If you pay much attention to the mobile backhaul space, you may have noticed a big press launch this week by Ericsson and Cisco for a new partnership between the two tech giants. Both vendors will partner in the mobile backhaul space reselling each other’s solutions.
Analysts inside and outside the backhaul space have been hot to lodge their points of view on this combination. But as in William Shakespeare’s overused quote about “the sound and the fury” it might signify nothing. OK, that’s a bit of an overstatement, but there’s less here than meets the eye.
Don’t let the facts get in the way of a good ‘story’
Let’s take a look at the facts, as commonly understood in the industry. While Cisco is the 800 lb. gorilla in the IP networking room, when it comes to cell site routers it’s less than a 90 lb. weakling for microwave backhaul. Truly, Ericsson ranks high among microwave backhaul vendors, but its IP routers are not top-shelf offerings and leave much to be desired. You may think, well that was the point of the announcement: for Cisco and Ericsson to bolster each other’s relative portfolio failings by teaming up.
However, just as two wrongs do not make a right, a duo of less-than-optimal products cannot have the makings of a No. 1 contender. The shortcomings of both vendors’ kit are still present. Customers do gain the advantage of having one throat to choke, but they will just be choking the same throat twice as often.
Tried-and-tired method of microwave and IP
The underlying tried-and-tired method of using a different microwave radio and IP router in conjunction to solve Layer 3 issues in microwave backhaul still remains: individual devices living separate operational lives. Like a divorced couple staying in the same house, they may talk to each other when they must, but they don’t really like to. So, too, do microwave radios and IP routers have the ability to communicate, but they’re not designed to interact and honestly they’re not very good at it.
Which brings us to the inspiration for the integrated microwave router—the CTR 8000 platform from Aviat Networks. As we’ve made the case before, CTR 8000 microwave routers have been engineered from the ground up to function natively in both the microwave and IP communications worlds. The two technologies function seamlessly within one device. And existing as one piece of gear, a microwave router is easier to deploy and manage in the mobile backhaul network than a pair of randomly cobbled together radio and networking boxes.
In addition, with Aviat’s coded-for-microwave-networking software, ProVision, the leading network management system, admins at Network Operation Centers (NOCs) have full monitoring and management capability. They can see with minimal latency just how effectively microwave and IP activities are being carried out by CTR.
To find out more about the family of CTR 8000 microwave routers, we invite you to see our video that explains the benefits in crystalline detail.
The microwave radio business: a small community in a niche market where everybody tends to know each other. However, if your involvement in the microwave backhaul space goes back any length of time, no doubt you recognize the outside influence that industry analyst firms play within the industry. The analysts at Heavy Reading, Sky Light Research, Infonetics and a handful of others play a prominent role in shaping opinions about microwave radio solutions providers as well as the solutions themselves.
Reports from these analyst research firms remain very important even in a tight-knit place like microwave backhaul. They can make or break the business environment for microwave vendors for months—or years—at a time. For example, Infonetics issued its latest “Microwave Strategies and Vendor Leadership” survey results at the end of June. In this survey, 23 operators—from incumbent to competitive to pure mobile—laid bare their perceptions of not only the dedicated microwave specialist solution providers but also the telecom generalists who dabble in wireless backhaul infrastructure as an afterthought.
What emerged captivates the collective commercial consciousness.
Representing 33 percent of all capital telecom expenditures made worldwide in 2014, the 23 operators polled by Infonetics revealed just what microwave-oriented issues interest them ranked in order from most important to least significant. For 2015, the top five considerations in microwave equipment for the operators in descending order are:
Among all the microwave specialists, Aviat placed first in product reliability, service and support and management solutions. Aviat also placed first in four other categories.
These other categories that also made the list somewhat lower down in Infonetics’ survey have much importance for operators but had their presence muted due to survey methodology, perhaps. For example, solution breadth and technology innovation did not make the top five but without them the operators’ very strong desires for sophisticated and robust microwave solution features such as cross polarization (83 percent rated very important) and high system gain (78 percent rated very important) could not reach fulfillment.
Infonetics did not survey how operators perceive solution providers on specific product features, but objectively Aviat leads not just the microwave only providers but all microwave providers with its extra high power Eclipse IRU 600 EHP +39 dBm radio and across the board support for XPIC (i.e., cross-polarization interference cancellation) on a number of products.
Full disclosure: Aviat also rated número uno for solution breadth and technology innovation among all microwave specialists.
Overall, Aviat Networks was rated No. 1 by Infonetics’ operator survey respondents.Read More
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”.Read More
LTE has been moving more and more to the forefront in mobile cellular networks around the world. Africa, and particularly the Republic of South Africa, is the latest hotbed of LTE rollouts, with the leading country operators of Vodacom, MTN and Cell C coming online since late in 2012. In conjunction with these LTE access rollouts, our technical marketing manager in the region, Mr. Siphiwe Nelwamondo, has been authoring a series of columns on enabling LTE in a leading regional technology media Internet site, ITWeb Africa.
Naturally, his focus has been on backhaul. In the first installment of his series, Mr. Nelwamondo looked closely at the backhaul requirements of LTE. Chief among these requirements are speed, Quality of Service (QoS) and capacity. He concluded that it is too early to close the book on the requisite parameters for supporting LTE backhaul. Part two of the features, he examined the basis on which microwave provides the technical underpinnings for LTE backhaul—especially as related to capacity. More spectrum, better spectral efficiency and more effective throughput were Mr. Nelwamondo’s subpoints to increasing capacity.
Having more spectrum for microwave backhaul is always nice, but it’s a finite resource and other RF-based equipment from satellites to garage door openers is in competition for it. Bettering spectral efficiency may be accomplished by traditional methods such as ACM and might be increased through unproven-in-microwave techniques like MIMO. Throughput improvement has wide claims from the plausible low single digit percentage increases to the more speculative of upping capacity by nearly half-again. Data compression and suppression are discussed. The truth is LTE, while data-intensive, probably will not require drastic measures for backhaul capacity until at least the next stage of LTE-Advanced.
If indeed capacity increases are necessary in the LTE backhaul, number three and the most current piece of Mr. Nelwamondo’s contains additional information. Nothing is better than having something bigger than normal or having many of the standard model. As the analogy applies to LTE microwave backhaul, bigger or wider channels will increase capacity, of course. A larger hose sprays more water. Or if you have two or three or more hoses pumping in parallel that will also support comparatively more water volume. The same is true of multiple microwave channels.
However, the most truly and cost effective capacity hiking approach is proper network planning. Mr. Nelwamondo points out that in Africa—more than some places—mobile operators are involved in transitioning from TDM planning to IP planning. While TDM planning was dependent on finding the peak traffic requirement per link, IP planning allows the flexibility to anticipate a normalized rate of traffic with contingencies to “borrow” capacity from elsewhere in a backhaul ring network that is not currently being utilized. Along with several other IP-related features, this makes determining the capacity a lot more of a gray area. Some operators solve this by simply “over-dimensioning” by providing too much bandwidth for the actual data throughput needed, but most cannot afford to do this.
The fourth and final entry in Mr. Nelwamondo’s series will appear soon on other LTE backhaul considerations of which you may not have thought. Sign up below to be notified when it is available. [contact-form-7 404 "Not Found"]
Small cells get all the press! As LTE rolls out in networks on every continent except Antarctica, small cells are grabbing headlines in technology trades and geek fan-boy blogs across the Internet. They’ll be needed sooner or later to provide LTE access in all those places around corners of buildings on business campuses, in urban parks surrounded by concrete canyons and other inaccessible locations. But little or only passing thought is paid to the ways in which small cell traffic will be aggregated back to the main network.
However, in a new FierceWireless ebook, microwave backhaul is pointed out as one of the critical strategies to provide throughput for all the small cell traffic to come. Microwave was here before small cell. And it’s such a good fit for small cell, if it had not already existed, we’d have to invent it now! Our director of product marketing, Stuart Little, tells FierceWireless that microwave meets the capacity needs of LTE backhaul. And Fierce adds modern microwave technology is changing the perceptions of its use for small cell backhaul.
Neither sleet nor rain nor changing K factors at night will stop microwave from small cell service. Specifically, Little tells Fierce that rain has little to no effect on microwave at the lower frequencies, and where it does have some effect in the higher bands, different technical techniques can help mitigate it. To find out more about small cell microwave backhaul, we recommend any of the Aviat blogs and related articles below. Or just read the FierceWireless ebook.
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.
1. What is QAM?
Modulation is a data transmission technique that transmits a message signal inside another higher frequency carrier by altering the carrier to look more like the message. Quadrature Amplitude Modulation (QAM) is a form of modulation that uses two carriers—offset in phase by 90 degrees—and varying symbol rates (i.e., transmitted bits per symbol) to increase throughput. The table in this blog post (Figure 1) describes the various common modulation levels, associated bits/symbol and incremental capacity improvement above the next lower modulation step.
2. Must all operators who use microwave backhaul use higher-order QAMs?
Higher-order QAMs are not necessarily a must-have for all network operators. However, higher-order modulations do provide one method of obtaining higher data throughput and are a useful tool for meeting LTE backhaul capacity requirements.
3. What is the main advantage of using higher-order QAMs with microwave radios?
The main advantage is increased capacity, or higher throughput. However, capacity improvement diminishes with every higher modulation step (i.e., moving from 1024QAM to 2048QAM the improvement is only about 10 percent!), so the real capability of higher-order modulations alone to address the objective of increasing capacity is very limited. Other techniques will be needed.
4. What are the tradeoffs of higher-order QAMs on RF performance?
First, with each step increase in QAM the RF performance of the microwave radio is degraded as per the Carrier-to-Interference (C/I) ratio. For example, going from 1024QAM to 2048QAM will produce an increase of 5 dB in C/I (Figure 2). This results in the microwave link having much higher sensitivity to interference, making it more difficult to coordinate links and reducing link density. Along with this increase in phase noise there will be an increase in design complexity cost.
Also, by increasing from 1024QAM to 2048QAM, system gain will decrease from above 80 dB to just above 75 dB (Figure 2). With much lower system gain microwave links will have to be shorter and larger antennas will have to be employed—increasing total cost of ownership and introducing additional link design and path planning problems.
All of the above are the results of linear functions: they degrade in a one-to-one relationship with the move to higher-order QAMs. Meanwhile, the capacity increases derived from higher-order QAMs are the function of a flattening curve: Each step increase in QAM results in a reduced percentage increase in capacity compared to prior increases in QAM. The added capacity benefits are diminished when considering the added costs of higher C/I and lower system gain.
5. Do you need to use Adaptive Coding and Modulation (ACM) while using higher-order QAMs?
ACM should be implemented while employing high-order QAMs to offset lower system gain. However, while ACM does help mitigate the effects of more difficult propagation when using higher-order modulations, it cannot help offset increased C/I.
6. What gives Aviat Networks a “heads-up” here when other big name companies seem to be supporting the technology?
Aviat Networks realizes higher-order modulations are not a panacea—a cure-all. While every minor technology improvement in throughput can help, a focus on technologies that grow capacity in hundreds of percentage points vs. tens of percentage points is most critical now. Aviat believes that these hundreds-of-percentage-points-of-improvement-in-capacity solutions will be the most important moving forward. It is in these technologies that Aviat has a “heads-up.” Such techniques include deploying more spectrum—particularly in the form of multichannel RF bonding (N+0) solutions—to achieve a minimum of 200 percent capacity increase. This technique is subject to frequency availability, but with flexible N+0 implementations (such as being able to use frequency channels in different bands and different channel sizes) many congestion issues can be avoided.
Second, intelligently dimensioning the backhaul network based on proven rules, best practices and L2/L3 quality of service (QoS) capabilities is another technique to provide potentially very large gains in backhaul capacity. Higher-order modulations can be one tool to achieve required capacity increases in the backhaul network. However, their inherent drawbacks should be well understood, while the most attention should be paid to other techniques that deliver more meaningful and quantifiable benefits.
7. Will operators need to “retrofit” microwave radios to be capable of higher-order QAM operation in their existing microwave infrastructure? Or will completely new hardware be required?
This depends on the age and model of the existing radios. Older microwave systems will likely need to be “retrofitted” to support 512QAM and higher modulations. Recently installed microwave systems should be able to support these technologies without new hardware.
8. How will QAM evolve in the future? Is the introduction of higher-order QAMs an indefinite process, with no end in sight?
The introduction of higher-order QAMs is not an endless process. As per Figure 1 above in this blog post, the law of diminishing returns applies: Throughput percentage improvement declines as modulation rates increase. The cost and complexity of implementing higher-order QAMs probably is not worth the capacity increase benefits derived—not past 1024QAM, in any event.
Director, Marketing and Communications
A different solution to handle the burgeoning demand for mobile broadband capacity will be needed. More spectrum coupled with more spectral efficiency will not be sufficient. A clear solution is more sites, but deploying more macro-sites in urban and dense urban areas (where most of the traffic will be needed) will not be feasible.
Small cells promise a new “underlay” of outdoor and indoor, low power micro-cells that are deployed on public and private infrastructure within the urban clutter, are seen as seen as a likely solution. Sites being considered include:
These new sites will need to be compact, simple to install, energy efficient and incorporate an organically scalable and tightly integrated backhaul solution. As a result, there will be many more sites—some projections estimate that up to 10 small cells will be deployed for every macro-site. Small cells hold out the promise of great gains for the end users but massive challenges for the operators.
Small cell deployments so far have mainly been concentrated in Europe (3G) and the USA (LTE). 3G small cells may also be deployed in other regions as a means to avoid the difficulties in obtaining planning approval for larger macro-cell sites.
It’s Still Early
Today, as far as wireless small cell backhaul (SCBH) solutions are concerned, there is evidence of product immaturity and hyperactivity in equal measure.
There is profusion of aggressively hyped solutions, including many that are a rehashing existing/niche solutions and at the opposite extreme some very new and unproven technologies. In practice, these solutions are jockeying for position while operators grapple to understand the formidable planning and infrastructure challenges being thrown up by their small cell ambitions. It is apparent that few appear that they will fully satisfy the anticipated and emerging requirements in terms of performance (i.e., capacity, latency, availability), size/shape, ease of deployment and most importantly, total cost of ownership. For the complete article, download the PDF.
Stuart D. Little
Director, Product Marketing