4g

INTRODUCTION 4G (also known as Beyond 3G), an abbreviation for Fourth-Generation, is a term used to describe the next complete evolution in wireless communications. A 4G system will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to users on an "Anytime, Anywhere" basis, and at higher data rates than previous generations. As the second generation was a total replacement of the first generation networks and handsets; and the third generation was a total replacement of second generation networks and handsets; so too the fourth generation cannot be an incremental evolution of current 3G technologies, but rather the total replacement of the current 3G networks and handsets. The international telecommunications regulatory and standardization bodies are working for commercial deployment of 4G networks roughly in the 2012-2015 time scale. At that point it is predicted that even with current evolutions of third generation 3G networks, these will tend to be congested. There is no formal definition for what 4G is; however, there are certain objectives that are projected for 4G. These objectives include: that 4G will be a fully IP-based integrated system. 4G will be capable of providing between 100 Mbit/s and 1 Gbit/s speeds both indoors and outdoors, with premium quality and high security Many companies have taken self-serving definitions and distortions about 4G to suggest they have 4G already in existence today, such as several early trials and launches of WiMAX Other companies have made prototype systems calling those 4G. While it is possible that some currently demonstrated technologies may become part of 4G, until the 4G standard or standards have been defined, it is impossible for any company currently to provide with any certainty wireless solutions that could be called 4G cellular networks that would conform to the eventual international standards for 4G. These confusing statements around "existing" 4G have served to confuse investors and analysts about the wireless industry.

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ISSUES OF 3G: Although 3G was successfully introduced to users across the world, some issues are debated by 3G providers and users: •

Expensive input fees for the 3G service licenses

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Numerous differences in the licensing terms

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Large amount of debt currently sustained by many telecommunication companies.

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Lack of member state support for financially troubled operators

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Expense of 3G phones

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Lack of buy-in by 2G mobile users for the new 3G wireless services

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Lack of coverage, because it is still a new service

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High prices of 3G mobile services in some countries, including Internet access

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

OBJECTIVES: 4G is being developed to accommodate the quality of service (QoS) and rate requirements set by forthcoming applications like wireless broadband access, Multimedia Messaging Service (MMS), video chat, mobile TV, HDTV content, Digital Video Broadcasting (DVB), minimal service like voice and data, and other streaming services for "anytime-anywhere". The 4G working group has defined the following as objectives of the 4G wireless communication standard: • A spectrally efficient system (in bits/s/Hz and bits/s/Hz/site) • High network capacity: more simultaneous users per cell • A data rate of at least 100 Mbit/s between any two points in the world • Seamless connectivity and global roaming across multiple networks • High quality of service for next generation multimedia support (real time audio, high

speed data, HDTV video content, mobile TV, etc) • Interoperability with existing wireless standards and • An all IP, packet switched network

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CONSIDERATION POINTS: •

Coverage, radio environment, spectrum, services, business models and deployment types, users

PRINCIPAL TECHNOLOGIES: •

Baseband techniques OFDM: To exploit the frequency selective channel property MIMO: To attain ultra high spectral efficiency Turbo principle: To minimize the required SNR at the reception side

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Adaptive radio interface

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Modulation spatial processing including multi-antenna and multi-user MIMO

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Relaying, including fixed relay networks (FRNs), and the cooperative relaying concept, known as multi-mode protocol

4G FEATURES: According to the 4G working groups, the infrastructure and the terminals of 4G will have almost all the standards from 2G to 4G implemented. Although legacy systems are in place to adopt existing users, the infrastructure for 4G will be only packet-based (all-IP). Some proposals suggest having an open platform where the new innovations and evolutions can fit. The technologies considered to be "pre-4G" include Flash-OFDM, WiMax, WiBro, iBurst, and 3GPP Long Term Evolution. One of the first technology really fulfilling the 4G requirements as set by the ITU-R will be LTE Advanced as currently standardized by 3GPP. LTE Advanced will be an evolution of the 3GPP Long Term Evolution. Higher data rates are for instance achieved by the aggregation of multiple LTE carriers that are currently limited to 20MHz bandwidth[

WIRELESS SYSTEM EVOLUTION: First generation: Almost all of the systems from this generation were analog systems where voice was considered to be the main traffic. These systems could often be listened to by third parties. Some of the standards are NMT, AMPS, Hicap, CDPD, Mobitex, DataTac, TACS and ETACS. 3

Second generation: All the standards belonging to this generation are commercial centric and they are digital in form. Around 60% of the current market is dominated by European standards. The second generation standards are GSM, iDEN, D-AMPS, IS-95, PDC, CSD, PHS, GPRS, HSCSD, and WiDEN. Third generation: To meet the growing demands in network capacity, rates required for high speed data transfer and multimedia applications, 3G standards started evolving. The systems in this standard are essentially a linear enhancement of 2G systems. They are based on two parallel backbone infrastructures, one consisting of circuit switched nodes, and one of packet oriented nodes. The ITU defines a specific set of air interface technologies as third generation, as part of the IMT-2000 initiative. Currently, transition is happening from 2G to 3G systems. As a part of this transition, numerous technologies are being standardized. •

2.75G: EDGE/EGPRS CDMA2000

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3G: o

UMTS (W-CDMA)

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CDMA2000 (1xEV-DO/IS-856)

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FOMA

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TD-SCDMA

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GAN/UMA

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WiMax

3.5G: o

UMTS (HSDPA)

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UMTS (HSUPA)

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CDMA2000 (EV-DO Rev.A)

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Flash-OFDM

3.75G o

UMTS (HSPA+)

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CDMA2000 (EV-DO Rev.B/3xRTT)

4G: o

3GPP LTE 4

Fourth generation: According to the 4G working groups, the infrastructure and the terminals of 4G will have almost all the standards from 2G to 4G implemented. Although legacy systems are in place to adopt existing users, the infrastructure for 4G will be only packet-based (all-IP). Some proposals suggest having an open platform where the new innovations and evolutions can fit. The technologies which are being considered as pre-4G are the following: Flash-OFDM, WiMax, WiBro, iBurst, and 3GPP Long Term Evolution. One of the first technology really fulfilling the 4G requirements as set by the ITU-R will be LTE Advanced as currently standardized by 3GPP. LTE Advanced will be an evolution of the 3GPP Long Term Evolution. Higher data rates are for instance achieved by the aggregation of multiple LTE carriers that are currently limited to 20MHz bandwidth

COMPONENTS: Access schemes: As the wireless standards evolved, the access techniques used also exhibited increase in efficiency, capacity and scalability. The first generation wireless standards used plain TDMA and FDMA. In the wireless channels, TDMA proved to be less efficient in handling the high data rate channels as it requires large guard periods to alleviate the multipath impact. Similarly, FDMA consumed more bandwidth for guard to avoid inter carrier interference. So in second generation systems, one set of standard used the combination of FDMA and TDMA and the other set introduced a new access scheme called CDMA. Usage of CDMA increased the system capacity and also placed a soft limit on it rather than the hard limit. Data rate is also increased as this access scheme is efficient enough to handle the multipath channel. This enabled the third generation systems to used CDMA as the access scheme IS-2000, UMTS, HSXPA, 1xEV-DO, TD-CDMA and TD-SCDMA. The only issue with CDMA is that it suffers from poor spectrum flexibility and scalability. Recently, new access schemes like Orthogonal FDMA (OFDMA), Single Carrier FDMA (SCFDMA), Interleaved FDMA and Multi-carrier code division multiple access (MC-CDMA) are gaining more importance for the next generation systems. WiMax is using OFDMA in the downlink and in the uplink. For the next generation UMTS, OFDMA is being considered for the downlink. By contrast, IFDMA is being considered for the uplink since OFDMA contributes more to the PAPR related issues and results in nonlinear operation of amplifiers. IFDMA provides less power fluctuation and thus avoids amplifier issues. Similarly, MC-CDMA is in the 5

proposal for the IEEE 802.20 standard. These access schemes offer the same efficiencies as older technologies like CDMA. Apart from this, scalability and higher data rates can be achieved. The other important advantage of the above mentioned access techniques is that they require less complexity for equalization at the receiver. This is an added advantage especially in the MIMO environments since the spatial multiplexing transmission of MIMO systems inherently requires high complexity equalization at the receiver. In addition to improvements in these multiplexing systems, improved modulation techniques are being used. Whereas earlier standards largely used Phase-shift keying, more efficient systems such as 64QAM are being proposed for use with the 3GPP Long Term Evolution standards.

IPv6: Unlike 3G, which is based on two parallel infrastructures consisting of circuit switched and packet switched network nodes respectively, 4G will be based on packet switching only. This will require low-latency data transmission. By the time that 4G is deployed, the process of IPv4 address exhaustion is expected to be in its final stages. Therefore, in the context of 4G, IPv6 support is essential in order to support a large number of wireless-enabled devices. By increasing the number of IP addresses, IPv6 removes the need for Network Address Translation (NAT), a method of sharing a limited number of addresses among a larger group of devices. In the context of 4G, IPv6 also enables a number of applications with better multicast, security, and route optimization capabilities. With the available address space and number of addressing bits in IPv6, many innovative coding schemes can be developed for 4G devices and applications that could aid deployment of 4G networks and services.

Advanced Antenna Systems: The performance of radio communications obviously depends on the advances of an antenna system, refer to smart or intelligent antenna. Recently, multiple antenna technologies are emerging to achieve the goal of 4G systems such as high rate, high reliability, and long range communications. In the early 90s, to cater the growing data rate needs of data communication, many transmission schemes were proposed. One technology, spatial multiplexing, gained importance for its bandwidth conservation and power efficiency. Spatial multiplexing involves 6

deploying multiple antennas at the transmitter and at the receiver. Independent streams can then be transmitted simultaneously from all the antennas. This increases the data rate into multiple folds with the number equal to minimum of the number of transmit and receive antennas. This is called MIMO (as a branch of intelligent antenna). Apart from this, the reliability in transmitting high speed data in the fading channel can be improved by using more antennas at the transmitter or at the receiver. This is called transmit or receive diversity. Both transmit/receive diversity and transmit spatial multiplexing are categorized into the space-time coding techniques, which does not necessarily require the channel knowledge at the transmit. The other category is closed-loop multiple antenna technologies which use the channel knowledge at the transmitter.

Software-Defined Radio (SDR): SDR is one form of open wireless architecture (OWA). Since 4G is a collection of wireless standards, the final form of a 4G device will constitute various standards. This can be efficiently realized using SDR technology, which is categorized to the area of the radio convergence.

4G WIRELESS STANDARDS: Pre 4G: iBurst: iBurst (or HC-SDMA, High Capacity Spatial Division Multiple Access) is a wireless broadband technology developed by ArrayComm. It optimizes the use of its bandwidth with the help of smart antennas. Kyocera is the leading manufacturer of iBurst devices. iBurst is a mobile broadband wireless access system that was first developed by ArrayComm, and subsequently adopted as the High Capacity – Spatial Division Multiple Access (HC-SDMA) radio interface standard (ATIS-0700004-2005) by the Alliance of Telecommunications Industry Solutions (ATIS). The standard was prepared by ATIS’ Wireless Technology and Systems Committee’s (WTSC) Wireless Wideband Internet Access subcommittee and has been accepted as an American National Standard. The HC-SDMA interface provides wide-area broadband wireless data-connectivity for fixed, portable and mobile computing devices and appliances. The protocol is designed to be implemented with smart antenna array techniques to substantially improve the radio frequency 7

(RF) coverage, capacity and performance for the system. In January 2006, the IEEE 802.20 Mobile Broadband Wireless Access Working Group adopted a technology proposal that includes the use of the HC-SDMA standard for the 625kHz Multi-Carrier Time Division Duplex (TDD) mode of the future IEEE 802.20 standard. One Canadian vendor operates at 1.8 GHz. HC-SDMA is also being incorporated by ISO TC204 WG16 into its standards for use of wireless broadband systems in the continuous communications standards architecture, known as CALM, which ISO is developing for intelligent transport systems (ITS). ITS may include applications for public safety, congestion management during traffic incidents, automatic toll booths, and more. An official liaison has been established between WTSC and ISO TC204 WG16 for this purpose Technology The HC-SDMA interface operates on a similar premise as GSM or CDMA2000 for cellular phones, with hand-offs between HC-SDMA cells reportedly providing the user with a seamless wideband wireless experience even when moving at the speed of a car or train. The protocol:  specifies base station and client device RF characteristics, including output power levels,

transmit frequencies and timing error, pulse shaping, in-band and out-of band spurious emissions, receiver sensitivity and selectivity;  defines associated frame structures for the various burst types including standard uplink and downlink traffic, paging and broadcast burst types;  specifies the modulation, forward error correction, interleaving and scrambling for various burst types;  describes the various logical channels (broadcast, paging, random access, configuration and traffic channels) and their roles in establishing communication over the radio link; and  specifies procedures for error recovery and retry. The protocol also supports Layer 3 (L3) mechanisms for creating and controlling logical connections (sessions) between client device and base including registration, stream start, power control, handover, link adaptation, and stream closure, as well as L3 mechanisms for client device authentication and secure transmission on the data links. Currently deployed iBurst systems allow connectivity up to 1 Mbit/s for each subscriber equipment. Apparently there will 8

be future firmware upgrade possibilities to increase these speeds up to 5 Mbit/s, consistent with HC-SDMA protocol. Commercial use Four access options are already commercially available using:  Desktop modem with USB and Ethernet ports (with external power supply)  Portable USB modem (using USB power supply)  Laptop modem (PC card)

 DOVADO Wireless Residential Gateway (WRG) in combination with Laptop modem  DOVADO USB Mobile Broadband Router (UMR) in combination with USB modem

An iBurst desktop modem by Kyocera iBurst is commercially available in twelve countries: South Africa, Azerbaijan, Norway, Ireland, Canada, Malaysia, Lebanon, Kenya, Ghana, Mozambique[3], Democratic Republic of the Congo[4] and USA. Companies in Southeast Europe and the Middle East are also looking to roll out the service. HiperMAN HiperMAN stands for High Performance Radio Metropolitan Area Network and is a standard created by the European Telecommunications Standards Institute (ETSI) Broadband Radio Access Networks (BRAN) group to provide a wireless network communication in the 2 - 11 GHz bands across Europe and other countries which follow the ETSI standard HiperMAN is a 9

European alternative to WiMAX (or the IEEE 802.16 standard) and the Korean technology WiBro. HiperMAN is aiming principally for providing broadband Wireless Internet access, while covering a large geographic area. The standardization focuses on broadband solutions optimized for access in frequency bands below 11 GHz (mainly in the 3.5 GHz band). HiperMAN is optimised for packet switched networks, and supports fixed and nomadic applications, primarily in the residential and small business user environments. HiperMAN will be an interoperable broadband fixed wireless access system operating at radio frequencies between 2 GHz and 11 GHz.[2] The HiperMAN standard is designed for Fixed Wireless Access provisioning to SMEs and residences using the basic MAC (DLC and CLs) of the IEEE 802.16-2001 standard. It has been developed in very close cooperation with IEEE 802.16,[3] such that the HiperMAN standard and a subset of the IEEE 802.16a-2003 standard will interoperate seamlessly. HiperMAN is capable of supporting ATM, though the main focus is on IP traffic. It offers various service categories, full Quality of Service, fast connection control management, strong security, fast adaptation of coding, modulation and transmit power to propagation conditions and is capable of non-line-of-sight operation. HiperMAN enables both PTMP and Mesh network configurations. HiperMAN also supports both FDD and TDD frequency allocations and H-FDD terminals. All this is achieved with a minimum number of options to simplify implementation and interoperability. WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-point links to portable internet access[citation needed]. The technology provides up to 75 Mb/s symmetric broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL Uses The bandwidth and range of WiMAX make it suitable for the following potential applications:  Connecting Wi-Fi hotspots to the Internet.  Providing a wireless alternative to cable and DSL for "last mile" broadband access.

 Providing data and telecommunications services. 10

 Providing a source of Internet connectivity as part of a business continuity plan. That is, if a business has a fixed and a wireless Internet connection, especially from unrelated providers, they are unlikely to be affected by the same service outage.  Providing portable connectivity. WiBro: WiBro (Wireless Broadband) is a wireless broadband Internet technology being developed by the South Korean telecoms industry. WiBro is the South Korean service name for IEEE 802.16e (mobile WiMAX) international standard. WiBro adopts TDD for duplexing, OFDMA for multiple access and 8.75 MHz as a channel bandwidth. WiBro was devised to overcome the data rate limitation of mobile phones (for example CDMA 1x) and to add mobility to broadband Internet access (for example ADSL or Wireless LAN). In February 2002, the Korean government allocated 100 MHz of electromagnetic spectrum in the 2.3 - 2.4 GHz band, and in late 2004 WiBro Phase 1 was standardized by the TTA of Korea and in late 2005 ITU reflected WiBro as IEEE 802.16e (mobile WiMAX). Two South Korean Telco (KT, SKT) launched commercial service in June 2006, and the tariff is around US$30. WiBro base stations will offer an aggregate data throughput of 30 to 50 Mbit/s and cover a radius of 1-5 km allowing for the use of portable internet usage. In detail, it will provide mobility for moving devices up to 120 km/h (74.5 miles/h) compared to Wireless LAN having mobility up to walking speed and Mobile Phone having mobility up to 250 km/h. From testing during the APEC Summit in Busan in late 2005, the actual range and bandwidth were quite a bit lower than these numbers. The technology will also offer Quality of Service. The inclusion of QoS allows for WiBro to stream video content and other loss-sensitive data in a reliable manner. These all appear to be (and may be) the stronger advantages over the fixed WiMAX standard (802.16a). Some Telcos in many countries are trying to commercialize this Mobile WiMAX (or WiBro). For example, TI (Italia), TVA (Brazil), Omnivision (Venezuela), PORTUS (Croatia), and Arialink (Michigan) will provide commercial service after test service around 2006-2007. While WiBro is quite exacting in its requirements from spectrum use to equipment design, WiMAX leaves much of this up to the equipment provider while providing enough detail to ensure interoperability between designs. 11

3GPP LTE (Long Term Evolution): 3GPP is currently standardizing LTE Advanced as future 4G standard. A first set of 3GPP requiremens on LTE Advanced has been approved in June 2008. The working groups are currently evaluating various proposals for standardization. LTE Advanced will be standardized as part of the Release 10 of the 3GPP specification 3GPP LTE (Long Term Evolution) is the name given to a project within the Third Generation Partnership Project to improve the UMTS mobile phone standard to cope with future technology evolutions. Goals include improving spectral efficiency, lowering costs, improving services, making use of new spectrum and refarmed spectrum opportunities, and better integration with other open standards. The LTE air interface will be added to the specification in Release 8 and can be found in the 36-series [1] of the 3GPP specifications. Although an evolution of UMTS, the LTE air interface is a completely new system based on OFDMA in the downlink and SC-FDMA (DFTS-FDMA) in the uplink that efficiently supports multi-antenna techologies (MIMO). The architecture resulting from this work is called EPS (Evolved Packet System) and comprises EUTRAN (Evolved UTRAN) on the access side and EPC (Evolved Packet Core) on the core side. Current State Much of the standard is oriented around upgrading UMTS to a so-called fourth generation mobile communications technology, essentially a wireless broadband Internet system with voice and other services built on top. The standard includes:  Peak download rates of 326.4 Mbit/s for 4x4 antennas, 172.8 Mbit/s for 2x2 antennas for every 20 MHz of spectrum.  Peak upload rates of 86.4 Mbit/s for every 20 MHz of spectrum.

 5 different terminal classes have been defined from a voice centric class up to a high end terminal that supports the peak data rates. All terminal will be able to process 20 MHz bandwidth.  At least 200 active users in every 5 MHz cell. (i.e., 200 active data clients)  Sub-5ms latency for small IP packets  Increased spectrum flexibility, with spectrum slices as small as 1.5 MHz (and as large as

20 MHz) supported (W-CDMA requires 5 MHz slices, leading to some problems with roll-outs of the technology in countries where 5 MHz is a commonly allocated amount of 12

spectrum, and is frequently already in use with legacy standards such as 2G GSM and cdmaOne.) Limiting sizes to 5 MHz also limited the amount of bandwidth per handset  Optimal cell size of 5 km, 30 km sizes with reasonable performance, and up to 100 km cell sizes supported with acceptable performance  Co-existence with legacy standards (users can transparently start a call or transfer of data

in an area using an LTE standard, and, should coverage be unavailable, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS or even 3GPP2 networks such as cdmaOne or CDMA2000)  Supports MBSFN (Multicast Broadcast Single Frequency Network). This feature can deliver services such as Mobile TV using the LTE infrastructure, and is a competitor for DVB-H-based TV broadcast. PU2RC as a practical solution for MU-MIMO has been adopted to use in 3GPP LTE standard. The detailed procedure for the general MU-MIMO operation is handed to the next release, e.g, LTE-Advanced, where the further discussion will be held. A large amount of the work is aimed at simplifying the architecture of the system, as it transits from the existing UMTS circuit + packet switching combined network, to an all-IP flat architecture system. Preliminary requirements have been released for LTE Advanced, expected to be part of 3GPP Release 10 If possible LTE Advanced will be a software upgrade for LTE networks and enable peak download rates over 1Gbit/s that fully supports the 4G requirements as defined by the ITUR. It also targets faster switching between power states and improved performance at the cell edge. A first set of requirements has been approved in June 2008.

Downlink: The subcarrier spacing in the OFDM downlink is 15 kHz and there is a maximum of 1200 subcarriers available. Number of subcarriers is dependent on the used bandwidth (1.4MHz and up to 20Mhz),subcarriers don't occupy 100% of the used bandwidth as Cyclic Prefixes (Guards) occupies a part of it.The Mobile devices must be capable of receiving all subcarriers but a base station need only support transmitting 72 subcarriers. The transmission is divided in time into time slots of duration 0.5 ms and subframes of duration 1.0 ms. A radio frame is 10 ms long. Supported modulation formats on the downlink data channels are QPSK, 16QAM and 64QAM. 13

For MIMO operation, a distinction is made between single user MIMO, for enhancing one users data throughput, and multi user MIMO for enhancing the cell throughput.

Uplink: The currently proposed uplink uses SC-FDMA multiplexing, and QPSK or 16QAM (64QAM optional) modulation. SC-FDMA is used because it has a low Peak-to-Average Power Ratio (PAPR). If virtual MIMO / Spatial division multiple access (SDMA) is introduced the data rate in the uplink direction can be increased depending on the number of antennas at the base station. With this technology more than one mobile can reuse the same resources. Carrier adoption  Most carriers supporting GSM or HSPA networks can be expected to upgrade their networks to LTE at some stage: 

AT&T Mobility has stated that they intend on upgrading to LTE as their 4G technology, but will introduce HSUPA and HSPA+ as bridge standards.

 T-Mobile, Vodafone, France Télécom, Telia Sonera and Telecom Italia Mobile have also

announced or talked publicly about their commitment to LTE.  However, several networks that don't use these standards are also upgrading to LTE:  Verizon Wireless, Bell Mobility, the newly formed China Telecom/Unicom and Japan's

KDDI have announced they have chosen LTE as their 4G network technology. This is significant, because these are CDMA carriers and are switching networking technologies to match what will likely be the 4G standard worldwide. [18] They have chosen to take the natural GSM evolution path as opposed to the 3GPP2 CDMA2000 evolution path Ultra Mobile Broadband (UMB). Verizon Wireless plans to begin LTE trials in 2008.[19] Bell Mobility plans to start LTE deployment in 2009-2010.  Telus Mobility has announced that it will adopt LTE as its 4G wireless standard.[20]  MetroPCS recently announced that it would be using LTE for its upcoming 4G network.

An "All IP Network" (AIPN) A characteristic of so-called "4G" networks such as LTE is that they are fundamentally based upon TCP/IP, the core protocol of the Internet, with higher level services such as voice, video, and messaging, built on top of this. In 2004, the 3GPP proposed this as the future of UMTS and began feasibility studies into the so-called All IP Network (AIPN.) These proposals, which included recommendations in 2005 for 3GPP Release 7 form the basis of the effort to build the 14

higher level protocols of evolved UMTS. The LTE part of this effort is called the 3GPP System Architecture Evolution. At a glance, the UMTS back-end becomes accessible via a variety of means, such as GSM's/UMTS's own radio network (GERAN, UTRAN, and E-UTRAN), WiFi, and even competing legacy systems such as CDMA2000 and WiMAX. Users of non-UMTS radio networks would be provided with an entry-point into the IP network, with different levels of security depending on the trustworthiness of the network being used to make the connection. Users of GSM/UMTS networks would use an integrated system where all authentication at every level of the system is covered by a single system, while users accessing the UMTS network via WiMAX and other similar technologies would handle the WiMAX connection one way (for example, authenticating themselves via a MAC or ESN address) and the UMTS link-up another way. E-UTRA Air Interface Release 8's air interface, E-UTRA (Evolved UTRA, the E- prefix being common to the evolved equivalents of older UMTS components) would be used by UMTS operators deploying their own wireless networks. It's important to note that Release 8 is intended for use over any IP network, including WiMAX and WiFi, and even wired networks. The proposed E-UTRA system uses OFDMA for the downlink (tower to handset) and Single Carrier FDMA (SC-FDMA) for the uplink and employs MIMO with up to four antennas per station. The channel coding scheme for transport blocks is turbo coding and a contention-free quadratic permutation polynomial (QPP) turbo code internal interleaver. The use of OFDM, a system where the available spectrum is divided into thousands of very thin carriers, each on a different frequency, each carrying a part of the signal, enables E-UTRA to be much more flexible in its use of spectrum than the older CDMA based systems that dominated 3G. CDMA networks require large blocks of spectrum to be allocated to each carrier, to maintain high chip rates, and thus maximize efficiency. Building radios capable of coping with different chip rates (and spectrum bandwidths) is more complex than creating radios that only send and receive one size of carrier, so generally CDMA based systems standardize both. Standardizing on a fixed spectrum slice has consequences for the operators deploying the system: too narrow a spectrum slice would mean the efficiency and maximum bandwidth per handset suffers; too wide a spectrum slice, and there are deployment issues for operators short on spectrum. This became a 15

major issue with the US roll-out of UMTS over W-CDMA, where W-CDMA's 5 MHz requirement often left no room in some markets for operators to co-deploy it with existing GSM standards. OFDM has a Link spectral efficiency greater than CDMA, and when combined with modulation formats such as 64QAM, and techniques as MIMO, E-UTRA has proven to be considerably more efficient than W-CDMA with HSDPA and HSUPA. Evolved UMTS Terrestrial Radio Access (E-UTRA) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. E-UTRA is the successor to HSDPA and HSUPA technologies specified in 3GPP releases 5, 6 and 7. Unlike HSPA, LTE's E-UTRA is an entirely new air interface system, unrelated to and incompatible with W-CDMA.

Features: E-UTRA has the following features: •

Flexible bandwidth usage with 1.25 MHz to 20 MHz bandwidths. By comparison, WCDMA uses fixed size 5 MHz chunks of spectrum.

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Increased spectral efficiency at 2-4 times more than in 3GPP(HSPA) release 6

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Peak download rates of 326.4 Mbit/s for 4x4 antennas, 172.8 Mbit/s for 2x2 antennas for every 20 MHz of spectrum.

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Peak upload rates of 86.4 Mbit/s for every 20 MHz of spectrum.

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Sub-5ms latency for small IP packets.

APPLICATIONS: At the present rates of 15-30 Mbit/s, 4G is capable of providing users with streaming highdefinition television, but the typical cellphone's or smartphone's 2" to 3" screen is a far cry from the big-screen televisions and video monitors that got high-definition resolutions first and which suffer from noticeable pixelation much more than the typical 2" to 3" screen. A cellphone may transmit video to a larger monitor, however. At rates of 100 Mbit/s, the content of a DVD-5 (for example a movie), can be downloaded within about 5 minutes for offline access.

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BIBLOGRAPHY: http://en.wikipedia.org/wiki/4G 4G - Beyond 2.5G and 3G Wireless Networks 4G - Beyond 2.5G and 3G Wireless Networks

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