SDR: the next big thing?

SDR systems can accurately be catalogued as ‘software-defined’ if they run on general purpose hardware, in a context where many existing technologies define themselves as SDR while running on special-purpose equipment.

With the adoption of more demanding technologies such as LTE, operators need to handle more traffic and deliver higher quality, meaning that mobile infrastructure needs to be run more efficiently and more profitably.

How can cost savings, resource efficiency, and flexible management be achieved in the mobile network? Our solution is the software-defined SatSite base station.

The reason for turning to SDR is the inflexibility of special-purpose hardware and software currently used in conventional base stations and what this entails in terms of costs, power consumption, and equipment.

sdr_2015-7-1_version6.3

Large expenses to upgrade, reprogram, or add new functions to the network

Because they are physically larger, base stations using conventional DSPs are more difficult to manage. What’s more, DSP boards can’t be modified to perform new functions or improve existing ones, so extending the RAN infrastructure usually requires new equipment to be added, leading to increased capital investment. Used on commodity hardware, SDR systems have lower manufacturing costs, making them more profitable when compared to the current heavy, static network equipment.

Increased power consumption

Special-purpose hardware products designed to perform complex functions come with high power demands. SDR allows more functions to be added to the same board, leading to the use of smaller equipment, with a lower power consumption.

Equipment supplier constraints

Another disadvantage of special-purpose equipment is that it is usually produced, serviced and supported by a particular vendor. In this case, operators are limited in recurring to different suppliers, as new equipment needs to inter-work with existing set-ups. SDR has the advantage of running on commodity hardware to avoid the use of specialized components and allow more flexibility to reconfigure or repurpose the hardware.

Dedicated staff training

Specialized hardware/software usually comes with specific vendor training and support. SDR offers operators more autonomy in configuring and managing base station equipment, relying entirely on their personnel.

SDR allows a high level of flexibility in designing and managing the RAN, with network functions being upgraded or reprogrammed with the simple use of software. While it is not a new concept, most base stations continue to use chip sets like DSPs, which are built on special purpose hardware, keeping equipment heavy, costly, and inflexible for changing traffic needs.

SDR is essential for the expansion of mixed networks to provide access across multiple technologies, such as 2G/4G, and prioritize service allocation depending on the needs. SatSite base station simultaneously provides 2G and 4G coverage using from the same equipment.

Built on general purpose hardware and using a non-proprietary operating system, SatSite allows operators to build smaller cell towers, with lower costs. SatSite cell sites can be suitably disposed to match the traffic needs in any area, and network performance can be improved remotely and easily, with a simple software change.

SatSite uses a high level language which enables it to support more complex functions than a conventional base station using a DSP. In highly populated areas or situations, increasing the network capacity to serve more subscribers usually requires a higher density of cell towers. SatSite can be dynamically reprogrammed to meet higher subscribers capacities by a software configuration for multiple-TRX.

Due to the flexibility, capacity, power and cost efficiency SDR brings to mobile networks design, its future probably holds good news.

Sources:

Wikipedia contributors. “Software-defined radio.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 24 Jun. 2015. Web. 2 Jul. 2015.

Off to greener networks

Going green is not just good for the environment, it’s also good for mobile operators.

It is common knowledge that the share of energy drives the largest costs in mobile network deployments – about 50% of the total OPEX in emerging markets. While diesel power systems play a large part in the high level of expenditure, according to a 2014 GSMA Green Power for Mobile report, they account today for nearly 90% of power solutions used in off-grid and unreliable grid sites.

Operational fuel costs, logistics (transportation, depositing), diesel pilferage – which alone increases costs with about 15%-20%, the need for continual service in areas where power outages are frequent, all add up to operators’ investment and operational expenditure, reflecting eventually in a higher service cost for users and therefore in a drop in use of mobile services.

green power SatSite

60% of the overall network infrastructure costs is attributable to building and powering cell towers [1], so saving on energy requires the choice of equipment that uses makes a more efficient use of power resources.

Deploying cell sites using green energy is easy when using a base station like SatSite, which requires a low power input (45W) and is ideal for installing in remote areas with unstable or no electrical grids. Cell towers using SatSite in either single or 3-sector configuration are a lightweight deployment which allows it to serve isolated or remote locations, relying only on the existing natural resources.

SatSite’s design differentiates from that of traditional base station by integrating a passive cooling system that makes its use independent from air conditioning or ventilation units. The power required for air conditioning makes up for a large part of the overall input needed to run operate a site. Eliminating air conditioning also frees up space to make cell towers more resilient.

Over diesel power systems, solar panels and wind turbines, for example, have a much longer life expectancy, that can range to 20-25 years. Combined with diesel power in hybrid energy systems, operators can achieve a longer and more reliable operation of cell towers, driving down fuel costs to save more than $10 billion annually.

Shifting to green towers has major implications. First, it reduces operators’ costs and allows them to extend mobile networks in places in areas that are completely deprived of coverage due to the lack of an adequate infrastructure. Then, it reduces the negative effects on environment; GSMA reports that an off-grid site in Africa has an average annual consumption of 13,000 litres of diesel, adding as much as 35 tons of CO2 emissions to the environment.

If they choose green energy for telecom towers in remote areas, operators must move to smaller, more autonomous cell sites; profitability will come not only from power savings and a rise in service use, but also from reshaping the overall network infrastructure to better manage power factors.

 

[1] Telecom infrastructure sharing, http://en.wikipedia.org/w/index.php?title=Telecom_infrastructure_sharing&oldid=624429583 (last visited June 10, 2015).

Off-grid technologies for sustainable mobile network deployments

Energy costs amount to 15% up to 50% of the total OPEX of deploying mobile networks in areas without power grid. Operators in developing countries, as those in the Sub-Saharan Africa region, need cost-effective solutions to face this issue, otherwise they will find it impossible to install new networks.

When we first heard about Tesla’s latest innovation we were impressed. It seemed the perfect solution for what households need right now. But then we gave it more thought and realized that Powerwall batteries are also an answer for mobile operators. We now know they would make a great match with our SatSite base stations.

Depending on the type of deployment, cell sites equipped with SatSite units have the following average consumption levels:

  • lightweight site, with omni antenna – approximately 45 Watts
  • three-sector site – less than 150 Watts
  • three-sector site with tower mounted booster – approximately 350 Watts

tesla_SatSite

A Tesla Powerwall battery offers either 7 or 10 kWh power output, is rechargeable with aid from solar panels and can be mounted indoors and outdoors. It also has a 10 years warranty and requires no additional maintenance costs. A single 7 kWh battery is enough for running 3 SatSite units.

Recent initiatives, like GSMA’s Green Power for Mobile, have stressed the importance of deploying network infrastructures powered by green energy (in most cases solar) in developing areas and regions beyond the electrical grid.

Since both equipments can be powered by solar panels we consider this pairing an easy and seamless solution, particularly in areas where connection to the electricity grid is an issue. It can also successfully replace diesel-powered telecom towers, reducing costs and environmental pollution.

Not only does this solution work well in rural or isolated areas, but it would be a great fit for urban areas in developing nations that have an unreliable power grid. Cell towers equipped with SatSite base stations could use Powerwall batteries as a dependable and renewable backup plan in case of power outage. National blackouts affecting hundreds of millions of people, like those in India (2012), Turkey (2015) or United States (2003), will no longer restrict vital mobile communications if operators choose self-sustaining power alternatives.

The Case for the Unconnected Billions

Sending text messages, going on hour-long calls, or live-streaming videos are such an integral part of our lives that most of us take them for granted. And yet around 3 billion people live, today, in areas without access to basic infrastructure – be it remote islands in the Pacific, developing extra-urban areas, or isolated rural areas everywhere around the world.

Mobile communication can connect these people with one another and with technologies that can prove to be vital. Mobile data enables job seeking in wider area ranges, instantly accessing health care information in case of emergency or risk, or keeping farmers in line with market prices and trends.

In remote, unconnected markets, bringing voice and data coverage can be best achieved using GPRS, which provides wider coverage than 3G, and is easier to adapt to rural, remote, or low density areas. In such places, traditional cellular networks have the disadvantage of being economically counterproductive to deploy, and operators are unlikely to invest in hefty infrastructures that generate relatively little revenue from usage compared to the networks’ lifespan maintenance costs.

The YateBTS technology addresses these issues differently than most other approaches to mobile networks. 2.5G networks using SatSite and YateUCN are a simplified, flexible, and low-cost solution that can be adopted anywhere in the world.

Lightweight, low-power sites

SatSite is smaller than typical base stations which makes it easy to build lightweight cell sites that are especially profitable in higher density networks. SatSite’s low power requirements allow operators to plan self-sustaining mobile networks running on solar or wind energy, avoiding the use of costly power grids or diesel systems.

Bandwidth-efficient backhaul

Unlike traditional networks, a YateBTS/YateUCN mobile network allows bandwidth savings of up to 60%, by using the GTP protocol across the entire network.

bring_cov_2015-6-4_version1.2SatSite acts as a BTS/BSC communicating with the YateUCN core network over GTP, without using any additional network nodes, to simplify the network architecture and minimize the backhaul load. Data sessions in networks using YateBTS SatSite can be established either locally, by assigning the IP directly in the SatSite, or in the YateUCN core network, adapting to the constraints of each location.

SatSite unifies the BTS and the BSC from traditional radio access networks architecture, to eliminate the Abis radio interface used to direct traffic between the BTS and the BSC. In conventional cellular networks, the BSC handling all the communication between the core network and the devices leads to high costs and a substantial load on the network. SatSite base station can communicate with YateUCN over satellite, using GTP to replace the signalling interfaces normally used inside the radio access network and to/from the core network.

A satellite backhaul architecture is adapted particularly to sparse networks in areas with a low density populations, where cell sites are far from the core network; satellite allows operators to serve any location, and improve bandwidth performance for both voice and data services. Combined with the light design and an autonomous operation of the SatSite base station, backhaul over satellite makes YateBTS/YateUCN networks ideal for extending connectivity to uncovered areas.

What we talk about when we talk about coverage

There are a multitude of factors operators take into account before deploying their networks in order to provide us with the best possible coverage. Since the radio communication of mobile networks is peer-to-peer, the most significant aspect of coverage is that the device sees the mobile mast. To bring some clarity to what coverage means, and how to calculate it, we will introduce: the elements that influence coverage for both operators and their subscribers, coverage planning and our coverage and range estimation tool.

Coverage varies from cell site to cell site, and depends on the type of terrain, the equipment used, the type of buildings around the site, the radio frequency but also, very importantly, on the sensitivity and transmit efficiency of the subscriber’s equipment.

The coverage level also relies heavily on the antenna type or the amplifier power levels. The further you get from the cell site, the weaker the signal gets, as the ground clutter standing in the signal’s way increases. This makes coverage drop exponentially. ground_clutter_2015-3-5_draft1.2.1

Operators can increase the strength of the signal and the coverage, through higher power transmissions, taller antenna masts, a higher antenna gain etc. Antenna gain is, in fact, a crucial factor in getting a broader coverage, as it accounts for the losses and the directivity of an antenna. The relation between the antenna gain and the coverage is directly proportional, i.e. the higher the antenna gain, the more coverage the cell site will deliver.

Network planners use propagation models like Hata, Cost231 or Walfisch-Ikegami, to roughly calculate, in a quantitative manner, what can be expected in a specific environment. They also utilize more accurate tools that take into account the exact type of environment where their cell sites will be deployed, as the Radio Mobile RF propagation simulation software.

We created a tool that uses a very specific coverage propagation model, so do check out how it works with our SatSite. For more information on SatSite’s coverage area, click here.

For mobile subscribers, coverage depends on their devices’ capabilities, since they are not all the same. Also, the coverage level will not be the same if they use their device attached to a car kit, handheld or with an external antenna.

As an important note, always keep in mind that most times, coverage depends on both the device’s ability to “see” the antenna and the antenna’s capability to reach the device.