eMBMS: Naughty after 11pm ;)

I have blogged about MBMS in past about how it didn't take off even though it was a promising technology. Now you may probably be aware that eMBMS is part of Release-9. I heard some interest in this feature.

The expectation is that the demand for data drops off later in the night after around 10pm. The operators may start some channels say after 11pm because the network will have lots of spare capacity that could be used for television channels. You could have late night movies, sports channels and adult channels.

An advantage of going eMBMS way would mean that even if you are roaming, you can have pay per view kind of approach as long as the other network is Release-9 compliant.

Interesting idea, not sure if it will take off.

Inter-Layer Communication Primitives

IEEE defines service primitives that are used for communication between different layers in a protocol stack. There are 4 types of service primitives as can be seen in the diagram above and are described below:

Request: This is sent by the initiating side and from a higher layer to a lower layer. For example when RRC wants to send a message to peer RRC entity, it sends an RLC Data Request to RLC.

Indication: This primitive on the receiving entity is passed from Layer N to the layer above (N+1). For example when RLC entity receives MAC data from MAC and its addressed to RRC, it sends RLC Data Ind to the RRC.

Response: This is the response to the Indication on the receiving entity. So in our example case, RLC Data Resp would be sent by RRC when it receives RLC Data Ind.

Confirm: This is used as a reply in the sending entity as the lower layer conveys the result of one or more previous request primitives. The confirm will generally contain status code indicating success or failure of the procedure. In our example, RLC Data Cnf will be sent by RLC as a response to RLC Data Req.

'One Voice Initiative': IMS Based approach adopted

AT&T*, Orange, Telefonica, TeliaSonera, Verizon, Vodafone, Alcatel-Lucent, Ericsson, Nokia Siemens Networks, Nokia, Samsung Electronics Co. Ltd., and Sony Ericsson have defined the preferred way to ensure the smooth introduction and delivery of voice and SMS services on Long Term Evolution (LTE) networks worldwide.

The above telecommunications industry leaders have jointly developed a technical profile for LTE voice and SMS services, also known as the One Voice initiative. The profile defines an optimal set of existing 3GPP-specified functionalities that all industry stakeholders, including network vendors, service providers and handset manufacturers, can use to offer compatible LTE voice solutions.

Open collaborative discussions have concluded that the IP Multimedia Subsystem (IMS) based solution, as defined by 3GPP, is the most applicable approach to meeting the consumers’ expectations for service quality, reliability and availability when moving from existing circuit switched telephony services to IP-based LTE services. This approach will also open the path to service convergence, as IMS is able to simultaneously serve broadband wireline and LTE wireless networks.

By following the jointly defined technical profile, the industry can help guarantee international roaming and interoperability for LTE voice and SMS services, ensuring subscribers continuity of these vital services – all while offering service providers a smooth and well-defined path to LTE.

The objective of the initiative is to ensure the widest possible ecosystem for LTE and to avoid fragmentation of technical solutions. LTE will, with this initiative, not only serve as a broadband access for increasing data traffic, but also for continuing voice and SMS services. Network operators will be able to more quickly develop their customized LTE ecosystem in collaboration with both network equipment vendors and device manufacturers. In addition, the reassurance of global interoperability in an LTE voice landscape and the ability to offer both broadband access and telephony services over LTE will create strong foundations for future business.

The profile for the initial solution has been finalized and is available through the companies associated with this press release. The objective is to hand over the profile and continuing work to existing industry forums.

To view the technical profile, please visit http://news.vzw.com/OneVoiceProfile.pdf.

From Rethink Wireless:

One of the trickiest issues for early LTE deployers is uncertainty over how voice and SMS services - still the key cash cows for most operators - can be supported. Eventually, all these services will be carried over IP, using the IMS (IP Multimedia Subsystem) standard, but only a few carriers, like Verizon Wireless, are looking to deploy all-IP from day one. However, there is pressure to accelerate the process and reduce the cost and risk of LTE/IMS for carriers, and this is the objective of the new One Voice initiative.

Some operators believe they will initially deploy LTE as a data-only network, but most want to support voice and, even more importantly, SMS (which underpins many cellco processes and customer communications). Faced with the risk that large players might delay their plans until they have a strong route to voice, One Voice has defined a profile based on existing 3GPP standards for IMS-enabled voice.

The work has initially emerged from Nokia Siemens, which was previously trying to get wide industry support for its own interim voice over LTE solution, VoLTE (which only worked with its own softswitches). The company's convergent core marketing manager, Sandro Tavares, said One Voice should ease fears over how voice will be deployed by resolving roaming and interworking issues at an early stage. It is not creating a new standard, but aims to ensure compatibility between networks and devices by creating a common profile, which defines an optimal set of existing 3GPP functionalities for use by vendors and operators. "There is no new standard," added Tavares. "It's just using what is there already."

NSN is already producing LTE equipment that complies with the new profile, and so has a headstart in offering an important feature to early triallists - which could boost its so-far low profile in LTE tests, dominated by Ericsson and Huawei. However, the vendor will now hand its work to the 3GPP and GSM Association so that other companies can work on and adopt the profile. So far, it has signed support from most of the key operators that tend to wield influence over cellular standards, apart from DoCoMo and China Mobile - AT&T, Orange, Telefonica, TeliaSonera, Verizon Wireless and Vodafone are there, plus a strong line-up of vendors. These are Alcatel-Lucent and Ericsson on the infrastructure side and Nokia, Samsung and Sony Ericsson for devices. The group needs to get the Chinese vendors on board to complete the set, as well as Motorola.

The supporters of the initiative say this is their "preferred path" for voice over LTE, though for carriers that do not want to move to IMS at an early stage, there are other options available - namely open web-based voice; the stopgap solution of Circuit Switch Fallback (also enshrined in 3GPP standards), where the handset is forced off the LTE network onto 2G or 3G for voice calls; and variations on the theme of using circuit switch over packet techniques. There are two main approaches to this - MSC Voice, which is tied to a switch, with NSN's VoLTE the most prominent example; and VoLGA, which is architecture independent, and uses the UMA/GAN (Unlicensed Mobile Access/Generic Access Network) protocol. This Kineto originated technology was originally adopted for Wi-Fi/3G fixed-mobile convergence and as such did find its way into the 3GPP. VoLGA does not require modifications in the LTE RAN or core, or the MSC, but uses a separate gateway controller.

Some of the One Voice supporters are already involved in VoLGA (though its major carrier T-Mobile has not yet joined the new group). Steve Shaw, who heads up corporate marketing for Kineto and VoLGA, believes that IMS is the way that, ultimately, voice will be handled, but it has a long way to go before it is usable, and so there will still be a role for several years for approaches like VoLGA.

T-Mobile will I assume soon have to follow suit and fall in line otherwise they may have limited devices that are available and there will also be inter-operability issues.

Last week I attended a presentation by IET Berkshire on Voice Services over LTE, presented by Iain Sharp from Nortel. Even though this announcement came yesterday, Iain did say that IMS is the way forward for Voice over LTE. If interested you can see the presentation here.

Network Operator commitments to LTE as of Oct. 2009

View Mapping it out: Operator commitments to LTE in a larger map

From Fierce Broadband Wireless:

Operators everywhere are talking up LTE as the future, but few have put a stake in the ground with specific timeframes. Even fewer have selected LTE vendors for their endeavors. Lack of spectrum, a shaky economy and the belief that existing networks still have some mileage are contributing to the not-so-solid commitments. Nonetheless, there are plenty of network trials to go around.

Operators everywhere are talking up LTE as the future, but few have put a stake in the ground with specific timeframes. Even fewer have selected LTE vendors for their endeavors. Lack of spectrum, a shaky economy and the belief that existing networks still have some mileage are contributing to the not-so-solid commitments. Nonetheless, there are plenty of network trials to go around.

As such, we've compiled this list of operators' LTE plans based on those companies that have made specific intentions around LTE. While South Korean operators KT Freetel and SK Telecom haven't made public specific dates regarding their commercial launch plans, they have indicated their intentions to invest in LTE by 2010. Zain in Bahrain hasn't announced a commercial launch date yet either, but has tapped Nokia Siemens Networks as its LTE vendor.

Fierce Broadband Wireless has compiled list of operators' LTE plans based on those companies that have made specific intentions around LTE. While South Korean operators KT Freetel and SK Telecom haven't made public specific dates regarding their commercial launch plans, they have indicated their intentions to invest in LTE by 2010. Zain in Bahrain hasn't announced a commercial launch date yet either, but has tapped Nokia Siemens Networks as its LTE vendor.

See the complete table of rollouts here.

Read more: http://www.fiercebroadbandwireless.com/pages/mapping-it-

out-operator-commitments-lte#ixzz0W0sBukPZ

As such, we've compiled this list of operators' LTE plans based on those companies that have made specific intentions around LTE. While South Korean operators KT Freetel and SK Telecom haven't made public specific dates regarding their commercial launch plans, they have indicated their intentions to invest in LTE by 2010. Zain in Bahrain hasn't announced a commercial launch date yet either, but has tapped Nokia Siemens Networks as its LTE vendor.

Read more: http://www.fiercebroadbandwireless.com/pages/mapping-it-out-operator-commitments-lte#ixzz0W0sBukPZAs such, we've compiled this list of operators' LTE plans based on those companies that have made specific intentions around LTE. While South Korean operators KT Freetel and SK Telecom haven't made public specific dates regarding their commercial launch plans, they have indicated their intentions to invest in LTE by 2010. Zain in Bahrain hasn't announced a commercial launch date yet either, but has tapped Nokia Siemens Networks as its LTE vendor.

Read more: http://www.fiercebroadbandwireless.com/pages/mapping-it-out-operator-commitments-lte#ixzz0W0sBukPZ

Read more: http://www.fiercebroadbandwireless.com/pages/mapping-it-out-operator-commitments-lte#ixzz0W0rO0tQk

WiMAX Network reference model

Continuing from yesterdays post.

The WiMAX network architecture is designed to meet the requirements while maximizing the use of open standards and IETF protocols in a simple all-IP architecture. Among the design requirements are supports for fixed and mobile access deployments as well as unbundling of access, connectivity, and application services to allow access infrastructure sharing and multiple access infrastructure aggregation.

The baseline WiMAX network architecture can be logically represented by a network reference model (NRM), which identifies key functional entities and reference points over which the network interoperability specifications are defined. The WiMAX NRM differentiates between network access providers (NAPs) and network service providers (NSPs). The NAP is a business entity that provides WiMAX radio access infrastructure, while the NSP is the business entity that provides IP connectivity and WiMAX services to WiMAX subscribers according to some negotiated service level agreements (SLAs) with one or more NAPs. The network architecture allows one NSP to have a relationship with multiple NAPs in one or different geographical locations. It also enables NAP sharing by multiple NSPs. In some cases the NSP may be the same business entity as the NAP.

The WiMAX NRM, as illustrated in Fig. 3, consists of several logical network entities: MSs, an access service network (ASN), and a connectivity service network (CSN), and their interactions through reference points R1–R8. Each MS, ASN, and CSN represents a logical grouping of functions as described in the following:

• Mobile station (MS): generalized user equipment set providing wireless connectivity between a single or multiple hosts and the WiMAX network. In this context the term MS is used more generically to refer to both mobile and fixed device terminals.

• Access service network (ASN): represents a complete set of network functions required to provide radio access to the MS. These functions include layer 2 connectivity with the MS according to IEEE 802.16 standards and WiMAX system profile, transfer of auathentication, authorization, and accounting (AAA) messages to the home NSP (HNSP), preferred NSP discovery and selection, relay functionality for establishing layer 3 (L3) connectivity with MS (i.e., IP address allocation), as well as radio resource management. To enable mobility, the ASN may also support ASN and CSN anchored mobility, paging and location management, and ASN-CSN tunneling.

• Connectivity service network (CSN): a set of network functions that provide IP connectivity services to WiMAX subscriber(s). The CSN may further comprises network elements such as routers, AAA proxy/ servers, home agent, and user databases as well as interworking gateways or enhanced broadcast services and location-based services.

A CSN may be deployed as part of a green field WiMAX NSP or part of an incumbent WiMAX NSP. The following are some of the key functions of the CSN:–IP address management–AAA proxy or server–QoS policy and admission control based on user subscription profiles–ASN-CSN tunneling support –Subscriber billing and interoperator settlement–Inter-CSN tunneling for roaming–CSN-anchored inter-ASN mobility–Connectivity to Internet and managed WiMAX services such as IP multimedia services (IMS), location-based services, peer-to-peer services, and broadcast and multicast services –Over-the-air activation and provisioning of WiMAX devices

• Base station (BS): a logical network entity that primarily consists of the radio related functions of an ASN interfacing with an MS over-the-air link according to MAC and PHY specifications in IEEE 802.16 specifications subject to applicable interpretations and parameters defined in the WiMAX Forum system profile. In this definition each BS is associated with one sector with one frequency assignment but may incorporate additional implementation-specific functions such as a DL and UL scheduler.

• ASN gateway (ASN-GW): a logical entity that represents an aggregation of centralized functions related to QoS, security, and mobility management for all the data connections served by its association with BSs through R6t. The ASN-GW also hosts functions related to IP layer interactions with the CSN through R3 as well as interactions with other ASNs through R4 in support of mobility.

Typically multiple BSs may be logically associated with an ASN. Also, a BS may be logically connected to more than one ASN-GW to allow load balancing and redundancy options. The WiMAX network specification defines a single decomposed ASN profile (ASN C) with an open R6 interface as well as an alternative ASN profile B that may be implemented as an integrated or a decomposed ASN in which R6 is proprietary or not exposed. The normative definitions of intra-ASN reference points (R6 and R8) are only applicable to profile C. Note that in release 1.5 profile A has been removed to reduce the number of implementation options and create a better framework for network interoperability.

Reference: Overview of Mobile WiMAX Technology and Evolution - Kamran Etemad, Intel Corporation

Mobile WiMAX technology and network evolution roadmap.

The Mobile WiMAX Release 1.0 System Profile, based on 802.16e or 802.16-2005, was completed in late 2006, and the radio-level certification of products began in 2007. The certification follows a phased approach to address deployment priorities and vendor readiness. System Profile Release 1.0 includes all 802.16-2005 mandatory features, and also requires some of the optional features needed for enhanced mobility and QoS support. This system profile is based on OFDMA, and enables downlink and uplink multiple-input multipleoutput (MIMO) as well as beamforming (BF) features. The release 1.0 system profile is defined only for the TDD mode of operation, with more focus on 5 and 10 MHz bandwidths in several band classes in 2.3 GHz, 2.5 GHz ,and 3.5 GHz bands, but it also includes 8.75 MHz specifically for Korea.

The WiMAX certification for the release 1.0 profile started with a Wave 1 subset, excluding MIMO and a few optimization features, to enable early market deployments. This was followed by Wave 2, which progressively adds more and more feature tests over time based on vendors and testing tool availability. The early phases of certification were also limited to MAC and PHY layer conformance and interoperability testing, which will be expanded to add networklevel testing.

Meanwhile, the development of WiMAX Forum Network Release 1.0 was completed in 2007, based on which the specific network-level device conformance testing as well as infrastructure interoperability testing projects were initiated. The goal was to ensure e2e interoperability of WiMAX devices with networks and also ensure multivendor plug and play network infrastructure deployments. Release 1.0 defines the basic architecture for IP-based connectivity and services while supporting all levels of mobility. Based on operators’ requirements for advanced services and new market opportunities to be more competitive with evolved 3G systems, the WiMAX Forum initiated interim releases for both the system profile and network without major modifications to the IEE 802.16 standard. The work on network release 1.5 network specifications was started in parallel, aimed primarily at enabling dynamic QoS and provisioning of open retail device and support for advanced network services as well as commercial grade VoIP.

The release 1.5 system profile work item was initiated to enable mobile WiMAX in new spectrum including frequency-division duplex (FDD) bands, address a few MAC efficiency improvements needed for technology competitiveness, and align the system profile with advanced network services supported by network release 1.5. All required fixes and minor enhancements needed to support release 1.5 are incorporated in IEEE 802.16 REV2, which combines the IEEE 802.16-2004 base standard plus IEEE 802.16e/f/g amendments and related corrigenda into one specification document.

Following Release 1.5, the next major release mobile WiMAX, Release 2.0, will be based on the next generation of IEEE 802.16, which is being developed in the 16m technical group (TGm) of 802.16. WiMAX Release 2 targets major enhancements in spectrum efficiency, latency, and scalability of the access technology to wider bandwidths in challenging spectrum environments. Currently the expected timeline for the formal completion of 802.16m and WiMAX Certification of Release 2 products are early 2010 and early 2011, respectively.

In parallel with developments in IEEE on the stage 2 system-level description of 802.16m, the requirements for network release 2.0 are being discussed in the WiMAX Forum, where stage 2/3 specifications are expected to be completed by 2010.

Reference: Overview of Mobile WiMAX Technology and Evolution - Kamran Etemad, Intel Corporation

Wavesecure: Helping track lost phones

Siliconindia organized Mobile Applications Conference (MAC) on October 31, where 25 mobile companies exhibited their applications and presented their business plans in NIMHANS (National Institute of Mental Health and Neuro Sciences) convention center, Bangalore, in front of around 400 people and entrepreneurs. Industry leaders within the mobile space also put some light on where the industry is headed and how entrepreneurs and developers can take advantage.

TenCube, whose anchor product, WaveSecure, is the market leading mobile security suite recognized by customers and analysts, won the best mobile application award. TenCube was the unanimous choice of judges as well as the audience. It got 71 votes followed by Eterno Infotech and Divium, which got 37 and 36 votes respectively. Originally developed for police and military use in Singapore, WaveSecure has become Nokia's preferred mobile security product, chosen to be bundled into millions of premium Nokia devices. It is also the preferred security service selected by leading operators like Telenor and SingTel for their subscribers.

Very interesting FAQ's for those interested.

See Demo below:

30 years for the first commercial mobile network in Dec.

Tomi recently posted a blog on Birthdays and how the first commercial network will complete 30 years. It was first of December 1979, that the world's first commercial cellular automated (and 'modern') mobile telecoms network went live in Tokyo Japan, launched by NTT.ANd yes the mobile phone subscriber count will hit 4.6 billion by the end of the year. We passed a billion users in 2002, so it only took 23 years to hit a billion mobile phones on the planet.

While looking for the photo of the original phone, I came across one of the earliest phones used by Martin Cooper of Motorola. He is known to have made the first public call in USA over36 years back. Wikipedia has a section on the Motorola DynaTAC in the picture above.

Here is the comparison of DynaTAC with the earlier model of iPhone.

And last but by no means least, the mobile internet is 10 years old. Launched by NTT DoCoMo of Japan in 1999, its iconic iMode mobile internet was the first mobile-optimized internet service and spawned countless copies and today counting all the WAP users etc, has over a billion users. That in only ten years.. Domo Arigato, NTT DoCoMo, you have invented the fastest technology to spread to a billion users.

Over-the-top (OTT) Applications and Services

I keep on hearing about OTT apps everywhere I go nowadays. I know roughly what they mean but I couldnt find a proper definition anywhere. Here is my attampt to write a bit about what OTT means.

Traditionally lots of services like Voice and Television for example is delivered in a conventional way where Voice was transferred via a PSTN or a Mobile network and similarly TV was delivered via Cable, Satellite, DVB-T kind of technology. With Internet becoming common and Broadband access available to everyone, easily and cheaply, new applications are available to deliver Voice and TV kinds of services. The most popular voice app is for example Skype and Youtube is an example of TV (even though its more like Video On Demand)

These apps cause two main problems. The first problem is that the companies using this traditional medium starts losing customers and their cost per person goes up forcing their profits down. At the same time the amount of data traffic for the ISP increases thereby increasing the number of bits/cent (bits/pence). This forces them to upgrade their infrastructure to provide the same quality of service (QoS).

What this would mean is that in future it would not be possible to get flat rate packages for Mobile broadband or there may be restrictions where certain applications wont run unless you pay extra.

The dilemma for carriers is that LTE’s all-IP architecture will create a more open environment for Over The Top (OTT) applications, including third-party VoIP services, which threaten to further commoditize the network. To overcome this threat and realize revenue gains from LTE, carriers will need to partner with content and application providers, develop application store-fronts such as Apple’s App Store, and perhaps deploy APIs that expose LTE’s value-added network capabilities to third-party application and content developers for a fee.

The only way to ensure profitability in this ‘cost-per-bit’ model is to maximise scale. We have seen this clearly in mobile telephony, where a lack of differentiation has led to intense price pressure, flat rate tariffs and a decoupling of the revenues from the costs. The mobile operator suffers the cost of deploying ever increasing bandwidth while the ‘value’ that this bandwidth enables – the access to over the top (OTT) applications and services benefits the OTT providers.

To avoid this commoditisation, service providers need to add intelligence to the way they deliver these bits. Adopting a ’value-per-bit’ strategy ensures that the value added over and above the simple transport of data is seen and desired by the consumer and by any upstream content or application provider.

This creates a tighter coupling between infrastructure costs and the revenue that infrastructure can attract, thereby ensuring a far more sustainable business model for the service provider. It also benefits consumers and application providers by providing them levels of security, performance and reliability appropriate to the transaction being carried out and the subscribed service.

Most of us wouldn’t dream of paying for a customized Internet experience on a tailor-made device from our broadband service provider. But that is the way we used to buy telephone service, and it continues to be the way we do things for mobile and video services. Over time, all of these businesses will follow a similar pattern, breaking down into their component parts so that the best adapted players win in each piece of the business. The only questions are: “Who are the best adapted?” and “How long will it take?”

Further Reading: Making the Network Relevant in an Over-the-Top World

LTE definitely needed and coming next year...dont mention Voice and SMS please

The unremitting growth in data traffic will bring about a 3G network capacity crisis for some mobile network operators as early as 2010. This dire scenario, according to a new study from Unwired Insight, will only be avoided by the early deployment of LTE, and the acceptance that additional LTE spectrum will be required to satisfy this demand.

With 3G traffic volumes set to increase by a factor of 20 by 2015--driven by many technology factors and also dramatic reductions in mobile data pricing--Alastair Brydon, co-author of the new study, points to the example of mobile broadband pricing that has fallen as low as US$2 per gigabyte, "which is nearly half a million times smaller than the price per gigabyte of an SMS message."

Brydon believes that early LTE will be necessary for the following reasons:

• As 2G users continue to migrate to 3G services, the available capacity per 3G user will decline rapidly in networks utilising HSPA, to less than 100MB per user per month in some cases. LTE will be essential to counter this decline.
• While LTE promises peak data rates of over 100Mbps, this is only possible with wide allocations of spectrum, and particularly good radio conditions. Average data rates from practical LTE networks will be nowhere near the peak values.
• Network operators will have an insatiable appetite for LTE spectrum, to stand any chance of keeping up with forecast traffic demand. For some operators, 10MHz of spectrum will be able to support forecast traffic levels only until 2011. A further 10MHz will be needed by 2012 and another 10MHz in 2013.
  

Unwired Insight claims LTE's ability to relieve the capacity constraints of HSPA networks will be limited initially, until operators can acquire additional spectrum and seed a sufficient number of LTE devices in the market place. "But, we don't expect to see LTE handsets until 2011," the company warns.

Fourteen operators have committed to LTE rollouts next year, up from 10 in March, the research firm said. It predicts the LTE network gear market will be worth more than $5 billion by 2013, dominated by E-UTRAN macrocell (eNodeB) deployments.

It also expects the LTE customer base to top 72 million by 2013, mostly users with laptops, netbooks or dongles, with the first smartphones expected to hit the market after 2011.

In another forecast, Informa Telecoms and Media said Japan would account for more than half of Asia's 14.4 million LTE subscribers by 2015.

NTT DoCoMo, Japanese rival eMobile and China Mobile will be the first to launch LTE in the region, Informa said, with Hong Kong's CSL likely to follow soon after.

But rollouts in the region may be hindered by delays, as Japan and Hong Kong are so far the only Asian countries to have awarded spectrum for LTE.

Regulators in other nations are scrambling to free up enough spectrum, Informa added. Even in Japan, there is not enough 2100MHz spectrum available to support DoCoMo's full LTE plans, so it will use its newly allocated 1.5GHz for LTE from 2010.

According to news sources in South Korea, LG Telecom (LGT) quietly revealed their intention to migrate to LTE for 4G service in South Korea. LG-Nortel and Samsung will provide the multi-mode base stations which are part of the company's green network upgrade. SKT and KTF (now part of KT), the other two mobile operators in the country, have already announced their LTE migration path for 4G previously. Unlike SKT and KTF who will migrate from HSPA to LTE, LGT will go from EV-DO to LTE, similar to the case of Verizon Wireless.

It was probably a matter of time for LGT to announce the LTE migration plan since it was only running EV-DO network, and this officially puts LGT on the LTE camp. Now, my speculation is that other major EV-DO operators (noticeably, Sprint) who haven't announced such plans will follow the same path down the road since WiMAX does not seem to be a viable migration path for the FDD part of the network.