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3g4g ktv2011

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  • 1. 3GPP Network Architecture Radio Access Technologies Discussion UMTS vs. LTE: a comparison overview Unik4230: Mobile Communications Khai Vuong May 16, 2011
  • 2. 3GPP Network Architecture Radio Access Technologies Discussion Agenda 3GPP Network Architecture UMTS LTE Radio Access Technologies WCDMA OFDMA Discussion
  • 3. 3GPP Network Architecture Radio Access Technologies Discussion 1 3GPP Standards (I) 3GPP: 3rd Generation Partnership Project Version Released Info Release 98 1998 specified pre-3G GSM network Release 99 2000 Q1 specified the first version of UMTS, in- corporating a CDMA air interface Release 4 2001 Q2 aka. Release 2000, added all-IP Core Network Release 5 2002 Q1 introduced IMS and HSDPA Release 6 2004 Q4 integrated operation with Wireless LAN networks and added HSUPA, MBMS, enhancements to IMS 1 http://en.wikipedia.org/wiki/3GPP
  • 4. 3GPP Network Architecture Radio Access Technologies Discussion 2 3GPP Standards (II) Version Released Info Release 7 2007 Q4 decreasing latency, improvements to QoS and real-time applications, HSPA+ , NFC, EDGE Evolution. Release 8 2008 Q4 First LTE release. All-IP Network (SAE), new OFDMA, FDE and MIMO based radio interface. Release 9 2009 Q4 SAES Enhancements, Wimax and LTE/UMTS Interoperability Release 10 2011 Q1 LTE advanced 2 http://en.wikipedia.org/wiki/3GPP
  • 5. 3GPP Network Architecture Radio Access Technologies Discussion 3 3GPP data evolution 3 Huawei Technologies Co., Ltd. 2009
  • 6. 3GPP Network Architecture Radio Access Technologies Discussion User experience Type of services UMTS LTE Web surfing 8 seconds immediately Download 5MB music 3 minutes 1 second Download 750MB movie 6.5 hours 2.5 minutes Download HD video ∼2-3 days ∼15 minutes √ √ Video telephony √ √ Corporate VPN, Intranet √ √ Mobile TV √ On-demand TV √ Video-based mobile advertising √ ... Table: Data services4 4 Huawei Technologies Co., Ltd. 2009
  • 7. 3GPP Network Architecture Radio Access Technologies Discussion Services for telecommunication systems 1. Teleservice: Information that transfered between end users, e.g speech service, messaging, emergency calls. 2. Bearer service: Different QoS classes for various type of traffic: • Conversasional: voice, video, telephony, video gaming • Streaming: multimedia, video on-demand, webcast • Interactive: web browsing, network gaming, database access • Background: email, SMS, downloading
  • 8. 3GPP Network Architecture Radio Access Technologies Discussion UMTS objectives 1. improvement in data performance, multimedia services and access to the Internet 2. new radio interface WCDMA 3. Core Network: connection function
  • 9. 3GPP Network Architecture Radio Access Technologies Discussion Core Network for UMTS • MSC:Mobile switching center, switch the CS transactions • GMSC: Gateway MSC: a switch that connects the UMTS PLMN to the external CS networks. • SGSN: Serving GPRS Support Node, similar to MSC/VLR but this is for PS traffic. • GGSN: Gateway GPRS Support Node, similar to GMSC but it serves for the PS traffic.
  • 10. 3GPP Network Architecture Radio Access Technologies Discussion 5 LTE’s objectives 1. higher data rates in both downlink and uplink transmission 2. reduce packet latency, more responsive user experience 3. flat architecture: IP-based, open interfaces, simplified network 4. flexible radio planning and high spectral efficiency 5. reduce delivery costs for rich communications 6. long-term revenue stability and growth 7. coexistence alongside circuit switched networks 5 UMTS Forum 2008
  • 11. 3GPP Network Architecture Radio Access Technologies Discussion Why LTE?6 GSM EDGE WCDMA HSPA LTE Non-3GPP technologies Figure: Flexible upgrade path Figure: Reduce pris per MB to remain profitable 6 Nokia Siemens Networks
  • 12. 3GPP Network Architecture Radio Access Technologies Discussion UMTS vs. LTE Architecture 7 Figure: Network architecture, simplified LTE: simplified IP flat architecture • BSC/RNC disappeared, functions transfer to eNodeB • All eNodeB connect directly through X2 interface • PS service only, voice over IP. 7 Image courtesy: UMTS Forum 2008
  • 13. 3GPP Network Architecture Radio Access Technologies Discussion 8 LTE’s interfaces: S1 and X2 • X2: connects eNodeB • MME (Mobility Management Entity): distribution of paging message to eNodeB • UPE (User Plan Entity): IP header compression, encryption of user data stream, termimating and • S1: self-optimizing network switching of U-plane 8 Image courtesy: developer.att.com
  • 14. 3GPP Network Architecture Radio Access Technologies Discussion Wideband CDMA 9 Figure: Access technique for UMTS 9 Huawei Technologies Co., Ltd. 2009
  • 15. 3GPP Network Architecture Radio Access Technologies Discussion CDMA: Principles • each user is assigned a spreading code for encoding it’s data • Receiver knows the code of user, it can decode the received signal, recover the original data • Bandwidth of coded data signal much larger than original data signal due to the encoding process spreads the spectrum of the origianl signal, based on spread-spectrum modulation
  • 16. 3GPP Network Architecture Radio Access Technologies Discussion WCDMA in UMTS [4] • Direct Sequence CDMA system, with chip-rate 3.84 Mc/s • Combined with FDMA: every carrier is allocated 5 MHz frequency band so that many operators can provide services without interference each other. • Codes: scrambling and channelization Channelization: seperates Scrambling codes: not traffic to and from different increase bandwidth, but is users, called Orthogonal used for distinguishing Variable Spreading Factor terminals in uplink and (OVSF) which varies from 1 sectors (cells) in downlink to 128
  • 17. 3GPP Network Architecture Radio Access Technologies Discussion LTE’s downlink: OFDMA OFDM: Multiple access scheme, allows simultaneous connections to/from multiple mobile terminals Users share different subcarriers, either consecutive or distributed manner.
  • 18. 3GPP Network Architecture Radio Access Technologies Discussion LTE’s uplink: Single Carrier-FDMA • SC-FDMA: hybrid modulation scheme that combines the low PAPR techniques of single-carrier transmission systems, such as GSM and CDMA, with the multi-path resistance and flexible frequency allocation of OFDMA • Data symbols in the time domain are converted to the frequency domain using a discrete Fourier transform (DFT) • Cyclic Prefix (CP) is added, a serial Figure: Structure for UL and DL in sequence of symbols is modulated LTE [5] and transmitted instead of parallel OFDM-scheme • On receiver’s side, an extra N-point An advantage of SC-FDMA compares to IDFT is applied to reconstruct the OFDMA is low Peak to Power Average original symbols. Ratio (PAPR), that helps increasing battery life.
  • 19. 3GPP Network Architecture Radio Access Technologies Discussion References Ville Eerola, LTE Network Architecture Evolution, Lecture note in T-109.5410 Technology Management in the Telecommunications Industry, Helsinski University of Technology, 2010. UMTS Forum, Toward Global Mobile Broadband, retreived May 16, 2011from www.umts-forum.org/component/option,com.../Itemid,12/ M. Neruda and R. Bestak, Evolution of 3GPP Core Network, IWSSIP 2008. Lecture notes in UniK 4230, UiO, Lecture9-10.pdf OFDM(A) for wireless communications, Telenor R&I R 7/2008
  • 20. 3GPP Network Architecture Radio Access Technologies Discussion 10 A brief comparision Requirements UMTS LTE Spectral Efficiency 0.2bit/s/Hz 1.57bit/s/Hz Peak Data Rate 2 Mbit/s 170 Mbit/s Sector Capacity 1 Mbit/s 31.4 Mbit/s No. of Tranceivers/Cell 30 1 RTT User Plane 50 ms 5 ms Call setup time 2s 50 ms Mobility 250 km/h 350 km/h Bandwidth 5 MHz scalable up to 20 MHz 10 UMTS/HSPA to LTE Migration, Motorola Inc. 2009
  • 21. 3GPP Network Architecture Radio Access Technologies Discussion Discussion Point to discuss, focus on this topic, futher questions?