June 15, 2012
Throughout Africa a wind of change is blowing as mobile network operators ponder, and in many cases implement, a wave of network modernization. The trigger for this is multi-faceted. Booming subscriber growth, introduction of new data services and arrival of new undersea fiber optic cable links are combining to strain existing network infrastructure to the breaking point.
Booming Mobile Subscriber Growth
According to the GSMA , as of September 2011 Africa has overtaken Latin America with 620m mobile connections, making it the second largest mobile market in the world after Asia-Pacific. The number of connections has more than doubled over the past four years, with growth expected to continue at the fastest rate of all global regions over the next four years.
First Voice, Now Increasingly Data
Most networks across Africa were built many years ago to serve the initial rollout of 2G/GSM mobile networks that were designed to provide basic voice services. Many operators have since introduced data services using EDGE, 3G WCDMA, and, more recently 3G HSPA, putting an incredible strain on these networks. These data services can be vital for the operator, as they are often supporting premium, prepaid subscribers or new fixed line data services being offered for small and medium-size businesses.
One example of network modernization in action is in East Africa, where a mobile network operator saw subscriber numbers increase 9 percent in 2011, with 3G customers increasing more than 85 percent. This operator was also offering fixed data services to private and corporate customers through the deployment of WiMAX base stations collocated with the existing mobile sites. All this new data traffic was growing exponentially and fast outstripping the legacy backhaul network capacity. The operator also had to ensure that existing voice traffic was protected.
Priorities Driving Network Upgrades
Today, several priorities are driving network operators to upgrade their networks including the need for:
These five priorities are closely interrelated. For more details, download the complete article.
Stuart D. Little
Director Corporate Marketing
June 12, 2012
Link between Honduras and Belize Crosses Water and Land
Last year I wrote about the world’s longest all-IP microwave link, stretching 193 km over the Atlantic Ocean in Honduras. Aviat Networks and Telecomunicaciones y Sistemas S.A. (TELSSA) designed and implemented this link together. This year, Aviat Networks and TELSSA again worked together to build another link and achieve another record—an Eclipse microwave link between Honduras and Belize that crosses 75 km of the Atlantic Ocean and 105 km of rugged terrain for a total path length of 180 km. This is a new world record for a hybrid diversity microwave link!
After the success of implementing the 193km link over water, Aviat Networks and TELSSA were eager to meet the challenge to connect Honduras and the neighboring nation of Belize using a single microwave link. Aviat Networks network engineers and TELSSA engineers were able to use their extensive knowledge of local propagation conditions, thorough understanding of long path design principles and precise installation practices to successfully implement this 180km microwave link.
Long Path Design Considerations
As outlined in the article last year for the longest all-IP hop, a deep understanding of path design considerations and experience in microwave transmission path design are necessary to successfully complete a long path design. Key considerations involved:
To read more about this world-record Hybrid Diversity IP microwave link, download the full article.
Senior Network Engineer
May 29, 2012
There’s a new arms race in the microwave industry, and it’s over who can claim support for the highest QAM level. Now two vendors are out in the market fighting it out over who had 2048QAM first, yet go back a little more than 12 months and 512 or 1024QAM had barely hit the market. We even are seeing mentions of 4096QAM in some conference presentations. We here at Aviat Networks view these advances as a good thing for our industry, but this heavy marketing of 2048QAM does no one any favors, as it focuses purely on only one aspect of high modulations—capacity—and ignores several other aspects that need to be understood, namely:
So as with most things that are presented as a cureall, higher order modulations are a useful tool to help operators address their growing backhaul capacity needs, but the catch is in the fine print. Operators will need to look at all the tools at their disposal, of which 1024/2048QAM is a useful option, albeit one that will require very careful planning and strategic deployment. In general, operators need practical solutions for capacity increases, as detailed in “Improving Microwave Capacity“. In fact, speaking of practicalities, the real challenges with LTE backhaul has very little to do with capacity…as detailed by this article. For the complete “Modulations Arms Race” article, click here.
Director, Corporate Marketing
May 25, 2012
Five-nines (99.999 percent) availability is a concept that is familiar in wireless engineering. Dick Laine, principal engineer of Aviat Networks, compares five-nines availability to 78-rpm records in our most recent episode of the Radio Head Technology Series.
As he relates, even with scratches and pops, a 78-rpm record still is able to transfer aural information so that you can hear it, i.e., its availability is intact, as it does not drop performance. Scratches and pops only represent degradation in the quality of communication. But when the record is broken, an outage occurs—no record, no communication.
The same goes for wireless communication systems. If a microwave link drops 315 or fewer seconds of microwave communications per year (in increments of up to 10 seconds at a time), it is maintaining five-nines availability. The microwave link is offering 99.999 percent availability for wireless backhaul. Only if the microwave link is unavailable for more than 10 seconds has an outage occurred, for the purposes of determining if microwave communications traffic has been dropped.
Dick goes on to explain about what happened in 1949 when 78-rpm records were superseded by 45-rpm records. Dick got a sneak peek at the top-secret 45-rpm record project when he visited the legendary RCA facility in Camden, New Jersey, which played a crucial role in the development of the modern music, radio and television businesses. Unfortunately, unlike a five-nines microwave link, 78-rpm and 45-rpm records are mostly unavailable nowadays.
May 22, 2012
UTC Telecom 2012 is the annual show of the utilities industry in North America. New technologies and products were displayed to help the industry with its latest challenges. Also various utilities shared their experiences in implementing new networks to deliver leading edge smart grid capabilities.
The show was extremely well attended with a myriad of vendors including many consulting firms. The key message that I took away was the need for utilities to work very closely with their equipment vendors—especially wireless backhaul solution providers—and consultants to implement next generation networks capable of handling the multitude of applications associated with smart grid.
It was interesting to hear from AltaLink about the findings from its extensive lab testing and network implementation:
BC Hydro talked to the two critical issues it is struggling with: end-to-end management and security across the entire network. Balance the needs/wants of the IT dept., the communications dept. and various internal administrative groups is a real task! Some people think that only the commercial mobile networks must deal with overzealous users demanding unlimited bandwidth to address their video/gaming/voice applications…what happens when all the utilities’ departments find out that there is bandwidth available?!
Aviat Networks’ Eclipse Packet Node radios and skilled network engineers can help you find the right solution for your smart grid implementation. Whether your utility is just starting to look at the issues or ready to buy the critical components of the network, Aviat Networks is able to help.
Director of Business Development
April 20, 2012
Transmission engineering of a microwave link requires creativity and skill. So if you are looking for inspiration as well as high-quality wireless engineering instruction look no further than the “Radio Head Technology Series.” Radio Heads is a collection of videos and podcasts featuring our very own Dick Laine. Dick is arguably the most experienced microwave engineer in the wireless communication business, having spent more than 50 years working with microwave radio from its inception—here at Aviat Networks and our predecessor companies (e.g., Farinon, Harris MCD).
Dick has been involved with nearly every aspect of RF transmission, microwave link and network transmission design, and the effects of geoclimatic conditions on transmission of voice and now IP radio data packets.
In his own unique style, Dick has been teaching basic and advanced concepts for digital microwave transmission in seminars and training classes worldwide. Students who have taken his classes return years later eager to get a refresher from Dick and to hear about some of his great adventures in Asia, the Middle East, Africa and in the Americas.
In the first Radio Heads video titled “Check List for a Successful Microwave Link,” Dick explains the four key objectives or requirements for a well-done microwave link design along with “check list” items that the project manager or transmission engineer evaluates for proper design and deployment of a digital microwave link. If you have not already signed up for this video series, register to view the content.
If you find this video of value, please pass along the information to your friends and colleagues via Facebook, Twitter, LinkedIn or your other favorite social media network.
April 13, 2012
As we blogged last summer, the FCC has released 650 MHz of new wireless technology spectrum for Fixed Service wireless communication technology operators. Now Comsearch, a leading provider of spectrum management and wireless engineering services in the US, has highlighted this issue in its latest online newsletter, with an article that includes some very informative coverage maps showing the zones where the new bandwidth is available.
These maps are excellent at conveying the limitations of the newly released spectrum for microwave link applications in the 7 GHz (6.875–7.125) and 13 GHz (12.7–13.1) bands. After taking into account the zones that are reserved for existing Fixed and Mobile Broadcast Auxiliary Service (BAS) and the Cable TV Relay Service (CARS) users, these new bands are only available in about 50 percent of the US land mass covering only 10 percent of the population.
What do you think? Should the FCC loosen the spectrum sharing rules even more for 7GHz and 13GHz bands? Take our poll and tell us:
March 23, 2012
Last autumn we wrote about potential plans from a microwave competitor regarding using asymmetric band plans for point to point microwave communication links. To update this topic, we have put 10 things in parentheses that you should know about the current status of asymmetrical links in wireless backhaul. Last month at an Electronic Communications Committee SE19 (Spectrum Engineering) meeting this microwave technology subject was discussed again. (1) The proposal under consideration has been reduced in scope and (2) the regulators present still wish to see more evidence regarding the need for change before agreeing to such significant amendments.
Asymmetric Band Plan Altered
A quick reminder of what was originally requested back in the autumn of 2011; a move from channel sizes of 7, 14, 28 and 56MHz to channel sizes of 7, 14, 21, 28, 35, 42, 49 and 56MHz in order to support different granularities of channel widths in all bands from L6GHz to 42GHz. However in March these proposals were altered to reflect channel sizes of 7, 14, 28 and 56MHz (i.e., no change to existing channel sizes) and asymmetric only in the 18GHz band and above.
The national regulatory authorities stated that even the (3) revised proposal cannot be accommodated with existing planning tools so they cannot imagine asymmetric links being deployed alongside existing links in their countries. A few stated that in block allocated spectrum the owner of the spectrum may be able to implement this channelization, but Aviat Networks believes that (4) the complexity of coordinating links even in block allocated spectrum should not be underestimated.
Traditionally, links are planned on an equal bandwidth basis, e.g., 28MHz + 28MHz, with a constant T/R spacing throughout the band in question. This new proposal would see links of 28MHz + 7MHz and furthermore makes the claim that spectrum would be saved. Numerically speaking this arrangement would save 21MHz for each pair, but (5) saved spectrum is only of value if it is reused. In many cases the “saved” spectrum would be orphaned due to difficulties coordinating it into usable pairs.
Asymmetric Channel Plan Limits Future
In our last blog on this topic we reflected on the fact that while there is some level of asymmetry today, (6) this trend may well be balanced in the near future by cloud services and other services that involve the user uploading content. We believe that (7) committing to an asymmetric channel plan now limits the future. (8) Symmetric channel planning allows networks to dynamically adjust to changing demands. A related concern is the fact that (9) spectrum once reallocated may not be easily clawed back to create symmetric pairs in the future. While some applications are experiencing asymmetry in traffic presently, we should not forget that some traffic patterns are still symmetric and where asymmetry is a feature, (10) the scale of this phenomenon may be overstated. Indeed, a major European operator present at the SE19 meeting voiced skepticism about the need for asymmetric support.
What do you think? Will mobile traffic remain or increasingly become asymmetric? Are asymmetric microwave links needed or can they be practically deployed in existing bands? Answer our poll below and tell us. Select all answers that apply.
March 8, 2012
Recently the U.S. Congress requested information from the FCC regarding the usage of the 11, 18 and 23GHz microwave point to point bands. This move is seen by many industry watchers as the first step in preparing these bands for auctioning.
Auctioning spectrum is seen by many in the political establishment as a good way of raising large sums of money. The 3G auctions in Europe raised $30 billion in the U.K. and $45 billion in Germany and although these figures will probably never be reached again, the attraction for governments trying to balance the books in an economic downturn is clear to see. However, these figures were for cellular access spectrum and there is evidence of microwave spectrum auctions being priced too high for operators and no bids being received, e.g. the original 28GHz auction in the U.K during 2000-2002. But even if the bidding process itself is successful, is granting large amounts of spectrum to a single operator the right way to allocate microwave spectrum?
Let’s look a little deeper into how microwave spectrum is used and allocated in most cases today in licensed common carrier frequency bands. An operator wanting to install a microwave link between points A and B would seek to obtain an individual license for that link in that specific location and frequency. This allows others to apply for other frequencies or even the same frequency in different locations. This approach maximizes use of the available spectrum.
Now let’s look at the block licensing approach. Here a block of spectrum (either on a national or regional basis) is allocated to one user. Block allocations on a regional basis make sense for multipoint applications like fixed wireless access or mobile network applications. However, in the case of point to point (PTP) allocation a block license holder may not have requirements for that entire spectrum, but because it is now their spectrum, no one else can gain access, often resulting in under utilization. This is the situation currently with the 38GHz band in the U.S. and is leading to some in the industry to push for the availability of additional spectrum.
Another example of this is the 28GHz LMDS band, where service take up has been very low, but has effectively blocked out this band from other uses/users. Another concern for the block licensing approach and one that affects equipment vendors is that with fewer operators there are fewer equipment contracts thus leading some manufacturers to be “frozen” out of the market. This will ultimately reduce choice for all and reduce innovation and competition.
Referring back to the announcement, it makes no mention of what would happen to the holders of existing link licenses who will have engineered their networks based upon the current rules. What would happen to these links should that band now be auctioned off as a block? Spectrum auctions also break the U.S. into many smaller regions, with each regional block license being auctioned to the highest bidder. This leads to the question of demarcation and coordination between adjacent regions, particularly for links that may need cross-regional boundaries.
All in all, it would appear that based on evidence to date, auctioning FCC Common Carrier microwave spectrum will be tremendously complicated and likely not in the long term interests of the industry.
December 6, 2011
Some leading telecommunications carriers are quietly effecting a shift in design priorities. For microwave radio, for example, output power, receive threshold, system gain and various other performance parameters (the dBs) have always been important product differentiators. Equipment vendors have also strived to make their equipment ever smaller to fulfil a requirement to pack more capacity into less rack space. There is, however, what appears to be a shift in some quarters.
British Telecom (BT), Verizon and AT&T are among those passionate about reducing their energy consumption and, hence, their carbon emissions. Environmentally aware operators that have set themselves the challenge of reducing their overall energy usage are facing the challenge of doing so at a time when there is an exponential increase in demand for their services. The frequency with which the kWh is referred to by operators increases with each passing year.
BT was an early mover and has already reduced its UK carbon emissions by 60% since 1997 and reduced its energy consumption by 2.5% year-on-year, as reported Spring 2011. BT has set an incredibly ambitious target of cutting its carbon footprint by 80% between 1997 and 2020. How are they doing this at a time of growth? Well, BT has reported that their new 21st century data centers use 60-70% less energy and the resulting financial savings have made the centers profitable within 18 months. BT estimates that an incredible 50% of the energy consumed by a typical data centre can be consumed by cooling. By introducing fresh air cooling they have reduced this requirement by 85%, as much of the year no refrigeration is required.
Among other measures, BT has focused on energy efficiency of network equipment and also increased efficiency by supplying DC power directly to equipment rather than sustaining significant losses associated with converting AC power to DC. This is an incredibly inspiring record. BT is genuinely committed to its environmental policy believing that it has a responsibility to reduce power consumption, as one of the UK’s top ten energy users. There is certainly a compelling business case for their policy too as they have seen substantial savings and also a significant increase in the volume of business that requires environmental reporting. BT estimates that its UK business alone saved £35M or $54M for the year 2010/2011 over where their energy usage would have stood without the efficiencies introduced by their energy program.
Verizon has emerged as a key North American player and, witnessing what they considered to be apathy with regard to standardization, the Verizon NEBS group released an energy efficiency standard (VZ.TPR.9205) in 2008. NEBS had been traditionally focused on EMC (electromagnetic compatibility) and physical protection requirements such as survival over temperature and earthquake resistance. Energy efficiency became, therefore, an unexpected but vital third strand of NEBS for Verizon. Since then, energy efficiency and related topics have become key at the Verizon-hosted annual NEBS conferences. Verizon has launched a carbon intensity metric which measures Verizon’s carbon intensity by factoring the amount of CO2 produced per Terabyte of data. Year-on-year, Verizon achieved a 15.75% reduction 2009/2010. Verizon’s projections show a forecasted financial saving of around $22M for 2011. Equipment cooling is recognized by Verizon and AT&T as a big factor in energy consumption too but their method of managing this varies.
At this year’s NEBS conference both AT&T and Verizon made announcements that will affect the way that some vendors design their equipment. AT&T announced that from 1st January 2012 they will mandate equipment with airflow that flows front to back within the rack. This move is related to the fact that AT&T has established ‘hot aisles’ and ‘cool aisles’ within its centers. The aisle facing the front of the rack is the cool aisle and the equipment draws air from this aisle, exhausting it into the hot aisle. This allows for the hot air to be efficiently extracted from the center, resulting in significant reductions in the energy consumed by the HVAC system. Verizon also announced that it would be mandating front-to-back airflow in the future. They are seeking to include this as a requirement within GR-63-CORE as this Telcordia standard currently states front-to-back airflow as an objective only. Verizon’s motive for seeking this change to GR-63-CORE is the fact that they also have a hot aisle/cool aisle system. Verizon is also hoping to have the core NEBS standards updated to include energy efficiency requirements. If successful this will mean that NEBS certification, whether it is for equipment intended for Verizon or not, will need to meet a minimum efficiency specification and have front-to-back cooling. Another shift is that efficiency of equipment cooling is starting to be regarded ahead of equipment size by some operators. A slightly larger mechanical enclosure is easier to cool, using less energy. All of these shifts seem to suggest that environmental performance is taking its place alongside other parameters as a key consideration for some operators.
Aviat Networks’ Eclipse product line meets the Verizon energy efficiency standard and additional energy efficiencies are being built into future products. Aviat Networks is committed to working closely with customers, vendors and standards agencies to both understand and promote the requirement for environmental sustainability within the telecoms sector at a time when it is challenged with an explosion in demand.
BT’s sustainability report, 2011
More information on Verizon’s environmental sustainability
Footnote – NEBS (Network Equipment Building Systems).
Product Compliance Manager
November 30, 2011
Aviat Networks is working hard to reduce the landfill associated with its business activities and products and this includes ensuring that, where recycling facilities exist, customer units that have been damaged beyond repair are recycled. For example, every unit that is scrapped at Aviat’s Hamilton repair and return centre is segregated and sent to a recycling centre called Datec in Kilwinning, Scotland. Datec was chosen because it is the closest authorised treatment facility and this actively reduces the carbon emissions associated with the transportation of the scrapped units. They complete some manual disassembly of the units to recover the mechanics of the unit and the electrical boards are shredded. These shredded boards are then shipped to SiPi Metals in Chicago, United States. This level of processing ensures the highest possible recovery rate.
SiPi Metals specialises in recovering precious metals from electrical boards and these precious metals then obviously go on to live yet another life.
Recently, Aviat was provided with a detailed report showing the percentage by weight that is recycled. The average percentage across eleven shipments to Datec is 98.7%.
So the answer is that your microwave link is very recyclable indeed!
Better still, Datec has just started a new initiative that will offset the carbon emissions associated with any transportation involved in the recycling process. Aviat Networks is moving forward with carbon offsetting for all shipments to Datec and SiPi Metals. Datec’s carbon offsetting involves planting oak, birch, ash, willow and rowan trees in Scotland in recognition of the fact that Scotland has been heavily deforested and now has only 17% woodland coverage, compared with an average of 32% in mainland Europe. Their fledgling woodland is in a beautiful location in Highland Perthshire. Aviat Networks may attend a future tree planting event – by train, of course!
Recycling these scrap units ensures that less is sent to landfill, brings materials back into the supply chain for re-use and gives Aviat’s customers the assurance of an environmentally sound end-of-life for these units. Aviat Networks recognizes that the packaging that the unit arrives in is also important to reducing landfill. The Aviat ODU 600 Outdoor Unit ships to customers in a completely recyclable box. Aviat Networks is currently working on releasing other environmentally sustainable product packs to reduce landfill in all 150 countries where we have customers.
Product Compliance Manager
September 22, 2011
Our partner, Symmetricom, recently announced the launching of a new segment of their SyncWorld ecosystem for microwave backhaul. Our hat’s off to them; this is great news for Symmetricom and the new players that are now on board. We boarded this train awhile back. After a couple years of collaborative testing between us, we first joined the ecosystem when it was initially launched in March at CTIA 2011.
So, what have we learned since then you might ask?
Well for one, packet based timing is still growing in interest, evaluation, and deployment. Customers around the world — including mobile operators, state and utility providers and others – are increasingly looking for timing solutions that operate over their Ethernet fiber and microwave network as effectively as their TDM timing solutions do. A recent Heavy Reading analyst report projects close to 2 million cell sites will have deployed the two most dominant solutions, IEEE 1588v2 and Synchronous Ethernet (SyncE), by 2015.
Secondly, we’ve learned this is by no means the technology race it started out to be. Remember when Blu-ray and HD–DVD were competing a few years ago? Or perhaps that has well faded into memory. Well, I still recall the industry buzz a couple years ago about whether Synchronous Ethernet (SyncE) was going to kill IEEE 1588v2, or vice-versa. Who was going to come out on top?
Telecom watchers and players are always primed for a tech battle it seems. Well lo and behold; this battle has become more of an alliance, as of late.
The dominant discussion today is now about how BOTH these technologies can co-exist, and where best to deploy them in a network, either side by side or in parallel, with one backing up the other. Hmmm, now that’s an interesting conclusion to a tech battle.
Case in point, a couple of our customers are planning to deploy both technologies to take advantage of their respective strengths and are in the process of doing just this. See this whitepaper for more information about synchronization over microwave backhaul or maybe this one for insight into deploying IEEE1588v2 synchronization.
So, with the reality today that packet timing is still growing and that options for packet timing (including TDM, 1588v2, SyncE, and GPS) will continue to co-exist for a long time, it becomes even more critical to seek experience when it comes to planning your sync migration.
An ecosystem is probably a good place to start, especially with those players that have been at it for some time.
Sr. Manager, Solutions Marketing