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From GSM to LTE: a practical evolution path with Alcatel-Lucent

JUNE, 2009

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Introduction LTE is commonly recognized as the preferred evolution path for 3GPP and 3GPP2 networks. The evolution path of W-CDMA networks to LTE is the focus of a lot of industry attention. However, this is not the only path to LTE for operators to consider, the evolution of GSM networks to LTE is also a valuable evolution path, especially for GSM operators who have deployed Alcatel-Lucent Multi-standard Base stations or are evaluating a GSM Infrastructure refresh plan.

Deploying LTE over GSM? ...A sensible option

Who is concerned?

GSM/WCDMA operators in developed markets Mobile adoption is growing exponentially with roughly 4 billion people expected to be carrying mobile devices by 2011. With over 400 operators worldwide, GSM is the mostly deployed standard. To face the increasing demand for data, GSM operators have been progressively upgrading their existing GSM infrastructure to GPRS/EDGE. In the meantime, many operators also acquired 3G spectrum and have been deploying W-CDMA infrastructure to absorb the ever-growing appetite for bandwidth in cities and urban areas, with GPRS/EDGE being used as a complementary solution in rural environments. This combination of 2G and 3G infrastructures with a software evolution from W-CDMA to HSPA and HSPA+ guarantee a global coverage and quality of service in the near future. However, within the next few years, the communication landscape will change, with more bandwidth-hungry applications, a flourishing ecosystem of new communication devices, and a mutation of behavior, supported by the "millennials" generation, born with the internet, and eager to bring their broadband experience to wireless. To cope with this evolution, operators will have to adapt and deploy more efficient technologies, providing higher throughput and lowering the cost per byte. LTE is the natural evolution path to provide installed base. However, although operators are committed to cover a given percentage of the population with GSM, their W-CDMA deployment is mostly concentrated on high traffic areas, i.e. cities and business areas. Upgrading their WCDMA base solely to LTE will therefore jeopardize service continuity. One option to guarantee a balanced offer is to migrate GSM sites to LTE to provide broadband coverage. The terminal ecosystem is at the heart of operators strategies and the availability of multi-techno GSM/W-CDMA handsets soon enriched with LTE capabilities will drive and support this complementarity.

GSM only operators in developing markets On the other end, many GSM operators have not made the leap to W-CDMA yet. It may be for various reasons: they did not get a WCDMA license, they have not started the WCDMA deployment yet, or simply because their market is not mature enough for broadband-hungry applications. However, sooner or later, those operators will be confronted to the boom of data traffic. For those operators, the question of going directly to LTE is a valid one. In developing countries where DSL penetration is low and copper

2001 2004-2006 2007-2008 2009-2010

Years

Downlink Throughput

1 Mbit/s 1 Mbit/s per User per User

300 kbit/s 300 kbit/s

240 kbit/s 240 kbit/s

80 kbit/s 80 kbit/s

2001 2004-2006 2007-2008 2009-2010

Years

Downlink Throughput

1 Mbit/s 1 Mbit/s per User per User

300 kbit/s 300 kbit/s

240 kbit/s 240 kbit/s

80 kbit/s 80 kbit/s

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deployment is costly, deploying LTE may also be a cost effective solution to provide broadband access for IPS.

GSM evolution to LTE: a global offer From the above, it is clear that the migration of GSM assets to LTE is critical, not only for GSM operators preparing for tomorrow's growing demand for bandwidth, but also for EDGE/HSPA+ operators in highly demanding markets, committed to deliver wireless broadband service continuity to their customers.

Benefits of deploying LTE on top of GSM

The site density argument GSM networks are characterized by the density of the installed base, which, unlike 3G, covers a vast majority of the population in most countries. Acquisition of new sites is now considered as the major issue for operators. Therefore, the ability to re-use the installed GSM cabinets to host LTE equipment brings important CAPEX savings: avoid re-negotiation with site landlords, avoid extra civil work, re-use of facilities such as the cabinet itself but also cooling system, power supply battery backup. Re-using an existing site brings an estimated gain of 40% compared to new site acquisition. The OPEX is also reduced, with a simplified installation procedure, and a common management.

Coverage quality (high/variable):

3G 2100 + GSM

GSM 900/1800

Compared 2G/3G coverage for a French operator

GSM evolutions smoothly paving the way to LTE In markets were the demand for broadband is not quite there, operators may be inclined to evolve their current GSM infrastructure to support more capacity, first by upgrading to GPRS and EDGE, then to GERAN evolution (if the ecosystem is ready) using Software Defined Radio equipment. The partial or complete migration of GSM equipment to LTE improves the site capacity and therefore puts higher constraints on the backhaul and transport network. Fortunately, the evolution of GSM equipments to all-IP allows a progressive deployment of IP transport

Full IP represents future-wise investment to sustain bandwidth explosion connected to GERAN Evolution and LTE introduction

A multi-standard approach is key to an easy LTE deployment

GSM networks provide nationwide coverage

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network. This smooth evolution allows operators to cope with growing demand in the near term while paving the way to an eventual LTE deployment. The partial or complete migration of GSM equipment to LTE improves the site capacity and therefore puts higher constraints on the backhaul and transport network.

Spectrum refarming is key LTE standards define a new radio access and flat-IP core, which enhances performance and operating costs, based on three technology pillars: Flat-IP, OFDM and MIMO. Beyond that, LTE is characterized by its ability to be deployed on various bandwidth (from 1.4MHz to 20MHz) and in different frequency bands, from 450MHz to 2.6GHz, including all of the 3GPP bands. This flexibility enables many deployment scenarios, including spectrum re-farming, i.e. re-allocation of spectrum used for GSM or W-CDMA to LTE. Lower frequency bands, which benefit from excellent propagation properties, can for instance be re-allocated for LTE coverage. Beyond the re-use of the cabinets, the value of co-locating GSM and LTE equipment also lies in the ability to share or re-use the radio equipments, hence further reducing the CAPEX. This flexibility is possible thanks to Software Defined Radio (SDR) equipment which has the ability to support different radio access technologies, and jumping from one technology to another via simple software upgrade. In advanced markets, GSM/WCDMA operators will initially deploy LTE in new bands (e.g. 2.6GHz in Europe) to cover hot zones. In a second step, re-farming of part of the GSM spectrum, especially in the 900MHz band allows for a broadband coverage in rural environment and better in-door penetration.

Inlay or overlay? The operator has two options: deploy LTE in the same band as GSM or in another band. In the first case, or inlay deployment, some of the GSM spectrum is allocated to LTE. SDR modules initially operate in GSM and the operator can dynamically allocate part of the spectrum resource to LTE. The LTE capacity grows while the GSM capacity decreases. In the second case, LTE equipments hosted in the GSM cabinets operate in another band, therefore not impacting the GSM capacity.

GSM to LTE: a judicious choice for service continuity Migrating GSM assets to LTE is critical to all operators, whatever their profiles. For 2G operators who have decided to skip 3G, it is an obvious choice. For a 3G operator also, migrating part of their GSM infrastructure to LTE, may it be in inlay or overlay, ensures a cost-effective way of sustaining service continuity.

900MHz spectrum refarming for coverage enabled by SDR assets (Software Defined Radio)

Deployment strategy varies upon spectrum availabilityLTE in new FDD or TDD frequency bands (overlay) and/or LTE in same band as 2G/3G

New spectrum for LTE

New spectrum for LTE

3Gspectrum

3Gspectrum

2Gspectrum

2Gspectrum

2Gspectrum

2Gspectrum

3G spectrumrefarming

3Gspectrum

3Gspectrum

2G spectrumrefarmingand/or and/or

New spectrum for LTE

New spectrum for LTE

700 MHz 2.6 GHz 1.9/2.1 GHz 850/900 MHz900 MHz 2100 MHz 1.9/2.1 GHz 850/900 MHz

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Alcatel-Lucent value proposition

Committed to LTE

An innovation leader Alcatel-Lucent is pro-active in the wireless standards groups (3GPP, 3GPP2), with many of our proposals becoming Approved Items for example, absence of Macro diversity, and Flat IP architecture. We have delivered in excess of 70 MIMO-related contributions over the last six years in 3GPP, and have held the Rapporteur position for the MIMO Working Group since 2002. The current Release 7 MIMO proposal is based on spatial multiplexing techniques first proposed in 3GPP standards by Lucent in 2000, with key MIMO techniques: Feedback Technique for Wireless Systems with Multiple Transmit and Receive Antennas and High-Speed Data Services Using Multiple Transmit Antennas. Alcatel-Lucent is deeply involved in the elaboration of inter-RAT mobility specifications which are key in establishing a significant ecosystem for LTE. In particular, in both the 3GPP and 3GPP2 working groups, we are driving LTE / EV-DO mobility, for example on Tunneling protocols for inter-techno Hand-Over (H/O), or on acquisition and synchronization procedures during H/O.

Strong presence in standard bodies Alcatel-Lucent is also leading the first phase (Proof of Concept) of the recently created LTE/SAE Trial Initiative (LSTI). Launched by a group of world leading telecom technology manufacturers and network operators, this initiative aims to drive forward the realization of the next-generation of high performance mobile broadband networks based on LTE/SAE specifications. The Group intends to do this by collaborating to demonstrate the potential of 3GPP LTE/SAE mobile broadband technologies through a series of joint tests, including radio transmission performance, early interoperability, field tests and full customer trials. The Initiative was officially launched in May 2007, and is expected to run for a period of 18-24 months. In Q4 2007, LSTI reported the successful delivery of the first in a series of test results aimed at proving the potential and benefits of LTE. In Germany also, Alcatel-Lucent has been selected for the EASY-C (Enablers for Ambient Services and Systems Wide Area Coverage) project. EASY-C is a 3 year-long project funded by the BMBF (German Ministry of Research). It has been developed in collaboration with T-Mobile and Vodafone in Germany. The main objectives are to deploy a first field trial of LTE Phase 2 technologies in Berlin and Dresden, to optimize MIMO algorithms and to prove them in field trials, and also to test MIMO with Remote Radio Heads and distributed MIMO.

Alcatel-Lucent & LG Electronics Strategic Partnership on End User Equipment The services offered by LTE will be significantly different from those with which we are familiar today. The devices will extend far beyond what we think of today as wireless devices. Devices are always a critical component in a new technology introduction, and will be even more significant and varied in 4G. Alcatel-Lucent has developed a strategic relationship with LG Electronics (LGE) to address this element in the end-to end solution. Our two innovative companies are working together to develop the vision for 4G devices and define requirements for LTE deployment.

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Stateof-the-art infrastructure

Innovative devices

Compelling applications

IOT testing

Technical cooperation

Market Research

Joint operator outreach

Stable, open and fully integrated LTE Ecosystem

LTE Commercial equipment availability

Alcatel-Lucent & LGE Strategic Collaboration

A comprehensive portfolio Re-use of the existing assets and seamless migration for ALU customers currently using W-CDMA and/or GSM are key elements of Alcatel-Lucent LTE strategy. The smooth evolution from both GSM and UMTS is enabled by a focus on:

Inter-technology roaming leadership Reuse of existing investments i.e. BTS assets Multi-standard Base stations Integrated OAM solutions Integrated transport capabilities Simple module upgrade to existing cabinets Addition of purpose built, high performance packet core elements

o Evolved from existing 3G platforms o Designed to meet the throughput and processing demands of 4G

Preparing the ground with GSM release B11 and META Alcatel-Lucent BSC and MFS products have supported IP connectivity since B10. The next BSS release, B11, introduces native IP connectivity on the BTS. This all-IP BSS portfolio allows the replacement of traditional PCM-based backhaul and transport network with a more efficient cost effective IP backbone. Besides, Alcatel-Lucent delivers a pre-validated Mobile Evolution Transport Architecture (META), based on highly efficient IP/MPLS routing products. Alcatel-Lucent has therefore a comprehensive portfolio to help operators smoothly migrate their installed base to all-IP. This IP evolution is a prerequisite to the LTE deployment.

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Network diagram showing GSM infrastructure evolution to all-IP

Converged RAN strategy

With more than 500,000 Multi-standard BTS installed since 1999 in over 180 countries, Alcatel-Lucent has an indisputable experience in this area. The successful MBI5 and MBO2 cabinets were initially designed to support multiple base band and radio units. With their ability to host multi-techno SDR radio modules, those cabinets enable a true converged RAN strategy, offering operators cost-effective and flexible deployment scenarios. This strategy is paying back for the operators, since the important GSM installed base can

now be leverage to deploy a zero-footprint LTE solution, reusing assets on a large scale (and not only in hotzones), hence making LTE a cost-effective broadband solution.

Digital module The Alcatel-Lucent field-proven 9326 W-CDMA digital module is software upgradeable to support LTE, hence allowing smooth evolution of 3G hotspots to LTE. The 9326 can also be integrated in any 19-inch cabinets. Existing Alcatel-Lucent macro cabinets, compact cabinets, Multi-standard Base Station cabinets can therefore be re-used for zero-footprint LTE deployment over an installed GSM network. More generally, 9326 can in principle be deployed in any 19-inch cabinet from any other technology or any other equipment vendor, as far as environmental constraints are compliant. Alcatel-Lucent LTE solution can then be seamlessly integrated into existing cabinets allowing for re-use of existing assets such as RF assets, power, backup, transmission equipment, antennas, feeders. In addition, the Alcatel-Lucent LTE digital modules integrate Ethernet bridge functionality, enabling both LTE and 2G traffic to share the same IP transport network and reducing LTE implementation costs. If needed, cell site aggregation solutions can also be provided for better flexibility in using different transport option and greater scalability to support Multiple Gigabit Ethernet & ATM interfaces. The solution will also benefit from the META program driving evolution of mobile transport networks to IP.

Alcatel-Lucent 9326 LTE digital module can be integrated in GSM multi-standard cabinet for zero-footprint LTE deployment

9326 digital

module

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Bell Labs innovations turned into MCPA products At the heart of its renovated portfolio, Alcatel-Lucent delivers in 2009 its SDR radio product family able to support different technologies (GSM, W-CDMA, LTE). They come in two different form factors: MC-TRX (on the left) and MC-RRH (on the right) and support GSM, W-CDMA and LTE operation. The MC-TRX module occupies one TRX slot only and is capable of supporting up to 6 TRX (GSM only) or up to 4 TRX + one 5MHz LTE radio link.

Unified O&M Alcatel-Lucents strategy for Wireless Networks Management is to provide a comprehensive harmonized and integrated solution across wireless and IP technologies. Alcatel-Lucent therefore offers a new unified management solution, known as Extended Management Solution (XMS). This Next Generation Management System is the main system - efficient, robust, scalable system - taking care of the network service fulfillment and service Assurance. It ensures plug and play deployment of the LTE RAN, provisioning activation, service Assurance (fault, correlation, state management, services overviews at a glance, troubleshooting), inventory and resource management, performance management and security. It leverages the Self-Organizing, Self-Optimizing Networks (SON) concepts in conjunction with the eNodeBs themselves for outstanding provisioning and QoS optimization simplification. The Extended Management System for LTE networks is also referred as 9453 XMS. The XMS integrates GSM, WCDMA, CDMA, LTE ePC Domain Managers / OMCs for managing the related devices depending on Operators network deployment. It allows the operator to preserve a single service Assurance system for Alcatel-Lucents multi-standard RAN, LTE ePC and underlying IP transport backhaul. The distributed architecture of the Software Application allows a large variety of deployment fitting operators operational need.

Alcatel-Lucent can cover all scenarios Alcatel-Lucent pursues a multi-standard approach since 1999: More than 500 000 Multi-Standard BTS have been deployed since 1999. This strategy has proved to be successful and now takes yet another meaning with the introduction of LTE. The numerous Alcatel-Lucent GSM installed base can indeed be leveraged to deploy LTE in a cost-effective manner: existing GSM BTS cabinet are re-used, allowing at the same time re-use of the site, power supply, battery back-up, antennas The 9326 LTE digital module can then be integrated in existing GSM BTS with no additional footprint. On the radio side, the wide offer of macro and distributed modules also enable smart LTE introduction, from re-farming of GSM spectrum to overlay deployment, hence fitting any operators strategy, spectrum and assets.

SDR modules from Alcatel-Lucent are ideal to add GSM capacity and introduce W-CDMA and/or LTE within the installed GSM cabinets

Provisioning

PerformanceSLA

Inventory

Optimization

Service Assurance

Security

Planning

OSS interfaces

Provisioning

PerformanceSLA

Inventory

Optimization

Service Assurance

Security

Planning

OSS interfaces

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Alcatel-Lucent strategy and key achievements Alcatel-Lucents initial commercial release is focused on the key functionality that will enable operators to launch LTE into commercial operation with VoIP and high bandwidth data support. As the system matures through subsequent releases, additional functionality will be added to support broadcast solutions with eMBMS functionality and with full multi technology mobility handoff being supported; this will allow subscribers to move seamlessly between different technologies. Our aggressive roadmap started in early 2007 with demos at 3GSM and CTIA, leading to field tests later in the year. It continues in 2008 with the commencement of Interoperability Testing (IOT) and technology trials, field trials in Q109. By the end of 2007 we had performed the 1st LTE air interface interoperability call with a leading terminal vendor, validating the expected performance of LTE in the field. By the end of 2007 we had performed the 1st LTE air interface interoperability call with a leading terminal vendor, validating the expected performance of LTE in the field. For Alcatel-Lucent, a fundamental part of implementing LTE into any network means the smooth evolution of the system currently deployed: WCDMA/HSPA, EV-DO, etc.

Alcatel-Lucent in LTE

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Learn more This section aims at providing some examples of migration scenarios from GSM to LTE on Multi-standard BTS products. In all scenarios, the multi-techno cabinet is re-used; therefore avoiding installation of additional cabinet or new site negotiation. The site, power supply and battery backup are reused. It is assumed that the GSM sites have been migrated to B11, and the IP connectivity on the GSM site has permitted the deployment of an all-IP transport network thanks to the META solution. It is for illustration only, as real deployments will depend on operators strategy and assets.

Inlay deployment with macro modules In this scenario, the operator re-farms its spectrum and allocates part of its GSM spectrum to LTE and uses macro radio solution. Replacement of TRX with MC-TRX MC-TRX modules can be integrated in at any point in time, to complement or replace the existing TRX or Twin-TRX products. Taking the example of cabinet with 12 TRX, the same capacity can theoretically be reached with 2 MC-TRX modules (6 TRX functions each). In our example, we use three MC-TRX, each module carrying 4 TRX for one sector. The GSM capacity is preserved while preparing the ground for LTE introduction. The depopulated TRX can be re-deployed for GSM extension. Integration of an additional 9326 LTE module within the existing cabinet When the operator decides to deploy LTE, an additional 9326 LTE module is added to the cabinet. Part of the spectrum is re-allocated to LTE. The MC-TRX are reconfigured to decrease the GSM footprint and introduce LTE, for instance 2 TRX + LTE 5MHz in each sector.

9326 LTE module

MC

PA

MC

PA

MC

PA

SUMX

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Inlay deployment with distributed radio modules

In this scenario, the operator re-farms its spectrum and allocates part of its GSM spectrum to LTE and uses a distributed radio solution. Replacement of TRX with MC-RRH MC-RRH modules can be integrated in at any point in time, to complement or replace the existing TRX or Twin-TRX products. As in the macro case, three MC-RRH can provide GSM capacity equivalent to 12 TRX. Integration of an additional 9326 LTE module within the existing cabinet When the operator decides to deploy LTE, an additional 9326 LTE module is added to the cabinet. Part of the spectrum is re-allocated to LTE. The MC-RRH are reconfigured to decrease the GSM footprint and introduce LTE, for instance 2 TRX + LTE 5MHz in each sector.

9326 LTE module

SUMX

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Overlay deployment with macro radio modules In this scenario, the operator has additional spectrum for LTE, for example in the 2.1 or 2.6GHz band. The GSM capacity is preserved in this case, and the two technologies are carried by two different radio links operated by macro radio modules. Replacement of TRX with MC-TRX MC-TRX modules can be integrated in at any point in time, to replace the existing TRX or Twin-TRX products. Each MC-TRX hosts 6 TRX functions, hence freeing up some space. Adding LTE radio macro modules This empty space can host additional radio modules, either TRDU or MC-TRX depending on the timeframe, requested capacity and operators current assets. Integration of an additional 9326 LTE module within the existing cabinet When the operator decides to deploy LTE, an additional 9326 LTE module is added to the cabinet. The GSM capacity is preserved while additional radio macro modules operate LTE in the additional band.

9326 LTE module

MC

PA

MC

PA

MC

PA

TRDU

TRDU

TRDU

SUMX

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Overlay deployment with distributed radio modules In this scenario, the operator has additional spectrum for LTE, for example in the 2.1 or 2.6 GHz band. The GSM capacity is preserved in this case, and the two technologies are carried by two different radio links operated by distributed radio modules. Replacement of TRX with MC-RRH MC-RRH modules can be integrated in at any point in time, to complement or replace the existing TRX or Twin-TRX products. As in the macro case, three MC-RRH can provide GSM capacity equivalent to 12 TRX. Adding LTE distributed radio modules Distributed radio modules are daisy chained to the existing GSM MC-RRH. Depending on the time frame, the requested capacity and the operators assets, MC-RRH or multi-techno RRH can be added. Integration of an additional 9326 LTE module within the existing cabinet When the operator decides to deploy LTE, an additional 9326 LTE module is added to the cabinet. The GSM capacity is preserved while additional radio macro modules operate LTE in the additional band.

SUMX

9326 LTE module

GSM

LTE

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Technical annexes

9326 LTE digital module Low Power Consumption 30% Power consumption 350 W max w/ 4 TRX @ full power New PA new Power Supply (PS) concept Optimize consumption based on actual traffic switching the supply voltage of the PA depending on the output powers

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WCDMA/LTE MiMO Optimized Remote Radio Head Alcatel-Lucent delivers its Dual PA Remote Radio Head 2x40W (RRH2x40W), a single sector self-contained radio module, including:

Two Tx chains (2*40W) for MIMO A duplexing system Two CPRI interfaces (2.4Gbp) A power system Compact size for easy deployment: weight