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FCC OK’s First Unlicensed LTE in 5 GHz

24 Feb

The Federal Communications Commission this morning announced that it had “just authorized the first LTE-U—LTE for unlicensed—devices in the 5 GHz band.” This was according to a tweet from @FCC on Twitter, and soon after, a rare blog post from Julius Knapp, chief of the FCC Office of Engineering & Technology.

“This action follows a collaborative industry process to ensure co-existence of LTE-U with Wi-Fi and other unlicensed devices operating in the 5 GHz band,” Knapp wrote.

(Addendum: Please note that after publication of this article, TV Technology was apprised of T-Mobile’s intention to launch LTE-U later this year: “T-Mobile Tees Up LTE-U for Spring Deployment,”  Feb. 23, 2017 )

There was no specific public notice on the action, but rather a couple of equipment modification grants for Ericsson and Nokia. The Nokia grant covered its FW2R LTE module, a 2×2 MIMO transmitter operating in the 5,160 to 5,240 MHz band at 0.581 watts maximum combined conducted output power; and at 5,745 to 5,825 MHz at 0.583 watts output—in both 20 and 40 MHz BW modes.

Nokia received a limited single-modular approval (click image at right for .pdf version) subject to a number of conditions, including that it the FW2R cannot be marketed to third parties or the general public. The antenna also must be installed to provide a “separation distance of at least 20 centimeters” from people and not be co-located or operating with another antenna or transmitter outside of the scope of the modification.

The Ericsson grant, below at right, covered its BS 6402 MIMO LTE base station, pictured above, in the 5,150-5,170 MHz and 5,170 to 5, 250 MHz bands at 0.119 watts output, for indoor operations only. A third set of frequencies, 5,735 to 5,845 MHz was approved at 0.112 watts output.

In addition to the tweet and the blog post, the grants were ballyhooed in a statement from FCC Chairman Ajit Pai:

“LTE-U allows wireless providers to deliver mobile data traffic using unlicensed spectrum while sharing the road, so to speak, with Wi-Fi,” he said. “…voluntary industry testing has demonstrated that both these devices and Wi-Fi operations can co-exist in the 5 GHz band. This heralds a technical breakthrough in the many shared uses of this spectrum.”
















A total of 192 telcos are deploying advanced LTE technologies

15 Aug

A total of 521 operators have commercially launched LTE, LTE-Advanced or LTE-Advanced Pro networks in 170 countries, according to a recent report focused on the state of LTE network reach released by the Global mobile Suppliers Association.

In 2015, 74 mobile operators globally launched 4G LTE networks, GSA said. Bermuda, Gibraltar, Jamaica, Liberia, Myanmar, Samoa and Sudan are amongst the latest countries to launch 4G LTE technology.

The report also reveals that 738 operators are currently investing in LTE networks across 194 countries. This figure comprises 708 firm network deployment commitments in 188 countries – of which 521 networks have launched – and 30 precommitment trials in another 6 countries.

According to the GSA, active LTE network deployments will reach 560 by the end of this year.

A total of 192 telcos, which currently offer standard LTE services, are deploying LTE-A or LTE-A Pro technologies in 84 countries, of which 147 operators have commercially launched superfast LTE-A or LTE-A Pro wireless broadband services in 69 countries.

“LTE-Advanced is mainstream. Over 100 LTE-Advanced networks today are compatible with Category 6 (151-300 Mbps downlink) smartphones and other user devices. The number of Category 9 capable networks (301-450 Mbps) is significant and expanding. Category 11 systems (up to 600 Mbps) are commercially launched, leading the way to Gigabit service being introduced by year-end,” GSA Research VP Alan Hadden said.

The GSA study also showed that the 1800 MHz band continues to be the most widely used spectrum for LTE deployments. This frequency is used in 246 commercial LTE deployments in 110 countries, representing 47% of total LTE deployments. The next most popular band for LTE systems is 2.6 GHz, which is used in 121 networks. Also, the 800 MHz band is being used by 119 LTE operators.

A total of 146 operators are currently investing in Voice over LTE deployments, trials or studies in 68 countries, according to the study. GSA forecasts there will be over 100 LTE network operators offering VoLTE service by the end of this year.

Unlicensed spectrum technologies boost global indoor small cell market

In related news, a recent study by ABI Research forecasts that the global indoor small cell market will reach revenue of $1.8 billion in 2021, manly fueled by increasing support for unlicensed spectrum technologies, including LTE-License Assisted Access and Wi-Fi.

The research firm predicts support for LTE-based and Wi-Fi technologies using unlicensed spectrum within small cell equipment will expand to comprise 51% of total annual shipments by 2021 at a compound annual growth rate of 47%

“Unlicensed LTE (LTE-U) had a rough start, meeting negative and skeptic reactions to its possible conflict with Wi-Fi operations in the 5 GHz bands. But the ongoing standardization and coexistence efforts increased the support in the technology ecosystem,” said Ahmed Ali, senior analyst at ABI Research.

“The dynamic and diverse nature of indoor venues calls for an all-inclusive small cell network that intelligently adapts to different user requirements,” the analyst added. “Support for multioperation features like 3G/4G and Wi-Fi/LAA access is necessary for the enterprise market.”

LTE network

The Return of the Small Cell

10 Feb

Not a long time ago, in a galaxy not far away – in fact this one – small cells made their first appearance on the scene. In a 3G network, small cells were primarily used for in building coverage where it was needed. It was an important role, but not a glamorous one.

So what awakening in the force is calling for a return of the small cells now? First, the demand for mobile data took over the world, leaving operators with overloaded networks and scrambling to add both coverage and capacity. Rolling out LTE networks for mobile traffic was the first step, but these networks are already being strained.

Strategy Analytics predicted in its report, Mobile Data Traffic Forecasts 2014-2018,that by 2018 mobile networks will carry 56.2 Exabytes of data, up from 21.3 Exabytes of mobile data traffic in 2014. This growth in traffic is being driven by both strong performance on 4G/LTE networks and rapid growth in smartphone data subscriptions, with future growth driven by tablets, consumer electronics and M2M devices contributing to a larger share of the total data traffic.

There are a number of ways that operators can add capacity to their networks, including acquiring new spectrum, which leads us to our second point – LTE spectrum is both scarce and expensive. Mobile operators are turning to a Heterogeneous Network model – or HetNet – to maximize their spectrum. A HetNet is composed of a combination of macrocells, Wi-Fi, distributed antenna systems (DAS) and small cells. By using a layered network model with deployed small cells, mobile operators not only address coverage concerns between macrocells and in indoor environments, they can also add much needed capacity to the network and improve the overall end user experience.

Provisioning Small Cells

The addition of small cells to the mobile network adds complexity when it comes to RF network planning as compared to a macrocell-only network; therefore, efficient and autonomous coordination between macrocells and small cells is key. Self-organizing Networks (SON) techniques provide the real-time self-configuration, self-optimization and self-healing capabilities that are becoming mandatory features for the HetNet to work as a cohesive network. SON offers the promise of reducing costs in initial rollouts, enabling more effective coordination of time and frequency resources, providing dynamic interference management, and adapting to changing network conditions.

Interference Management and Carrier Aggregation

Mobile operators are deploying LTE-Advanced capabilities such as carrier aggregation and interference management techniques to make their networks even more efficient. Here again, small cells remain critical to operators’ overall strategy as they provide additional capacity in dense indoor environments where a majority of data traffic will be generated.

In a HetNet scenario combining small cells with Wi-Fi and macrocells, mobile operators are rolling out a number of interference management techniques to ensure the network is optimized for capacity and coverage.

  • Enhanced Inter-cell Interference Coordination (eICIC) works as the interference manager for small cells as part of a HetNet. It uses advanced time domain scheduling to reduce radio interference and increase the coordination between network cells to ensure a streamlined flow of information.
  • Multiple Input and Multiple Output (MIMO) is an approach which serves to increase efficiency across the spectrum by leveraging smart antenna technology that analyzes how base stations, antennas and user equipment communicate.
  • Coordinated Multi-Point (CoMP) is a technique that ensures that even greater performance is achieved at the edge of the network, by increasing coordination between small cells, and between small cells and macro cells.
  • Relay Nodes are low-power base stations that reduce the site-to-site distance in the macro network. They were added to the LTE Release 10 specification.

Mobile operators are currently focused primarily on deploying eICIC and MIMO. Relay nodes add additional complexity to the network and will be rolled out at a later date.

Carrier aggregation aggregates mobile operators’ 3G spectrum freed up by LTE roll-outs along with LTE and LTE-Advanced spectrum to add increased throughput to the network. The scarcity of spectrum has led to faster adoption of carrier aggregation by mobile operators as compared to other LTE-Advanced capabilities. Carrier aggregation is also being used for both LTE-FDD and LTE-TDD modes, allowing mobile operators with both network assets to adopt the technology to gain even more performance.

Carrier Aggregation and LTE-Unlicensed

One of the biggest innovations in driving the return of the small cells is LTE-Unlicensed technology, also known as LTE-LAA (LTE-License Assisted Access). Mobile operators are beginning to aggregate unlicensed spectrum in the 5 GHz band with their available licensed spectrum to add even more bandwidth.

As LTE-LAA is an extension of LTE-Advanced and is based on carrier aggregation, it’s no surprise that small cells remain central to its deployment. Leveraging small cells for LTE-LAA provides a localized approach to carrier aggregation that helps mobile operators co-exist with the Wi-Fi community, while being able to further maximize their spectrum to increase capacity and coverage and ease network strain. Small cells are also suited to deployment in the LTE-LAA 5 GHz band as they are better suited to the band’s low power requirements as opposed to macrocells.

LTE-LAA is expected to be fully standardized in 3GPP Release 13, currently planned to be finalized in 2016.

Breaking Down the Numbers

Dell’Oro Group has forecast that small cell RAN revenues will account for 16% of the total RAN market by 2020. According to Pongratz, “the indoor enterprise/public access market improved significantly in 2015, though outdoor revenues still account for the greatest portion of revenue. We expect the indoor segment to grow at a quicker pace and expect the revenue split between indoor and outdoor to be closer to 50/50 by 2020.” And 5G small cells will account for close to 5% of the small cell market by 2020.

Deployments Around the World

A large proportion of the world’s small cells have been deployed in Asia Pacific in Korea and Japan, with volumes picking up in China and India. In dense environments, mobile operators are deploying enterprise and residential small cells in indoor venues to add capacity locally, with the potential for a 1-to-4 ratio of macrocells to small cells.

Outdoor picocells will most likely leverage a Cloud-RAN architecture and will roll out in 2017. Cloud-RAN deployments are now out of the proof of concept stage and are currently in trials. These cloud-based access points, which are also known as virtual base stations or C-RANs, will form the base of a 5G network architecture. They will handle not only the voice and data traffic for consumers, but will also support the M2M and IoT applications that form the ‘connected network’ of the future.

The majority of small cells will be multi-mode, supporting both LTE and Wi-Fi in the 5GHz band, allowing operators to take advantage of cost savings due to leveraging unlicensed spectrum. By supporting the 5GHz band, mobile operators can also deploy LTE-LAA on the same small cell.

Critical Lessons Learned

Each small cell deployment is unique – and what happens in the lab is never replicated exactly in the field. In addition, we learned that focusing on data speeds in trials wasn’t enough. In real-world deployments, it’s more important to make sure that the small cells gel with the network from all angles and not just provide the required data speeds.

Mobile operators also need to plan for more than just mitigating interference between small cells and macrocells. They also need to mitigate issues associated with small cell placement and acquiring the necessary real estate. This needs to happen early in the planning process to ensure a smooth roll-out.

Small cells have returned in a big way. From a role of just filling coverage gaps in 3G networks, small cells now form a major part of mobile operators’ strategy as they contend with exploding mobile data traffic on their networks and chart their path towards 5G. It’s all about adding capacity efficiently and economically. Now that the small cell force has awakened, we can’t wait for the next sequel.




LTE-U v. Wi-Fi Battle Set to Escalate

4 Feb

The battle between LTE-U and Wi-Fi will continue, even escalate – there is a lot at stake. LTE-U is designed to let cellular networks boost data speeds over short distances. Additionally, because no added rights that have to be purchased, LTE-U would allow carriers to extend their core networks at a fraction of the cost of their existing systems.

But they stomp on Wi-Fi signals. Because upper unibands can have a watt, or more, of transmit power in outdoor usage, they can overpower the shared Wi-Fi bands. Testing has shown that to be the case, and an LTE-U network can “override any Wi-Fi signal in the area, creating enough interference to block nearby corporate networks and public Wi-Fi hotspots – not good!

Proponents of LTE-U argue that it is a legitimate competitor to Wi-Fi technology, and should therefore be allowed to operate in the same spectrum. That is not the argument. The argument is that if it is going to share, then it has to be a good neighbor, and it is tuning out that such is not the case.

Wi-Fi currently uses an 802.11 listen-before-talk (LBT) contention-based protocol. LTE-U relies on an arbitrary duty cycle mechanism. LTE-U needs to adopt the same LBT protocol so everyone can just get along and share the medium. In the United Kingdom, they have acknowledged the problem and have regulated the 5 GHz spectrum. Is that what has to happen here?

Carriers are rushing LTE-U into the market because it is a cash cow. They want to get it out before the FCC has a chance to rule, because they know LTE-U, as it stands today, is a flawed platform and if they end up having to re-engineer the access protocols, it will cost them a lot of money. If the carriers succeeded, traditional Wi-Fi vendors will be forced to look for clean spectrum. The FCC, and industry leaders need to stop the 800 pound gorillas from bullying their way into the spectrum, and regulate the 5 GHz band.


LTE like you have never seen before, or you will never see at all…

19 Jun

We can be sure that the hunger for data transmission will grow rapidly and that the mobile networks will not be able to deliver the expected capacity. On top of the current avalanche of the data created and consumed by humans we will soon see a completely different order of magnitude of the traffic Not only traffic generated by the machines in so-called Internet of Things or Internet of Everything.

A year ago, 3GPP consortium was approached by the mighty Qualcomm with the proposal to include in the next release of the 3GPP specs the extensions of LTE Advanced framework into two very interesting options promising both dramatic increase of networks capacity and the local peering interfaces.

Promised land

The most rare resource in the mobile world are the frequencies operators can use to build their networks. Based on the old paradigm of licensing, giving the exclusivity of the spectrum usage to a certain entity are in fact the foundation of cellular carriers business model. They pay fortunes for the license and are the only landlords of the assigned band. Also the protocols running there (GSM/3G/4G/LTE) behave like the only kid on the block expecting no interference in the area and enforcing the exclusivity rights.

Quality of service predictability is linked to the exclusivity and the binary access to a given spectrum resource, at a given location and a given time.”

However the licensing model assigns very small spectrum to an operator. Those can be even highly-priced 5 MHz pieces! Very often the frequencies are fragmented and do not allow aggregation of the transmission channels which is vital to increase the data throughout. And since rarely operators decide to merge their frequency assets (like formation of Everything Everywhere by Orange and T-Mobile in the UK or NetworkS! in Poland), there seems to be no way out from the spectrum trap.

But wait a minute! There is a great open field out there – the unlicensed bands. Originating back from back in 1985, when so-called “junk bands” of 2.4 and 5.8 GHz were declared free to use by anyone, they are right now occupied mostly by WiFi (IEEE 802.11). Subsequently the set of the unlicensed frequencies got expanded and right now almost entire 5 GHz range is available – 775 MHZ of continuous spectrum. Recently released TV broadcasting bands (sub 1 GHz) are tested for long-range rural internet access and 60 GHz (massive 7 GHz cluster) is already used as either point-to-point connectivity or short-range multimedia streaming at home (802.11ad standard).

The free spectrum is not only home for WiFi, but also a place of co-existence of many other protocols – Bluetooth, Zigbee. Over time the base rules of the game were defined to guarantee problem-free common usage of the frequencies with good neighbours trying to limit the impact of their actions on the others lives.

How will a selfish kid like LTE behave in this good neighbourhood? It’s not like having a racetrack just for yourself. It’s more like driving a car in the city, where streets are available to everyone who is able to understand the rules and play by those rules. Will LTE learn the traffic or crash spectacularily?

The key to success

The proposal from Qualcomm defines LTE-U extension to use the U-NII-3 part of the 5 GHz band, which has highest EIRP emission power allowed. While in 2.4 GHz regulatory bodies limit EIRP to 100 mW (Europe) or 200 mW (USA), the U-NII-3 enjoys the rights to go as high as 1000 mW outdoors.
Yes – 1 watt of power…

However, the LTE will not move entirely to the unlicensed area. The postulate is to keep the control channel still operational in the reserved frequency so that “the crucial signaling information is always communicated properly.” Which also means that only true MNO will be able to deploy the technology. It’s a big goodbye kiss to the enterprises hoping they could build private LTE networks without licensing cost…

In fact the LTE-U proposal is built on another LTE Advanced standard extension called “carrier aggregation”. It allows using multiple communication channels to transfer data in parallel. Originally it was designed to solve the problem of the “frequency mosaic”. Instead of exchanging and merging the frequencies with the other players to gain higher bandwidths, mobile operators will be able to use the radio resource they have right now “as-is”. LTE-U is simply saying that instead of the owned frequencies, some channels will be formed in the 5 GHz band. Carrier aggregation is pretty adaptive structure, so we can end up in multiple, dynamically changing topologies where all links work in licensed channels, all work in unlicensed spectrum or we have a mixture. System shall adapt to the congestion of the mobile network and availability of the unlicensed frequencies.

Here is the key to the co-existence of the selfish LTE kid with WiFi – effective sensing of available resources without pre-empting all of them. Qualcomm argues that there will be no noticeable degradation of the competing WiFi networks, while allegedly more efficient LTE-U encoding will deliver larger capacity than neighboring 802.11 systems.

Feasibility of the LTE-U

Control channel for LTE-U still needs to be realized via licensed band so the technology is possible to be implemented only in the existing LTE coverage areas. Carriers already struggle with the overwhelming investments that are necessary for LTE rollouts. Will they be willing to add more money to the budget for the promised added capacity, seamless aggregation the unlicensed downlink channels and ability to transition VoLTE calls? Especially that in order to use the LTE-U, their subscribers will need to have fully-compatible terminal with newest chipset, which will not happen overnight.

It might be a good choice for the smaller players on the market strangled by the lack of spectrum and pressured by the quality demand from their customers. That could be a good selling point for them without otherwise unavoidable huge license fees infrastructure expenses.

On the other hand why shall they wait for the specification to be finalized and equipment to be available, while already they can build WiFi networks delivering the same added capacity, seamless roaming between radio networks and even voice transitioning from VoLTE to VoWiFi and back? Maybe because the intention is to make WiFi and other wireless technologies obsolete and take over full control over previously free area? Another Qualcomm extension to LTE Advanced seems to be a step into such direction.

Direct communication – reinvented

The future uber-connected world with everybody and everything talking to each other will likely consume all possible centralized network resources. Not only licensed , but also the previously mentioned unlicensed spectrum. Hence the concept of direct device-to-device communication without engaging of central management seems to be the way forward for some specific types of applications, like location of devices or social media check-ins or individual/group messaging.

Nowadays such applications are based either on modified Bluetooth protocols or exisiting blanket coverage WiFi networks. Using the characteristics of those systems and add-on modules in the operating systems of our smartphones or tablets, it is possible to locate the user in the indoor environment and trigger some action.

Typical example is the shopping assistance. Wandering in the vast public venue like a shopping mall frequently requires some “indoor navigation” aid. Positioning of the customer gives also the opportunity to analyze the behavior of the visitors and pushing to them marketing messages when they enter certain zones (eg. promo messages when passing by a shop which paid for such advertisement). All based on the assumption that the user has got his WiFi and Bluetooth modules active and his terminal is equipped with the application able to receive such information.

LTE Direct proposed by Qualcomm taps on this opportunity by replacing WiFi/BT communication with yet another LTE Advanced extension. It is using as little as <1% of the network signaling, yet provides direct messaging between user devices. There are two types of messages defined – public and private expressions.

Public expressions are exactly matching the Bluetooth iBeacon functionality. They can be used to locate the user and push any kind of message to his device. The messages are not filtered and do not require applications to be presented to the customer. Excellent marketing tool with larger than iBeacon range (ca. 500 meters instead of 50), promised lower power consumption and better accuracy. Moreover working both outdoors and under roof.

Private expressions are linked with particular messaging/presence app and can be subject to special filtering and privacy settings enforced already on the device chipset level. They can be used to communicate with friends wishing to join the party, seek for people with the same interests at an event or simply as next generation social messaging with geo-location context.

In order to work, LTE Direct still needs licensed spectrum and the LTE control channel. It means that, just like LTE-U, its applicability is strongly dedicated to the mobile carriers and not the enterprises. Exactly opposite to the current beneficiaries of location based services, which are public venues of different kinds: shopping malls, transportation hubs or hospitality properties. One might even interpret such definition of the standard as an attempt to bring back to the operators the opportunity to tap on the revenues right now leaking to such enterprises or OTT (over the top) application owners like Facebook or Google. Bringing back human-to-human communication management (and payments) to the carriers. Especially in the context of classical texting and phone call role diminishing. Finally they could charge again for the actual usage of the network and not just deliver the capacity.

However, there are still some unresolved issues with LTE Direct. While WiFi and Bluetooth work in “neutral host” mode and serve all the user devices, irrespectively of the actual mobile operator and even the ones which are not equipped with cellular interface, LTE Direct requires one common signaling band. The open question remains if the operators will be able to agree on one shared control frequency and under which conditions. Especially that such arrangement shall work for their entire coverage area in order for this extension to be a valid upsell option.

Busines case

Both extensions are part of the new 3GPP releases and expected to approved and possible to implement in 2015-2016 timeframe. As part of the LTE Advanced rollout effort, they require substantial investment in the infrastructure (order of magnitude more expensive than WiFi), but above all – compatible user devices. Low number of termials might limit the business feasibility of such “unlicensed offload” or added-value services, while WiFi and BT are already present in all mobile phones (standard supported globally) and are usable immediately. Also majority of tablets, mobile computers and the expected Internet of Everything devices are SIM-less. This dooms LTE-U/Direct to be just an auxiliary, “nice to have” service for years and only few most desperate operators will decide to go their way.

The WiFi revolution seems to be progressing faster than LTE-A and can make a lot of the mobile carrier business obsolete? We already spend 85% of our time in the coverage of WiFi. Do we really need SIM cards for communication? Do we really need phone calls to talk? Maybe it’s time to kill the phone call? SIM-less future?

Pictures and diagrams are from Qualcomm and Aptilo materials.



LTE-A in Unlicensed Band (LTE-U)

28 Nov
Qualcomm has recently floated the idea of deploying LTE in unlicensed bands, particularly focusing on the 5GHz band, which is currently used mostly for WiFi. According to a document (RP-131635) submitted to the upcoming 3GPP plenary meeting, the proposal is to deploy LTE as Supplemental Downlink (SDL) in 5725-5850 MHz in USA, with the PCell (Primary Cell) always operating on a carrier in a licensed band. Verizon has also submitted a Work Item Proposal (RP-131680) to to introduce the new band for SDL usage. There’s also a Study Item proposal from Ericsson (RP-131788) is the rapporteur to study the modifications necessary to the LTE radio.

These documents can be downloaded from the 3GPP FTP site.

In addition, there’s a presentation from Qualcomm on the same topic.

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