Applications

Mobile TV 

Video on demand 

Video conferencing 

Tele-medicine 

Location-based services 

Evolution of 3G

Cellular mobile telecommunications networks are being upgraded to use 3G technologies from 1999 to 2010.

Japan was the first country to introduce 3G nationally, and in Japan the transition to 3G was largely completed in 2006.

Korea then adopted 3G Networks and the transition was made as early as 2004.

Some Representative Current Wireless Options

3G Cellular (WCDMA)

Wi FI

WI MAX

Blue Tooth

Conclusion

It’s a new technology but has vast unexploited market and revenue base.

3G - Anywhere Anytime Connectivity.

Challenges makes everything perfect!!!

Coming 4G and beyond…..

Its not the end, Way ahead…

THANK YOU!!.........

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