Artificial Intelligence. Photo credit: miuenski / Foter / CC BY-NC-SA
Once upon a time, cell sites served as little more than passive pass-throughs for phone calls and text messages. Because voice calls and SMS posts did not require much wireless capacity cell sites did not require very robust provisioning. Now that the Internet has gone fully mobile with streaming videos and real-time applications such as VoLTE and IPTV regularly crushing network capacity design parameters, the time to get smart about backhaul and access traffic has arrived. The time for Layer 3 intelligence is now.
In fact, for some time mobile cell sites have transitioned from simple Layer 2 connected sites for 1990s-style mobile phone and data access to multipurpose centers for delivering new, smart device services. However, they can only provide new, smart services if they are built upon Layer 3 technology that offers intelligent handling of wireless traffic. Only IP routing technology is capable of such functionality.
But here comes the catch regarding IP routers providing Layer 3 intelligence at the cell site. With more than 50 percent of the wireless traffic in the world going to and coming from mobile sites through backhaul radio, Layer 3 intelligence must have awareness of microwave networking. And regular routers just do not offer microwave awareness. A new class of device must fill the void left by regular routers that frankly do not have enough “smarts” to deliver Layer 3 intelligence for cell sites that depend on microwave backhaul. A device that combines the best attributes of microwave radios and IP routers.
To provide a closer examination of this issue, Aviat Networks has authored a new white paper—no registration required—that makes the case for Layer 3 intelligence at the cell site. And how to implement a new class of “smart” devices that enable microwave radio awareness with IP routing.
Cell sites will need to begin to transition to Layer 3 IP services. Photo credit: zdenadel / Foter / CC BY-ND
The entire wireless industry is on the cusp of a transitive time where Layer 3 IP services will be needed in the access portion of the network. And the backhaul will be needed to provide them.
Under the pain of restating the obvious, we have all seen the explosive growth of smartphones, tablet computers and other radio-frequency-loving gadgets like e-readers. All these new-fangled high-tech contraptions need Layer 3 IP/MPLS services in the access and backhaul in order to deliver a satisfying, seamless user experience—especially for enterprise services. The question is how will the mobile network operators (MNOs) be able to deliver these services from their thousands or tens of thousands of cell sites?
Typically, the answer would involve deploying a regular router for IP services at each and every cell site. But have you seen the prices of routers lately? Cisco didn’t get to where it is today without having some heavy pricetags attached to all the heavy iron it’s shipped over the last 20-odd years. Suffice to say, it would be a pretty penny if MNOs equipped all their cell sites with their own dedicated routers. So what else can be done, you query?
It just so happens that Aviat Networks’ director of corporate marketing, Gary Croke, has posted an article at RCR Wireless going over what to do in these types of situations. But we’ll give you a hint: the IP router function should be folded into a single multi-service, multi-layer cell site device. Read the rest and let us know what you think.
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Cell tower, Ghana. Photo credit: aripeskoe2 / Foter.com / CC BY-NC-SA
A growing telecommunications trend in South Africa and other emerging markets across the African continent is the move to cell tower sharing. There are many reasons for this, but the need to reduce capital expenditure (capex) on towers and other infrastructure and retarget spending toward network development, customer acquisition and retention and need to accommodate growing mobile data traffic levels have forced the issue.
The trend toward independent ownership of telecommunications infrastructure such as tower sites, with leasing arrangements for multiple operators on each tower, closely mirrors moves in mature telecommunications markets around the globe, including the U.S. and Europe, as well as other big emerging markets such as India and the Middle East.
Tower sharing prevalent
While there is some reluctance by industry incumbents to offload tower infrastructure because they fear losing market share and network coverage, the tower-sharing model is still becoming more prevalent. This is particularly evident in markets where there are new players trying to penetrate the market, as well as in countries where coverage in rural, sparsely populated areas is needed to drive growth. Other important factors, such as the rising cost of power in South Africa, or unreliable power delivery in other parts of the continent have also helped to drive this trend.
Thus, the adoption of this model has gained significant momentum in Africa since 2008, with major mobile operators in Ghana, South Africa, Tanzania and Uganda striking deals to offload existing infrastructure to independent companies. These independent “tower operators” handle the operation and management of these towers, leasing space back on the towers to multiple network operators. This helps to reduce operating costs, improve efficiency and potentially boost an operator’s network coverage significantly and rapidly.
Smaller equipment requirements
To accommodate multiple network operators on a tower and cell site, smaller antennas are preferred, with additional requirements for smaller indoor equipment that draw less power. This configuration helps to decrease power consumption and cooling requirements resulting in more efficient use of diesel generators during times of power failure. However, having smaller antennas affects transmission power, capacity and efficiency. As such, mobile operators are turning to on-site solutions that offer all these benefits, but do not compromise on quality of service, capacity or data transmission speeds.
This also extends to the backhaul network, which often poses the most significant challenge for mobile network operators, especially as mobile networks continue to evolve from 2G and 3G to LTE. For example, as mobile networks continue to evolve, backhaul network architectures will need to change from simple point-to-point to more complex ring-based architectures. Operators that choose to share infrastructure will need on-site equipment that is capable of accommodating these changes, while still offering optimal transmit speeds and reduced operational costs.
Traditionally, most network operators also used optical fiber for their high-capacity fixed line core/trunking networks. However, as tower sharing becomes more prominent fewer operators are willing to spend the capital required to enable fixed-line backhaul from shared sites due to the associated costs. Therefore, more operators are turning to wireless backhaul as a suitable solution to transport data between the cell site and the core transport telephone network.
More capacity needed
As users demand more capacity on the access portion of the network, the core/trunking network also needs to sufficient capacity to be able to transport the aggregated traffic from all these sites. Many operators have turned to high-capacity trunking microwave systems to provide the required high capacity. These high-capacity trunking microwave systems have traditionally been installed indoors, usually in a standalone rack. They were also installed in a way that radio signal strength diminished significantly before reaching the antenna at the top of the tower, ,necessitating a bigger antenna to compensate. These all-indoor configurations also required big shelters and costly air conditioning.
Developing new technologies
In an effort to improve the efficiencies of mobile backhaul to meet modern demands, tower operators and their solution providers are reconfiguring these shared sites, and new technologies are being developed to solve these challenges.
For example, split-mount trunking solutions allow for up to four radio channels on a single microwave antenna, and lower costs associated with deploying and operating ultra-high capacity microwave links for increased capacity. Smaller and lighter antenna solutions can also be lifted and installed higher on towers more easily, which helps to decrease tower space and loading requirements, making these solutions less prone to wind damage. Moving radios from the shelter to the tower, next to the antenna, further reduces deployment and operational costs and simplifies antenna connections (e.g. eliminates inefficient, long waveguides; costly unreliable pressurization/dehydration systems). In these cases, smaller shelters or cabinets can be used, which decrease air-conditioning requirements even further.
However, regardless of how tower operators are able to reduce costs and improve efficiencies, the trend of this form of infrastructure sharing is set to continue, which will help to drive increased competitiveness in mobile markets across Africa. This will have a positive impact on the prices end-users pay for mobile data and voice services, and will help to accelerate the availability of connectivity across the continent.
Siphiwe Nelwamondo
Technical Marketing Manager, South Africa
Aviat Networks
To compare how different wireless backhaul network topologies perform under the same operating scenario, let’s analyze how a traditional hub-and-spoke and a ring configuration compare in connecting the same six sites (See table below). For the hub-and-spoke configuration, each cell site is provided 50 Mbps capacity in 1+1 protection. With five links and no path diversity, full protection is the only way to achieve five nines reliability. In this configuration, 10 antennas are employed, which average a large and costly 5.2 feet in diameter. Total cost of ownership for this six-site network is close to $700,000 for five years.
For a ring design for the same six sites, throughput of 200 Mbps is established to carry the traffic for each specific hop and any traffic coming in that direction from farther up the network. Designed to take advantage of higher-level redundancy schemes, the ring configuration only requires antennas that average 2.3 feet in diameter, which are much lower in cost compared to the antennas in the hub-and-spoke configuration. And even though the ring configuration requires 12 antennas and six links, its overall TCO amounts to a little under $500,000 over five years—30 percent less than TCO for the hub-and-spoke design for the same six sites.
This comparison is based upon deployments in the USA, where most operators lease tower space from other providers.
Gary Croke
Senior Product Marketing Manager
Aviat Networks
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