The London 2012 Olympic and Paralympic Games present a major logistical challenge. Some eight million spectator tickets will be on sale, park and ride spaces are being arranged for 21,000 cars per day, and over 135,000 hotel rooms are promised within 50km of the Olympic Park. Within the Olympic village there will be accommodation for 17,320 athletes and staff.
The London Olympics, however, will be different to all previous Games, thanks to the ubiquity of smartphones. But this creates a whole new nightmare – how to provide cell coverage to support an absolute tsunami of data traffic in what will be the world’s first smartphone-enabled Olympics.
Thousands of smartphones simultaneously transmitting video files from a single stadium will be a data traffic nightmare. How can the system cope without overload, backhaul problems, dropped calls, or compromised quality? Not only will the public be angry if they cannot use their smartphones on the day, there are also critical communications between organisers, messages to and from athletes or between lost spectators – messages that must be delivered in order to avoid chaos.
It is too simple to see this problem only in terms of quantity, or bandwidth demand. It is also a question of the type of traffic – both the special demands of smartphones and the changes in user behaviour that they encourage. Mobile data traffic has overtaken voice and is flooding the system. And a lot of attention is now focused on the limitations of the mobile backhaul network.
The backhaul burden
The capacity of the core network is not such an issue, the main bottleneck now lies in the link between the cell tower and the high bandwidth core. Traditionally this was provided by leased lines. The trouble with doing this is that, as bandwidth demands soar, scalability becomes a problem. An extra leased line to each tower is a major investment and represents a big jump in capacity.
It is broadly accepted that the future lies with Carrier Ethernet backhaul, or something very similar, because it is the ideal all-IP complement to the nascent LTE wireless technology. Ethernet backhaul still offers the most scalable and future-proof option. So, there is a solution to the backhaul crisis, but how can the supplier offer any guarantee of service levels until the system has been thoroughly tested to meet those levels?
Whether operator-owned or leased, mobile service providers are beefing up their backhaul to cope with anticipated demand during the Olympic rush. Worst case scenarios can be calculated to make sure that the bandwidth is available to carry peak demand, but that’s not the whole story.
Network testing is not simply a question of piling massive amounts of data onto the network to see how much it can carry, since most real life network traffic comes in bursts, made up of different patterns overlayed. Every transaction on the network has its own pattern, a pattern partly dictated by the technology and its communication protocols, but also by the human operator. Voice calls have their moments of silence, internet browsing has different rhythms, while a big download could come as one big rush.
So the real test is to simulate that real-world traffic and increase it to peak levels and beyond. Sophisticated network test devices generate large volumes of simulated traffic to monitor what happens and pinpoint bottlenecks or contentions in the system. In some data networks this can save a lot of money – rather than imposing a forklift upgrade of the whole network, pinpointing exactly where the bottlenecks are in the system can solve the problem with just minor upgrades, or even simply by adjusting what is already in place.
With the industry’s current focus on the backhaul problem, it is tempting to concentrate on that key bottleneck and overlook the greater picture. The user is not interested in bottlenecks, but in end-to-end performance, and this is ultimately what must be tested.
No one can predict what might happen during the Olympics, but it makes a big difference if you know what the peak capacity of your mobile network would be under all likely load scenarios. In addition, ongoing performance monitoring will provide a warning should conditions approach a critical limit, so remedial measures can be taken before the actual crash.
The Apollo TETRA network
The London Organising Committee of the Olympic and Paralympic Games (LOCOG) requires a safe voice communications network for the 18,000 staff and volunteers at the Games. It contracted Airwave Solutions, which operates the UK’s TETRA emergency services network, to provide it. The result is the Apollo network, a standalone TETRA system that uses Airwave’s infrastructure but operates separately from the main emergency services network on additional spectrum made available by the Government to ensure the latter is not impacted by traffic during the Games.
The network has similar resilience and robustness built in as the main Airwave network and there are two network management centres to monitor and control the system. Airwave has set up 60 radio distribution rooms to ensure that each volunteer is issued with the correct radio with the right call groups pre-programmed.
Richard Bobbett, CEO of Airwave Solutions, told Wireless: ‘We must expect the unexpected. We’ve been there and done a lot of this already as the network got a real test with the riots in the UK last year. We went from 3,000 users on the London network to 22,000 users in one night; 600 to 3,600 in Birmingham in 24 hours – that is a large unexpected increase, but that gave us the chance to test and prepare.’
Bobbett says that perhaps the key challenge is dealing with thousands of volunteers who are not at all familiar with two-way radios and how they work. ‘We are dealing with a largely volunteer workforce, or a short-term retained workforce. It is a huge transient force coming in and they are not traditional radio users. We’ve put a huge amount of effort into this by putting our people into every venue, so trained Airwave staff are handing out radios and can talk to the volunteers.’
BT rolls out communications provision for London 2012 Olympics
BT is the official communications services partner for the London 2012 Olympic and Paralympic Games. It is delivering a single communications network across 94 Olympic locations (including 34 competition venues).
Every official photograph and sports report and millions of calls, emails, texts and tweets will be carried over BT’s communications network. At peak times during the Games, BT’s network will be carrying 60 Gigabits of information – the equivalent of 3,000 photographs every second.
BT is responsible for delivering Wi-Fi, including being the sole Wi-Fi provider within the Olympic Park. It is installing an extensive high density, Wi-Fi infrastructure with nearly 1,000 access points across nine venues including the Olympic Stadium, the Aquatics Centre, Velodrome and public areas of the Olympic Park in east London.
The Olympic Park will be the largest high density Wi-Fi venue deployment ever with more Wi-Fi users in any one place than any event before. BT Wi-Fi will complement 3G networks and allow users to download and upload as much data as they like without the worry of exceeding their data allowance.
On 24 May 2012, BT also said it was on track to meet its commitment to have 500,000 Wi-Fi hotspots across the capital in time for the Games.
Here, Wireless asks BT how it will meet voice and data demands from smartphone users during the Games.
What is the wireless distribution system (cellular and Wi-Fi) for the Olympic venues?
In-building infill is provided to augment public coverage where external public services are unable to provide the necessary levels of service. For cellular, this covers the full range of technologies from Distributed Antenna Systems (DAS) to femtocells, and for wireless a range of standard and high density access point solutions.
Which companies are involved in providing wireless services, and in what capacity?
Wireless services are provided by BT, using Cisco equipment. Cellular services are being provided by a shared infrastructure, specified and implemented by the mobile network operators.
What additional equipment is being installed in the Olympic venues?
In addition to the in-building infill for each stadium, there are a number of temporary macro-cell sites being installed across the Olympic venues by the mobile operators. BT is not involved in the selection of this equipment.
What were the key challenges that needed to be overcome in terms of radio frequency design and planning?
The in-building cellular infill is designed as an extension to the public networks of the operators specifying it. Typically each venue in the Olympic Park has its own extensions to 2G and 3G services. For wireless, there is no current wireless footprint and hence it has been designed to maximise the use of the available spectrum. In areas where a high density of users is expected, then dedicated antennas will be installed with a tightly controlled signal footprint.
How will the system manage to provide the necessary cell capacity to cope with the high demand for data?
High density capacity planning techniques have been used for both cellular and wireless services to ensure that a small geographical area is supported by each focused antenna. Where appropriate, use has been made of high density extensions to protocols.
What demand are you expecting in terms of voice, text and data?
The solutions have been sized to cope with the peak volumes of people in the Park and usage profiles based upon market intelligence of user behaviours and device capabilities. This has been augmented with additional intelligence gained from other large scale events, such as the Super Bowl in the US.
What download and upload speeds do you expect to be able to provide at peak times?
These will depend upon the usage that customers make of the service.
How will the system avoid overload, dropped calls and delays in sending SMSes and data?
This will be achieved by providing sufficient capacity, offloading data from 3G to wireless where possible and ensuring that the more important services such as voice are prioritised.
What kind of resilience is built into the system should there be a capacity overload?
Resilience is an integrated part of the design.
What are the backhaul solutions being employed to cope with the demand?
The backhaul from venues is supplied by BT’s standard MEAS services, provided to the mobile operators as the customer.
What end-to-end testing have you been able to carry out?
Testing has been a continual element of all deployment activities. We have used performance testing equipment to understand the performance under load. We have also used test events with spectators to tune the performance.