Sharing the 3G burden - Product Announcement

As UMTS rollout takes its first tentative steps in western Europe, would-be 3G operators stand face-to-face with a double headed deployment dragon -- limited base station site availability in urban areas, coupled with increasing pressure to drive capital expenditure (capex) levels down, courtesy of last year's [euro]l17 bn spectrum price tag. Added to this is an overriding pressure to complete these networks as quickly as possible. When commercial-grade handsets and node Bs finally become available, the race will be on to win subscriber market share.

Other pressures will also come into play as 3G rollout commences. After all, the move to UMTS marks a major technology change for Europe -- a move from TDMA-based GSM technology to CDMA-based UMTS modulation. Engineering skills and know-how may ultimately prove to be the weakest link, as network designers and planners try to clamber up the UMTS learning curve.

2G and 3G comparisons

Some industry observers claim the problems of 3G deployment are strikingly similar to that of last decade's 2G rollout. Others believe that the current challenges are quite unique. Helmut Heinz, director of RF engineering at Siemens, cites two key differences -- a chronic shortage of sites across Europe and dramatically elevated levels of environmental sensitivity and subscriber expectations.

"The first 2G operators in Europe had extremely good [site] locations," says Heinz. "The latecomers on the 2G market had to take the rest. For 3G, I'm afraid we're picking over the 'rest of the rest'. It will be very tough to acquire good new sites."

The high penetration and strong growth of GSM in Europe over the past four to five years has, according to Heinz, elevated subscriber expectations to almost unattainable levels. "Today's subscriber is not willing to take a step back. If you want a 2G customer to convert to 3G, he expects at least the same quality of services and coverage he has today."

What is strikingly similar between the 2G and 3G deployment is the race to roll out service. "3G operators will need very good coverage in a very short time to meet customer expectations," says Heinz. This urgency to roll out paves the way for 'infrastructure sharing', particularly for those operators with no established 2G base.

In late June this year, rival networks Deutsche Telekom and BT announced they would cooperate in the construction of network infrastructure and initial network operation in both Germany and the UK. In the same month, the German regulator, RegTP, announced it would allow licence holders to share some network infrastructure. While the detail is uncertain, these are clear indications that a shared approach will certainly play a significant role in early 3G rollouts.

Three approaches to sharing

Most infrastructure-sharing concepts and technologies fall into one of three basic models. The first is base station site sharing -- a technique well-established in contemporary 2G deployment across site-starved Europe. Typically, operators share site space, civil structures, power and so on. The radio access networks (RANs) remain completely separate. In some cases, antennas themselves are shared, but almost exclusively within a single network.

The two new models most recently spoken about -- and those presenting the greatest cost-saving opportunities and implementation challenges -- are the network company (NETCO) and radio access network company (RANCO) models.

In the first, a separate company is established to run the entire network, including the core network itself, as a shared entity. The RANCO model again requires a separate company to own and operate the radio access infrastructure elements -- node Bs, radio network controllers, antennas and so on -- but with each operator owning and running separate core networks. In both models, billing, maintenance and operating expenditure (OPEX) costs are all teased out and allocated to each network 'user'.

Making real these more complex cooperation proposals presents many challenges. These range from the practicality of actually administering network OPEX costs and billings revenue, through to the delays and inefficiencies that might occur in such 'cooperative' designs. Mast important is the issue of maintaining industry competition and the ultimate rulings of Europe's regulators. Some observers believe the degree of 2G penetration achieved in Europe was largely due to the essentially competitive nature of its deployment. Could a more cooperative 3G market achieve the same success?

Sharing 'brokers'

Some of the major players in infrastructure sharing -- the 'brokers' in the infrastructure sharing arena -- are showing a decided interest in the RANCO and NETCO models. Crown Castle International is a global owner and operator of shared wireless communications and broadcast infrastructure. It deployed the world's first 3G network for Manx Telecom on the Isle of Mann, and, in the UK alone, the company owns and operates more than 2,400 sites.

At the moment, Crown Castle is focusing its efforts on deploying its own and its clients' 3G base stations as quickly as possible. "Speed to market is essential," says Mark Dismorr, Crown Castle's director of engineering. "Whoever gets their network out there first is obviously going to see revenues coming in quicker and that will help their whole balance sheet."

To date, Crown Castle's main focus has been on actual site and structure sharing, but Dismorr believes the immediate future for 3G cellular will be quite different. "We're promoting the NETCO and RANCO models and are talking to a number of operators about these options. This is indeed where we see ourselves going," says Dismorr. "We believe it is technically possible. Whether it is commercially viable or regulatory acceptable ore big issues being explored at the moment."

Dismorr points to the obvious advantages of a dramatic reduction in both network CAPEX and OPEX -- same estimate in the order of 30 per cent -- and an overall faster deployment and time to market. He also points out more subtle advantages, such as achieving speedier site planning approval by making a unified submission via an 'independent' group such as Crown Castle.

He acknowledges that some operators might struggle with the change in mindset required to work within these models. Operators will need to see themselves more as service providers than traditional network owner/operators. There is also the issue of competitive transparency. An advantage of using a third party network 'broker', Dismorr believes, is that 'Chinese Walls' can be built to effectively segregate such strategic network information transfer.

Some industry analysts have expressed doubts about the NETCO and RANCO models. They point to the difficulty of achieving true differentiation for new operators using shared infrastructure -- specifically the problematic issue of guaranteeing service speed and quality via a shared network. Others express concerns about the lack of flexibility of these complex structures, as the industry pitches and rolls under the pressures of a changing 3G market place.

Undeniably, the potential CAPEX and deployment time-savings resulting from these Models are huge, and will present a major incentive for operators, infrastructure developers and authorities alike to overcoming these initial problems.

Site sharing

While the technical and operational issues of the NETCO and RANCO models are being smoothed out, the immediate reality of infrastructure sharing today is essentially site sharing. This offers operators the most practical and immediate 3G deployment path. Dismorr points out that conservative estimates gauge around, 1 0,000 sites will be required for each of the UK's five 3G licence holders. "But you won't see 50,000 3G sites in the UK," Dismorr insists. "There'll be a great deal of network sharing at the site level, and many of these are going to be deployed on existing towers. Some incumbent operators are, looking to deploy in excess of 80 per cent of their [3G] sites on existing radio structures."

Tower manufacturers and designers are also acknowledging this trend and developing innovative technologies to support it. Paris-based CGTI Pylones is currently developing uniquely tall, enhanced-rigidity structures, specifically designed to support multi-platform antenna configurations for cellular co-siting applications. "There's a general trend towards these shared tower structures, particularly to meet the growing demand from cellular infrastructure brokers. 3G will escalate the need dramatically," explains CGTI sales engineer Didier Girardeau. CGTI also plans foundation-free towers, which will permit easy turnkey development of 3G towers without the conventional delays associated with acquiring building permits.

In Norway, operator and 3G licence holder Netcom is a case-in-point, demonstrating this site sharing trend. The company owns and operates around 2,500 GSM sites and is currently actively co-siting 3G base stations on its own 2G locations.

"In the first phase of our rollout we are trying to use our own sites as much as possible, because of the complexity of sharing with other parties, particularly when key 3G base station components are not yet available," says Trond Botheim, Netcom's engineering manager of UMTS. Botheim acknowledges that both Netcom and Norwegian competitor Tele2 were instructed to explore networksharing options by their parent company, but that the outcome of this study was inconclusive.

What is conclusive is the importance of deploying new 3G networks at the earliest opportunity. "We will need at least two years to be able to provide coverage and then services to the majority of the Norwegian population, so an early start was imperative," says Botheim. "This is fine, so long as you rollout in a 'future proof' way by ensuring the hardware is compliant with the final release 99 standard."

Crown Castle's Dismorr concurs: "The whole of the release 99 standard is pretty mature now. Certainly at the Layer 1 level, it is very much set in stone," says Dismorr. This, he believes, is clearly a chequered flag for site UMTS radio access network deployment to commence apace. "Traditionally, the longest time in network development is spent acquiring and deploying the sites. So there are huge time to market advantages to be had in designing the network, acquiring sites and gaining permission as early as possible."

Shared RF solutions

A powerful and increasingly popular infrastructure alternative is the range of 'shared RF' options. Botheim points out that for those 2G/3G co-sites where multiple antennas prove difficult, Netcom opts for dual and sometimes triple band UMTS/GSM antennas. "We use multiband antennas for five to ten per cent of the sites," says Botheim, "particularly in urban areas with strong aesthetic requirements, or if we feel we are being asked to meet unreasonable (rental] demands from a building owner."

Indeed, some of today's most enterprising operators are rolling out 3G passive sites now, with shared RF solutions factoring high on the list. These consist of ready-fitted masts with antennas and feeders, without node Bs. "They will be able to plug equipment to the site when it is ready," says Pierre Clavel, strategic marketing manager with wireless technology group Radio Frequency Systems (RFS). "It is a low capital investment into the least expensive and most time-consuming part of network deployment. Shared RF solutions can play a key role here."

An important factor to consider in co-sited antenna solutions, as Clavel points out, is to ensure there is adequate RF isolation between each system -- 3G to 3G, and 2G to 3G and vice-versa. "The release 99 layer 1 standards are mature and very clear as to what is required here," says Clavel. "It's very important to ensure that the co-sited antenna outputs and interference levels fall below the isolation levels specified, to avoid BTS and node B blocking and interference problems. Typically, this sort of data should be provided for a range of antenna configurations and separation distances."

Multi-band and shared antenna options help overcome the key hurdle of environ mental impact, by reducing the total number of 'visual antennas' from two -- and sometimes three -- to just one. To this end, RFS has developed a family of cross-polarised multi-band GSM/UMTS antennas known as 'antenna a la carte'. This range offers a selected combination of the existing GSM and UMTS antenna ranges, including tri-band options, fitted within a GSM antenna-sized radome.

Network planning and optimisation for W-CDMA is entirely different to that for GSM, Clavel advises. "Aside from the smaller W-CDMA cell size, the cell is said to 'breathe' -- expand and contract in footprint size -- which is a unique CDMA operational characteristic. From this point of view, GSM/W-CDMA sharing a broadband antenna simply isn't an option. Separate antennas with independently adjustable tilt optimisation in each band are essential -- even in multi-band antennas." To address this problem, each element of the antenna a la carte is supplied with independent fixed tilt, or with continuously adjustable variable electrical tilts (VET) for each band.

Clavel acknowledges that in some specific cases, feeder sharing will also be necessary. "It's a solution we're not recommending, but in some difficult-to-cable situations it's necessary." He cites three problems associated with shared feeders -- at least 1 dB attenuation loss in shared GSM/UMTS feeders, a loss of critical isolation between the GSM BTS and UMTS node B (possibly leading to inter-modulation problems) and lastly, a loss of system redundancy.

"Certainly the more services you put on a single feeder, the more intermodulation problems you can expect. High rejection rate filters can resolve this, and tower mounted amplifiers (TMAs) might be required to compensate gain loss in theuplink. This adds to the system complexity, but in some cases there is no alternative." In late-2001 RFS plans to launch a range of precision filters and TMAs, specifically to meet this growing need for filters.

"In reality, there's potentially a whole spectrum of 3G scenarios -- 2G/3G cositing, 3G/3G co-siting, 3G gap-filling and micro-cell sites, stand-alone 3G sites and even RANCO and NETCO deployment," says Clavel. "The challenge here is to provide the widest RF technology range to ensure optimal site fit-out flexibility."

Optimal solutions

What ultimately proves the best 'infrastructure sharing' choice will depend on just how the European 3G market evolves. An important factor will be whether 3G is fought on traditional network coverage and quality issues, or whether services will be the decider. Many believe coverage and quality will be a secondary issue, but Clavel disagrees. "A number of European operators are actually struggling with the capacity of their existing 2G networks," Clavel says. "Capacity might be an important reason for migration to 3G, which will shift the focus back to coverage.

When operators are comfortable with their 3G networks, Clavel believes they will search out means of differentiation. He predicts that availability and reliability of high-speed data services would achieve this differentiation, with both indoor and outdoor application playing a key role.

Market trends will also be a big factor, with consolidation widely predicted. "I believe there will be 'shake out' of operators in the coming years," Siemens' Heinz asserts. "The German market, for instance, simply can't support six separate operators." Heinz is not alone in this view. Many market analysts forsee the same future, with one well-known Merchant Bank predicting the entire European market may ultimately be served by just five 'mega' operators.

Netcom's Botheim sees a more radical rationalisation happening -- a distinct separation of network owner/operators and service providers. "In the long run network operations will be a type of separate business," says Botheim. "You cannot easily cooperate in the whole vertical chain, except the top services."

The ultimate 'shared infrastructure' solution will no doubt be a blend of shared sites and site structures, shared RF solutions, RANCO/NETCO-style operator 'cooperatives' and leased facilities, and virtual private network operators [VPNO]. The challenge to operators will be to decide swiftly and deploy -- at least at the base station layer 1 level -- as soon as possible. The release 99 standard is ready, and node B, radio network controllers and handsets not too far away. Like 20, the first to realise coverage will win the richest revenue streams.

COPYRIGHT 2001 Horizon House Publications, Inc.
COPYRIGHT 2001 Gale Group