As one of the most anticipated network technologies, Voice over LTE (VoLTE) has been discussed by operators for years. The expectation was that deployments would start in 2013, but roll-outs in North America were delayed.
Operators have faced a series of issues that include poor voice quality and long call establishment times. Once these problems are solved, it is expected that VoLTE will allow operators to provide voice and data services using an integrated packet network. As the problems described show, the implementation of VoLTE presents challenges for the entire LTE ecosystem including microwave backhaul.
We have produced a white paper to describe some of the VoLTE requirements that must be met in order to overcome these technical challenges, which must encompass a flexible microwave backhaul as a key factor for a successful transition to all-packet voice and video VoLTE networks. A brief introduction to VoLTE is presented and then different VoLTE backhaul requirements are described with possible solutions.
Click here to download a white paper on this subject titled “VoLTE and the IP/MPLS Cell Site Evolution”.
Typically, low-latency microwave is used to “replace” traditional-fiber based networks linking financial centers. The business driver for microwave-instead-of-fiber in low latency is the time it takes to transmit trading instructions. With microwave, latency is reduced by a few milliseconds as compared to fiber. Nevertheless, those few milliseconds can translate into a trading edge over rival investors, which means big bucks. Low latency investors will pay a premium for this edge resulting in increased revenue for low-latency microwave network operators.
However, as with most financial functions, low latency is subject to a set of stringent regulations. The scenario is doubly difficult when low-latency microwave networks transmit across international boundaries. This compares to linking financial centers within a single country, which is relatively straightforward from a regulatory perspective because there is only one set of rules. The fact is when connecting financial centers in different nations and the operator’s network has to traverse other countries’ borders, the process becomes orders of magnitude more complex. Download the complete article for a fuller examination of some of these issues and why there should be widespread support for greater international harmonization of microwave regulation.
Competitive licensing of fixed microwave backhaul bandwidth is a bad idea. And it should not go any further. The reasons why are laid bare in a new article in IEEE Spectrum by former electrical engineer and current telecom law firm partner Mitchell Lazarus. In general, he argues against federal spectrum auctions for microwave frequencies, and in particular for fixed microwave links. Undoubtedly, readers are familiar with the large cash bounties governments around the world have netted from competitive bidding on cellular bandwidth—first 3G and now 4G. An inference can be drawn from Lazarus’ article that some governments (i.e., the United States, the United Kingdom) had in mind a similar, if perhaps smaller, revenue enhancement through competitive auctions of microwave channels.
The problem lies in the fallacious thinking that operating fixed point-to-point wireless backhaul bandwidth is comparable to that of mobile spectrum. Whereas mobile spectrum license holders can expect to mostly—if not fully—use the frequencies for which they have paid top dollar, the same has not historically been true of license holders of microwave backhaul bandwidth. In most cases, mobile license holders have a virtual monopoly for their frequencies on a national, or at least regional, basis. Their base stations send and receive cellular phone signals omnidirectionally. They expect throughput from any and all places. So they have paid a premium to make sure no competitors are on their wavelengths causing interference.
On the other hand, U.S. holders of microwave backhaul licenses have specific destinations in mind for the operation of their point-to-point wireless networks. They only need to communicate between proverbial Points A and B. And, historically, they have only sought licenses to operate in their particular bandwidth on a particular route. They had no need to occupy all of their licensed frequency everywhere. That would be a waste. They just have to make sure they have a clear signal for the transmission paths they plan to use. To do that, before licensing, they would collaborate with other microwave users in the vicinity and a frequency-coordination firm to establish an interference-free path plan. Any conceivable network issues would usually be resolved at this stage prior to seeking a license from the Federal Communications Commission. Essentially, the FCC is just a glorified scorekeeper for fixed microwave services, passively maintaining its transmitter location license database.
But starting in 1998, with dollar signs in their eyes, governmental spectrum auctioneers started to sell off microwave frequencies in block licenses. The need for fixed microwave wireless services then was growing and has only grown fiercer with each additional iPhone and iPad that has been activated. However, access device throughput demand on one side of a base station does not necessarily fully translate all the way to the backhaul. Lazarus points out the example of now defunct FiberTower and its failure to make block microwave licenses work economically. After buying national block microwave backhaul licenses at 24 and 39 GHz, Lazarus notes, the firm resold the frequencies to Sprint and a county 911 emergency network operator. But those were the only customers. Lacking a robust enough utilization of its licensed backhaul frequencies, FiberTower had several hundred of its licenses revoked by the FCC and was forced into bankruptcy November 2012.
Subsequent auctions have attracted far fewer bidders and generated much less income for the Treasury Department. Much bandwidth has lain fallow as a result. And infrastructure buildout has stagnated.
Regulators should return the microwave backhaul licensing process to that of letting wireless transmission engineers cooperate informally among themselves, with the help of frequency-coordination firms, to arrive at fixed point-to-point wireless plans in the public interest. These are then submitted only for maintenance by the FCC or other regulators for traditionally nominal license fees—currently $470 per transmitter site for 10 years in the U.S., per Lazarus.
Forget the quixotic quest for chimerical hard currency. The commonweal demands it. You should demand it of the regulators—you can still give input regarding this scheme in some jurisdictions where it is under consideration. Clearly, the most efficient use of spectrum is to make it openly available to all because it means that every scrap of commercially useful spectrum is picked clean. We welcome your comments pro or con.
Germany is well-known for its autobahn highway system, where there are no official speed limits. Now there is a new high-speed network that traverses Western Europe from Frankfurt in Germany to London in the UK.
In addition, you may have read elsewhere in recent weeks about low latency microwave networks being constructed in the United States in support of the financial markets. The busiest route there is between the financial centers in Chicago and New York, where microwave can shave off 5 milliseconds off the transmission time along the 700 mile (1,000 km) route when compared to fastest fiber network (13 milliseconds). This saving directly equates to revenue for trading houses that are able to leverage this speed advantage.
In the United States, planning and deploying a point-to-point (PTP) microwave network is relatively predictable and straightforward: acquire sites and avoid interference from other network operators. Where PTP wireless networks cross state boundaries, a network operator need only deal with the national telecom regulator, the Federal Communications Commission (FCC), when obtaining required licenses to operate the microwave system.
But in Europe, this is a very different matter. While trans-European fiber networks have been a reality for many years, a microwave route like London to Frankfurt must traverse several national borders, forcing operators to deal with multiple regulators, with complex negotiations needed for microwave paths that cross national boundaries. For this reason very few—if any—microwave networks of this type have been built, up until now. However, the opportunities offered by the combination of the new low latency sector, along with the performance advantage of microwave over fiber, have now made the case for these kinds of networks compelling enough to outweigh the challenges, and costs, of planning and implementing them.
For a low-latency microwave network servicing the financial sector on the London-to-Frankfurt route, there are a number of major challenges beyond just identifying and securing suitable sites and coordinating frequencies. The difficulty of planning a long trunk route is also greatly exacerbated by going through the densely urbanized region of Western Europe. This results in a constant iteration between finding the right route, identifying accessible sites, and securing required microwave frequencies. To be successful you need all three—a site on a great route is useless if no microwave spectrum is available. All the while, there are other competing providers all trying to complete the same route in the fastest time possible—not only in latency terms, but also time to revenue.
This poses huge potential pitfalls in having to take the long way around, requiring additional sites and links, if a site is not available. The added latency caused by any such deviation could kill the entire project. This race is like no other in the microwave business—whoever is fastest wins first prize, and it is winner take all in this competition. The potential revenue for the London-to-Frankfurt low-latency path is quite staggering, even on a regular day, but on busy days when the market is volatile the potential can be much higher. Operators can plan on recouping their total investment in the microwave network in well under a year. Then once you have the most direct route, compared to your competitors, your problems may not be over, so it can come down to squeezing those extra few microseconds, or even nanoseconds, out of your equipment.
On this particular route there is also one significant natural barrier to contend with—the English Channel. There are only a few ways across that are short enough to allow a reliable microwave path, space diversity protection is a must and only a few towers are tall enough to support these distances. Even though there are no obstacles over the channel (apart from the occasional container ship), towers need to be high enough to allow the microwave signal to shoot over the bulge of the earth. Again, securing tower space at these sites is critical to success, but also obtaining the right to use one or more of a finite pool of available frequency channels, otherwise fiber may be needed across this stage, adding latency. One group even took the step of purchasing a microwave site in the Low Countries to secure it precisely for this purpose.
London to Frankfurt will only be the start for low latency microwave networks in Europe, as there is always a need and an opportunity to provide competitive transmission services to other financial centers throughout the continent. The winners will be those with the speed and agility to quickly seize these opportunities, along with working with the right microwave partner who can help them with the intensely complex business of planning and deploying these trans-national networks, and who can also supply microwave systems with ultra-low latency performance.
We will have more to say publicly on this topic in the near future. Or if you prefer not to wait that long, we would be more than happy to have a private conversation about low-latency microwave with you.
Microwaves Could Solve Need for Long-Haul, Low-Latency Networks (via slashdot)
While high-speed optical fiber might be the way to go for large national research networks, point-to-point microwave connections have emerged as key links between financial exchanges. The reason? Ultra-low latency. With widespread interest in sending the timeliest data possible, two separate microwave…
A quick Google-glance around the Internet will reveal a panoply of all-outdoor radios (ODRs) in both microwave and millimeter-wave bands. ODRs do not conform to a universal norm in terms of networking features, power consumption, bandwidth scalability (i.e., capacity) or outright radio horsepower (i.e., system gain).
So if you find yourself asking the questions, “Which ODR is the best fit for my network?” or “How do I narrow the ODR field?” it is good to start with the basics.
The right product choice can be quickly resolved—or at least the candidates can be short-listed—by focusing on three ODR product attributes that most heavily influence the value-for-the-money (i.e., total cost of ownership or TCO) equation:
For many microwave backhaul networks, the growth in underlying traffic is such that products which cannot scale to 500 Mbps/1 Gbps per channel will run out of momentum too early and precipitate the dreaded “forklift upgrade” (also known as the “CFO’s nightmare”).
These same CFOs are also suffering sleepless nights due to rising energy costs—which in some countries can double year-over-year. Therefore, it behooves the operator to seek and prioritize the use of über energy-efficient products, such as the Aviat WTM 3200, which—and this is important—do not compromise on RF performance.
That brings me to my last point: System gain (RF performance) remains a core TCO factor insofar as it can drive smaller antenna usage with the concomitant capex savings. Still, there might be little to differentiate ODRs in terms of RF performance—in which case the spotlight will fall on these other attributes to sway the decision.
Having worked on the operator side and wrestled with TCO analysis on many occasions, my experience tells me that you can narrow your ODR choice quickly by reflecting on these three attributes and the TCO gains they can deliver.
Product Marketing Manager
Are you considering building an ultra-low latency microwave network? Then you are not alone. Microwave is quickly becoming the default transport choice for low latency networks. However, building an ultra-low latency microwave network is not simple; there are many considerations. Latency through the “box” is important, but it is not the only factor, and too much focus on this metric may be a distraction. What is most important is end-to-end latency of the link. Aviat Networks recently addressed this topic in a webinar (registration required) and free presentation download and answered three very important questions regarding ultra-low latency microwave technology.
Also in this webinar, Travis Mitchell, Aviat Networks director of low latency business development, and Sergio Licardie, Aviat Networks senior director of systems engineering, consider the best practices for ultra-low latency microwave networks as they explore the techniques, technologies and design approaches necessary to ensure lowest end-to-end latency. They also discuss some innovations to look for in microwave networking to ensure continuous improvement in end-to-end latency performance. Other topics covered include:
One of the great things about the microwave radio market today is the diversity of products available to network operators. But like many situations where there is a glut of options, it tends to put more stress on making the right choice.
An operator looking at products in the microwave radio sector will notice that there are three general categories of product to choose from: all-indoor, split-mount and all-outdoor, and within each, they are myriad different flavors.
All-outdoor radios are the most recent addition to the microwave radio party, and for the sake of easy reference, I’ll refer to them as ODRs (outdoor radios). These self-contained systems incorporate the traffic interfaces, switching/multiplexing elements, radio modem and radio transceiver—all packaged in a weatherproof outdoor housing. By contrast, an outdoor unit (ODU) used in split-mount systems only contains the radio transceiver, which connects to a radio modem embedded in an indoor unit (IDU). In a split-mount radio system, the IDU also provides the traffic interfaces and switching/multiplexing elements.
The rationale for ODRs is straightforward—networks are getting denser, new sites are getting smaller and established sites more densely populated. Space for equipment such as IDUs is at a premium and costs of upgrading sites with bigger equipment shelters is often not viable or possible due to site constraints. As a result, more network devices are being repackaged for deployment outdoors on supporting structures such as towers, walls or masts. Advances in electronics have made microwave radios viable for all-outdoor treatment, so ODRs came into being.
They did so to a fanfare of claims that pointed to fantastic gains in terms of operator TCO (total cost of ownership). No doubt, an ODR can deliver cost benefits, but it is important to fully scope and quantify those benefits, because although ODRs represent simplification in terms of product architecture, most networks have remained stubbornly complex. In practical terms, this means for each type of site in the network an operator needs to closely examine the gains an ODR might generate vs. a split-mount radio, for example. Our experience is that ODRs provide the most operator benefits at sites where:
Once operators consider sites with requirements beyond this scope—usually the majority—then ODRs (somewhat ironically) start to generate complexity and cost. This becomes manifest in the form of multiple Ethernet cable runs, multiple power cable runs, multiple PoE injectors, multiple lightning protection devices and, in some cases, the need for a separate outdoor Ethernet switch.
Even at modestly complex sites, the overhead costs ODRs can generate mean that a split-mount radio will often be a more effective option and deliver better TCO, assuming space can be found. On that note it is worth highlighting that IDUs already deployed at such sites are often modular and can be scaled without consuming any additional rack space, and the most advanced fixed (i.e., non-modular) IDUs only consume a half-rack unit of space.
On the surface, the case for ODRs can seem compelling but before jumping in, I would encourage operators to carefully examine how marketing claims translate into meaningful (real) TCO gains.
I am convinced ODRs represent a new and potentially very useful product category for microwave radio, but they are not a panacea; our experience (at Aviat Networks) is that optimum TCO is based on a mix of split-mount and all-outdoor radios (i.e., one “size” does not fit all).
So there you have it, in the right environment, an ODR can offer a winning formula but in other situations, it may not work so well. An old saying comes to mind: Knowledge is knowing a tomato is a fruit, but wisdom is knowing not to put a tomato in a fruit salad.
Next time, we will examine ODRs in more detail, how they differ and how to choose the best option for your network.
Product Marketing Manager
Recently we’ve kicked off the “Aviat Technology Series” – which are a series of bi-monthly live video streaming webinars for our customers and partners, giving a detailed overview of various technology topics (these are NOT sales pitches…)
Last week, Stuart Little and I gave a live streaming video webinar where we gave an in-depth analysis of all the possible technology options for getting the most out of your microwave system including what’s possible, what’s not, and a realistic look at what you can expect to achieve. We covered the below topics:
• Options for maximizing IP microwave capacity
• Understanding capacity requirements: What’s real and what’s hype
• The timing/availability of new capacity improvement technology
We reviewed techniques for increasing spectrum, improving spectrum utilization and growing effective utilization using higher layer protocol optimizations. Technologies covered included: ling aggregation, co-channel dual polarization (CCDP), adaptive coding and modulation, 512/1024QAM, ethernet header compression, payload compression and asymmetrical RF.
We had lots of great questions and a ton of good feedback. Please email: email@example.com to get the URL for the microwave capacity webinar replay.
Thanks to all who participated and see you in 2 months for the next one when we’ll talk about “Ethernet Protection and Redundancy”
This white paper was extremely popular when we featured it in our eNews newsletter recently. Now it’s time to share it with a wider audience.
It talks about how there are several considerations when establishing realistic outage or reliability objectives for and how the effects of long-term and short-term outages differ when it comes to microwave path engineering.