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 are more expensive initially in terms of capital expenditures, but they’re cheaper to expand and (as electronics are accessible without tower climb) are more easily serviced. While an outdoor radio connects to the antenna with Ethernet or coax cable, indoor radios usually need a more expensive waveguide to carry the RF signal from the radio to the antenna. So you pay more up front with an all-indoor radio but as the radio’s capacity grows you save money. There are several reasons.
When everything related to the radio is indoors, you just have a waveguide and an antenna up on the tower. To add radio channels with an all-indoor radio you go into the cabinet and add an RF unit. With an outdoor radio, you have to climb the tower, which can cost as much as $10,000. Also, when you add a new outdoor RF unit you may have to swap out the antenna for a larger one due to extra losses incurred by having to combine radio channels on tower….(read the full story at RCR Wireless).
Senior Product Marketing Manager
Migrating legacy mobile backhaul networks that were designed for TDM traffic to add support for high-speed Ethernet data for 3G and 4G mobile technologies is one of the biggest challenges for operators worldwide. Each case is unique and poses its own quirks and potential pitfalls. Mobile operators must juggle new technologies, cost pressures and the need to maintain existing services or risk driving customers to the competition.
For Safaricom, the leading mobile operator in Kenya and one of largest in all Africa, the case involved preserving its E1 capacity for voice calls and simultaneously adding Ethernet/IP bandwidth for burgeoning 3G and WiMAX data traffic. As many mobile operators have done in the past, Safaricom built its network over time. Many parts of the network are still legacy 2G TDM technology. However, things are changing rapidly, with 3G subscriber numbers up 85 percent in 2011 year over year.
Many of these subscribers are consuming ever-increasing amounts of data bandwidth. Safaricom’s TDM based backhaul, making use of Ethernet-to-E1 converters, is finding it hard to keep up with demand. To help resolve the situation, the operator called on Aviat Networks, one of its incumbent solution providers. Using its market leading hybrid radio solution, the modular Eclipse microwave networking platform, Aviat Networks enabled Safaricom to add IP data capacity as necessary while keeping E1 capacity for voice calls.
In addition, the stage has been set for Safaricom to make the eventual migration to all-IP backhaul. With the modular Eclipse platform, it can transition on its own schedule. For more information, read the complete Safaricom case study in the frame below or download the PDF:
Aviat Networks has been deploying LTE networks for well over a year now to operators globally, including the largest live commercial LTE network in operation today. So, it’s probably a good time to reflect on some key observations and lessons learned to date. Here are the top 3 things we’ve learned from our LTE microwave backhaul deployments that are most notable:
1. LTE backhaul capacity needs are being easily addressed by packet microwave:
– When it comes to capacity there is a perception that fiber is the only answer. The reality is that based on current LTE deployments, 50Mbps is more than adequate for most LTE cell sites today. Yet, for comfort and long term growth most of our customers are licensing and deploying 100-200Mbps of microwave capacity to their LTE equipped cell sites. For intermediary sites that aggregate traffic, link aggregation techniques are being utilized to effectively bond multiple channels for higher capacities, all well within the multi Gbps reach of advanced microwave systems, such as ours.
2. Ease of deployment and fast time to market (TTM) are critical for success:
– This LTE operator quote speaks volumes regarding the real challenge he faces: “Whoever can deliver the quickest with the least amount of pain will win most of the business”. TTM is most crucial for operators trying to stay one step ahead of their competition… more markets served, better coverage etc. To address this, we have seen a growth in our customers seeking a one stop shop approach for LTE microwave backhaul deployment where we engineer, configure, test, and deploy the full end–to-end system, providing overall project management, frequency coordination, installation and a host of other services. The fact that most microwave systems can be installed in a few weeks as opposed to months for fiber, is also playing a key role in microwave growth in areas like North America where microwave penetration is low, but growing as a result of LTE rollout.
3. Backwards compatibility with multivendor interoperability is key:
– It’s all about LTE, right? Well, yes and no. LTE is driving the new investment and deployments, but the reality is that 2/3G will be around for a long time. So, while the new deployments are driven by all-IP LTE, there are still ‘legacy’ T1/E1s still hanging around that also need to be backhauled. This has been a perfect fit for Aviat’s all-in-one Hybrid (TDM+IP) and All-IP microwave systems, which allow our customers to easily software configure their mix of traffic. So, while the bulk of the transport bandwidth is provisioned for IP to support LTE, some is still reserved for good ‘ole TDM.
– Another related aspect is multivendor interoperability across a variety of product types. The backhaul market has flourished in the last few years as we know, and so has the variety of cell site switches, routers, packet optical devices etc. that our microwave systems interoperate with to fulfill our customers ‘end-to-end’ LTE backhaul solution. Consistent Carrier Ethernet standards applied across both the microwave and fiber core makes this very straightforward when it comes to provisioning Ethernet backhaul services, supporting packet network synchronization, and managing these services.
So, in summary, I would say we’ve learned that packet microwave is well suited for LTE capacity needs; it can be rapidly and easily deployed; and provides great flexibility for legacy services and multi-vendor interoperability. But the best proof of all this is in our customers’ live networks.
Fore more information on LTE microwave backhaul and a customer case study click here.Read More
What is the best migration strategy for utility networks migrating to Smart Grid using Hybrid Radios? We look at the technology choices that are available to support legacy TDM and IP-based services and investigate the many demands placed on utility networks. Demands include seamless migration, increased capacity, security, and interoperability.
We believe a hybrid network is the best solution and we explain why in this white paper:
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
On 9 August 2011, the FCC announced several changes to the rules (Part 101) that govern the use of microwave communications in the Fixed Service bands in the U.S. These changes are great news for operators and will be encouraging increased adoption of microwave technology as a wireless transmission alternative to fiber for next generation mobile networks and fixed/private networks.
New Frequency Band for Fixed Services
The FCC opened 650 MHz of new spectrum for Fixed Service (FS) operators in the 6875-7125 MHz and 12700-13100 MHz bands, which will be shared with the incumbent Fixed and Mobile Broadcast Auxiliary Service (BAS) and Cable TV Relay Service (CARS). These bands will primarily be used as an alternative to the 6 and 11 GHz “Common Carrier” bands in rural areas, where the band is not currently licensed to TV mobile pickup stations used in newsgathering operations.
Frequency allocations in these new bands should commence later this year and will be based upon the existing 25MHz channelization. To facilitate adoption, the FCC is also allowing the use of 5, 8.33 and 12.5 MHz channels, as well as 50 MHz channel operation in the 12700-13100 MHz band using two adjacent 25MHz channels.
Allowing Adaptive Modulation
Adaptive Modulation, or AM—or ACM when used with Adaptive Coding—is a relatively recent innovation in microwave technology that allows the radio to dynamically adapt to path conditions to allow a much higher degree of spectrum efficiency, increased wireless link throughput, use of smaller antennas or a combination of all three benefits.
Up until now, the use of AM was restricted by the requirement to comply with FCC spectrum efficiency rules, which dictate a minimum data rate for certain bands. For example in the 6 GHz band a minimum capacity of 130 Mbit/s, or 3xDS3, must be maintained at all times within a 30 MHz channel assignment, using 64QAM modulation. The FCC now allows AM operation where the capacity of the link may drop below the minimum data rate, as long as the operators “design their paths to be available at modulations compliant with the minimum payload capacity at least 99.95 percent of the time,” or in other words, operators will have to “design their paths to operate in full compliance with the capacity and loading requirements for all but 4.38 hours out of the year.”
Aviat Networks, through our membership of the Fixed Wireless Communications Coalition (FWCC), supported rule changes to permit ACM, and the FCC included in its Rulemaking (Clause 48) our analysis on the benefits of ACM in terms of reducing the costs associated with tower leasing:
By way of hypothetical, consider a single link in the 6 GHz band that would require 10-foot antennas with a 99.999 percent standard instead of 6-foot antennas under the 99.95 percent standard. The total cost increase over a 10-year period in this hypothetical example could exceed $100,000.
The smaller antennas offer a number of advantages over larger ones, including more TCO savings over those 10 years.
Still Under Consideration by the FCC
Of all the new proposals being considered, the FCC also announced a Further Notice of Proposed Rulemaking (FNPRM) to further investigate the following proposals:
Aviat Networks continues to work on these issues, via the FWCC, which we believe will assist operators in lowering their total wireless network operational costs by taking advantage of the newest innovations that are now available in microwave technology.
With these new rules, along with the potential for further changes under consideration, microwave solutions provide an even more compelling case to enable mobile operators in the U.S. to keep pace with the IP mobile backhaul capacity demand driven by the introduction of new 4G wireless/LTE wireless networks.
Regulatory Manager, Aviat Networks
Last year in August, Aviat Networks presented its argument for why fiber optics technology isn’t everything where backhaul of wireless networks is concerned. If anything, this point has only been reinforced by analyses and anecdotal stories showing that fiber can be overkill for the mobile backhaul requirements of LTE wireless. Plus, there is the simple truth that fiber cannot be deployed to every cell site due to financial and topological issues. That’s why microwave technology remains the world’s first choice for backhauling wireless networks. So let’s look at last year’s FierceWireless webinar slide presentation and refresh our memories.
Ovum found that demand for wireless backhaul equipment in North America will continue to grow as mobile operators upgrade their networks to support higher-speed LTE networking technologies. The most common backhaul strategy for mobile operators in the region comprises leasing services over fiber combined with owning and operating microwave-based facilities. Microwave has a distinct advantage vis-a-vis leased services over the long-term due to the opex associated with leasing.
If you would like to see more, you may register for the on-demand replay of the full webinar. It will also present the latest trends and advancements in microwave transmission technology that support the evolution of mobile backhaul networks to all-IP.
The cloud is an all-encompassing thing that’s actually been around for a while (e.g. distributed computing, Network Attached Storage). Most of it exists today in the enterprise but is being pushed to the Internet and rebranded “The Cloud.” This affects three wireless networking segments: consumers (e.g., you, me, mom, dad), Internet providers (e.g., mobile operators, ILECs, CLECs) and wireless solutions vendors (e.g., Symmetricom, Aviat Networks).
For consumers, it represents the ability to store information—pictures, music, movies—virtually and access them wherever we go from devices of our choice. No longer do we have to worry about backing up smartphones, tablets or laptops. The downside is that this magic is going on in the background all while your data caps are being reached. So, watch out….
On the mobile operator side, this will represent a substantial increase in bandwidth used. In addition, bandwidth usage starts to become more symmetrical as more uplink bandwidth is utilized while uploading to the cloud. This also means more frequency consumption on the RAN-side as subscribers stay “on” more often. Operators need to figure how to get users off the air interface as quickly as possible. This calls for greater throughput and potentially much lower latency. Trickling data to end users compounds the air interface problem. For the most part, subscribers won’t realize what’s happening and data caps are more likely to be reached. This translates into either more revenue and/or dissatisfied customers. Clearly, operators must monetize transport more effectively and at the same time provide more bandwidth.
Lastly, for wireless solutions vendors this translates into increased sales of wireless equipment to ease the sharp increase in bandwidth consumption. This also translates into more intelligent and robust network designs (e.g., physical and logical meshes, fine-grained QoS controls) as subscribers rely more on network access for day-to-day activities. As for the cloud in general and the overall effect:
Therefore, the amount of bandwidth consumption will rise dramatically this September when Apple releases iOS 5 and iCloud. Android has already driven much bandwidth demand, but it’s not nearly as “sexy” as what Apple is releasing for its 220 million users—or alternately total iOS devices: iPod touch, iPad, iPhone). It’s more than just bandwidth—it’s quality, reliable bandwidth where QoS and Adaptive Modulation will play significant roles—of this, I’m certain.
At a recent TNMO event they were talking about LTE-Advanced and leveraging the cloud for virtual hard drives. Imagine, no physical hard drive in your computer. Laptops are connected via 4G wireless/5G LTE wireless to a cloud-based hard drive, equating to lots and lots of bandwidth plus stringent latency requirements….
Director of Product and Solutions Marketing, Aviat Networks