I HSPA Handbook

I-HSPA Handbook

Table of content

1. Introduction..................................................................................................3

2. Flat Architecture...........................................................................................4

3. Nokia Siemens Networks I-HSPA Solution.................................................7

3.1 Terminals..................................................................................................................7

3.2 Radio Access............................................................................................................7

3.3 SGSN.........................................................................................................................9

3.4 GGSN.........................................................................................................................9

3.5 Network Management............................................................................................10

3.6 Fulfilling Regulatory Requirements.....................................................................11

3.7 Multi-Vendor Interoperability................................................................................11

4. I-HSPA Transport........................................................................................13

4.1 Transport Technologies and Interfaces...............................................................13

4.2 QoS on the Transport Layer..................................................................................13

4.3 Synchronization.....................................................................................................14

4.3.1 Layer 3 solutions................................................................................................................14

4.3.2 Layer 1 solutions................................................................................................................15

4.4 Satellite based Iu for I-HSPA.................................................................................17

5. Quality of Service for I-HSPA traffic..........................................................18

6. Deployment Scenarios...............................................................................19

6.1 Greenfield I-HSPA Deployment.............................................................................19

6.2 Existing NSN customer with 3G network.............................................................20

6.3 Non NSN customer with 3G network....................................................................22

7. Competitor Status......................................................................................23

8. Glossary.......................................................................................................24

Copyright 2010 Nokia Siemens Networks.All rights reserved.

Technical Solution Description - Version 1.0 SWF68272

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1. IntroductionToday, the industry is experiencing steep growth in mobile data traffic. One trigger has been the introduction of HSPA to WCDMA networks, enabling end users to experience true broadband speeds via their mobile devices. Using advanced mobile data services is becoming more convenientand more enjoyable. HSPA was introduced in 2005 and now commands a place in more than80% of the world’s WCDMA networks. Offering peak data rates ten times greater than early WCDMAimplementations, HSPA has brought the fixed xDSL experience to mobile subscribers. What’s more, HSPA enables mobile service providers to grow their share of the residential broadband business.

Telecommunication industry over the past decade has seen optimization or maturation of the voice segment and emergence of the data segment. Though in many markets globally the thrust is still on voice but the way demand for data is increasing and margins on voice are declining the next war is in the data segment. This brings all together a new set of user expectations and consequently new set of operator challenges.

Figure 1: User expectations and Operator challenges

The resulting increase in data traffic threatens to stress existing infrastructure. Many networks facepressure to move from voice-driven to data-driven architectures. This pressure is being met by flat network architecture. I-HSPA (Internet- HSPA) is the first standardized flat 3GPP architecture for mobile networks optimized for mobile broadband.

Figure 2: Revenues and Traffic are becoming decoupled

To improved end user experience and at the same time to remain profitable, it is very critical to reduce the cost per Mbyte and to do so evolution towards the flat network architecture is the way forward solution.



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2. Flat ArchitectureFlat architecture in simple words means networks which are characterized by fewer network elements, lower latency, greater flexibility and lower operation cost. Flat network architecture is a keyenabler of the mobile data future. Flat architecture enables networks to be scaled up cost effectively as data traffic increases. End users benefit from improved service continuity and attractive data prices which translate into increased loyalty and improved business for service providers. Flat architecture is characterized by a simplified structure that enables network elements to directly connect the Radio Access Network (RAN) to the core packet network. Traditional hierarchical dependencies are removed, streamlining data flow and enabling capacity to be scaled up flexibly and cost-effectively.The first 3GPP-standardized commercial implementation of flat architecture is I-HSPA. This simplifiedtwo-node architecture (see Figure 3) employs a base station that integrates a subset of Radio Network Controller (RNC) functionality and Serving GPRS Support Node (SGSN), supporting the Direct Tunnel feature. This enables data traffic to by-pass the RNC and SGSN for the user plane, however control plane information flows through SGSN as in the current scenario.

Figure 3: Evolution of WCDMA networks to Flat Architecture

I-HSPA can be a evolution path to operators which plan to move to 4G (LTE) technology in short time duration. For operators which have just launched 3G services or plan to not to move to 4G (LTE) in short duration of time, I-HSPA can work as solution for enhancement in data throughputs for better end use experience.

Flat network architecture is standardized by the 3GPP Consortium in 3GPP Release 7 for WCDMAand in 3GPP Release 8 for LTE. Standardization brings a wealth of benefits, from competitive markets and diversity in end-user equipment, to interoperable solutions and roaming.I-HSPA introduces true flat architecture to WCDMA. The technology is standardized in 3GPP Release 7 as ‘Direct Tunnel with collapsed RNC’, which ensures interoperability with existing WCDMA core networks and 3GPP terminals. This standardized ‘direct tunnel’ functionality is essentially an SGSNfeature that does not affect the specification for existing GGSN platforms. Furthermore, neither I-HSPA nor ‘direct tunnel’ functionality have any impact on the air interface and user terminals, so all I-HSPA implementations will support today’s widely deployed 3GPP Release 5 HSDPA and 3GPP Release 6 HSUPA terminals. This means that a service provider can enjoy all the many benefits of an I-HSPA network upgrade which remains invisible to subscribers, except for the improved end-user experience.



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Benefits of Flat Architecture

Higher network connectivity and availability

With I-HSPA, investments in SGSN and RNC network elements to increase throughput are no longernecessary. These investments can instead be redirected to fully use the potential of the HSPA air interface. Investing in I-HSPA enables a significantly higher number of broadband subscribers to be served and removes the risk of investments becoming obsolete when upgrading to LTE in the future. I-HSPA enables service providers to flexibly increase HSPA carriers and BTSs without laborious RNC and SGSN re-dimensioning. Avoiding the need for RNC and SGSN upgrades also improves network availability for end users.

Lower cost transportI-HSPA enables the use of packet based transport for simpler capacity management with scalable and remotely operated Ethernet connections. Low cost transport options such as xDSL and GigabitPassive Optical Networks (GPON) can be used as first mile technologies to carry Internet traffic towards the Gateway GPRS Support Node (GGSN). Packet traffic aggregation can be flexibly implemented within Next Generation Synchronous Digital Hierarchy (SDH), Carrier Ethernet orother packet-based networks to benefit from the greatest transport cost savings. I-HSPA transport is also streamlined by terminating RNC protocols at the BTS to reduce the backhaul load. These benefits add up to substantially reduced capital and operating expenditures, offering serviceproviders the cost structure they need to profitably address the mass market with mobile broadband services.

Simplifying the step to LTEI-HSPA uses identical network architecture as LTE, which is standardized in 3GPP Release 8 (I-HSPA has even been referred to as pre-LTE). These similarities smooth network evolution to LTE, which offers even higher data rates and increased spectral efficiency that will further drive down the cost per delivered bit. Flat architecture also simplifies the transport topology for high capacity connections. The transport network can be optimized to carry bandwidth greedy data traffic directly to the core network sites. This removes the need to upgrade traditional connections as they will only have to serve low capacity control and voice traffic. LTE can directly benefit from the flat transporttopology implemented for I-HSPA. Smooth evolution protects existing 3G network investments and enables an earlier time to market with LTE.

Benefits for the end userThe greatest I-HSPA opportunity for end user perception is the affordable mobile broadband data consumption pattern which invites rich variety of mobile data services for daily usage. The mobile operator’s offering will further accelerate the user traffic development through the proven success factors of mobile system like ‘it works every where’, ‘I’ve got my terminal always with me’ and ‘it’s easy to use’. Some indications from the attractively priced mobile data packages suggest that the traditionally quite moderate mobile data traffic would easily reach 1 Gbyte/month/sub range.In addition to the economical advantages I-HSPA also clearly improves end-user usability. The flat architecture ensures low latencies. The robust and efficient HSPA radio interface will implement extremely high peak rate and channel set-up times also for new truly real time applications.As a very important development the I-HSPA simplified network architecture results in a shortened round trip and channel set-up time which can be seen in a tangible user experience improvement. For the performance of many IP based applications such as music download, fast email synchronization, real time gaming, VoIP the system latency is similarly important as the peak data rate.



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Impact on Transport network due to I-HSPAThe transport network will also need to be evolved to provide greater and more cost effective backhaul capabilities. The radio and transport networks are vitally interlinked and need to be addressed together. Being initially voice centric, early WCDMA deployments had littleimpact on backhaul networks. However with the roll out of HS PA over WCDMA, scalability difficultiesarise. With HSPA, the traffic profile of a BTS changes dramatically from a few hundred kbps of fairly uniform traffic, to bursts of several Mbps. Conventional Internet Protocol / Multi-Protocol Label Switching (IP/MPLS) technology is not optimized for these new service types and is not cost-effective when scaling up transport. Service providers need to widen their backhaul infrastructure, taking advantage of packet-based transport technologies and statistical multiplexing, to avoid large static pipes running through the entire backhaul network. This is true whether the service provider owns a dedicated backhaul network, relies on a third party provider, or merges fixed and mobile traffic to a common network. The solution lies in Carrier Ethernet which offers the kind of carrier grade, high Quality of Service (QoS), five-nines (99.999%) availability and performance that broadband communications service providers need. I-HSPA is inherently IP/Ethernet-based and takes full advantage of packet based transport solutions.



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3. Nokia Siemens Networks I-HSPA SolutionNokia Siemens Networks is the leader in developing flat architecture. I-HSPA was invented by Nokia Siemens Networks and is now fully standardized and it is still the only vendor with true flat architecture from today and we can offer our I-HSPA solution to the 3G customers.

3.1 TerminalsStandard 3GPP Rel5 (or later) compatible Nokia or any other standardized terminals are applicable. Typical terminals are

laptop with an integrated HSPA module

laptop with a plug-in HSPA data card

HSPA mobile terminal

The I-HSPA network uses standard interfaces towards the terminals. Therefore, the operator and the end users can use normal terminals.

3.2 Radio AccessBase station in I-HSPA is generally referred to as I-BTS. I-BTS is not a new BTS but a concept actually. The I-BTS functionality includes a base station that integrates a subset of Radio Network Controller (RNC) functionality and Serving GPRS Support Node (SGSN), supporting the Direct Tunnel feature. We can achieve the I-BTS functionality either from Flexi WCDMA BTS or from Flexi Multiradio BTS. Currently we can offer I-HSPA Release 1 and Release 2. Since in the Release 1 and Release 2, the Flexi WCDMA and Flexi Multiradio BTS have FTIB as the transport module, thus they require additional hardware which is I-HSPA adapter module. But with I-HSPA Release 3, Flexi WCDMA\Flexi Multiradio BTS comes with an integrated solution with FTLB based transport module. There is no need of any additional adapter unit in I-HSPA Release 3.

Roadmap and Timelines: I-HSPA Release 2 is available from 03/10. I-HSPA Release 3 is expected by Q4/10, however with the availability of WCDMA release RU20 from 03/10, we can offer Flexi WCDMA BTS / Flexi Multiradio BTS with integrated FTLB module. Most of the features are available with the availability of RU20 but for some features specific to I-HSPA we’ll have to wait till Q4/10 for I-HSPA Release 3.

Figure 4: I-HSPA Roadmap



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The standard 3GPP WCDMA UE and Nokia Siemens Networks I-HSPA WCDMA BTS are connected through 3GPP standard air interface. The BTS includes the majority of the I-HSPA system functionality. The functions are very similar to the HSPA part of a traditional RNC but scaled down to the scope of one BTS. Thus the complexity and related cost of the system is minimized. In I-HSPA scenario the I-BTS is seen as “standard” RNC. So the logical interface from I-HSPA base stations to traditional BTS and interface between one I-BTS to another I-BTS is called as Iur.The resources of the BTS can be shared for I-HSPA radio network layer and traditional 3G network layer. The BTS air-interface remains fully 3GPP standards compliant and ensures the full inter operability with the standard 3GPP terminals.

The BTS network interface can be either 3GPP standard IuPS +Gn for the SGSN+GGSN solution. BTS implements the HSPA traffic parts of traditional 3GPP RNC. The following figure gives an overview of the features in the respective I-HSPA releases.

Figure 5: I-HSPA Features Overview

HSPA Adapter

The I–HSPA Adapter provides the extended functionality (RNC functionalities) at the NodeB site.The capacity of each I–HSPA Adapter is set by the capacity license. Each license is per I–HSPA Adapter, which allows capacity to be increased with a higher capacity license on a site by site basis without the need for hardware upgrading.

Figure 6: I–HSPA Adapter



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The I–HSPA Adapter has been designed as a 1U high 19-inch rack element to be installed in any BTS cabinet or enclosure where the FlexiBTS can be installed, such as the Flexi BTS indoor and outdoor cabinets, the WCDMA UltraSite Optima Compact outdoor (inside the LTE) and on top of WCDMA UltraSite Supreme indoor; and standard 19-inch equipment racks.

The I–HSPA Adapter can be fitted to a FlexiBTS 2U module casing. When used with the FlexiBTS module casing, the I–HSPA Adapter can be installed with the Flexi WCDMA BTS in stand-alone configurations, such as free-standing, wall mounted or pole mounted.

Figure 7: I–HSPA Adapter and Flexi BTS module casing

3.3 SGSNI-HSPA system uses standard SGSN interfaces. In I-HSPA, the tunnel solution allows truly flat architecture for user plane traffic as the user plane goes directly from BTS to GGSN. Nokia Siemens Networks recommends using the one tunnel solution for the low delay and high capacity networks like I-HSPA. The Nokia Siemens Networks’ SGSN supports the “direct tunnel solution”. Only the Iu-PS control plane is processed in SGSN. The one tunnel solution uses standard Iu-PS and Gn interfaces, so it is also possible to use it with current the RNCs and GGSNs.

Flexi NG SGSN SG8 can be offered as SGSN in the I-HSPA scenario and it also provides LTE readiness. However SGSN SG7 can also support I-HSPA but it requires a feature I-HSPA Enhancement.

Integrating I-HSPA with SGSNIn I-HSPA Enhancement feature, the connection to the serving GPRS support node (SGSN) is established through the Iu-PS-CP (Control Plane) interface. The Iu-PS-CP interface carries control plane data between the I-HSPA RAN and the SGSN with I-HSPA Enhancement.

3.4 GGSN

I-HSPA system uses standard SGSN interfaces. I-HSPA uses standard GGSN interfaces and any standard based GGSN can be used. Nokia Siemens Networks GGSN solution for I-HSPA is based on Flexi ISN or the latest Flexi NG.

Flexi ISN

Flexi ISN is a scalable carrier-grade gateway GPRS support node (GGSN) incorporating advanced service-aware and traffic analysis functionality. It acts as a gateway between wireless data networks and external data networks like operator’s service networks, corporate networks, and the Internet. The Flexi ISN GGSN functions are based on 3GPP Release 7, supporting both 2G and 3G (GSM, EDGE and WCDMA) wireless access networks, flat architecture, and high-speed HSPA/HSPA+ and



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I-HSPA data connections. It is a carrier grade platform for both GGSN and Home Agent. It offers fully resilient PDP contexts. The resiliency prevents extra signaling messages in the access network. Flexi ISN can act as common anchor point for I-HSPA, traditional 3GPP PS traffic and 2G network. Flexi ISN supports wide variety of charging (both pre- and post paid), service awareness.

Flexi NG

The new Flexi NG product targets current and future mobile networks. It supports a variety of access network types, including Long Term Evolution (LTE), high-speed packet access (HSPA), evolved high-speed packet access (HSPA+), 2G/3G GPRS access, Internet high-speed packet access (I-HSPA) and direct tunnel. Different applications, such as serving gateway (S-GW), packet data network gateway (P-GW) or gateway GPRS support node (GGSN), can be installed on the same hardware using the same software. Flexi NG provides excellent throughput and signaling capacity to accommodate the traffic growth in next generation networks. The key to Flexi NG performance is in the use of multi-core packet processor (MPP) technology in the control plane and in the user plane. MPPs are designed for fast networking applications and contain several hardware units that accelerate packet data processing. The MPP technology is highly flexible and scalable, and enables faster development cycles. The use of MPP technology also allows, for example, rapid changes between signaling and user plane processing capacity. The high availability options available in Flexi NG enable 99.999% reliability at different redundancy levels, including session continuity through the use of session replication in active-standby service blade pairs.

Flexi NG is based on the Nokia Siemens Networks AdvancedTCA (ATCA) hardware platform and Nokia Siemens Networks FlexiPlatform operating software and middleware. FlexiPlatform is a robust, carrier-grade Linux based platform, offering versatile services for operation and maintenance (O&M), networking and platform services using the latest technologies available.

Integrating I-HSPA with GGSNThe connection with the gateway GPRS support node (GGSN) is made through the Iu- PS-UP interface. The Iu-PS-UP interface carries user plane data to the GGSN. The Iu-PS user plane interface utilizes the Direct Tunnel feature of the SGSN. This feature provides a direct user plane tunnel between the I-HSPA RAN and the GGSN through the IP backbone, bypassing the SGSN.

3.5 Network Management

NetAct provides seamless management of different network technologies with integrated and inter working tools, which enables the operator to control costs while redeploying competencies and resources from 2G to 3G, HSDPA, HSUPA and I-HSPA. Further, as a pre-integrated and process-based management system, NetAct visualizes all network element failures, service quality indicators and entire traffic on a single screen. NetAct makes it possible for the operator to act more proactively, and reach for optimal network and service quality to the end customer.

NetAct functionality for I-HSPA covers fault management, performance management and software management functions for the I-HSPA network. Hardware inventory management for I-HSPA (Applications Software) facilitates operator asset management.

NetAct performance management functionality helps the operators to ensure their I-HSPA customer business case by offering data for analyzing the geographical areas where high speed data access is most needed and used. NetAct Key Performance Indicators enable the operator to analyze the HSPA penetration in their network, and follow the number of active HSDPA or HSUPA capable mobiles and the typical behavior of the HSPA subscribers in terms of, for example, throughput or connection times. Further, NetAct fault management and performance management functionality together can help operators guarantee end user access to 3G services, thus improving subscriber perception of service quality. Problems with, for example, WSPC cards, physical channels or priority settings, or in packet transmission or mobility can be detected without delay, and of course corrected immediately.



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In the first I-HSPA release, Configuration Management support will be provided with an off-line only tool, which enables modification and preparation of radio network plans that can be imported to Radio Access Configurator. In further I-HSPA releases, Radio Access Configurator for I-HSPA (Applications Software) completes the management solution by cost-efficient configuration management operations through centralization, integration and automation, instead of verifying each NodeB separately using an element manager. Radio Access Configurator enables, for example, dimensioning the NodeB according to power usage and optimizing and verifying the tuning in the entire radio network.Radio Access Configurator also speeds up and automates the rollout of I-HSPA, as the NodeB parameters can be planned and set in advance conveniently with the help of default parameters, templates and site configuration files, and activated to the entire network with one enabler parameter. Radio Access Configurator makes it also possible to check the I-HSPA related status of hardware prior to rollout.

3.6 Fulfilling Regulatory Requirements

I-HSPA fulfills all relevant regulatory requirements typically set for telecommunication networks. Lawful Interception is supported in regular manner as GGSN offers connection to legal interception GW. The E911 emergency call regulatory requirement is also fulfilled and there are two solutions for it. If there is no underlying GSM network with positioning support, Nokia Siemens Networks can support either a control-plane or user-plane A-GPS solution.

In the control-plane A-GPS solution, the I-HSPA adapter in each NodeB is connected via the 3GPP-defined Iu-pc interface to a Stand-Alone SMLC (SAS). The Nokia Siemens Networks I-HSPA RAN can support UE-based A-GPS and requires an interface to a SAS and a GPS reference network covering the same geographic area.

In the user-plane A-GPS solution, the Radio Access Network (RAN) and Core Network is not aware of the location system. The SMLC functionality resides in the our iGMLC product, which is connected to the GGSN over the Gn reference point, meaning that the communication is IP-based between the terminal and iGMLC. The iGMLC-integrated SMLC supports Cell ID, 3G Matrix/LMU-less OTDOA, and A-GPS (both UE- and NW-based) location methods and is compliant with OMA Secure User Plane Location 1.0 (SUPL). If there is an underlying GSM network with positioning support deployed, E911 calls can be diverted during call establishment to a GSM-based CS call, via the CS call enabling handover mechanism. The GSM network will then recognize the emergency nature of the call and initiate positioning with the 2G positioning solution (e.g. U-TDOA) that is compliant with the FCC requirements.

3.7 Multi-Vendor InteroperabilityAs I-HSPA is fully 3GPP standards compliant, standard 3GPP terminals are applied. 3GPP Rel7 One tunnel solution and HSPA Evolution standardizes the flat architecture by allowing RNC functionality in the Node B site, increasing RNC ID and with CS enabling HO.All I-HSPA related flat RAN standardization are summarized in 3GPP document TR25.999.I-HSPA introduces first time ever in telecommunication industry an open interface to the BTS. In the picture below the solid grey line is Gn user-plane interface and dotted red line between I-HSPA BTS, i.e. I-BTS and SGSN is Iu-ps control-plane and dotted red line between SGSN and GGSN is Gn control-plane. These are all truly open and well inter-operability tested interfaces.



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Figure 8: Multi-Vendor Interoperability



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4. I-HSPA TransportNokia Siemens Networks provides a rich portfolio of transport options for the last mile to the site. Details can be found in specific transport solution documents.

4.1 Transport Technologies and InterfacesUser, control and management plane are carried over IP. While Ethernet is expected to become the mainstream technology for BTS backhaul in the future, many existing BTS sites are connected with PDH/SDH links. Consequently, the BTS supports various options for the combination of IP with underlying L2/L1 layers. The actual choice will be determined by availability and price. In the first I-HSPA release, the following options are available:

Layer 2 Layer 1 (I-BTSInterface)

Ethernet 10/100/1000Base-T (electrical)1000Base-LX/SX (optical)

LLC/SNAP/AAL5/ATM 4/8/16 x E1/T1/JT1 with IMA (electrical)16 x E1 with IMA over FlexBus1) (electrical)STM-1 (VC-4) (optical)

Table 1: I-BTS Interfaces

FlexBus is a Nokia Siemens Networks proprietary interface to connect a microwave radio outdoor unit (ODU) directly.

I-HSPA Rel. 3 also supports hybrid transport. The FTLB transport module, that handles the I-HSPA functionality, supports Ethernet as well as 4 x E1 interfaces. This allows the operator in addition to a pure IP backhaul as for I-HSPA Rel. 1 and Rel. 2 to go for a hybrid backhaul approach. Typically non real time traffic would be handled by Ethernet while time critical services such as voice would stay on E1.

Figure 9: Hybrid backhauling with I-HSPA Rel 3.

4.2 QoS on the Transport LayerIn order to avoid over-dimensioning in the BTS backhaul network, the I-HSPA BTS supports QoS differentiation between user, control and management traffic on multiple layers:

on the IP layer, using DiffServ on the Ethernet layer, using IEEE802.1q VLAN ID and IEEE802.1p priority bits (Rel.2) on the ATM layer, using different VCC’s (Rel.2)

Since the BTS provides an Gn/IuPS/Iur interface (not Iub), the latency and latency variation requirements on the transport network can be relaxed correspondingly. For the Gn user plane, the required maximum latency is depending on the offered user service (e.g. VoIP). For the IuPS and Iur



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control plane latency is less important, but increased round trip times may affect user applications and impact system performance. In order to reduce BTS backhaul capacity requirements further, the Iur user plane can be switched off (no uplink MDC). Only in case the Iur user plane is switched on, 200 ms latency should not be exceeded.

4.3 SynchronizationThe I-HSPA adapter provides a native IP interface. While in classic and hybrid architectures the TDM network is used to reliably distribute the Primary Reference Clock to cell sites new solutions are required for inherently asynchronous packet networks:

GPS receiver at BTS site can be used for synchronizing I-HSPA BTS In case there is a synchronized neighboring BTS, e.g. GSM/EDGE BTS, the synchronization can

be derived from it for I-HSPA BTS With layer 3 solutions the clock can be distributed across any layer 3 or layer 2 network. Timing

packets are transparent to intermediate routers and switches. For this reason layer 3 solutions are without alternative where mobile operators rely on third party Ethernet services, unless that third party provider makes clock distribution a part of the service offering

Alternatively most of the technologies discussed herein allow clock distribution at layer 1: microwave radios, SHDSL, GPON and NG-SDH. Synchronous Ethernet is an emerging technology for pure packet platforms such as Carrier Ethernet switches. Layer 1 solutions reliably work under all network load conditions. For this reason mobile operators with self built backhaul will prefer the layer 1 approach – despite the fact that all intermediate nodes on the way to the cell site are affected

Obviously layer 3 and layer 1 solutions may also be mixed

4.3.1 Layer 3 solutions

Timing over PacketTiming over Packet is the Nokia Siemens Networks denotation for using a standardized protocol to transparently synchronize cell sites over layer 3 or layer 2 networks. The chosen protocol is IEEE1588 version 2, a protocol originally developed for factory floor applications and now being extended for wide area networks.

The two main components of the Timing over Packet solution are:

An IEEE1588v2 master clock. This may be a dedicated node or a plug in unit added to an existing Primary Reference Clock. The master clock is fed with a 2MHz, 2Mbit/s or GPS reference and could be located at the BSC / RNC- or Core Network site

An IEEE1588v2 slave clock at the cell site. Flexi WCDMA BTS will provide integrated slave clocks, residing on IP/Ethernet interface units / transport sub modules respectively. Alternatively cell site nodes such as SURPASS hiD3105 and Tellabs 8605 may provide this function

Figure 10: Timing over Packet



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The master clock generates a flow of time stamped IP packets for each of its slaves. The packet rate is configurable, resulting in additional traffic in the order of a few tens of kbit/s per slave. Slave clocks receive the timing packets and recover the original clock.An important prerequisite for quick lock in and high frequency stability is expedite forwarding of timing packets by intermediate routers and switches. At present the network properties required to operate IEEE1588v2 for cell site synchronization cannot be easily and comprehensively described yet. The statistical distribution of delay is a key factor for successful clock recovery; and that distribution is obviously influenced by a number of factors, such as, network load, software versus hardware based forwarding planes etc. Together with specialized vendors and through active participation in standardization bodies Nokia Siemens Networks is working on a set of parameters that can be added to Service Level Agreements with Ethernet service providers.

Adaptive timingAdaptive timing based on TDM pseudo wires is an alternative to Timing over Packet. As with Timing over Packet cell sites can be transparently synchronized over layer 3 or layer 2 networks. As shown below the pseudo wire extends between two PWE3 gateways, one at the cell site, and the other at the BSC / RNC site. The recent GSM/EDGE BTS families also provide an integrated IP/Ethernet interface to terminate the pseudo wire at.

Figure 11: Adaptive timing

At the BSC / RNC- or Core Network site E1/T1 frames ingress the PWE3 gateway at a constant rate (which represents the clock to be distributed). Frames are concatenated inside IP packets, which then traverse the packet network. At the egress side the original frame rate is recovered. As with Timing over Packet the required network properties cannot be easily and comprehensively described yet.

4.3.2 Layer 1 solutionsAs summarized in the figure below most of the technologies discussed herein allow clock distribution at layer 1:

PDH / SDH microwave radios can convey a 2MHz reference even when operated as packet radios, i.e. when dedicating all channels to form a single Ethernet pipe

SHDSL is inherently synchronous (NTR, Network Timing Reference) and therefore commonly used for carrying E1/T1. This also applies when using SHDSL for carrying Ethernet instead of E1/T1. The IP DSLAM at the other end of the copper pair can be synchronized through a number of options (external 2MHz or 2Mbit/s reference, Synchronous Ethernet, IEEE1588v2)

Also GPON is inherently synchronous and can be used for carrying E1/T1. SURPASS hiX 5705, the Single Business Unit, provides both Ethernet and E1 interfaces. SURPASS hiX 5750, the Optical Line Terminator at the other end of the fiber, can be synchronized through a number of options (external 2MHz or 2Mbit/s reference, Synchronous Ethernet, IEEE1588v2)



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Figure 12: Layer 1 mechanisms

In case the uplinks of IP DSLAM and GPON OLT are purely packet based (not NG-SDH) a dedicated, parallel synchronization network is required. Synchronous Ethernet, an emerging alternative for point to point Ethernet, is being studied for Carrier Ethernet switches, IP DSLAM and GPON OLT uplink and MSAN point to point fiber downlink.

Figure 13: Parallel synchronization network

I-HSPA offers security level identical to WCDMA or HSPA access. Neither the terminal nor network security level can be compromised. User access, authentication and authorization support standard SIM and USIM equipped terminals. Authentication functionality is not located in I-HSPA but higher up in the network in SGSN or AAA server. SGSN and AAA server can use HLR via MAP or external database to get user credentials.Air interface cryptographic protection (UE-BTS) uses 3GPP Rel. 5/6 interface. Control and users plane between network elements can optionally be encrypted using IPSec tunnels. The mechanisms used to protect the core system include traffic separation, the use of firewalls and the use of IPsec VPN connections, if needed in some of the system interfaces.



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Traffic separation: The user traffic is carried in a GTPl between the BTS and the GGSN or Home Agent functionality

in the Nokia Siemens Networks ISN. Thus, the end-users cannot access the operator internal IP network between the BTSs and the NSN ISN, but the user traffic is visible only from the Gi interface of the NSN ISN onwards

The BTS as well as the Nokia Siemens Networks ISN and optional NSN IMS elements implement a separate IP interface for the O&M traffic. Thus, O&M traffic is separated from the user (and control) traffic already in these elements

Additionally VLANs and MPLS VPNs can be utilized to separate the user traffic (IP packets to/from the end-user’s terminal), control traffic (e.g., Radius signaling) and O&M traffic from each other

Firewalls:

Firewalls are used for perimeter protection as normally in the cellular networks. I.e., the operator should utilize a firewall in the Gi interface, next to the Nokia Siemens Networks ISN, to block attacks from the Internet towards the end-users and the operator network elements

Firewalls and access lists should be used to protect the control plane elements (SGSN/AAA server, GGSN/HA in the Nokia ISN, HLR/ HSS) so that only the required signaling traffic is allowed to the control plane elements

The network should be divided into separate security domains as specified in the 3GPP TS 33.210. The SEG functionality in the edge of each of the security domains should include a firewall. The details of the overall structuring of the network security domain is dependent on the operator’s environment and practices, and is therefore a matter of network planning carried out before the system is deployed

VPNs

IPsec VPN connections should be used to connect elements in different security domains. The VPN connections are realized with VPN GW functionalities implemented in the SEG elements

VPN connections may also be used between network elements in the same security domain. The need for such use may arise for example due to a physically insecure link between the network elements, such as a microwave link between BTSs

4.4 Satellite based Iu for I-HSPAIn case it is required to provide coverage of remote places like islands which cannnot be reached by other technologies like microwave radio at affordable costs, it is also possible to provide satellite Iu for PS as well for CS services.

Figure 13: Satellite based Iu for I-HSPA



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5. Quality of Service for I-HSPA trafficThe solution is most importantly based on Differentiated Services (DiffServ) model as well as on the 3GPP-specified air interface priority support and QoS-parameter negotiation. The proposed architecture supports both service and subscriber differentiation.

No QoS-specific functionality is expected from applications or subscriber devices as the entire solution can be implemented fully network based. In practice, this means support for negotiation the default/subscribed QoS-values for the PDP-contexts from the device perspective

The traffic recognition and priority marking is based on the L4-L7 packet looks-ups as well as the 3GPP-standardized Gx+ policy control interface support in the Nokia ISN. The Gx+ interface can be used to pass e.g. SIP/SDP-based policy information from the IMS. Subscriber specific information is available from HSS/AAA

Based on the marked priority, standardized air interface priorities and different DiffServ code points can be applied for the traffic

3GPP air interface QoS is supported and mapped to information in PDP context

I-HSPA subscribers can also be categorized to different user levels (Gold, Silver and Bronze) based on subscription information to prioritize the user service quality

Support for differentiated Quality of Services is needed in I-HSPA when voice (VoIP) is supported. The minimum requirement is thus to have 2 different priority classes, VoIP (and other higher priority) and other traffic. QoS support starts at the “IP network” / open Internet interface, where ISN (or other gateway, if used) needs to mark the downstream IP packets according to the traffic priorities, see picture below.

Figure 14: Basic I-HSPA QoS support components

These priorities are carried to the BTS over the IP based access/transport network as DiffServ code point (DSCP) markings in the IP packets. They are utilized in the base station for setting priorities for the radio scheduling (thus the priority information must be extracted from the IP packets and forwarded to the radio scheduler). DSCP markings are also be used for traffic prioritization in the access transport network.



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6. Deployment Scenarios

I-HSPA is not a destination solution but a transit solution between 3G and 4G technologies. I-HSPA would actually be deployed either by a new operator in a green field network or by a 3G operator who has not launched 4G technology but wants to offer maximum speeds out of its 3G network. So, from market and Nokia Siemens Networks perspective I-HSPA would be deployed in the following scenarios.

Greenfield I-HSPA Deployment Existing NSN customer with 3G network Non NSN customer with 3G network

6.1 Greenfield I-HSPA Deployment

Green fielders with no existing 3G infrastructure have the full flexibility to decide how to roll out I-HSPA. With I-HSPA Rel. 3 this can be done without the need of an RNC and still have a fully 3GPP compliant solution, supporting CS and PS traffic on standard Rel. 5 terminals. I-BTS, SGSN and GGSN are part of the I-HSPA only network elements. Flexi Multiradio BTS with in built FTLB transmission module can be offered as I-BTS part of the deployment. SGSN SG8 as SGSN and Flexi ISN/Flexi NG can be offered as GGSN can be offered as part of packet core network.

Figure 15: I-HSPA basic architecture deployed with 3G network

Depending on the traffic distribution over the network it might however be more efficient to go for a hybrid approach. In that case only sites at which a certain amount of data traffic is expected would be enhanced by I-HSPA. Depending on local circumstances this would be sites with a data traffic of more than 2-7 Mbps during busy hour. With the solution in the following diagram, the end users receive full CS service support.



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Figure 15: I-HSPA interworking with CS

6.2 Existing NSN customer with 3G network

This is how a classical WCDMA Nokia Siemens Networks network looks like and upgrading an existing 3G network which is already based on Nokia Siemens Networks Flexi base station is especially easy.

Figure 16: Classical WCDMA network

For I-HSPA Rel. 2 only an I-HSPA adapter is required at a site. The I-HSPA adapter is based on the same HW architecture as the other Flexi modules. The only work which has to be done at the site would be to plug in the I-HSPA adapter into the Flexi base station. With the I-HSPA enabled Flexi the operator can fully use I-HSPA and it’s features without limits.



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Figure 17: Upgrade of NodeB to I-BTS

With I-HSPA Rel. 3 the I-HSPA functionality will be handled by the FTLB transport module. For sites, where FTLB is already available, the introduction of I-HSPA Rel. 3 becomes a simple SW upgrade. At sites, where an older version of transport module is being used, only that single blade has to be replaced. The FTLB transport module is also capable of handling LTE as well as HSPA traffic. A later upgrade from I-HSPA to LTE will be a purely SW upgrade for sites that are already FTLB enabled.

Support of I-HSPA for Ultra base stations is available with I-HSPA Rel. 2. As Ultra and I-HSPA are using the same Iub interface, the upgrade of Ultra sites is very handy. In fact only the I-HSPA adapter has to be placed and connected to the site after the site has been upgraded to native IP with the IFUH card. With the I-HSPA enabled Ultra base station the operator can fully use I-HSPA Rel. 2.If SGSN SG8 is being deployed in the existing network then there is no need of upgrade as it is already I-HSPA and LTE ready. However in case of SGSN SG7, I-HSPA enhancement feature is required to support I-HSPA. In case of GGSN, both Flexi-ISN as well as Flexi NG as GGSN are ready to support I-HSPA. The below figure shows the up gradation of a Nokia Siemens Networks 3G network to I-HSPA.

Figure 18: Classical WCDMA network upgraded to I-HSPA network



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6.3 Non NSN customer with 3G network

I-HSPA can easily be introduced in any existing 3G network, also in case of legacy equipment and no installed Nokia Siemens base. The requirements for such an approach with minimum impact on existing infrastructure are:

One free carrier for the I-HSPA overlay network

Load and Service based hand over feature on the 3rd party RNC to support full mobility

If these HO are not available then the 3rd party RNC needs to be tuned with air-interface parameter settings to push HSPA terminals to I-HSPA layer by default

Direct Tunneling on the 3rd party SGSN would be helpful to achieve the full benefits. However as I-HSPA supports standardized IuPS interface this is not necessarily required

With the Flexi Base station the introduction of I-HSPA can be done at minimum costs and with minimum impact on existing sites. It is possible to completely reuse the existing radio hardware consisting of feeders, mast head amplifiers and antennas. The combination of the radio signal from the 3rd party and the I-HSPA can be done with the Nokia Siemens Networks Multi Radio Combiner. This is a passive device which will be integrated into the Flexi.

Figure 19: I-HSPA introduction with shared antenna system

The full flexibility of the Flexi in terms of installation requirements also makes it possible to acquire new sites easily and provide a higher cell density for I-HSPA for a maximum end user perceived quality.



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7. Competitor Status

E\\\ has no concept for flat radio, only Nokia Siemens Networks provides fully flat architecture. E\\\ is not seeing the trend, still behind – fighting against flat architecture. This could probably be due to the reason that E\\\ sees I-HSPA as non standardized, which is an wrong assumption. The figure below shows possible E\\\ statements with Nokia Siemens Networks response to it.

Figure 19: E\\\ possible statements with Nokia Siemens Networks response

Though, in some their presentations E\\\ has Flat Radio Architecture. Huawei also has Flat RAN in their roadmap for 2010.



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8. Glossary

Term Abbreviation

2G 2nd Generation mobile communications

3G 3rd Generation mobile communications

3GPP 3rd Generation Partnership Project

4G 4th Generation mobile communications

AMR Adaptive Multi-rate

AMR FR AMR Full Rate

AMR HR AMR Half Rate

BCCH Broadcast Control Channel

BSC Base Station Controller

BSS Base Station System

BTS Base Transceiver Station

C/I Carrier-to-interference ratio

CAPEX Capital Expenditure

CDR Charging data record

CDS Circuit Switched Data Server

CM Configuration Management

CQI Channel Quality Indicator

CS Circuit Switching

CS1 Capability set 1

CS2 Capability set 2

DC-HSDPA Dual Cell - High Speed Downlink Packet Access

DFCA Dynamic Frequency and Channel Allocation

DL Downlink

DLDC Downlink Dual Carrier

DPTRX Double Power TRX

DSP Digital Signal Processor

DTRX Dual Transceiver

EDGE Enhanced Data Rates for GSM Evolution

EFR Enhanced Full Rate

EGSM Enhanced General Packet Radio Service

EMS Element Management System

eTOM Enhanced Telecom Operations Map

FER Frame Error Rate

Flexi-NG Flexi Network Gateway

FTP File Transfer Protocol

GGSN Gateway GPRS support node



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Term Abbreviation

GMM GPRS mobility management

GPRS General Packet Radio Service

GSA Global mobile Suppliers Association

GSM Global System for Mobile Communications

GUI Graphical User Interface

GUIS Graphical User Interface Server

HARQ Hybrid ARQ Scheme

HLR Home Location Server

HR Half Rate

HSDPA High-Speed Downlink Packet Access

HS-DPCCH High-Speed Dedicated Physical Control Channel

HSPA High-Speed Packet Access

HSUPA High-Speed Uplink Packet Access

HU Height Unit

ID Indoor

I-HSPA Internet HSPA

IETF Internet Engineering Task Force

ITIL Information Technology Infrastructure Library

IMPEX Implementation Expenditure

IP Internet Protocol

LIG Lawful Interception Gateway

LTE Long Term Evolution

MAC-ehs Medium Access Control - enhanced high speed

MCPA Multi-Carrier Power Amplifier

mcRNC Microcontroller RNC

MGW Multimedia Gateway

MHA Mast Head Amplifier

MIMO Multiple Input and Multiple Output

MPP Multi-core packet processor

MS Mobile Station

MSS MSC Server

NBAP Node B Application Part

NE Network Element

O & M Operation and Maintenance

OC-3 Optical Carrier Level 3

OD Outdoor

OPEX Operating Expenditure

OSS Operation and Maintenance Subsystem



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Term Abbreviation

PCU Packet Control Unit

PS Packet Switched

PWSM Power Saving Mode

QAM Quadrature Amplitude Modulation

QoS Quality of service

QPSK Quadrature Phase Shift Keying

RAN Radio Access Network

RFM Radio Frequency Module

RNC Radio Network Controller

RRC Radio Resource Control

RTC Remote Tune Combining

RXQUAL Received Signal Quality

SAIC Single-Antenna Interference Cancellation

SDH Synchronous Digital Hierarchy

SDR Software Defined radio

SF Spreading Factor

SGSN Serving GPRS support node

SNMP Simple Network Management Protocol

SO Service Operator

SOAP Simple object access protocol

SON Self Optimising Network

SRC Smart Radio Concept

STM-1 Synchronous Transport Module 1

SW Software

TC Transcoder

TCH Traffic Channel

TCP Transmission Control Protocol

TCSM Transcoder Submultiplexer

TrFO Transcoder Free Operation

TRX Transmitter-Receiver

TTI Transmission Time Interval

UDP User Datagram Protocol

UE User Equipment

UL Uplink

UMTS Universal Mobile Telecommunications System

VLR Visitor location register

VOIP Voice over IP



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Term Abbreviation

WB-AMR Wideband Adaptive Multi-rate Speech Codec

WBC Wideband Combiner

WCDMA Wideband Code Division Multiple Access

Xdsl Digital Subscriber Line

Table 2: Abbreviations



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