• Ericsson, Qualcomm Technologies and Sierra Wireless provided the first public demonstration of LTE Carrier Aggregation at Mobile World Congress (MWC) 2013.
• Ericsson and Telstra will trial and deploy LTE Carrier Aggregation in Australia at 900MHz and 1800MHz.
• Huawei and Lebanon Touch have completed Carrier Aggregation trials in a live LTE network in Lebanon, operating at 800MHz and 1800MHz.
• EE will trial Carrier Aggregation in the UK before the end of 2013.

Carrier Aggregation is an important new feature of LTE Advanced, first introduced in 3GPP Release 10 (frozen 2011) and enhanced in 3GPP Release 11.  Basic LTE, originally defined in 3GPP Release 8, is able to achieve peak data rates of 300Mbit/s downlink and 75Mbit/s uplink (using 4×4 MIMO antennas and the maximum 20MHz spectrum). This is a significant improvement on previous mobile systems and is achieved partly by improvements in spectral efficiency and partly by operating in a wider bandwidth. Even so, LTE is unable to achieve the ITU target of 1Gbit/s downlink data for low mobility communication in 4G systems.

The key to achieving higher data rates with LTE is to enable network operators to use the technology in bandwidths wider than 20MHz. Some network operators may be lucky enough to have contiguous spectrum allocations of more than 20MHz. However, the nature of spectrum allocation over the years is such that most operators have a mix and match of spectrum within and between frequency bands. Following the redistribution of analogue TV spectrum and the provision of higher frequency spectrum, an operator might have LTE spectrum at one or more of 700MHz, 800MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, 2500MHz and 2600MHz.

LTE Carrier Aggregation enables a network operator to combine radio channels within the same frequency band or across different bands to achieve much higher data rates and lower latency than otherwise would be possible. In principle the LTE Advanced standard will allow for the aggregation of up to five carriers, each of up to 20MHz, to achieve a total effective bandwidth of 100MHz, although early implementations will be limited to two carriers and therefore a maximum of 40MHz.

Carrier Aggregation can be applied to both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) variants of LTE and it allows the combination of different carrier bandwidths in number of ways, as illustrated by the examples in the figure below.

The simplest form of carrier aggregation, shown in example (a), is where the carriers are contiguous and lie within the same frequency band. In this case it is feasible for a mobile device to handle the signals using a single transceiver, providing it is able to operate efficiently over the aggregate bandwidth.

Example (b) shows intra-band non-contiguous carrier aggregation, in which the carriers lie within the same frequency band, but they are not adjacent. In this case it is necessary for the mobile device to use a separate transceiver for each carrier.

The final example of carrier aggregation is based on inter-band non-contiguous carriers, as shown in example (c). In this case the carriers fall in different parts of the radio spectrum, such as 900MHz and 1800MHz. The ability to combine such carriers is particularly useful for network operators with fragmented spectrum allocations, although it does bring challenges for the mobile device. As in example (b) it is necessary to include a transceiver for each carrier and there is a need for careful design to ensure that the device can operate effectively in two (or more) different bands simultaneously.

Each individual component carrier used for aggregation adopts one of the standard LTE bandwidths defined in 3GPP Release 8 (1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz or 20MHz), to achieve backward compatibility with existing mobile equipment. Legacy devices can be allocated capacity on any one of the component carriers, while mobiles supporting carrier aggregation can be allocated capacity aggregated across two (or more) carriers.

LTE Carrier Aggregation will provide mobile network operators with even greater scope to support services that hitherto would have been restricted to fixed networks, and may open up the possibility of providing a viable alternative to fixed network broadband services, particularly in rural locations where fixed broadband provision may be poor.

The latest “Evolution to LTE Report” from the Global mobile Suppliers Association (GSA) includes, among other things, a (very short) list of Voice over LTE (VoLTE) launches around the world. Over two years ago I expressed my concern at the lack of long term solutions for voice over LTE. While the situation is gradually becoming clearer, there is still some way to go before there is wide deployment of a common approach to LTE voice.

Unlike previous mobile systems, such as GSM and UMTS, LTE does not provide a circuit-switched method for carrying voice traffic. However, voice services still generate something like 70% of network operator revenues worldwide. LTE is fundamentally a packet switched system, and therefore voice traffic must be a carried either as Voice over IP (VoIP) or by relying on existing 2G or 3G systems.

It is now generally accepted that the preferred long term solution for voice and messaging over LTE is VoLTE, which has been supported by the GSM Association (GSMA) since 2010. VoLTE is critically important for mobile network operators, by enabling them to integrate telecom grade voice telephony with a range of rich media services over a variety of packet switched networks and devices. However, there are significant challenges to overcome in implementing VoLTE and a number of stop-gap solutions have been put in place in early LTE networks. The longer it takes to implement the ultimate solution, the stronger become third party “over the top” VoIP services such as Skype and Google Talk, which undermine network operator revenues.

VoLTE is underpinned by the IP Multimedia Subsystem (IMS), which provides a framework for basic voice and messaging services and integration with a variety of multimedia applications. The approach offers some important potential benefits:

• a standard method for carrying voice and messaging, integrated into LTE devices and networks in much the same way as today’s voice services
• interoperability between different networks and devices
• economies of scale enabled by a common approach across multiple platforms
• roaming between networks
• integration with rich media services including presence, messaging, video telephony, video sharing, file sharing, desktop sharing
• high quality of service achieved by tight integration with the underlying LTE transmission methods e.g. reserved bandwidth
• high definition (HD) voice, enabled by wideband codecs and the high data rates of LTE
• lower battery consumption than previous voice communication methods
• fast call setup (less than 1 second)
• automatic fallback to 2G/3G services when outside LTE coverage
• the facility for third parties to develop applications building on the capabilities of VoLTE

However, there are significant challenges to overcome in delivering VoLTE, including:

• introduction of an IMS core and its integration with other network systems
• implementation of radio network features to prioritise VoLTE traffic over other classes of IP data
• co-ordinated operation of devices, radio network, core network and service platforms to provide an end-to-end path with the quality of service parameters required by voice
• scheduling of variable packet sizes generated by VoLTE, to maintain system performance
• management of IMS protocol stacks and registrations to support multiple applications in a device
• possible routing of VoLTE traffic to dedicated network destinations
• new approaches to charging for voice

So far only a small number of network operators have launched commercial VoLTE services. In South Korea, KT, LG U+ and SK Telecom are all early adopters of VoLTE. In the USA, metroPCS already offers VoLTE in some of its markets and Verizon Wireless has announced that it will launch services late in 2013 or early in 2014. VoLTE is particularly attractive for CDMA operators, such as metroPCS and Verizon Wireless, because switching between LTE and CDMA to deal with voice traffic is cumbersome and consumes significant power in the mobile device. Therefore, moving to a pure LTE solution will have capacity, performance and battery-life benefits.

Most network operators are taking their time with VoLTE. Recognising the critical importance of voice revenue they know it is crucial that VoLTE delivers on its promises. Rushing to market with immature VoLTE services could be highly damaging. If the quality, reliability or capabilities of VoLTE are perceived as no better than low-cost or free over-the-top services, there is a risk that voice revenues could rapidly evaporate. In many cases LTE network operators have implemented temporary solutions for voice telephony, which either fall back to existing 2G or 3G circuit switched services, or employ power-hungry dual-radio solutions.

Mobile network operators must strike a careful balance. The longer they wait to introduce VoLTE, the more mature the technology will be and the broader the ecosystem of devices, networks and applications will become. However, all the time, over-the-top VoIP services are gaining market traction, customers and usage, while also improving their service capabilities and voice quality. Also, short-term solutions such as circuit-switched fallback will become increasingly entrenched over time and it will become more difficult to phase them out and introduce new solutions.

While over-the-top VoIP services may not be able to meet the reliability of traditional circuit switched voice services, their low cost makes them an attractive option. Downloading a Skype app to a mobile handset (or integrating it into the operating system) will be commonplace and services such as Skype will be embedded in the psyche of many users, particularly the younger generation who have grown up with them as free communication services.

The battle over mobile voice will not be won by technology alone. Recognising this, the GSM Association (GSMA) has launched the joyn initiative as a focal point for the development of an ecosystem that enables mobile network operators to deploy Rich Communication Services (RCS), which exploit VoLTE and the associated IMS architecture to deliver integrated voice, SMS, presence information, instant messaging, video and file sharing across devices and networks.

As the technology and marketing battle heats up, the only thing that is clear is that the future for mobile voice will remain highly uncertain for sometime yet.

In a previous post on 3GPP Standards Releases for LTE I identified a number of features related to the support of small cells, including the home eNodeB in Release 9, relay nodes and interference coordination in Release 10, and coordinated multipoint operation in Release 11. However, there has been no shortage of ideas to enhance the support of small cells in 3GPP Release 12 and beyond. The general aim is to use small cells to extend the capacity, coverage and service capability of LTE in a manner that is energy- and cost-efficient. This requires careful and potentially dynamic co-ordination of the activities of large and small cells, for example to balance their use of system resources and to manage the interference between them.  

In this post I want to talk about one particular aspect of enhanced small cells, which was brought to my attention recently by my ex-colleague Sunil Chotai (also known as “Zed”). The idea is known variously as “soft cells”, “phantom cells” and “amorphous cells” and could transform the way multimedia content is delivered in densely populated areas. One example application is the distribution of video content at sports stadia or concert venues.

The principle of soft cells is to provide a mobile terminal with simultaneous logical connections (although not necessarily physical connections) to both a macrocell and a picocell, in an arrangement described as ”wide-area assisted local-area access”, as illustrated in the figure below.

The macrocell provides an “anchor carrier”, which gives the mobile terminal a robust wide-area signalling connection, carrying system information and basic radio resource control (and potentially low rate or high reliability user data). The picocell provides a “booster carrier”, which supports highly efficient delivery of user traffic within its local area. The anchor carrier ensures that a mobile terminal has a reliable signalling connection as it moves around a network coverage area, but traffic can be offloaded to a local booster carrier if a user requires a period of intense communication.

The solution is particularly effective when the booster carriers can be deployed in a different frequency band to the anchor carriers, because this relaxes the interference problems between the layers. However, it can also be used where the macrocells and picocells are deployed in the same band. Picocells are particularly suited to new spectrum at higher frequencies, where range is not so important.

A number of features are required to enable the soft cell concept in LTE. The mobile terminal has to be able to support multiple transport channels and MAC entities, along with scheduling of the activities related to the anchor and booster carriers. It must also be possible for the mobile terminal to discover and synchronise to the booster carriers, while maintaining a signalling relationship with an anchor carrier. Also the operation of the booster carriers can be optimised to their traffic-related role, by minimising overheads, controlling interference and increasing battery efficiency.

Enhanced small cell developments offer the prospect of substantial capacity gains, but they will not be available until Release 12 and will they require new mobile terminals to enter the market before they have a significant impact. Therefore it will be sometime beyond 2015 before their full benefit is brought to bear.

For many years it has been recognised that the point-to-point delivery of video services is a major drain on the capacity of mobile networks and that broadcasting would be a much more efficient approach in situations where the same content is being sent to multiple users. There have been a number initiatives to satisfy this need, including dedicated mobile broadcasting networks, such as Digital Video Broadcasting-Handheld (DVB-H) and Digital Multimedia Broadcasting (DMB), and adaptations to cellular networks, such as MBMS. However, these have met with limited commercial success to date. There have been various reasons for this, including the cost of deploying high quality services, the need for special terminals, and limited picture quality. A problem with broadcast services is that consumers are becoming increasingly accustomed to consuming multimedia content as and when they want to, for example using personal video recorders (PVRs) and online “catch-up” services, rather than being constrained to a broadcaster’s schedule. However, there are certain occasions when broadcasting comes into its own, such as during major live news or sports events. Also, there may be opportunities to broadcast certain material to the memories of mobile devices, to be consumed later, rather like a mobile PVR. As well as providing video and audio broadcasts, the same approach could be used to deliver software, games and music to mobile devices. Given the potential for network operators to off-load large quantities of point-to-point multimedia traffic during these occasions, there remains considerable interest in a flexible, efficient mobile broadcasting system that requires minimal changes to existing networks. 

MBMS was first introduced into the 3GPP specifications in Release 6, in 2005, with the aim of enabling multicasting or broadcasting of multimedia content over 3G UMTS radio access networks. While the technology was effective, the service was not a great success. One of its weaknesses was the limited capacity that could be set aside in a UMTS radio access network, which restricted the number and/or quality of channels it could deliver. A typical configuration would be five channels running at 256kbit/s.

In 3GPP Release 9, in 2009, MBMS was enhanced to take advantage of the capabilities of the LTE radio interface, with the potential to enable more attractive services. The faster throughput and greater capacity of the LTE interface offer the prospect of more channels at higher quality and the flexible allocation of resources in LTE avoids the need to dedicate spectrum permanently, which was a weakness of 3G MBMS solutions. Instead, the channels required by a broadcast can be set up and cleared down in an LTE network as and when required. A particularly attractive feature of the LTE radio interface is that it can provide broadcast services across a set of cells as a Single Frequency Network (SFN), whereby all of the cells delivering a particular broadcast channel can operate on the same frequencies, providing they are closely synchronised. Rather than causing interference to each other, the signals can be combined constructively. This is particularly helpful near cell boundaries, where coverage and interference problems are generally at their worst. Modelling by Qualcomm suggests that eMBMS could offer a substantial broadcasting capability. For example, if a network operator with 10MHz LTE spectrum temporarily allocated 60% to eMBMS it could deliver 16.9Mbit/s of user throughput in an urban environment.

3GPP Release 11,  under development during 2012 and 2013, introduces a number of further benefits, including new video coding to enable higher frame rates and picture resolution, and improved error correction.

It remains to be seen whether network operators can find the right combination of service propositions, content and pricing to exploit the full benefits of LTE’s broadcasting capabilities, but with multimedia services consuming more and more network capacity the benefits could be substantial. More than ever eMBMS provides network operators with the tools for the job.

From the outset, LTE and LTE-Advanced have been designed to take advantage of mixed network architectures (often referred to as Heterogeneous Networks, or HetNets) comprising macrocells, picocells and femtocells. New features of the LTE radio interface, such as Orthogonal Frequency Domain Multiplexing (OFDM), Multiple Input Multiple Output (MIMO) antennas and advanced error correction help to improve the performance of its macrocells. However, they can never entirely solve the problems of delivering coverage and capacity everywhere, particularly indoors and towards the edge of cells. Therefore new network architectures will be crucial to maximising the potential of LTE.

LTE and LTE-Advanced already include features to facilitate the introduction of HetNets and further developments are underway. A significant step in 3GPP Release 10 (frozen in 2011) was the the introduction of relay nodes as a new component of the LTE network architecture. Relay nodes provide a highly flexible and effective way of introducing new cells into a network quickly and easily, without the need for fixed backhaul.

As the name suggests, a relay node acts as a relay for a “donor” base station (eNB), to which it is connected by nothing more than an LTE radio link. However, rather than simply relaying the radio signal (along with any noise and interference it may have accumulated), like a traditional repeater, a relay node can demodulate, decode and error correct a received signal before retransmitting it.

A number of operating modes are possible for relay nodes. For example, a Type 1 relay has its own base station identity and synchronisation channel, and appears to a mobile terminal to be a normal LTE base station. A Type 2 relay node has no identity of its own and as far as the mobile terminal is concerned it appears to be the donor base station. An inband relay node uses the same carrier frequencies for the link between the mobile terminal and the relay as between the relay and the donor base station, whereas an outband relay uses different frequencies. A half-duplex relay node can carry data in only one direction at a time, whereas a full-duplex node can carry data in both directions simultaneously.

Relay nodes have a number of potential roles, including:

• extending the coverage of existing cells (which is the main focus of the Release 10 implementation)
• enabling rapid roll-out of services, because there is no need to deploy fixed backhaul
• improving data throughput for users located near the edges of cells
• increasing the overall capacity delivered by a cell by achieving higher average throughput across the cell

As a wide variety of new HetNet products come onto the market in the coming years, we are likely to see significant changes to the shape of cellular networks.

While the basic LTE system (first defined in 3GPP Release 8) is often referred to in the media as 4G technology, actually LTE-Advanced is the first member of the GSM/UMTS/LTE family of standards to satisfy the International Telecommunication Union (ITU) requirements of 4G, for example by achieving a peak downlink user data throughput of more than 1Gbps.

LTE-Advanced builds on the same underlying radio interface as LTE, including an Orthogonal Frequency-Division Multiple Access (OFDMA) downlink and Single-Carrier Frequency Division Multiple Access (SC-FDMA) uplink. The first version of LTE-Advanced, defined in 3GPP Release 10, includes a number of new developments to improve the performance of LTE, including:

Carrier Aggregation: Basic LTE can operate in bandwidths ranging from 1.4MHz to 20MHz. LTE-Advanced allows for up to five sets of LTE carriers to be combined to achieve a total bandwidth of up to 100MHz.

Enhanced multi-antenna techniques: LTE-Advanced supports Multiple Input Multiple Output (MIMO) antenna configurations up to 8×8 (i.e. 8 transmitting antennas and 8 receiving antennas) on the downlink and 4×4 on the uplink, to achieve increased throughput in good signal conditions.

Relay Nodes: Heterogeneous Networks (or “HetNets”) comprising a wide variety of cell sizes will become increasingly important as LTE networks are deployed. Relay Nodes will form an important component of these networks by boosting the coverage and capacity towards the edge of cells, by relaying signals to and from a donor base station over a radio connection.

These developments achieve a number of benefits, including greater spectral efficiency, improved performance towards the edge of cells, support of a greater number of simultaneous active users, and an increase in user data throughput to 3Gbps in the downlink and 1.5Gbps in the uplink.

A variety of further developments are planned for LTE-Advanced in forthcoming releases, including cognitive radio, higher order modulation, complex antenna arrays and intense frequency use through advanced HetNets. I will look at these in more detail in future posts.

Here I provide a short summary of the 3GPP releases relevant to LTE, including brief highlights of their contents.

3GPP Release 8 – Freeze Date 2008

Release 8 introduced LTE for the first time, with a completely new radio interface and core network, enabling substantially improved data performance compared with previous systems. Highlights included:

• up to 300Mbit/s downlink and 75Mbit/s uplink
• latency down to 10ms
• implementation in bandwidths of 1.4, 3 ,5 , 10, 15 or 20MHz, to allow for different deployment scenarios
• orthogonal frequency domain multiple access (OFDMA) downlink
• single-carrier frequency domain multiple access (SC-FDMA) uplink
• multiple input multiple output (MIMO) antennas
• flat radio network architecture, with no equivalent to the GSM BSC or UMTS RNC, and functionality distributed among the base stations (eNodeBs)
• all IP core network, the System Architecture Evolution (SAE).

3GPP Release 9 – Freeze Date 2009

Release 9 brought a number of refinements to features introduced in Release 8, along with new developments to the network architecture and new service features. These included:

• introduction of LTE femtocells in the form of the Home eNodeB (HeNB)
• self organising network (SON) features, such as optimisation of the random access channel
• evolved multimedia broadcast and multicast service (eMBMS) for the efficient delivery of the same multimedia content to multiple destinations
• location services (LCS) to pinpoint the location of a mobile device.

3GPP Release 10 – Freeze Date 2011

Release 10 provided a substantial uplift to the capacity and throughput of the LTE system and also took steps to improve the system performance for mobile devices located at some distance from a base station. Notable features included:

• up to 3Gbit/s downlink and 1.5Gbit/s uplink
• carrier aggregation (CA), allowing the combination of up to five separate carriers to enable bandwidths up to 100MHz
• higher order MIMO antenna configurations up to 8×8 downlink and 4×4 uplink
• relay nodes to support Heterogeneous Networks (“HetNets”) containing a wide variety of cell sizes
• enhanced inter-cell interference coordination (eICIC) to improve performance towards the edge of cells.

3GPP Release 11 – Freeze Date 2013

Release 11 will build on the platform of Release 10 with a number of refinements to existing capabilities, including:

• enhancements to Carrier Aggregation, MIMO, relay nodes and eICIC
• introduction of new frequency bands
• coordinated multipoint transmission and reception to enable simultaneous communication with multiple cells
• advanced receivers.

3GPP Release 12 – Freeze Date 2014

Potential features for Release 12 were discussed at a 3GPP workshop in Slovenia in June 2012. A strong requirement was the need to support the rapid increase in mobile data usage, but other items included the efficient support of diverse applications while ensuring a high quality user experience.  Some of the candidates for Release 12 included:

• enhanced small cells for LTE, introducing a number of features to improve the support of HetNets
• inter-site carrier aggregation, to mix and match the capabilities and backhaul of adjacent cells
• new antenna techniques and advanced receivers to maximise the potential of large cells
• interworking between LTE and WiFi or HSPDA
• further developments of previous technologies.

Unfortunately, there is still a cloud on the horizon. While Ofcom was of the view that the consumer benefits of an early 4G launch outweighed any distortion of competition, O2, Vodafone and Hutchison 3G are rather less relaxed about the situation. Everything Everywhere was given the go ahead to offer LTE services from today, 11 September 2012, while the other UK players will have to wait for the conclusion of the UK spectrum auction in early 2013. Amid threats of legal action and potential further delays to the auction process, the government has now been forced to step in to call a ceasefire, according to the Financial Times today.

Everything Everywhere has agreed to put its launch plans on hold and its UK competitors have agreed to refrain from legal action for one month, to allow time for constructive negotiations. As we have discussed many times before, the UK is already trailing in the deployment of 4G wireless services and clearly the government sees the prospect of yet more delays as unacceptable. It remains to be seen whether an agreement can be reached and how quickly Everything Everywhere can reinstate its plans. In the meantime, it will take the opportunity to prepare and test its network. Live testing and systems integration are already underway in London, Bristol, Cardiff and Birmingham.

The decision will not be without controversy. Earlier in the year we reported that O2 and Vodafone will work together to share infrastructure for the delivery of 4G services. However, they will be unable to offer these services until they have spectrum available, and according to the latest auction plans issued by Ofcom, it seems unlikely that the auction will be concluded before spring 2013. Hutchison 3G will be in a similar position. This gives Everything Everywhere a six month head start, including the valuable pre-Christmas period.

Ofcom’s view is that the benefits to consumers outweigh any distortion of the UK marketplace. Perhaps a more accurate way to look at the situation is that UK consumers are currently at a significant disadvantage compared with other markets, and there is a need to do something about it before the UK becomes a backwater. At the last count by the Global Suppliers Association (GSA), in July 2012, there were 89 LTE networks in commercial operation around the world, and it is expected that there will be 150 by the end of the year. Many of the latest premium wireless devices support LTE, including Apple’s new iPad, Nokia’s Lumia 920 and Samsung’s Galaxy SIII LTE, and it is widely expected that the forthcoming iPhone 5 will also support LTE. Earlier in the year the lack of 4G networks in the UK led to the embarrassing situation that Apple had to modify the marketing of its new iPad, to avoid giving customers the impression that UK customers would be able to take advantage of the device’s 4G capabilities.

Congratulations to Ofcom on taking the bold move to expedite the introduction of LTE and we look forward to investigating 4G from Everything Everywhere later this year.

While the announcement has been some time coming, I’m delighted to see that the commercial realities of 4G LTE investment have caused O2 and Vodafone to make a very wise partnership decision. Vodafone and O2 have announced that they will pool their networks of radio masts and antennas, which will accelerate their roll-out of 4G LTE services.

In reality, Vodafone and O2 had little choice, unless they were prepared to fail with LTE services due to severe underinvestment. I’ve written many times about the effect that having so many separate 2G and 3G networks has had on the UK mobile industry. 3G networks have suffered from severe underinvestment as mobile operators have tried to achieve their internal profitability targets. With mobile users spread among so many disparate networks, operators have simply not been able to gain the critical mass of users needed to justify, and sustain, adequate investment in either 3G or 4G network infrastructure.

The UK mobile industry moved a major step forward with the merger between Orange and T-Mobile to form Everything Everywhere. At last, we had a business entity that could create a viable business case for widespread and extensive deployment of LTE.

However, the move by Orange and T-Mobile left Vodafone and O2 very exposed, particularly as substantial mobile revenue growth (forecast by industry analysts back in the early days of 3G) has failed to materialise. Growth in data revenues has, at best, only been able to keep pace with the substantial declines in voice revenues caused by intense price competition and regulation. While the business cases for early 3G deployments were made on the basis of often-ridiculous revenue growth assumptions, operators have learnt to be cautious this time.

Without substantial growth in revenues to justify huge LTE investment, 4G business case viability now demands dramatic reductions in network infrastructure costs. There’s only so far that mobile operators can go in pushing network infrastructure vendors to reduce their prices, as demonstrated by the dire profitability levels of vendors such as Nokia Siemens Networks. So, network sharing is the only realistic path.

Before Orange and T-Mobile announced their intention to merge, I was fearful about the prospects for the UK mobile industry. At the time, Ofcom was continuing to strongly promote the competition benefits of having a substantial number of separate networks, and it seemed highly likely that the UK industry would enter another prolonged period of network underinvestment – one in which the UK would languish near the bottom of the international LTE league table. 

The Orange/T-Mobile merger heralded a fresh approach that has finally destroyed the unviable industry structure that previously existed.

It is early days with the Vodafone and O2 relationship, and it is important to note that this is not a full-blown merger. However, there is much to be cautiously optimistic about. Vodafone and O2 intend to share a combined network portfolio of 18,500 masts. Vodafone and O2 claim that their partnership will accelerate their plans for widespread LTE deployment, so that they will be able to cover 98% of the population with LTE by 2015. Vodafone and O2 also plan to extend existing 2G and 3G coverage. 

At last, we have the prospect of LTE being deployed extensively by more than one operator by the end of 2015, although the UK still has to hold the spectrum auction (which has already suffered significant delays).