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3G and beyond. Introduction. GPRS improves GSM in a number of ways: Increases data communication speed Increases interoperability with packet switched data networks, e.g. internet. Allows billing by data transaction rather than billing by connection time
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Introduction • GPRS improves GSM in a number of ways: • Increases data communication speed • Increases interoperability with packet switched data networks, e.g. internet. • Allows billing by data transaction rather than billing by connection time • However, GPRS itself still has some issues: • Still quite slow, especially for multimedia and other high bandwidth transmission situations • Speech quality • Inconsistent user interface across different networks
UMTS vs GPRS • UMTS: Addition of a new radio access network (RAN) • UTRAN: UMTS Terrestrial radio access network • UTRAN and GSM RAN can coexist and connect to the same core network • UMTS: The CS-domain may be based on packet based transport • Evolution towards all IP • Some day the CS-domain may be abandoned • Introduction of IMS (in Rel-5) • IP Multimedia subsystem • Supports IP based multimedia services • IMS vital for locating IP address of addresses
Push-to-talk GSM 9.6 kbps GPRS 171 kbps EGPRS 473 kbps WCDMA 2 Mbps HSDPA 1-10 Mbps CDMA2000-EVDO CDMA2000-EVDV CDMA2000 1x Service Roadmap Improved performance, decreasing cost of delivery Broadband in wide area 3G-specific services take advantage of higher bandwidth and/or real-timeQoS Video sharing Video telephony Real-time IP multimedia and games Multicasting A number of mobile services are bearer independent in nature Multitasking WEBbrowsing Corporate data access Streaming audio/video MMS picture / video xHTML browsing Application downloading E-mail Presence/location Voice & SMS Typical average bit rates (peak rates higher)
High Speed Circuit Switched Data Dedicate up to 4 timeslots for data connection ~ 50 kbps Good for real-time applications compare with GPRS Inefficient -> ties up resources, even when nothing sent Not as popular as GPRS (many skipping HSCSD) Enhanced Data Rates for Global Evolution Uses 8PSK modulation 3x improvement in data rate on short distances Can fall back to GMSK for greater distances Combine with GPRS (EGPRS) ~ 384 kbps Can also be combined with HSCSD HSCSD GSM 9.6kbps (one timeslot) GSM Data Also called CSD GSM GPRS WCDMA General Packet Radio Services Data rates up to ~ 115 kbps Max: 8 timeslots used as any one time Packet switched; resources not tied up all the time Contention based. Efficient, but variable delays GSM / GPRS core network re-used by WCDMA (3G) EDGE GSM Evolution to 3G
UMTS • Universal Mobile Telecommunications System (UMTS) • UMTS is an upgrade from GSM via GPRS or EDGE • The standardization work for UMTS is carried out by Third Generation Partnership Project (3GPP) • Data rates of UMTS are: • 144 kbps for rural • 384 kbps for urban outdoor • 2048 kbps for indoor and low range outdoor • Virtual Home Environment (VHE) • users are consistently presented with the same personalised features, User Interface capabilities and services in whatever network and whatever terminal, where ever the user may be located
UMTS Frequency Spectrum • UMTS Band • 1900-2025 MHz and 2110-2200 MHz for 3G transmission • In the US, 1710–1755 MHz and 2110–2155 MHz will be used instead, as the 1900 MHz band was already used.
UMTS Network Architecture • UMTS network architecture consists of three domains • Core Network (CN): Provide switching, routing and transit for user traffic • UMTS Terrestrial Radio Access Network (UTRAN): Provides the air interface access method for user equipment. • User Equipment (UE): Terminals work as air interface counterpart for base stations. The various identities are: IMSI, TMSI, P-TMSI, TLLI, MSISDN, IMEI, IMEISV
UTRAN • Wide band CDMA technology is selected for UTRAN air interface • WCDMA • TD-SCDMA • Base stations are referred to as Node-B and control equipment for Node-B is called as Radio Network Controller (RNC). • Functions of Node-B are • Air Interface Tx/Rx • Modulation/Demodulation • Functions of RNC are: • Radio Resource Control • Channel Allocation • Power Control Settings • Handover Control • Ciphering • Segmentation and reassembly
3.5G (HSPA) • 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
4G (LTE) • LTE stands for Long Term Evolution • Next Generation mobile broadband technology • Promises data transfer rates of 100 Mbps • Based on UMTS 3G technology • Optimized for All-IP traffic
Lte benefits in a nutshell Higher Speeds Low latency Faster downloads Simpler networks More capacity New services Differentiation Greater End-User Experience
3GPP LTE Performance Targets • High data rates • Downlink: >100 Mbps • Uplink: >50 Mbps • Low delay/latency • User plane RTT: <10 ms • Channel set-up: <100 ms • Cost-effective migration
LTE radio access Downlink: OFDM Uplink: SC-FDMA OFDMA SC-FDMA Advanced antenna solutions Diversity Beam-forming Multi-layer transmission (MIMO) TX TX Spectrum flexibility Flexible bandwidth New and existing bands Duplex flexibility: FDD and TDD 1.4 MHz 20 MHz Key LTE radio access features
Motivation • Need for higher data rates and greater spectral efficiency • Can be achieved with HSDPA/HSUPA • and/or new air interface defined by 3GPP LTE • Need for Packet Switched optimized system • Evolve UMTS towards packet only system • Need for high quality of services • Use of licensed frequencies to guarantee quality of services • Always-on experience (reduce control plane latency significantly) • Reduce round trip delay • Need for cheaper infrastructure • Simplify architecture, reduce number of network elements
LTE performance requirements • Data Rate: • Instantaneous downlink peak data rate of 100Mbit/s in a 20MHz downlink spectrum (i.e. 5 bit/s/Hz) • Instantaneous uplink peak data rate of 50Mbit/s in a 20MHz uplink spectrum (i.e. 2.5 bit/s/Hz) • Cell range • 5 km - optimal size • 30km sizes with reasonable performance • up to 100 km cell sizes supported with acceptable performance • Cell capacity • up to 200 active users per cell(5 MHz) (i.e., 200 active data clients)
LTE performance requirements • Mobility • Optimized for low mobility(0-15km/h) but supports high speed • Latency • user plane < 5ms • control plane < 50 ms • Improved spectrum efficiency • Cost-effective migration from Release 6 Universal Terrestrial Radio Access (UTRA) radio interface and architecture • Improved broadcasting • IP-optimized • Scalable bandwidth of 20MHz, 15MHz, 10MHz, 5MHz and <5MHz • Co-existence with legacy standards (users can transparently start a call or transfer of data in an area using an LTE standard, and, when there is no coverage, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS)
Key Features of LTE • Multiple access scheme • Downlink: OFDMA • Uplink: Single Carrier FDMA (SC-FDMA) • Adaptive modulation and coding • DL modulations: QPSK, 16QAM, and 64QAM • UL modulations: QPSK and 16QAM • Rel-6 Turbo code: Coding rate of 1/3, two 8-state constituent encoders, and a contention- free internal interleaver. • Bandwidth scalability for efficient operation in differently sized allocated spectrum bands • Possible support for operating as single frequency network (SFN) to support MBMS
Key Features of LTE(contd.) • Multiple Antenna (MIMO) technology for enhanced data rate and performance. • ARQ within RLC sublayer and Hybrid ARQ within MAC sublayer. • Power control and link adaptation • Implicit support for interference coordination • Support for both FDD and TDD • Channel dependent scheduling & link adaptation for enhanced performance. • Reduced radio-access-network nodes to reduce cost,protocol-related processing time & call set-up time
LTE vs UMTS Functional changes compared to the current UMTS architecture