4G rollout: the road ahead

Author : Phil Sorsky, CommScope

29 May 2013

Figure 1 Active antennas give operators the means to support larger volumes of subscribers by providing the ability to sectorise coverage areas vertically
Figure 1 Active antennas give operators the means to support larger volumes of subscribers by providing the ability to sectorise coverage areas vertically

The UK has finally come to the 4G party, joining countries such as the US, South Korea and Romania in rolling out high speed mobile technology. Yet, with just a single player in the 4G market in the form of EE, 4G is still in the process of taking off.

A spectrum auction is currently underway and likely to be finalised in the coming months. Current mobile incumbents O2, Vodafone, Three and EE will be joined by new players BT, MLL Telecom and PCCW in rolling out 4G, meaning that by midway through the year the UK is likely to have one of the most competitive mobile landscapes in the world. As well as the entry of new players, some operators such as Three have already revealed their plans for an aggressive range of 4G price plans that will guarantee a rapid uptake of 4G services. As a result, operators are investigating various technologies and solutions to ensure that networks can provide the high-capacity, ubiquitous coverage subscribers are coming to demand and mobile services will increasingly rely on.As operators begin to utilise their newly purchased spectrum over the next few months, a key issue they will need to contend with will be how to provide the backhaul capacity needed to support ever-growing data traffic. It’s a problem specifically relevant to operators in the UK, given the shear hunger for mobile data in this country. A recent Ofcom report showed that consumers in the UK use a per-person average of 424MB of mobile data per day – more than any other nation in the world and well above the US where the average consumption sits at 319MB per person per day. Of the several solutions available to deal with backhaul capacity, microwave backhaul is seeing increased popularity amongst operators as it can be installed faster and at a lower cost than fibre and cable solutions – especially in environments with rugged terrain where laying miles of cable would be prohibitively expensive.Thanks to rising data traffic, operators are deploying an increasing number of both conventional macro and newer small-cell base station links. This in turn puts greater pressure on microwave backhaul throughput – that is, the speed at which data from the wireless network can be fed back to the core network. As a result, more microwave backhaul links are being deployed in networks, resulting in a higher risk of signal interference in congested areas. Thus it is critical for operators to deploy high-quality backhaul antennas that make the best use of the available spectrum and avoid interference as much as possible in order to obtain the best capacity and data throughput. For microwave to remain the best solution for backhaul the antennas should produce highly directional, point-to-point beams that meet minimal interference – an issue that designers and engineers have been keen to address.Additionally, the self-backhauling mesh network is another solution seeing attention. Unlike traditional networks which connect base stations from a central point, base stations in a mesh network are connected to each other as well as a central point, extending network reach considerably. Self-backhauling systems can also reduce network congestion with capacity scaled up and down as required.Subscribers now consider mobile connectivity an indispensable utility. As far as mobile users are concerned, data is data. Whether they stream or download content over one technology or another isn’t important to them, their main concern is having a connection capable of delivering the service they want, wherever and whenever they want it. If such services are not available, operators not only miss out on revenue opportunities, but their customers may become frustrated by the lack of connectivity and go elsewhere. No operator can afford this in an environment of greater than 100% penetration and falling voice and SMS revenue streams and the issue will only become more pressing as 4G become ubiquitous.To keep up with this rapid growth in data capacity demands, operators are looking to increase the density of their networks through sector splitting or adding entirely new cell sites. Over 90% of all capacity gains in cellular networks over the past 20 years have been achieved by one of these two methods. However, while every subscriber wants seamless coverage and capacity, operators are increasingly encountering NIMBY (not in my back yard) when it comes to cell sites. Therefore, to provide even more capacity and speed in urban areas, operators will look to install a microcell layer (sometimes referred to as metrocells) on street furniture and buildings, thus upgrading site capacity. Active antennas appear to be a likely technology in next generation mobile networks. In active antennas, the radio section is separated into several radios that each drives an individual antenna element, instead of a single 60W RF amplifier driving all the antenna elements in parallel. Active antennas give operators the means to support larger volumes of subscribers by providing the ability to sectorise coverage areas vertically. With active antennas, operators can take a sector, split it vertically, and come close to doubling its capacity – improving the service for subscribers and generating more revenue. This kind of additional sectorisation is being carried out today using twin beam antenna technology to upgrade sites from three sectors to six sectors and using advanced optimisation solutions.  The challenge to this approach is the continued evolution of frequency band plans capable of launching high speed data systems.  The additional theoretical benefits of the active antenna systems must be carefully evaluated relative to the need for flexibility and scalability. Ultraband and multiband antenna systems can easily be combined with a variety of radio technology today and provide a proven way to add new technologies for capacity enhancement.With 4G set to go mainstream, the demand for data in the UK is going to increase exponentially as consumers gain access to services such as video and online games. Vodafone Germany, which has been quick to deploy LTE services, has already found that 75% of the traffic over its 4G network is from video consumption. In order to cope with this rapid increase in data demand, operators are investigating solutions that combine multiple technologies. One such solution is Heterogeneous Networks (or HetNets). This term relates to network deployments that encompass multiple base station types, as opposed to Macro-only cell deployments.HetNets will play a crucial role in 4G deployments since they can utilise multiple technologies to provide a seamless 4G experience. The premise of HetNets is to seamlessly combine Micro and Macro networks to ensure ubiquitous coverage and capacity, with the Macro network providing the coverage range, while the Micro network provides greater capacity for usage hotspots. The former is served by a high-power base station providing broad coverage, whereas the latter is made up of multiple lower power technologies, designed to cover limited areas, such as office blocks or shopping centres. The Micro networks consist of multiple low power technologies such as Picocells, Microcells, Distributed Antenna Systems (DAS) and Wireless LANs, that can support a very high capacity of data traffic. Meanwhile the operator’s core cellular network - or Macro network - delivers widespread, lower capacity coverage. The big advantage for operators is that HetNets allow for a much higher quality of coverage, but also at a much lower cost than rolling out universal high-capacity coverage.This approach allows operators to build-up their Micro network to reinforce high-usage hotspots whilst simultaneously expanding the network to eliminate blind spots. Wireless LANs can also be incorporated into the HetNet to converge mobile and fixed-line networks, helping to relieve traffic congestion on the core mobile network.We have already seen several different frequencies used in today’s active 4G networks, ranging from 800Mhz to 2.6Ghz. This variation, coupled with the prospect of new frequencies being re-farmed in the future, makes it essential for operators to ensure that both the coverage and capacity networks can support multiple frequencies. It’s equally important for the infrastructure to support multiple operators, enabling certain carriers to share implementation costs.As with all new rollouts, UK operators will face a number of challenges over the course of 2013. However, numerous technologies are available to help operators deal with these hurdles. It’s an exciting time to be a part of this country’s mobile industry as it forges ahead with the next chapter in its history, bringing the UK back to the forefront of cutting edge mobile technology and showing that the our mobile know-how is second to none.

Figure 1 Active antennas give operators the means to support larger volumes of subscribers by providing the ability to sectorise coverage areas vertically

Figure 2 Active antenna technology can be used upgrade sites from three sectors to six sectors


<Quote 1> Consumers in the UK use a per-person average of 424MB of mobile data per day – more than any other nation in the world

Figure 2 Active antenna technology can be used upgrade sites from three sectors to six sectors
Figure 2 Active antenna technology can be used upgrade sites from three sectors to six sectors

<Quote 2> Multiple low power technologies such as Picocells, Microcells, Distributed Antenna Systems (DAS) and Wireless LANs, that can support a very high capacity of data traffic.




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