cellular radio networks - aalto university · wcdma (umts) gprs egprs (edge) ... nokia bt =...

1.11.2005 T-110.5120 Next Generation Wireless Networks 1

Cellular Radio Networks

Samiseppo Aarnikoivu

Juha Winter


Contents

� Introduction 3

� Core Development 6

� 2G Radio Development 10

� 3G Radio Development 13

� Long-Term Radio Evolution 17

� Service Evolution 19

� Summary and Conclusions 23

� References 24

� Additional Material 25


Introduction, 1/3

� Current 2G/3G architecture

� 3GPP Release 4 is being deployed


Introduction, 2/3

� Current 2G/3G performance

� End-user throughput and latency

150-250350-700~900Average RTT (ms)

384 (DL) / 64-384 (UL)

236 (pract.), 384 (theor.)

85 (pract.), 115 (theor.)

Peak rate (kbps)

In line with peak rates

80−160 (2 slots),

160−200 (4 slots)40−50

Typical rate (kbps)

WCDMA (UMTS)

EGPRS (EDGE)GPRS (GSM)


Introduction, 3/3

� Current 2G/3G services� Basic services

� Voice telephony, CS and PS data

� Messaging

� SMS, MMS, Instant Messaging (IM)

� Push-to-Talk over Cellular (PoC)

� E-mail, web browsing

� Video telephony

� Streaming media

� Audio streaming

� Video streaming/sharing


Core Development

� There is a clear need to build only one core network that provides access-independent and flexible services:� AAA� Call processing and management� Mobility� Secure transport with QoS support� Gateways� Network management etc.

� Core network machinery and interfaces are a vital counterpart and enabler for the actual radio access evolution


IP Multimedia Subsystem (IMS)

� Defines a horizontal architecture of service enablers and common functions providing� Interoperability� Roaming� Bearer control� Charging� Security

� Generic architecture for offering VoIP and multimedia services in multiple networks� Migration path to an all-IP

network

� Utilizes heavily the Session Initiation Protocol (SIP, RFC3261)

� Trials and first commercial deployments are on-going

Source: Ericsson

AS = Authentication ServerCSCF = Call Session Control FunctionHSS = Home Subscriber ServerMRF = Media Resource FunctionSG/MGCF = Service Gateway / Media Gateway Control Function


Multi-Access

� Modern terminals already contain a number of air interfaces, and a lot more can be expected

� Operators, enterprises or even end users are able to extend the access networks with what they already may have

� Interworking aspects are addressed in many 3GPP Release 6 specifications

� Focus is at least on WLAN and WiMAX

Source: Nokia

BT = BluetoothDVB-H = Digital Video Broadcasting for HandheldsMBWA = Mobile Broadband Wireless AccessNFC = Near Far CommunicationRFID = Radio Frequency IdentificationUWB = Ultra Wide Band


Unlicensed Mobile Access (UMA)

� Network coverage enhancement, which provides access to 2G services over unlicensed frequency spectrum� WLAN, WiMAX� Bluetooth etc.

� Seamless mobility between 2G BSS and UMA accesses� Originally developed by Kineto, now a 3GPP standard� First commercial products out in 1H/2006


2G Radio Development, 1/3

� Dual Transfer Mode (DTM)� Simultaneous voice & data connections in

GSM/EDGE

� Specified in 3GPP TS 43.055

� Mixed use of time slots for CS & PS traffic� DTM multi-slot classes (5, 9, 11) and high multi-slot

classes with Enhanced Dynamic Allocation (EDA)

� 1 time slot for CS services (DL/UL), multiple for PS data, e.g. CS 1/1 + PS 2(DL)/1(UL)

� E-mail, SMS and web browsing during voice calls ⇒improved usability

� New services for GSM/EDGE

� Video sharing (previously only in 3G!)



� Why DTM?� Increased flexibility of services for the end-user in

GSM/EDGE networks� New revenue opportunities for operators due to new

(enabled) services� Enhanced service continuity in GSM/EDGE/WCDMA

multi-radio networks� WCDMA already supports simultaneous CS & PS

connections, but coverage may be limited in some areas

� Incremental upgrade to existing BSS network elements and terminals

� Only a SW upgrade may suffice, depending on vendor specific implementation

� First DTM compliant terminals already on the market, commercial launches expected in early 2006



� EDGE Evolution� Will be standardized from Release 7 onward

� Aims to tighten the gap between current GSM/EDGE and WCDMA/High Speed Packet Access (HSPA) technology

� Improved service performance, enhanced service continuity, more cost-efficient coverage

� Increased spectral efficiency

� Offers 2−3 fold increase in data rates

� Halves the latency (RTT)

� Can be implemented to existing GSM/EDGE networks with low network impact

� Backwards compatible with existing EDGE solutions


3G Radio Development (3.5G)

� Current 3G networks have not been able to actually respond to the high expectations of mobile broadband� Performance not on par with xDSL� Relatively high costs for operators as well as end

customers

� A number of competitive techniques are now beginning to enter the market� CDMA 450� Flash-OFDM� Mobile WiMAX (806.11e)

� 3GPP Releases 5 and 6 will address these issues� 3G network architecture can be optimized to be

more cost-effective for packet data


High Speed Downlink Packet Access (HSDPA)

� New shared channels (HS-SCCH and HS-DSCH) with functionalities pushed to Node B� Adaptive modulation and

coding (16-QAM & QPSK)� Fast scheduling (2 ms)� Fast retransmission (HARQ)

� DL Throughput and delay improvements� ~1500 kbps (first phase),

>10 Mbps possible in practice

� RTT < 100 ms

� Software update (some vendors may require HW update as well)

� First commercial HSDPA network has already been opened (O2/Isle of Man), mainstream launches will happen during 2006

Source: Siemens


High Speed Uplink Packet Access (HSUPA)

� New uplink data path (E-DCH) below the RLC layer parallel to DCH, similar improvements as HSDPA (except for adaptive modulation, which is not feasible)� Layer1 hybrid ARQ� Node B based scheduling for uplink� Frame sizes 2 ms & 10 ms

� UL Throughput and delay improvements� ~1 Mbps (first phase)

>5 Mbps possible� RTT < 50 ms

� Software update (some vendors may require HW update as well)� Commercial launches will probably start to happen in late 2006 -

early 2007

Source: Nokia


PS-optimized Network Architecture

� UTRAN architecture is designed to provide both CS and PS services� Layered functionality between

Node B and RNC� ATM-based transmission etc.

� UTRAN evolution is clearly happening with PS services� Air interface may no longer be

the actual bottleneck

� Nokia’s Internet-HSPA is one solution to optimize the already deployed network for PS services� I-HSPA is also sold for

greenfield operators as an alternative for other mobile broadband techniques

� Scalability, lower cost� Better RTT


Long-Term Radio Evolution

� UTRAN LTE is a 3GPP research item for Release 8� Also known as 3.9G or “Super 3G”

� Still a long way from being commercial (2009?)

� Aims at peak data rates of 200 Mbps (DL) and 100 Mbps (UL)

� Optimized for PS only

� New architecture

� New modulation

� Spectrum and bandwidth flexibility

� Lower latency (<30 ms?)

� Interworking with 3.5G evolution


Potential 3.9G Enablers

� MIMO (Multiple Input Multiple Output)� Multiple antennas on both receiver and transmitter

side� Increased capacity (e.g. 3x) due to multi-stream

transmissions and code reuse� Already accepted to 3GPP Release 7� Demands high processing power

� OFDM (Orthogonal Frequency Division Multiplexing)� Already used e.g. in ADSL and DVB transmission� Available bandwidth is split into many (100-8000)

narrowband channels� Low symbol rate => high multipath delay tolerance

=> allows high spectrum efficiency


Service Evolution, 1/4

� New speech codecs� Adaptive Multi-Rate Wideband (AMR-WB)

� Standardized by both 3GPP (TS 26.171) and ITU-T (G.722.2), intended to be used in UMTS

� Multi-mode speech codec supporting 9 wide band speech coding modes with bit rates 6.6−23.85 kbps

� Wider speech bandwidth of 50−7000 Hz compared to narrowband speech codecs ⇒ excellent speech quality

� Performs reasonably well also under severe background noise conditions and in the case of music as input

� Adaptive Multi-Rate Wideband Plus (AMR-WB+)� Supports even higher sampling rates and stereo signals

(for high quality music)� Greatly improved generic audio coding capabilities due to

use of transform coding in addition to Algebraic Code Excited Linear Prediction (ACELP)



� Rich media and mobile multicast� Increased data transfer capabilities are a key

enabler for broadcast/mobile/Internet convergence services

� Mobile TV (IP datacast over DVB-H)� High quality audio/music streaming (e.g.

mobile jukebox)� Scheduled audio/video distribution, push

media� Video announcements� Real-time, content-rich multiplayer games� File distribution between multiple parties,

mobile P2P systems



� Voice over IP (VoIP)� Cost-efficient telephony using existing IP network

infrastructure, mobile access through IMS� Already massively utilized by telco carriers and corporate

offices but also increasingly popular with private consumers (e.g. Skype)

� Natural consequence of the all-IP convergence� VoIP codecs

� Internet Low Bit-rate Codec (iLBC)� Dual rate operation: 15.2 kbps with 20 ms frames or 13.33

kbps with 30 ms frames

� ITU-T G.723.1� Capable of achieving up to 12:1 compression ratio� Dual rate operation: 5.3 kbps or 6.3 kbps

� ITU-T G.729(/A/AB)� 8 kbps, speech quality similar to that of 32 kbps ADPCM

landline connections



� Multimedia Broadcast/Multicast Service� Point-to-multipoint (p-t-m) bearer service enabling

efficient unidirectional multimedia content delivery to mobile subscribers

� Two modes of operation� Multicast

� Users need to subscribe to and join specific services

� Broadcast� Service data is sent to predefined network area without

system knowledge of the presence of potential users, no charging data collected

� Impact on RAN radio resource and mobility management, type of used radio bearers in WCDMA

� Idle-mode reception: UE must be able to receive data also when idle (no signaling connection to the network) to reduce battery power consumption


Summary and Conclusions

� There are several different (and changing) drivers and enablers for network development and new services – performance is only one of them

� Radio evolution is pushed by increased competition and interworking support within the core network, cost goes down all the time

� 2G/3G has the most vendors and users, so it will be hard to beat

� Network capabilities and resulting services will be at least an order of magnitude better and more versatile than today

� “You ain’t seen nothing yet”


References

1. http://www.3gpp.org/specs/specs.htm

2. http://www.ericsson.com/products/white_papers_pdf/ims_ip_multimedia_subsystem.pdf

3. http://www.ietf.org/rfc/rfc3261.txt

4. http://www.sipcenter.com/

5. http://www.wimaxforum.org/

6. http://www.umatechnology.org/

7. http://www.europe.nokia.com/BaseProject/Sites/NOKIA_MAIN_18022/CDA/Categories/Business/Technologies/EDGE/_Content/_Static_Files/nokia_edge_evolution_wp.pdf

8. http://www.netlab.hut.fi/opetus/s38310/04-05/Kalvot_04-05/H%E4m%E4l%E4inen_070605.ppt

9. http://www.nokia.com/NOKIA_COM_1/Operators/Mobile_Operators_&_Service_Providers/Mobile_Networks/WCDMA/radio_network_evolution_a4_02-2005_net.pdf

10. http://www.nokia.com/NOKIA_COM_1/About_Nokia/Press/White_Papers/pdf_files/hspa_a4_02-2005_net.pdf

11. http://www.siemens.com/Daten/siecom/Germany/COM/Internet/Mobile_Networks/WORKAREA/com_mnde/templatedata/Deutsch/file/binary/HSDPA_0105_1306647.pdf

12. http://www.nortel.com/solutions/wireless/collateral/nn_112020.06-01-05.pdf

13. http://en.wikipedia.org/wiki/COFDM

14. http://www.mobiletv.nokia.com/resources/files/mobile_tv_brochure_2005.pdf

Further information: http://www.google.com


Additional Material

HSDPA User Plane

HSUPA User Plane


HSDPA User Plane

RNCNode BUE

WCDMA L1

MAC

RLC

WCDMA L1

MAC-hs FP

Transport Transport

FP

MAC-d

RLC


HSUPA User Plane

RNCNode BUE

WCDMA L1

MAC-es/e

MAC

WCDMA L1

MAC-es FP

Transport Transport

FP

MAC-e

MAC-dRLC

RLC

cellular radio networks - aalto university · wcdma (umts) gprs egprs (edge) ... nokia bt =...

Documents