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Fundamental of Microwave Radio Communication for IP and TDM

9 Dec


 The field of terrestrial microwave communications is constantly experiencing a steady technological innovation to accommodate the ever-demanding techniques telecom providers and private microwave users employ when deploying microwave radios in their cloud networks. • In the beginning of this wireless evolution, the ubiquitous DS1s/E1s and DS3s/E3s crisscrossed networks transporting mainly voice communications, data, and video. • With the advent of Carrier Ethernet and IP, new techniques had to be developed to ensure the new Layer 2 radios were up to par with the new wave of traffic requirements including wideband online-streamed media. These new techniques come in the form of Quality of Service (QoS), Traffic Prioritization, RF Protection and Design, Spectrum Utilization, and Capacity Enhancement. • With Carrier Ethernet and IP, network design becomes more demanding and complex in terms of RF, Traffic Engineering, and QoS. However, the propagation concepts remain unchanged from TDM link engineering while the link’s throughput of L2 radios doubles, triples, or quadruples employing enhanced DSP techniques. 


Improving Capacity Coverage at the Network’s Edge

7 Aug

While all the commotion is in the small cell domain, let’s look at a traditional tail site and see what are the main ideas for capacity coverage improvement.

Just seven years ago, a tail site was connected with a single DS1 or E1. With LTE, we went up to 100-150 Mbps per site. Now we’re pitching 1Gbps per tail site. Mainly because LTE-Advanced can deliver 1Gbps using 100 MHz of spectrum with carrier aggregation.

Improvinf Capacity Coverage

The first question that arises in the minds of network engineers is, “Where am I supposed to get 100 MHz of spectrum?” The main option today is to re-farm old 2G and 3G spectrum to gain better spectral efficiency with  new gear.  The second option is to bid for new channels such as LTE3500. Upon release, 3.5GHz LTE will bring with it a potential 400 MHz for distribution in many countries.  In the meantime, the eco-system is not there yet but with 200MHz in FDD, 200 MHz in TDD – it is safe to say that it is likely to happen.

Higher spectrum is not very efficient for coverage but it is the right choice for small cells and tail sites.  We can reuse this spectrum many times due to its short range.  This spectrum was sub-optimal for WiMAX because it didn’t go very far but for small cells or a tail site that is covering a small area, 3.5GHz  is an excellent spectrum.

But this does not conclude all my capacity requirements in this particular location.  I am likely to have a RAN sharing model one way or another, with more than one mobile operator. This sharing concept requires a short explanation. The obvious trends are whole operations sharing such as EE in UK or a backhaul joint venture such as NetShare in Ireland. However the case of backhaul service provides (Carriers of Carriers – CoC or alternate access vendors – AAV) is very similar – it its about transparency and service differ nation. But it also means a need to serve additional spectrum slices per site in terms of capacity or marinating a more sophisticated timing scheme

And even more interesting, this is considered to be the best place to aggregate all my other small cells.  My offload, integrated, coordinated models, not to mention more sectors connected to a tail site –  aka, Distributed Base Station as we discussed in my past post.

All of these capacity requirements surface as this is my point of presence.  However, when we start talking about coordinated multi-point capabilities and carrier aggregation (CoMP). More coordination between the sites means higher capacities and lower latencies. Though it has yet to be seen how to implement these concepts in an ideal or non-ideal backhaul environment.  So in essence, it’s easy to see that 1 Gbps is going to be the new E1 for a tail site.

Stay tuned for part three of this conversation where I will discuss taking the distribution concept to the extreme with a move to Cloud-RAN (C-RAN).

In the meantime, for more information on how to increase capacity coverage, feel free to take a moment to view Ceragon’s new white paper on Capacity Coverage or feel free to reach out to me with any questions at


5 Microwave Operators tell us their Biggest Backhaul Challenge

31 Jul


The general mobile industry sentiment has typically been that the capacity bottleneck is the biggest challenge in backhaul. Thus, the focus has been on adding more capacity to address the surge of 3G and now 4G traffic. So you might think that this concern would rank first, particularly among microwave-centric operators, who are often looking to maximize their network throughput. We recently commissioned the experts at Heavy Reading to do a custom survey to get some quantifiable data to clarify this key question and a few others.


85 mobile operators were selected and surveyed globally, including a good cross-section from both developed and emerging markets. The respondents were screened to ensure that they all had a stake in microwave-specific backhaul: 93 percent had deployed microwave and the rest had plans to deploy it. In fact, 45 percent were categorized as heavy microwave users—those where more than 50 percent of their cell sites were served by microwave backhaul.

So we asked this select group, which consisted of mostly planners, engineers and strategy leaders,“What is the biggest challenge your company faces regarding the future development and deployment of microwave backhaul?” 

The results were interesting in that “total cost of ownership” actually eclipsed “increasing capacity” as their biggest challenge, as shown in the pie chart of survey responses below.


Total Cost of Ownership (TCO) is definitely top of mind for most operators, with 25 percent of those surveyed ranking this as their top priority. And it was much higher for operators in developed countries—33 percent, possibly due to the lack of available fiber to enable high network capacities. The next pressing issue found was that of Increasing Capacity (22 percent)—not too far behind, but the close ranking of both capacity and TCO shows that increasing capacity without closely paying attention to total costs will not work. This is especially true in microwave, where higher capacity always comes at a price. There are many new and tempting techniques becoming available that are designed to boost throughput, such as very high-order modulation levels, line-of-sight MIMO, etc., which need to be balanced with the impact of more and/or larger antennas, more difficult frequency coordination and shorter microwave paths, all which can significantly increase both deployment and tower leasing costs.

So, why would TCO be the most pressing challenge one might ponder? We would propose a primary reason is the fact that backhaul networks are becoming increasingly complex, both in terms of the amount of equipment needed—which leads to higher real estate, power and ongoing maintenance costs and complexity from an IP networking perspective—requiring more advanced gear and technical skills to design, deploy and operate.

This same group was also asked, “For your cell sites that are now served by microwave backhaul, how many networking devices (i.e., microwave indoor units, Ethernet switches, routers, demarcation devices) are typically found at these sites today?” Of the survey respondents who gave a definitive response, 85 percent stated that two or more devices are typically found at their microwave-served cell sites and one-third reported it to be four or more! Talk about a lot of equipment to deploy and manage! One operator who was interviewed elaborated that “maintaining service quality, with the number of boxes in the network, and how to manage the complexity” was his biggest concern.

Networking complexity is also increasing as a result of the penetration of IP technology into the access portion of the backhaul and not just in the core and aggregation.

When asked, “In the 2014-2016 timeframe how likely are you to have L3 protocols (IP, MPLS, L3 VPNs) in service in the access part of the backhaul network?”:

  • 42 percent of all mobile operators responded that L3 is “very likely”
  • 32 percent said “somewhat likely”
  • Only 4 percent consider this “very unlikely”

This was a rather surprising endorsement for the penetration of L3 into access backhaul networks and provides a clear warning signal for microwave network providers that they must adequately evolve to support this oncoming migration.

A few years ago, the migration from TDM to Ethernet (L2) was the primary focus, now the next wave is migrating toward IP/MPLS (L3). As complex and challenging as the first migration was, the next wave further increases the level of complexity, some would argue, by an order of magnitude. Planning for, deploying and maintaining IP networks, the skill set of a typical IT organization will now be required in the microwave transmission side of the house, and will be a key factor driving increased OPEX investments going forward and impacting the bottom line TCO.

With networking complexity increasing in terms of the number of devices and L3 technology penetration, one may wonder if the future is all gloom and the TCO battle can never be won. Do not despair—advances in microwave networking are now on the horizon to tackle these issues—if not for all 85 operators, hopefully for you. Stay tuned for more outcomes from our custom survey in the next part of this series. Feel free to provide your email address and we will be sure to notify you when Part II is posted.


England: Campion Hills communications mast with microwave antennae. Photo credit: David Stowell [CC-BY-SA-2.0], via Wikimedia Commons

Critical Role of Microwave in LTE and Small Cell Backhaul

8 Mar

AVIAT NETWORKS: Official Wireless Transmission Blog

Mobile backhaul has become one of hottest and most contentious subjects in telecommunications ever since LTE cellular phone technology started to ramp up. One much overlooked aspect of deploying LTE lies not in the capacity required to backhaul cell site traffic but the effort required to build out the required sites. It is really about site surveys, frequency coordination, engineering, planning and installation. Aviat Networks’ chief technology officer (CTO), Paul Kennard, addressed this dichotomy and others related to LTE in his presentation to the IEEE’s Communications Society.

Although, Paul did have plenty to present regarding capacity. For example, with proper use of rings, overbooking, QoS, XPIC and other techniques and technologies, microwave backhaul can provide 400 Mbps-plus throughput. Compare this to the realistic throughput demands of a typical LTE site that max out at about 100 Mbps.

He also delved into the emerging backhaul category for Small Cells—designed to…

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Know Your Microwave Backhaul Options

10 Nov

AVIAT NETWORKS: Official Wireless Transmission Blog

If you look in the November issue of MissionCritical Communications, you will see an article by Aviat Networks director of marketing and communications, Gary Croke. In his article “Know Your Microwave Backhaul Options,” Gary covers:

  • Benefits of using indoor, outdoor and split-mount microwave radios in various scenarios
  • Rationale for choosing microwave over fiber (especially for LTE)
  • Deployability of microwave
  • Software-upgradeable capacity for “pay-as-you-grow” capex scalability
  • Cost contribution of towers over the first 10 years of LTE implementation
  • And more

You can read Gary’s article (on page-30) here—MissionCritical Communications—November 2012.

Related articles

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How To Build A Successful Radio Link

30 Oct

Most Network Managers know that microwave radio links require a clear line of sight and access to spectrum, but to achieve a successful link that is going to deliver service 99.999% of the time the devil is in the detail.

In-house vs. Managed service
You may choose to do it yourself, with your own trusted team of experts, and subcontract each step to the most cost effective company, or you may choose to use a company that offers a complete turnkey service.

You can use unlicensed or light-licensed spectrum, but you risk the link failing in the future due to interference. For an interference free wireless service you need private spectrum. You can obtain private licences from Ofcom for a few thousand pounds and subject to availability. Alternatively if you are going down the managed service route your supplier will deal with this for you, or better yet they will own their own licensed spectrum which makes the process of obtaining it infinitely quicker and it offers lower risk.

Even if you use light-licensed spectrum for rapid deployment at less cost, you would need an operator licence to give you a high level of visibility when it comes to other planned uses of this spectrum.

Desktop Line of Sight
This can be carried out by looking at the lie of the land on a map to see if it is theoretically possible to get a line of sight between your two points. Ideally you need a specialist who uses satellite imagery and specialist desktop planning tools. They will look at building structures, any planning constraints and any planned builds, as well as look at the ease of access to the site for maintenance.

Choose the Correct Technology

The technology will depend on the functionality you require, e.g.: the speed; resilience; availability; redundancy; reporting and diagnostics; traffic management, etc. Choosing the correct technology is essential and there are a number of options out there. If you are sourcing it in-house you need to be acknowledging any limitations that the devices have that may not be evident from the technology vendor’s specifications – variations on performance as a result of the weather, for example.
If you outsource the build of your link it is also pertinent to check that your provider is technology agnostic. This is how you can ensure they will not be bias in their choice and therefore use the right equipment for the job.

Physical Line of Sight
If the desktop line of sight has been carried out to a high standard, this step in planning your microwave link should not throw up many surprises. There are however additional factors that may affect the link’s functionality and so a physical line of sight is still essential. A drive by or ground level survey may be sufficient, however a double ended line of sight survey from height is a likely requirement. You will need a team of engineers qualified to work safely and legally at height. Ideally at this stage an MSV (Multi Skilled Visit) should be carried out, by accessing the cabin (viability having been ascertained at the desktop line of sight stage) and assessing the available rack space, power supply and cable runs.

The Fresnel Zone needs to be clear of any flora and fauna, and should any need to be removed you will require a licensed arborist or tree surgeon to do so. If you have a service provider they will work with the appropriate body to overcome them – for example attending Council general meetings to request permissions.

Site Acquisition
On occasion you will need to install a link somewhere other than on one of your buildings – and you will require planning permission to install it. An expert in surveying is beneficial for the understanding of the property laws and in finding the most appropriate site for the link. Line of sight is not the only consideration; the site’s readiness needs to be assessed for compatible power and space requirements. Environmental concerns may also need to be addressed. Site rental costs will need to be considered when budgeting for your link – and these may not be included in the managed service price. It helps to outsource to a company who is used to dealing with these issues, as they will often have preferential agreements in place with site landlords.

Once happy that the Fresnel Zone is clear, the link needs to be installed. Access to the site needs to be agreed with the site owners. The installing engineers need to be qualified for the technology, structure access (e.g. IRATA 1, Spainhoist Rope Descent, Rigging, RF awareness, First Aid and Rescue) and accredited by the third party structure owner, if applicable. Testing and commissioning on the equipment needs to be carried out to ensure the link is working in line with the design parameters – a situation facilitated if the design and install of a link is carried out by the same party. Acceptance testing will need to meet the criteria to accord with the appropriate industry British Standards. Performance values also need to be in accordance with those stated in the Ofcom licence.

You can either use separate suppliers for each element or use a company who offers a turnkey service for this.

Maintenance and Management

Your link will have to be monitored around the clock. If you don’t have the ability to do so yourself your managed service provider should have the scale to deliver a Network Operations Centre (NOC) 24/7 that is fully backed up with redundancy built into the NOC systems and follows full Disaster Recovery processes.

Having a managed radio network reduces downtime (for example at MLL Telecom 90% of faults are discovered and fixed without the need for the deployment of a network engineer and typically before our customers notice an issue).

Whether you are self-managing your link, or out-sourcing to a service provider, you can normally manage the balance of your CAPEX versus OPEX spend to what suits you – and with attention to detail with thorough planning a high quality link is attainable.


All-Indoor Microwave: LTE’s Best Backhaul Solution for North American Operators

8 Sep

AVIAT NETWORKS: Official Wireless Transmission Blog

There’s a lot of buzz in the microwave industry about the trend toward all-outdoor radios, but those who haven’t been through LTE deployments may be surprised to learn that based on our experience deploying LTE backhaul for some of the world’s largest LTE networks, all-indoor is actually the best radio architecture for LTE backhaul.

We can debate today’s LTE backhaul capacity requirements, but one thing we do know is that with new advances in LTE technology, the capacity needed is going to grow. This means that microwave radios installed for backhaul will likely have to be upgraded with more capacity over time. Although people are experimenting with compression techniques and very high QAM modulations and other capacity extension solutions, the most proven way to expand capacity is to add radio channels because it represents real usable bandwidth independent of packet sizes, traffic mix and the RF propagation environment.

All-indoor radios…

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Microwave Backhaul to Grow at Near Double the Rate of Leased Line Spending

20 Aug

ABI Research shows that capital expenditures on microwave backhaul equipment for mobile networks will grow at a compound rate of 4.3 percent. It will reach almost $5 billion in 2012 as mobile network operators upgrade and transition to more cost-effective packet microwave systems. With a combined share of 61 percent in 2017, the Asia Pacific and Western European regions will continue to dominate the market for microwave equipment.

World-wide opex from leased T1/E1 and fiber backhaul represents $6.2 billion in 2012, growing at a CAGR of 2.2 percent. “We believe mobile network operators are increasingly lowering their TCO by using capex to replace leased T1/E1 and fiber backhaul with modern, high-capacity, cost-effective, packet-based microwave links,” said Nick Marshall, principal analyst at ABI Research.

Marshall told Backhaul Bulletin that with data growing exponentially as mobile networks transition from 3G to LTE, the costs involved with fiber installation can become expensive in relation to distance. “Microwave is not a function of distance,” he said.

He continued to tell the Bulletin that in order for networks to handle more traffic and more subscribers, they are evolving to more distributed, feature-rich small cell architectures, especially in dense urban areas.

Backhaul opex on leased copper-based T1/E1 lines will continue to shrink at a CAGR of −1.1 percent reaching only $4 billion in 2017. “T1/E1-based backhaul is no longer compatible with modern 3G/4G mobile networks and will phase out as operators increasingly transition away from legacy TDM systems,” continued Marshall, in a company release.

ABI Research has focused on the last-mile and the access layer of backhaul in its newly published backhaul forecast database that provides backhaul forecasts for T1/E1, Ethernet over copper and fiber, cable, microwave and WiMAX. The research includes global and regional forecasts on data consumption, backhaul opex, capex for microwave, revenue for leased backhaul access technologies, cumulative macro base station shipments, as well as wireless traffic and bandwidth demands broken out to provide a comprehensive look at the access technologies pertaining to backhaul, as well as data traffic expected.


Best practices for ultra low latency microwave networks

21 Jul

For discussion purposes of ultra low latency, two theoretical ultra low latency microwave networks are compared to an existing optical Chicago-NY network.

In today’s ultra-competitive High Frequency Trading markets, speed is everything, and recently wireless technologies, and specifically microwave networking, have been recognized as a faster alternative to optical transport for ultra-low latency financial applications.

Even though microwave technology has been in use in telecommunications networks around the world for more than 50 years, new developments have optimized microwave products to drive down the latency performance to the point that microwave can significantly outperform fiber over long routes, for example between Chicago and New York. This has provided a new market opportunity for innovative service providers to venture into the microwave low latency business.

Although reducing the latency of the equipment is an important consideration, the most important metric is the end-to-end latency. Many factors that influence overall end-to-end latency require a deep understanding of the technology and how this is applied in practice.

This white paper will show that to achieve the lowest end-to-end latency with the highest possible reliability and network stability not only requires a microwave platform that supports cutting edge low latency performance but also a combination of experience and expertise necessary to design, deploy, support and operate an microwave transmission network.

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