Showing posts with label Spectrum. Show all posts
Showing posts with label Spectrum. Show all posts

Thursday, 3 July 2025

Transforming Poles into 5G Sites with Alpha Fusion Streetworks Solutions

During a recent visit to Glasgow for the SCONDA project showcase, a collaborative initiative focused on advancing urban connectivity, I was struck by how far street-level network infrastructure has come in combining functionality with aesthetics. Among the most visually discreet and technically advanced deployments were those featuring Alpha Wireless' wraparound antennas. The AW4032 antenna stood out for its innovative design, enabling mid-pole mounting in a configuration that blended effortlessly with the urban environment while delivering high-performance 5G coverage. 

Live tests on attendees’ devices showed 5G download speeds reaching up to 720 Mbps, with improved coverage and congestion relief across city-centre locations. One attendee reported that the deployment achieved average 5G download speeds of 520 Mbps, while also reducing low-speed hours by 89% and reaching peaks of over 1 Gbps on small cells in a live dense environment.

Alpha Wireless has developed its Fusion Streetworks solutions with a clear understanding of the challenges faced by operators in urban areas. As network densification accelerates, especially with the move towards 5G standalone architectures, securing new street-level sites is proving increasingly difficult. The Fusion Streetworks platform responds to this by making better use of existing infrastructure such as lamp posts and streetlights. The AW4032 antenna, which forms the centrepiece of this platform, is designed to mount mid-pole without requiring sidearms or external hardware that would increase wind loading or visual impact. As it is an antenna-only product, the AW4032 pairs with external small cell radios, offering operators flexibility in radio selection.

The AW4032 combines compact form with support for advanced radio capabilities. It supports 16 ports across dual bands — 1695 to 2690 MHz and 3300 to 4200 MHz — and enables 4x4 MIMO, delivering strong signal quality and throughput. When ports in adjacent sectors are connected, the antenna produces a pseudo-omnidirectional pattern, providing seamless 360-degree coverage suitable for dense urban environments, hotspots and high-traffic venues. It is also highly adaptable. Operators can configure the ports to suit different patterns: back-to-back for focused directional coverage, or four-way for broader area coverage, all using the same hardware.

This modularity means the same unit can serve single or dual-operator deployments, with each operator connecting to a separate set of ports. This enables shared infrastructure without interference and lowers total cost of ownership. For instance, the dual-operator setup divides the 16 ports between two MNOs while still offering pseudo-omni performance, which is particularly useful in areas where zoning permissions limit the number of separate installations.

What makes the solution especially effective in public spaces is the attention to detail in concealment. The Fusion platform includes options for radio shrouds and integrated cabling management to maintain a neat appearance. This has been instrumental in speeding up approvals in areas traditionally sensitive to new telecoms infrastructure.

Alpha Wireless has already seen its Fusion Streetworks solutions rolled out as part of a 5G standalone deployment in central Birmingham. Working with Ontix and Virgin Media O2, these antennas have been deployed on existing poles in busy city locations, demonstrating how legacy infrastructure can be revitalised to meet the demands of next-generation connectivity.

From an infrastructure perspective, the AW4032 exemplifies how antenna technology is evolving to match the operational and regulatory pressures of modern small cell deployment. It simplifies rollout, minimises street clutter, and offers a level of future readiness that is essential for long-term network planning. For cities looking to accelerate their 5G ambitions without compromising on design, Alpha Wireless’ Fusion Streetworks platform offers a proven and practical approach.

Tuesday, 22 April 2025

FDD Tri-Band Massive MIMO: Unlocking Sub-3 GHz Potential for 5G Evolution

Huawei has begun commercial deployments of its FDD Tri-Band Massive MIMO solution, focusing on sub-3 GHz spectrum across Africa and several other global markets. Countries such as Nigeria, Angola, and Côte d'Ivoire are among the first to benefit, with deployments also expected across Asia Pacific, Central Asia, and Latin America.

This new technology is being positioned to solve two key challenges for mobile operators. First, it tackles the persistent increase in 4G traffic, which continues to grow year on year. Second, it enhances the user experience for 5G services without demanding vast new spectrum allocations. Huawei claims the solution delivers significant performance improvements over the conventional 4T4R setup, including handling almost twice as much 4G traffic during peak times, tripling user-perceived speeds, and halving the use of physical resource blocks.

Underpinning these benefits are innovations like Real Wide Bandwidth and Compact Dipole technologies. These allow multiple FDD bands such as 1.8 GHz, 2.1 GHz, and 2.6 GHz to be processed using a shared filter, antenna array, and power amplifier. This not only enables efficient spectrum use but also simplifies site deployments. Huawei reports that 5G network capacity can be boosted up to sevenfold with uplink coverage extended by 8 dB, both of which are especially important as mobile AI services increase the demand for higher uplink bandwidth and wider coverage.

The market conditions in Africa illustrate why this approach is timely. Rapid urbanisation and a large population base have created surging demand for mobile data, leading to congestion and degraded user experience. Many sites already host conventional Massive MIMO technology, but with traffic increasing by 50 percent annually, a more efficient capacity solution is urgently needed.

The broader role of sub-3 GHz FDD spectrum in 5G development is also coming into sharper focus. While early 5G investment emphasised the upper mid-band due to its wide contiguous spectrum, the sub-3 GHz FDD bands now represent a crucial part of the coverage and capacity equation. These bands collectively offer around 100 MHz of paired spectrum and are essential for extending 5G services beyond dense urban centres into suburban and rural areas. Their propagation characteristics provide better in-building penetration and a stronger uplink experience.

Operators have traditionally used these bands to complement mid-band deployments, but case studies suggest they can form the backbone of high-performance networks when optimised correctly. In the Netherlands, for example, delays in mid-band spectrum availability led operators to rely heavily on FDD spectrum. Despite these constraints, they achieved strong data rate and latency performance by tightly integrating 4G and 5G technologies.

One persistent issue is the fragmentation of spectrum across multiple bands, which can complicate radio access network design. Physical site constraints and antenna complexity remain challenges, particularly as physical cell site growth slows. This has led to a push for site simplification through wideband and multiband radio solutions. Many equipment vendors now offer radios that can support three FDD bands within a single unit, often using a shared power amplifier and filter. This not only reduces size and weight but also lowers power consumption and speeds up deployment.

Although Massive MIMO is generally seen as more effective with TDD, Huawei believes its latest advancements in intelligent beamforming and multi-band serving cell configurations can change that narrative. By treating multiple FDD bands as a single carrier and applying advanced beamforming, spectral efficiency can be dramatically improved. According to Huawei, this combination can deliver a tenfold gain in throughput and a 10 dB improvement in coverage compared to standard 4T4R systems.

With the shift toward 5G Advanced on the horizon, operators must get the most out of their existing spectrum assets. Sub-3 GHz FDD spectrum may not be new, but with the right technology, it can provide the performance needed to meet modern data demands and support the next wave of mobile services.

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Friday, 27 January 2023

Seoul Metro Wi-Fi Backhauled by Samsung's 5G mmWave Network Solution

In our earlier posts we talked about how Wi-Fi 6 is being promoted by South Korea's ministry and also how mmWave has not been very successful in Korea. Having said that, earlier last year, Samsung Electronics announced that it has signed contracts with all three South Korean operators to supply its 5G mmWave network solutions and boost connectivity for passengers on the Seoul subway system:

Over 3.6 million passengers use the Seoul subway daily across over 300 stations. With a population of 9.6 million, Seoul is one of the world’s most densely populated cities, with its subway serving as one of the major means of public transportation for the busy metropolitan area. The subway system is expansive, resembling a spider web network that connects Seoul and the surrounding areas, carrying over 30 percent of the city’s population.

While the Seoul subway system has already been providing stable 5G (3.5GHz), 4G and Wi-Fi services, mobile data demands in subways continue to rise exponentially as Korea’s monthly average 5G data consumption reaches approximately 25GB per person.

Later this year, Samsung’s 5G mmWave solutions will enable the subway’s Wi-Fi services to meet increasing data demands by leveraging mmWave’s wide bandwidth, extensive capacity and massive throughput. Subway passengers will be able to enjoy bandwidth-intensive applications such as high-speed, superior-quality streaming for live sports games, movies, mobile games and video communications. These will be delivered at Wi-Fi speeds up to ten times faster on average than currently provided.

In addition to transforming the daily mobile experience for subway users, Samsung’s advanced 5G mmWave solutions will drive a diversified range of use cases and business opportunities for new entrepreneurs, app development startups and consumers. Utilizing mmWave bandwidth can not only bring to life next-generation services such as the metaverse, cloud gaming and Extended Reality (XR) remote learning, but it can also be expanded beyond transportation to industries like retail, medicine, media and entertainment.

A key component of the Seoul subway commercial deployment is Samsung’s mmWave 5G radio solution, Compact Macro, which brings together a baseband unit, radio and antenna in a single form factor. Optimized for mmWave 5G, it uses in-house modems, radio frequency integrated circuits (RFICs) and digital analog front end (DAFE) ASICs.

Complete press release here. Embedded below is a short promo video on this

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Friday, 25 March 2022

Taoglas Advanced Antennas and RF Components

Taoglas is a leading provider of advanced technology for a smarter world. Focused on best-in-class, high-performance antenna and RF design with advanced positioning, imaging, audio and artificial intelligence technologies, Taoglas has unique expertise in integrating and commercializing highly complex technology solutions. 

At the Mobile World Congress 2022, we caught up with Baha Badran, Global Head of Engineering at Taoglas to tell us about the different types of antennas and what they are used for. Baha didn't disappoint us and gave us a whirlwind tour of all the antennas on the display at their booth. The video is embedded below.

To learn more about Taoglas, visit their website here.

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Friday, 9 July 2021

NEC's O-RAN Compliant Massive MIMO Radios


NEC has recently started receiving recognition and the attention is deserves for its massive MIMO radio units and other 5G infrastructure. Back at MWC 2019, they was already showing showing their O-RAN compliant Open RAN radio units (see tweet below)

Just in time for MWC 2021, NEC announced the launch of new radio units (RU) for 5G base stations that are geared for global markets and are scheduled to be available in 2022. Their press release said:

In terms of functionality, the new RUs will be compatible with the n77, n78 and C-Band 3.7GHz frequency band (3.3-4.2GHz), which is globally used as a 5G frequency. In addition, ultra-multi-element antennas utilizing Massive MIMO (*) and digital beamforming for high-precision beams will help to provide high-speed, high-capacity communications between a wider range of terminals. Also, the new RUs will feature higher output and wider bandwidth when compared to conventional products, thereby expanding the communications area and providing high-speed transmission. NEC's proprietary high-density mounting technology, power saving technology, and fanless design will also enable a compact format that is lightweight and power efficient.

The RUs will conform to O-RAN fronthaul interface specifications defined by the O-RAN Alliance and will be compatible with base station equipment from different vendors, making it possible to realize open, flexible and optimized networks according to a wide range of use cases.

At the MWC 2021 Virtual Stand, NEC was boldly showing off their O-RAN Compliant 5G Radio Units. Their product features include:


  • Full Digital Beamforming to Improve Customer Experience: AAS(Active Antenna System) improves the radio quality and realizes stable quality of service by Full Digital Beamforming
  • Sub6GHz Massive MIMO AAS for Macro Cells: Best suited for optimizing coverage and capacity in dense population areas. Can also be utilized as an “in-building” solution by horizontally penetrating the beam into buildings.
  • mmWave Massive MIMO AAS for Small Cells: Designed to be compact and light weight easing installation and expanding site options, and also reducing operational cost with its low power consumption feature.

With so many new hardware players emerging as a result of Open Networks, it remains to be seen if NEC is able to make most of its Massive MIMO leadership.

Related Posts:

Friday, 29 January 2021

Samsung Link Indoor Solutions

Late last year, Samsung launched the Full Suite of 5G Indoor Products aimed at improving 5G connectivity indoors. As we move to higher frequencies for 5G, especially mmWave, alternative solutions will definitely be required to provide higher data rates. 

As can be seen in the picture above, there are three different solutions for different scenarios. The brochure here and this website here provides details but I have highlighted the relevant information below:

Link Cell is a compact indoor small cell that offers robust, ubiquitous in-building 5G mmWave coverage to deliver the high bandwidth, low latency and fast throughput needs for these businesses and public venues. The indoor solution can connect a large number of indoor users to data applications where signals from the outside 5G mmWave networks are hard to reach, enhancing productivity and providing a premium business experience. For enterprises that require dedicated connectivity and additional security needs the Link Cell can also serve as the foundation for a 5G private network. By combining a private 5G Core with Link Cells, an enterprise can have a secure, ultra-reliable, high-speed, low-latency 5G network that can accelerate their automation and digitization efforts.

To meet indoor coverage demands, particularly where capacity expansion is required or anticipated in the near future, Samsung offers a 5G Active DAS (Distributed Antenna System) solution called the Link HubPro. This system is especially useful in large buildings with extensive IT infrastructure. The solution includes two main components: a Radio Hub and Indoor Radio, and supports more diverse spectrums including, low-band and mid-band. With this simple architecture, single Radio Hub will allow a mobile operator to connect multiple radios and making multiple radios work as a single cell to build wide 5G indoor coverage without interference. 

Samsung Link Hub acts as a radio to connecting passive antennas supporting both LTE and 5G. If a building already has an existing passive DAS system, service providers can easily upgrade their indoor network to provide 5G service and reuse legacy cabling to save both time and costs. The Link Hub will act as a bridge between the 5G baseband and antennas by converting data traffic to radio signals, and vice versa, making 5G data traffic possible. The Link Hub can be managed remotely by an operator’s network management system.

The video below explains the solution in detail:

Here is another video that explains the indoor small cell, Samsung Link Cell

As a final thing, it should be pointed out that Samsung’s Link Cell features the Qualcomm 5G RAN platform, which builds on the collaboration between Qualcomm Technologies, Inc. and Samsung. 

Related Posts:

Tuesday, 30 June 2020

QCell - ZTE’s 5G Solution for Gigabit Indoor User Experience

ZTE unveiled its 5G RAN product portfolio for the 'Networks of the Future' back in February, just in time for the MWC that was unfortunately cancelled. One of the products was QCell.

ZTE’s QCell 5G indoor solution provides not only multi-mode, multi-frequency, ultrawide-bandwidth and large-capacity 4TR products, but also a more budget-friendly 2TR product that supports 300 MHz bandwidth, which is ideal for indoor RAN sharing and rapid introduction of 5G with lower deployment cost.



Yesterday, ZTE announced that along with the Jiangsu branch of China Telecom, they have deployed 5G 200 MHz Qcell 4T4R digital indoor distribution system in the indoor scenarios with high amounts of data traffic, such as shopping malls and subway stations, in Xuzhou, China. The system provides high-quality 5G indoor coverage, and accelerates future 5G indoor system deployment.


This commercial deployment has employed ZTE’s latest 5G Qcell ultra-wideband product series, which supports 200MHz continuous ultra-large bandwidth at 3.5 GHz frequency band, and 100MHz+100MHZ dual-carrier aggregation technology that doubles download rate. 

For the time being, by virtue of China Telecom’s 100MHz 5G bandwidth, the single 5G user download rate has turned out to exceed 1 Gbps. In case of the activation of 200 MHz bandwidth in the future, the single 5G user download rate will exceed 2 Gbps, providing an excellent 5G experience. 

Moving forward, ZTE will give full play to its technical and commercial advantages in the 5G field, continue to work closely with China Telecom to build high-quality 5G digital indoor networks, and develop 5G industrial applications, thereby facilitating the development of smart cities.

A partner feature on Mobile World Live provides a lot more technical details:

The ZTE QCell system consists of pRRU/pBridge/BBU (Baseband Unit) 3-level equipment. The 3-level efficient architecture supports the rapid cabling of CAT6a network cables or optical-electrical hybrid cables. It supports pBridge multi-level cascading, cell splitting and combination, and can rapidly respond to the operator’s requirements for the complex networking of different frequency bands and systems, rapid adjustment and flexible expansion of capacity and coverage.

The 300 MHz large bandwidth products with multi-mode and multi-frequency band enable the ZTE QCell solution the powerful network architecture integration capability, to meet the requirements of multi-operator’s co-building and sharing and have the compatibility and adaptability of global deployment. It not only supports the overlay networking of the existing DAS and 5G QCell, but also supports the feed-in of the GSM/UMTS DAS RF signals from different manufacturers in the existing network through the MAU, to protect the operator’s existing indoor distribution investment and introduce value-added services based on 5G coverage and precise positioning. QCell supports GSM/CDMA/UMTS/FDD LTE/TDD LTE/5G NR, which makes once deployment to implement the multi-operator/multi-band/multi-system indoor distribution system that achieves agile, long-term, co-construction, sharing, and lowest cost indoor distribution network, multi-system equipment and common management and maintenance. It only needs software upgrade for service expansion and network architecture evolution in the future so as to protect the investment in early-stage 5G indoor deployment and reduce the overall TCO cost from the perspective of long-term operation.

ZTE adopts innovative design of QCell products to reduce the cost and power consumption of equipment units. The pRRU transceiving channel not only supports high-performance 4T4R, but also supports low-cost 2T2R, further reducing the cost and power consumption. The pBridge enhanced product is designed to reduce the cost and power consumption after the electrical interface and optical interface are separated and the SoC solution is introduced. Moreover, the simplest BBU product is introduced to further reduce the QCell system networking cost.

The hierarchical QCell networking well matches diverse scenarios

Based on the analysis of the requirements for indoor distribution of operators, vertical industry enterprises, and large business owners, the indoor distribution scenarios can be divided into three types: capacity-sensitive scenario (type A), capacity and coverage balancing scenario (type B), and coverage-sensitive scenario (type C).

For the above three types of scenarios, ZTE provides hierarchical QCell networking solutions. Compared with the Benchmark QCell solution of 4T4R built-in antenna pRRU, ZTE provides a cost reduction solution of 2T2R built-in antenna pRRU and a low cost solution of 4T4R pRRU+ connected with external DAS antenna according to the scenario requirements, thus achieving the accurate network construction and saving operators’ investment. Evaluations based on the 40,000 square meters isolated indoor distribution scenario show: for scenario type B, the total main equipment investment is reduced by about 1/4; for scenario type C, through the external DAS antenna, the single-pRRU coverage area is greatly expanded and the overall investment is greatly reduced by about 1/2.

Extensive QCell Digital Smart Indoor Application, Making 5G Service Ubiquitous

The QCell digital intelligent indoor distribution system can be deployed for indoor and semi-indoor to achieve wireless coverage and service provision in high-value areas, such as large traffic hub, large stadiums, CBD and university campuses.

The large-scale traffic hub scenarios, such as airports, railway stations, and subway stations, have a large area and high population density, and are high-value areas for operators to guarantee both coverage and performance. The Wi-Fi system of most transportation hubs is often limited in capacity and cannot meet passengers’ requirements for future 4K/8K HD video. In Changsha Huanghua Airport, ZTE deployed the indoor high-capacity digital intelligent QCell solution with high-density networking and the first 3-carrier aggregation technology in China, to achieve the throughput of 8400Mbps for the airport. The solution supports 3,500 people simultaneously to enjoy HD video smoothly. At present, the QCell solution has been widely used in various metropolitan airports and railway hub stations, including Changsha Airport in Hunan, Xiaoshan Airport in Hangzhou, Nanjing South Station and Xining Railway Station, serving millions of passengers. Nanjing South Railway Station has a total building area of 45.8 million square meters, which is the largest railway station in Asia. After QCell is deployed, the SINR is increased by 13% and the throughput is increased by 91.8%.

The large stadiums, such as stadiums and exhibition halls, have a large number of users and a huge amount of data volume in a centralized manner. The QCell solution supports vertical partitioning to achieve seamless multi-layer coverage from the upper stands, the middle mezzanines to the bottom passages. At present, the QCell solution has been widely deployed in large stadiums such as Hangzhou Olympic Center, Hangzhou Expo Center, Suzhou International Expo Center, and Shenzhen New High-Tech Center. In August 2019, the ZTE 5G Smart Digital Indoor Division QCell solution covered many important sports venues including the Main Conference venue of the Red Lantern Stadium for the second National Youth Games (Shanxi), and made the Game the first “5G Games” in China. Through such technologies as MEC deployment and low delay coding, the ZTE 5G Smart stadium solution reduces the end-to-end live broadcast delay to 1 second, and provides audience with the excellent experience comparable to watching on the spot. In addition, ZTE also provides audience with brand-new experience in three 5G scenarios: immersive viewing experience from multi-angle live streaming, “Flexible Zooming” and “360-degree Free View” services. As an iconic application in the Game, the 5G Smart Stadium Solution provided an excellent demonstration for the live broadcast of sports events.

A recent promo video of QCell is embedded below:




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Saturday, 15 February 2020

Verizon's Small Cells Start Paying Dividends

Pictures Source: Dr Jonathan L Kramer

In their recent investor meeting presentation, Verizon talked about many different approaches that have helped them keep pace with the increasing traffic.


While basic improvements like 256-QAM, 4x4 MIMO, Carrier Aggregation and CBRS/LAA have helped, other innovations like Interference Management Software has helped improve capacity.


Densification solutions include increasing number of small cells and more carriers per sector.


This chart above from the deck is a good summary of how different enhancements affect the LTE User Peak Throughput as well as the LTE Network Spectral Efficiency. According to the graph, this year they are planning to deploy FD-MIMO, a.k.a. Full-Dimension MIMO.

This research paper (link) on FD-MIMO provides an excellent overview of the topic. According to that "3GPP decided to use tens of antennas with a two dimensional (2D) array structure as a starting point. Full-Dimension MIMO (FD-MIMO), the official name for the MIMO enhancement in 3GPP, targets the system utilizing up to 64 antenna ports at the transmitter side."


This chart above is a good summary of how these enhancements have helped Verizon expand capacity to handle the increase of user traffic.


With regards to the small cells, the number of 5G small cells is expected to increase by at least 5 times this year to cope with the 5G traffic increase and coverage improvement. As Verizon has deployed mmWave spectrum for 5G, they will need significant number of smaller cells to provide coverage.


The tweet below shows an example of 5G Small Cell


Here is an interesting recent video from Verizon explaining small cells to their end users.


It would be interesting to see in the next few years how these small cells solve the coverage gap and handle the capacity need.

Related Posts:

Friday, 5 May 2017

Sprint's Magic Box


Is Sprint doing Small Cells? That's a question probably asked too many times. Back in January, their COO Günther Ottendorfer said the company’s small cell partners conducted a range of trials last year in order to determine fast and efficient methods to deploy small cells, a situation he said led to some misunderstandings in the market. However, he said those trials are largely behind the carrier and that he expects the carrier’s small cell efforts to expand this year.

“There was a learning process in 2016. We did a lot of trials in the beginning. We had some trials that led to misunderstandings, when you have a lot of boxes there because you were trialing different things, different—for example—transmission methods,” said Ottendorfer, Sprint’s chief operating officer for Technology, in a recent interview with FierceWireless. “But now we have streamlined the concepts and so I’m very confident that with streamlined and very elegant small cell solutions we will have a good rollout this year.”

They again mentioned about their small cells commitment at MWC. Finally this week, they announced the Magic Box.

Sprint has billed it as "World’s First All-Wireless Small Cell". This is a point where I would disagree with them, mainly for two reasons.The first being that for an all-wireless claim, they have to get wireless power to the small cell and secondly, this has already been done for a while. I have explained about In-band backhaul here and have provided examples of how Parallel Wireless has been using this for a while.

The Magic Box is made by Airspan and is 4G/LTE only in band 41 (2500 MHz TD-LTE). One of these units provide an average coverage of 30,000 square feet indoors and can benefit adjacent Sprint customers inside the building. The signal can also extend coverage 100 meters outside a building, benefiting customers in nearby buildings and improving street–level network performance. It does not use the closed subscriber group (CSG) feature hence anyone can camp on it and use it.


Sprint has a large amount of 2.5GHz spectrum available, as a result they are able to use dedicated spectrum for the Magic Box. This ensures that interference is kept to minimum. They also announced the availability of HPUE that will allow this band reach to improve. See my blog post here for details.

“It’s a far cry from just a repeater,” he said, explaining that it improves the efficiency of the network as long as it has a good connection to the macro cell. It will work with any Sprint phones using 2.5 GHz. The backhaul channel uses 2.5 GHz or 1.9 GHz, but ideally it would use 2.5 GHz because that offers a lot more capacity.

The Magic Box includes self-organizing network (SON) capabilities and operates on its own channel in Sprint’s spectrum, allowing it to decrease the noise level and increase the capacity of the overall system, which is the big difference from repeaters, explained Sprint Technology COO Guenther Ottendorfer.

Some of the details I couldn't find but hopefully some of the readers would know and can answer are:
  • Whats the power output of these small cells?
  • I am assuming they will support VoLTE calling for voice - even though generally that feature is transparent to small cells?
  • Does the small cell radiate a single 20MHz channel?
  • Does the backhaul do carrier aggregation?

Further Reading:

Monday, 19 May 2014

Unlicensed LTE (LTE-U) for Small Cells

I first wrote about LTE-U (or U-LTE as referred by others) back in December last year pointing towards the Qualcomm presentation here. As things move fast in our industry, quite a few things have happened in the last 6 months. Huawei did a demo of U-LTE in Mobile World Congress this year and LTE-U has been a constant topic of discussion in various 3GPP meetings. A half-day workshop is due to take place in June to discuss this topic further. In the meantime I have summarised some of the discussions that took place (unofficially?) in Jan 2014 between the interested parties.
To be clear, the discussions for LTE-U are centred on the 5GHz unlicensed spectrum. As you can see from the picture above, there is a massive amount of spectrum that is available, either free to use (unlicensed) or in a lightly licensed way.
There are strict rules and regulations in place to make sure this license is not misused or monopolised. There will be a need for Dynamic Spectrum Access (DSA) techniques that I have discussed here. The current LTE standards do not have a DSA inbuilt and hence referred to as "Rude". The following is from a recent Light Reading article.

The technical concern with LTE-U, as Peters describes it, is that LTE is a "rude" technology. WiFi includes a "politeness protocol" that LTE lacks, meaning that WiFi will back off if it senses interference from other users. Eventually rude ol' LTE operating in WiFi's polite bands could take over the band.
The 3GPP called another unofficial meeting in January to discuss concerns around LTE-U, which also included the potential effect on the value of licensed spectrum, the need for international harmonization of the unlicensed bands used for LTE-U, and whether the technology would be for downlink only or uplink as well. The group met again in March, primarily to work out timing for the new technology's deployment.



Huawei presentation explains why unlicensed carrier offloading, see the embedded presentation for details.
NTT Docomo shows the various deployment scenarios and also lists the regulatory aspects, especially in Japan. See the complete presentation below:




Nokia has even gone ahead and done simulations for different scenarios. The scenario above shows LTE deployment in the same unlicensed band as WLAN as you can see, the results are similar to the interference in WLAN-WLAN case.

There is also a roadmap to how LTE-U standardisation will work in 3GPP, hopefully after the workshop in June, we will probably hear more.

As expected, some of the operators with heavy investments in WiFi (like AT&T) have some reservations on LTE-U. Some analysts on the other hand are sceptical on how much savings there would be, taking the interference into account. Note that spectrum is just one part of deployment costs, there are many other factors to consider. Personally, I don't have an issue whether this will work or not, it definitely would do but with all the advancements in LTE-Wi-Fi Interworking, I think we may be able to do a better job with just selective deployment of LTE-U and using technologies like MAPCON, IFOM, Hotspot 2.0, etc.

Added on 9th July 2014

3GPP held their workshop on unlicensed LTE on 13/06/2014. See the news on 3GPP website here. All documents are available here.

Sunday, 18 May 2014

Dynamic Spectrum Access (DSA) techniques for Small Cells and Wi-Fi

Licensed shared access and unlicensed shared access
Picture Source: Analysis Mason

There is a lot of spectrum which is used sparingly or is kept reserved for unlicensed or shared access. Any party that wishes and is allowed to use this spectrum has to co-ordinate with the license holders or others in similar situations. Hence we have different access mechanisms which are collectively called as Dynamic Spectrum Access (DSA) techniques.

An article by Analysis Mason on this topic suggests the following:

The term DSA has come to encompass a number of different approaches and techniques that aim to increase the utilisation of the radio frequency spectrum. At its most ambitious, it is hypothesised that cognitive and software-defined radios could intelligently choose when to transmit, so as to avoid other radio transmissions and also to avoid causing undue interference to fellow frequency users. Short-term propositions include near-real-time spectrum assignment in certain bands and greater use of long-term secondary spectrum leasing to authorised spectrum partners.
DSA is therefore all about making better use of radio spectrum through re-use of 'idle' bandwidth, being either frequencies that are not used in all locations, in which other systems could be deployed, or frequencies that are only used intermittently, and which could therefore be re-used outside these times. These 'gaps' in utilisation, which provide opportunities for DSA, arise for a number of reasons.
  • Coverage: a licence holder might not be using its allotted licence in a specific region.
  • Time: an area of spectrum might by less-frequently required at different times during a day (or on longer timescales).
  • Lack of service users: there may be a limited number of subscribers taking advantage of a service.
  • Licence technical parameters: the regulator may have mandated that a piece of spectrum can only be used for a specific purpose, while other technologies emerge during the life of a licence that can use the same spectrum.
  • Pragmatic under-utilisation to prevent interference: empty guard bands are placed between spectrum bands to stop transmission leakage to prevent interference, which could be re-used by systems that have the appropriate characteristics to avoid interference.
One of the overarching drivers for DSA is to help overcome spectrum shortages – particularly noting that under-utilised bands may exist across a relatively wide range of the spectrum. Even in the economies where wireless communications have developed the most and usage restrictions have been removed, thus making spectrum use as flexible as possible, spectrum under-utilisation is still considered to be widespread.

The Cisco vision on the other hand seems far too optimistic and suggests the following:


TV White Spaces (TVWS) are spectrum allocated to TV broadcasts, but not being used in a given geographic location. TVWS radios allow for use of white space spectrum for unlicensed wireless access.
Authorized Shared Access (ASA) or Licensed Shared Access (LSA) allow a secondary licensee to use the “shared” spectrum when the primary licensee is not using it.
The United States Federal Communications Commission (FCC) has proposed a three-tier model for shared access in the 3.5-GHz band. Tier 1 would be for incumbent federal agencies, including military radar users. Tier 2 would be authorized prioritized access similar to ASA and LSA. Tier 3 would be generalized authorized access, which is similar to unlicensed access.
A number of DSA technologies already exist or are in exploration.
Geo-location, database-based spectrum sharing techniques have the most traction as a practical approach to spectrum sharing. Devices that want to use shared spectrum must geo-locate themselves and consult a database to determine what spectrum is available.
The geo-location database manages the spectrum resource allocation based on predefined policies and availability to ensure the primary licensee is not impacted. An enhanced version of the geo-location database system—called a Spectrum Access System (SAS)—is the basis for the FCC spectrum-sharing proposal in the 3.5-GHz band.
A second technology is cognitive radio, which senses and monitors the radio environment. This includes knowing the location and policies for self-regulation. Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) are cognitive radio techniques that allow co-existence with radar and satellite systems.
Another technology is Software-Defined Radio (SDR), which allows devices to adapt to local radio conditions and use the appropriate radio frequencies.
I came across this very interesting whitepaper by MIT that details all the DSA techniques and its progress. Paper embedded below:


We will discuss in the future post how the DSA techniques could be useful for using Small Cells in the unlicensed spectrum (a.k.a. LTE-U).

Monday, 2 December 2013

LTE-U: First step towards 'Operator-neutral' Small Cells

3GPP member companies have decided to take the Small Cells vs WiFi fight back into the Wi-Fi camp by unveiling the initiative to have LTE in the unlicensed band (officially known as LTE-U but another interesting term uLTEA has been proposed unofficially too). 

Mike Roberts wrote an interesting post on ITM Blog:
Qualcomm has launched a radical initiative to deploy LTE Advanced in the unlicensed 5GHz band, which has traditionally been the preserve of Wi-Fi devices. If the initiative gains support, it could be a hammer blow to carrier Wi-Fi, though Qualcomm says it is still a strong supporter of all types of Wi-Fi, given its Qualcomm Atheros division, which is a leading producer of Wi-Fi chipsets. 
Qualcomm CEO Paul Jacobs unveiled the company’s initiative for LTE Advanced in unlicensed spectrum at its financial-analyst day in New York on Nov. 20. It was interesting timing, considering that the main annual carrier Wi-Fi event, the Wireless Broadband Alliance’s Wi-Fi Global Congress, was taking place on the same day on the other side of the world, in Beijing. 
The chipset giant followed the announcement by its CEO with detailed presentations on the initiative at Informa’s LTE North America event in Dallas on Nov. 21-22. The essence of Qualcomm’s proposal is that it is complicated to integrate LTE and Wi-Fi to create carrier Wi-Fi, so a better option could be to use LTE Advanced to extend LTE into unlicensed spectrum, thus eliminating the need for Wi-Fi in that context....So how does Qualcomm plan to square this circle and offer reliable mobile services in unreliable unlicensed spectrum? By using LTE Advanced to create a hybrid system operating in both licensed and unlicensed spectrum at the same time. Specifically, Qualcomm is proposing a system that uses the carrier-aggregation (CA) feature of LTE Advanced to aggregate licensed LTE spectrum with unlicensed spectrum in the 5GHz band. The unlicensed spectrum, which would be aggregated with licensed spectrum on the downlink only, would only be used for data services. The licensed spectrum would be used for uplink and downlink and would support network control as well as voice and data services. Given the power limits placed on devices using the unlicensed 5GHz band, uLTEA would be used mainly in small cells, similar to Wi-Fi.

'All about 4G' did a good quick write-up on this topic from standards perspective, as follows:
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.

One of the big issue (though small cell vendors often play it down) that has been delaying the rollout of Small Cells has been interference management in co-channel deployment cases. The operators are worried about ad-hoc small cells creating interference with the properly planned and optimized Macro cells (though in practice its not as bad as they think it is). With LTE-U, this issue can be put to rest.

I can see LTE-U, if adopted, can also help create new business models around Small cells. Neutral Small cells, deployed in the hotspots like stadiums, shopping malls, etc. can serve users of all networks. The signalling can take care of each user connecting to its own network using backhaul.

Femto as a Service (FaaS) and Small Cells as a Service (SCaaS) would probably become a common approach as there would be no concerns about which spectrum is being used. 
There would be a small concern about interference between Wi-Fi and Small cells. Most of the existing Wi-Fi and other devices that use unlicensed spectrum use the 2.4GHz band with a few using 5GHz band now. If LTE-U uses the 'Listen Before Talk' approach, other technologies can be enhanced to probably do the same. Another thing worth remembering is that there is nearly 300MHz of spectrum in 5GHz band available universally. In certain countries the available spectrum can be as much as 500MHz. This should be enough for LTE-U as well as other technologies in the unlicensed spectrum.

The complete Qualcomm presentation is embedded below and is available to download from here: