Showing posts with label Carrier Aggregation. Show all posts
Showing posts with label Carrier Aggregation. Show all posts

Sunday, 29 October 2017

5G Forecasts and 5G Deployed Claim

Source: GSA

5G forecasts have been arriving steadily with many different figures. Here are some numbers:

Date Predicted by Number of Connections Year Any other comments
23-Aug-16 Strategy Analytics 690 million 2025 "690M Connections and 300M Handset Shipments"
15-Nov-16 Ericsson 500 million 2022 "North America will lead the way in uptake of 5G subscriptions, where a quarter of all mobile subscriptions are forecast to be for 5G in 2022."
30-Nov-16 ABI Research 500 million 2026 "500 Million 5G cmWave and mmWave Subscribers Will Bring $200 Billion in Service Revenue through 2026" - what about non mmWave/cmWave 5G subs?
12-Apr-17 CCS Insight 100 million 2021 "Smartphones sales will rise to 1.90 billion in 2021, when smartphones will account for 92 percent of the total mobile phone market."
26-Apr-17 GSMA 1.1 billion 2025 "5G connections are set to reach 1.1 billion by 2025, accounting for approximately one in eight mobile connections worldwide by this time."
16-May-17 Ovum 389 million 2022 "Ovum now forecasts that there will be 111 million 5G mobile broadband subscriptions at end-2021, up more than fourfold from Ovum’s previous forecast of 25 million 5G subscriptions at end-2021"
14-Aug-17 Juniper Research 1.4 billion 2025 "an increase from just 1 million in 2019, the anticipated first year of commercial launch. This will represent an average annual growth of 232%."
17-Oct-17 GSMA 214 million in Europe 2025 "30 per cent of Europe’s mobile connections will be running on 5G networks by 2025"
23-Oct-17 CCS Insight 2.6 billion 2025 "1 Billion Users of 5G by 2023, with More Than Half in China", "broadly similar path to 4G LTE technology...more than one in every five mobile connections."

If we just look at 2025/2026, the estimates vary from 500 million to 2.6 billion. I guess we will have to wait and see which of these figures comes true.

I wrote a post earlier titled '4G / LTE by stealth'. Here I talked about the operators who still had 3G networks while most people had 4G phones. The day the operator switched on the 4G network, suddenly all these users were considered to be on 4G, even if they didn't have 4G coverage just yet.

I have a few questions about what 5G features are necessary for the initial rollout and when can an operator claim they have 5G? In fact I asked this question on twitter and I got some interesting answers.

Just having a few 5G NR (new radio) sites enough for an operator to claim that they have deployed 5G? Would all the handsets with 5G compatibility then be considered to be on 5G? What features would be required in the initial rollouts? In case of LTE, operators initially only had Carrier Aggregation deployed, which was enough to claim they supported LTE-A. Would 100MHz bandwidth support be enough as initial 5G feature?

Please let me know what you think.

Tuesday, 26 September 2017

5G Dual Connectivity, Webinar and Architecture Overview

One of the things that will come as a result of NSA (Non-StandAlone) architecture will be the option for Dual Connectivity (DC). In fact, DC was first introduced in LTE as part of 3GPP Release 12 (see 3G4G Small Cells blog entry here). WWRF (Wireless World Research Forum) has a good whitepaper on this topic here and NTT Docomo also has an excellent article on this here.

A simple way to understand the difference between Carrier Aggregation (CA) and Dual Connectivity (DC) is that in CA different carriers are served by the same backhaul (same eNB), while in DC they are served by different backhauls (different eNB or eNB & gNB).


We have produced a short video showing different 5G architectures, looking mainly at StandAlone (SA) and Non-StandAlone (NSA) architectures, both LTE-Assisted and NR-Assisted. The video is embedded below:



Finally, 3GPP has done a short webinar with the 3GPP RAN Chairman Balazs Bertenyi explaining the outcomes from RAN#77. Its available on BrightTalk here. If you are interested in the slides, they are available here.

Related posts:

Sunday, 16 October 2016

Inside 3GPP Release-13 - Whitepaper by 5G Americas


The following is from the 5G Americas press release:

The summary offers insight to the future of wireless broadband and how new requirements and technological goals will be achieved. The report updates Release 13 (Rel-13) features that are now completed at 3GPP and were not available at the time of the publication of a detailed 5G Americas report, Mobile Broadband Evolution Towards 5G: 3GPP Release 12 & Release 13 and Beyond in June 2015.
The 3GPP standards have many innovations remaining for LTE to create a foundation for 5G.  Rel-12, which was finalized in December 2014, contains a vast array of features for both LTE and HSPA+ that bring greater efficiency for networks and devices, as well as enable new applications and services. Many of the Rel-12 features were extended into Rel-13.  Rel-13, functionally frozen in December 2015 and completed in March 2016, continues to build on these technical capabilities while adding many robust new features.
Jim Seymour, Principal Engineer, Mobility CTO Group, Cisco and co-leader of the 5G Americas report explained, “3GPP Release 13 is just a peek behind the curtain for the unveiling of future innovations for LTE that will parallel the technical work at 3GPP on 5G. Both LTE and 5G will work together to form our connected future.”
The numerous features in the Rel-13 standards include the following for LTE-Advanced:
  • Active Antenna Systems (AAS), including beamforming, Multi-Input Multi-Output (MIMO) and Self-Organizing Network (SON) aspects
  • Enhanced signaling to support inter-site Coordinated Multi-Point Transmission and Reception (CoMP)
  • Carrier Aggregation (CA) enhancements to support up to 32 component carriers
  • Dual Connectivity (DC) enhancements to better support multi-vendor deployments with improved traffic steering
  • Improvements in Radio Access Network (RAN) sharing
  • Enhancements to Machine Type Communication (MTC)
  • Enhanced Proximity Services (ProSe)
Some of the standards work in Rel-13 related to spectrum efficiency include:                                                                                                                       
  • Licensed Assisted Access for LTE (LAA) in which LTE can be deployed in unlicensed spectrum
  • LTE Wireless Local Area Network (WLAN) Aggregation (LWA) where Wi-Fi can now be supported by a radio bearer and aggregated with an LTE radio bearer
  • Narrowband IoT (NB-IoT) where lower power wider coverage LTE carriers have been designed to support IoT applications
  • Downlink (DL) Multi-User Superposition Transmission (MUST) which is a new concept for transmitting more than one data layer to multiple users without time, frequency or spatial separation
“The vision for 5G is being clarified in each step of the 3GPP standards. To understand those steps, 5G Americas provides reports on the developments in this succinct, understandable format,” said Vicki Livingston, Head of Communications for the association.

The whitepaper as follows:



Related posts:

Tuesday, 21 July 2015

TDD-FDD Joint Carrier Aggregation deployed


As per Analysis Mason, of the 413 commercial LTE networks that have been launched worldwide by the end of 2Q 2015, FD-LTE accounts for 348 (or 84%) of them, while TD-LTE accounts for only 55 (or 13%). Having said that, TD-LTE will be growing in market share, thanks to the unpaired spectrum that many operators secured during the auctions. This, combined with LTE-A Small Cells (as recently demoed by Nokia Networks) can help offload traffic from hotspots.

Light Reading had an interesting summary of TD-LTE rollouts and status that is further summarised below:
  • China Mobile has managed to sign up more than 200 million subscribers in just 19 months, making it the fastest-growing operator in the world today. It has now deployed 900,000 basestations in more than 300 cities. From next year, it is also planning to upgrade to TDD+ which combines carrier aggregation and MIMO to deliver download speeds of up to 5 Gbit/s and a fivefold improvement in spectrum efficiency. TDD+ will be commercially available next year and while it is not an industry standard executives say several elements have been accepted by 3GPP. 
  • SoftBank Japan has revealed plans to trial LTE-TDD Massive MIMO, a likely 5G technology as well as an important 4G enhancement, from the end of the year. Even though it was one of the world's first operators to go live with LTE-TDD, it has until now focused mainly on its LTE-FDD network. It has rolled out 70,000 FDD basestations, compared with 50,000 TDD units. But TDD is playing a sharply increasing role. The operator expects to add another 10,000 TDD basestations this year to deliver additional capacity to Japan's data-hungry consumers. By 2019 at least half of SoftBank's traffic to run over the TDD network.

According to the Analysis Mason article, Operators consider TD-LTE to be an attractive BWA (broadband wireless access) replacement for WiMAX because:

  • most WiMAX deployments use unpaired, TD spectrum in the 2.5GHz and3.5GHz bands, and these bands have since been designated by the 3GPP as being suitable for TD-LTE
  • TD-LTE is 'future-proof' – it has a reasonably long evolution roadmap and should remain a relevant and supported technology throughout the next decade
  • TD-LTE enables operators to reserve paired FD spectrum for mobile services, which mitigates against congestion in the spectrum from fixed–mobile substitution usage profiles.

For people who may be interested in looking further into migrating from WiMAX to TD-LTE, may want to read this case study here.


I have looked at the joint FDD-TDD CA earlier here. The following is from the 4G Americas whitepaper on Carrier Aggregation embedded here.

Previously, CA has been possible only between FDD and FDD spectrum or between TDD and TDD spectrum. 3GPP has finalized the work on TDD-FDD CA, which offers the possibility to aggregate FDD and TDD carriers jointly. The main target with introducing the support for TDD-FDD CA is to allow the network to boost the user throughput by aggregating both TDD and FDD toward the same UE. This will allow the network to boost the UE throughput independently from where the UE is in the cell (at least for DL CA).

TDD and FDD CA would also allow dividing the load more quickly between the TDD and FDD frequencies. In short, TDD-FDD CA extends CA to be applicable also in cases where an operator has spectrum allocation in both TDD and FDD bands. The typical benefits of CA – more flexible and efficient utilization of spectrum resources – are also made available for a combination of TDD and FDD spectrum resources. The Rel-12 TDD-FDD CA design supports either a TDD or FDD cell as the primary cell.

There are several different target scenarios in 3GPP for TDD-FDD CA, but there are two main scenarios that 3GPP aims to support. The first scenario assumes that the TDD-FDD CA is done from the same physical site that is typically a macro eNB. In the second scenario, the macro eNB provides either a TDD and FDD frequency, and the other frequency is provided from a Remote Radio Head (RRH) deployed at another physical location. The typical use case for the second scenario is that the macro eNB provides the FDD frequency and the TDD frequency from the RRH.

Nokia Networks were the first in the world with TDD-FDD CA demo, back in Feb 2014. In fact they also have a nice video here. Surprisingly there wasnt much news since then. Recently Ericsson announced the first commercial implementation of FDD/TDD carrier aggregation (CA) on Vodafone’s network in Portugal. Vodafone’s current trial in its Portuguese network uses 15 MHz of band 3 (FDD 1800) and 20 MHz of band 38 (TDD 2600). Qualcomm’s Snapdragon 810 SoC was used for measurement and testing.

3 Hong Kong is another operator that has revealed its plans to launch FDD-TDD LTE-Advanced in early 2016 after demonstrating the technology on its live network.

The operator used equipment supplied by Huawei to aggregate an FDD carrier in either of the 1800 MHz or 2.6 GHz bands with a TDD carrier in the 2.3 GHz band. 3 Hong Kong also used terminals equipped with Qualcomm's Snapdragon X12 LTE processor.

3 Hong Kong already offers FDD LTE-A using its 1800-MHz and 2.6-GHz spectrum, and is in the midst of deploying TD-LTE with a view to launching later this year.

The company said it expects devices that can support hybrid FDD-TDD LTE-A to be available early next year "and 3 Hong Kong is expected to launch the respective network around that time."

3 Hong Kong also revealed it plans to commercially launch tri-carrier LTE-A in the second half of 2016, and is working to aggregate no fewer than five carriers by refarming its 900-MHz and 2.1-GHz spectrum.

TDD-FDD CA is another tool in the network operators toolbox to help plan the network and make it better. Lets hope more operators take the opportunity to deploy one.

Sunday, 19 April 2015

3GPP Release-13 work started in earnest


The 3GPP news from some months back listed the main RAN features that have been approved for Release-13 and the work has already started on them. The following are the main features (links contain .zip files):

  • LTE in unlicensed spectrum (aka Licensed-Assisted Access) - RP-150055
  • Carrier Aggregation enhancements - RP-142286
  • LTE enhancements for Machine-Type Communications (MTC) - RP-141865
  • Enhancements for D2D - RP-142311
  • Study Item Elevation Beamforming / Full-Dimension MIMO - RP-141831
  • Study Item Enhanced multi-user transmission techniques - RP-142315
  • Study Item Indoor positioning - RP-141102
  • Study Item Single-cell Point-to-Multipoint (SC-PTM) - RP-142205


Another 3GPP presentation from late last year showed the system features that were being planned for Rel-13 as shown above.

I have also posted a few items earlier relating to Release13, as follows:


Ericsson has this week published a whitepaper on release 13, with a vision for 'Networked Society':
The vision of the Networked Society, where everything that benefits from being connected will be connected, places new requirements on connectivity. LTE is a key component in meeting these demands, and LTE release 13 is the next step in the LTE evolution.
Their whitepaper embedded below:



It should be pointed out that 5G work does not start until Release-15 as can be seen from my tweet

xoxoxo Added Later (26/04/2015) xoxoxo
I came across this presentation from Keysight (Agilent) where Moray Rumney has provided information in much more detail.


Sunday, 12 April 2015

LTE-Hetnet (LTE-H) a.k.a. LTE Wi-Fi Link Aggregation (LWA)


We have talked about the unlicensed LTE (LTE-U), re-branded as LTE-LAA many times on this blog and the 3G4G Small Cells blog. In fact some analysts have decided to call the current Rel-12 non-standardised Rel-12 version as LTE-U and the standardised version that would be available as part of Release-13 as LTE-LAA.

There is a lot of unease in the WiFi camp because LTE-LAA may hog the 5GHz spectrum that is available as license-exempt for use of Wi-Fi and other similar (future) technologies. Even though LAA may be more efficient as claimed by some vendors, it would reduce the usage for WiFi users in that particular spectrum.

As a result, some vendors have recently proposed LTE/WiFi Link Aggregation as a new feature in Release-13. Alcatel-Lucent, Ruckus Wireless and Qualcomm have all been promoting this. In fact Qualcomm has a pre-MWC teaser video on Youtube. The demo video is embedded as follows:



The Korean operator KT was also involved in demoing this in MWC along with Samsung and Qualcomm. They have termed this feature as LTE-Hetnet or LTE-H.

The Korean analyst firm Netmanias have more detailed technical info on this topic.

Link aggregation by LTE-H demonstrated at MWC 2015 (Source: Netmanias)

As can be seen the data is split/combined in PDCP layer. While this example above shows the practical implementation using C-RAN with Remote Radio Head (RRH) and BaseBand Unit (BBU) being used, the picture at the top shows LTE Anchor in eNodeB. There would be a need for an ideal backhaul to keep latency in the eNodeB to minimum when combining cellular and WiFi data.

Comparison of link level Carrier Aggregation technologies (Source: Netmanias)

The above table shows comparison between the 3 main techniques for increasing data rates through aggregation; CA, LTE-U/LAA and LTE-H/LWA. While CA has been part of 3GPP Release-10 and is available in more of less all new LTE devices, LTE-U and LTE-H is new and would need modifications in the network as well as in the devices. LTE-H would in the end provide similar benefits to LTE-U but is a safer option from devices and spectrum point of view and would be a more agreeable solution by everyone, including the WiFi community.

A final word; last year we wrote a whitepaper laying out our vision of what 4.5G is. I think we put it simply that in 4.5G, you can use WiFi and LTE at the same time. I think LTE-H fulfills that vision much better than other proposals.

Thursday, 23 October 2014

Detailed whitepaper on Carrier Aggregation by 4G Americas

4G Americas has published a detailed whitepaper on Carrier Aggregation (CA). Its a very good detailed document for anyone wishing to study CA.


Two very important features that have come as part of CA enhancements were the multiple timing advance values that came as a part of Release-11 and TDD-FDD joint operation that came part of Release-12

While its good to see that up to 3 carriers CA is now possible as part of Rel-12 and as I mentioned in my last post, we need this to achieve the 'Real' 4G. We have to also remember at the same time that these CA makes the chipsets very complex and may affect the sensitivity of the RF receivers.

Anyway, here is the 4G Americas whitepaper.


LTE Carrier Aggregation Technology Development and Deployment Worldwide from Zahid Ghadialy

You can read more about the 4G Americas whitepaper in their press release here.

Sunday, 24 August 2014

New LTE-A UE Category 9 and 10 in Rel-11

Its been a while since we saw any new UE categories coming but then I noticed some new categories came earlier this year for Release-11. The latest 3TPP TS 36.306 have these new Category 9 and Category 10 as follows.
For those who are aware of the categories of the UE's being used in practice may be aware that the most common ones have been 'Category 3' with 100Mbps max in DL and 50Mbps max in UL. The new 'Cat. 4' devices are becoming more common as more manufacturers start bringing these devices to the market. They support 150Mbps max in DL and 50Mbps max in UL. Neither of them supports Carrier Aggregation.

Having said that, a lot of Cat. 4 devices that we may use in testing actually supports carrier aggregation. The next most popular devices soon to be hitting the market is Cat. 6 UE's with 300Mbps max in DL and 50Mbps max in UL. Category 6 UE's support 2 x 20MHz CA in downlink hence you can say that they can combine 2 x Cat. 4 UE's in DL but they do not support CA in uplink hence the UL part remains the same as Cat. 4 device.

Cat. 9 and 10 are interesting case as Car. 8 was already defined earlier to meet IMT-A requirement as shown below.


To meet IMT-A requirements of peak data rates of 1Gbps in UL and DL, LTE-A had to define category 8 with 5 band CA and 8x8 MIMO to be able to provide 3Gbps max in DL and 1.5Gbps max in UL. No one sees this device becoming a reality in the short term.

The new categories will have to be defined from Cat. 9 onwards.

Cat. 9 allows 3 x Cat. 4 device CA in the downlink to have the maximum possible downlink data rates of 450Mbps but there is no CA in the uplink. As a result, the UL is still 50Mbps max. Cat. 10 allows carrier aggregation in the uplink for upto 2 bands which would result in 100Mbps max in UL.

The LG space website gives a better representation of the same information above which is shown below:



A UE category 9 transmits Rel 11 category 9 + Rel 10 category 6 + Rel 8 category 4

With Release-12 due to be finalised later in the year, we may see new UE categories being defined further.

Sunday, 20 July 2014

LA-LTE and LAA


Recently came across a presentation by Ericsson where they used the term LA-LTE. I asked a few colleagues if they knew or could guess what it means and they all drew blank. I have been blogging about Unlicensed LTE (a.k.a. LTE-U) on the Small Cells blog here. This is a re-branding of LTE-U

LA-LTE stands for 'Licensed Access' LTE. In fact the term that has now been adopted in a recent 3GPP workshop (details below) is Licensed Assisted Access (LAA).

Couple of months back I blogged in detail about LTE-U here. Since then, 3GPP held a workshop where some of the things I mentioned got officially discussed. In case you want to know more, details here. I have to mention that the operator community is quite split on whether this is a better approach or aggregating Wi-Fi with cellular a better approach.

The Wi-Fi community on the other hand is unhappy with this approach. If cellular operators start using their spectrum than it means less spectrum for them to use. I wrote a post on the usage of Dynamic Spectrum Access (DSA) Techniques that would be used in such cases to make sure that Wi-Fi and cellular usage does not happen at the same time, leading to interference.

Here is a presentation from the LTE-U workshop on Use cases and scenarios, not very detailed though.



Finally, the summary presentation of the workshop. As it says on the final slide "The current SI proposal focuses on carrier aggregation operations and uses the acronym LAA (Licensed Assisted Access)", you would be seeing more of LAA.


Friday, 4 July 2014

Cell capacity and Opportunistic Use of Unlicensed and Shared Spectrum

One very interesting presentation from the LTE World Summit was about Improving the cell capacity by using unlicensed and shared spectrum opportunistically. Kamran Etemad is a senior advisor to FCC & UCMP and even though he was presenting this in his personal capacity, it reflected some interesting views that are quite prevalent in the USA.

If you don't know about Dynamic Spectrum Access Schemes, I wrote a post on the Small Cells blog here. The slide above is quite interesting as it shows the possibility of a 'Generalized' Carrier Aggregation in 3GPP Release-13. Personally, we believe that LTE + WiFi working together will be far more successful than LTE + LTE-U (unlicensed). As the blog readers would be aware, we have been pushing our vision of LTE + Wi-Fi working together; which we are calling as 4.5G. In case if you have not seen, our whitepaper is here.

The presentation is embedded below for reference:


Saturday, 28 June 2014

EE: The Implications of RAN Architecture Evolution for Transport Networks


Here is a presentation by Andy Sutton, EE from the recent LTE World Summit 2014. Unfortunately the event was too big to be present in all presentations but in his own words, "As always the bullet points don’t tell the full story as there’s considerable narrative that goes with this, however it does stress some major themes."

Slides embedded below, can be downloaded from Slideshare:


Saturday, 26 April 2014

LTE Deployment Dilemma


Earlier this month during our Cambridge Wireless Small Cells SIG event, I presented a small quiz in the final session. The first part of the quiz was titled "LTE Deployment Dilemma" and it generated lots of interesting discussions. After the event, I did a more detailed writeup of that and Cisco has kindly published it in their SP Mobility Blog. Since many people have told me that they cannot anonymously post comments there, I am now bringing it to this blog. I am interested in hearing what others think.

Here is the complete post



Saturday, 15 March 2014

HSPA+ Carrier Aggregation



Came across Qualcomm's HSPA+ Carrier aggregation video (above) and whitepaper. Interesting to see that HSPA/HSPA+ is still growing. As per my earlier post, half of the connections in 2018 would be HSPA/HSPA+.

As can be seen in the picture above, there are quite a few features that may be of interest to the operators. Scalable UMTS is one such feature as I have put in the blog before.


You will notice that upto 4 bands can be aggregated. It would be interesting to see which operators have these bands available and if they would be willing to use HSPA+ CA with upto 4 bands. The presentation by Qualcomm is embedded below and is available to download from here.



Related posts:



Sunday, 27 October 2013

TDD-FDD Joint CA


From a recent NTT Docomo presentation (embedded below). Whereas right now 3GPP has only been working on FDD or TDD scenarios, this proposal is a combination of FDD as P-Cell and TDD as S-Cell. Inter-Technology carrier aggregation is another possible option. Anyway, the complete presentation is below.


LTE-Advanced Enhancements and Future Radio Access Toward 2020 and Beyond from Zahid Ghadialy

Updated on 29/10/2013

3GPP has already started working on this work item. See RP-131399 for details.

Thursday, 26 September 2013

Multi-stream aggregation (MSA): Key technology for future networks


In our recent 5G presentation here, we outlined multi-technology carrier aggregation as one of the technologies for the future networks. Some of the discussions that I had on this topic later on highlighted the following:
  1. This is generally referred to as Multi-stream aggregation (MSA)
  2. We will see this much sooner than 5G, probably from LTE-A Rel-13 onwards 


Huawei have a few documents on this topic. One such document is embedded below and aanother more technical document is available on slideshare here.



Monday, 24 June 2013

3 Band Carrier Aggregation in Release-12


So it looks like in the latest 3GPP RAN meeting finally more than 2 carriers have been proposed for Carrier Aggregation. The TDoclist has a few items on 3 carriers for CA. In some cases its been specified that there is 1 uplink component carrier (1UL CC) but in other cases its not specified and I have not looked into details. Its good to finally see more than 2 carriers being discussed.

Rohde&Schwarz have explained in one of their whitepapers about the numbering of CA bands.

Now there is a possibility that we may have 2 contiguous bands and 1 band from an Inter-band so the naming would be accordingly. There are also going to be new carrier types (NCT), Band 29 for example. See details here.

Finally, If you want to learn more about Carrier Aggregation (CA) or other LTE-Advanced features, my article from last year, here, would be useful.

Monday, 3 June 2013

New Carrier Type (NCT) in Release-12 and Band 29

One of the changes being worked on and is already available in Release-11 is the Band 29. Band 29 is a special FDD band which only has a downlink component and no uplink component. The intention is that this band is available an an SCell (Secondary cell) in CA (Carrier Aggregation). 

What this means is that if this is only available as an SCell, any UE that is pre-Rel-11 should not try to use this band. It should not read the system information, reference information, etc. In fact the System Information serves little or no purpose as in CA, the PCell will provide the necessary information for this SCell when adding it using the RRC Reconfiguration message. This gives rise to what 3GPP terms as New Carrier Type for LTE as defined here. An IEEE paper published not long back is embedded below that also describes this feature in detail. 

The main thing to note from the IEEE paper is what they have shown as the unnecessary information being removed to make the carrier lean.

China Mobile, in their Rel-12 workshop presentation, have suggested 3 different types/possibilities for the NCT for what they call as LTE-Hi (Hi = Hotspot and Indoor).

Ericsson, in their Rel-12 whitepaper mention the following with regards to NCT:

Network energy efficiency is to a large extent an implementation issue. However, specific features of the LTE technical specifications may improve energy efficiency. This is especially true for higher-power macro sites, where a substantial part of the energy consumption of the cell site is directly or indirectly caused by the power amplifier.

The energy consumption of the power amplifiers currently available is far from proportional to the power-amplifier output power. On the contrary, the power amplifier consumes a non-negligible amount of energy even at low output power, for example when only limited control signaling is being transmitted within an “empty” cell.

Minimizing the transmission activity of such “always-on” signals is essential, as it allows base stations to turn off transmission circuitry when there is no data to transmit. Eliminating unnecessary transmissions also reduces interference, leading to improved data rates at low to medium load in both homogeneous as well as heterogeneous deployments.

A new carrier type is considered for Release 12 to address these issues. Part of the design has already taken place within 3GPP, with transmission of cell-specific reference signals being removed in four out of five sub frames. Network energy consumption can be further improved by enhancements to idle-mode support.

The IEEE paper I mentioned above is as follows:



Monday, 1 April 2013

The 'Phantom Cell' concept in LTE-B


One of the LTE-B proposals by NTT Docomo is this 'Phantom Cell' concept. A recent article from the IEEE Communications Magazine expands this further:


Phantom Cell Concept — In the current deployments, there are a number of capacity solutions for indoor environments such as WiFi, femtocells, and in-building cells using distributed antenna systems (DAS). However, there is a lack of capacity solutions for high-traffic outdoor environments that can also support good mobility and connectivity. Thus, we propose the concept of macro-assisted small cells, called the Phantom Cell, as a capacity solution that offers good mobility support while capitalizing on the existing LTE network. In the Phantom Cell concept, the C-plane/U-plane are split as shown in Fig. The C-plane of UE in small cells is provided by a macrocell in a lower frequency band, while for UE in macrocells both the C-plane and U-plane are provided by the serving macrocell in the same way as in the conventional system. On the other hand, the Uplane of UE in small cells is provided by a small cell using a higher frequency band. Hence, these macro-assisted small cells are called Phantom Cells as they are intended to transmit UE-specific signals only, and the radio resource control (RRC) connection procedures between the UE and the Phantom Cell, such as channel establishment and release, are managed by the macrocell.

The Phantom Cells are not conventional cells in the sense that they are not configured with cell specific signals and channels such as cell-ID-specific synchronization signals, cell-specific reference signals (CRS), and broadcast system information. Their visibility to the UE relies on macrocell signaling. The Phantom Cell concept comes with a range of benefits. One important benefit of macro assistance of small cells is that control signaling due to frequent handover between small cells and macrocells and among small cells can be significantly reduced, and connectivity can be maintained even when using small cells and higher frequency bands. In addition, by applying the new carrier type (NCT) that contains no or reduced legacy cell-specific signals, the Phantom Cell is able to provide further benefits such as efficient energy savings, lower interference and hence higher spectral efficiency, and reduction in cellplanning effort for dense small cell deployments.

To establish a network architecture that supports the C/U-plane split, and interworking between the macrocell and Phantom Cell is required. A straightforward solution to achieve this is to support Phantom Cells by using remote radio heads (RRHs) belonging to a single macro eNB. This approach can be referred to as intra-eNB carrier aggregation (CA) using RRHs. However, such a tight CA-based architecture has some drawbacks as it requires single-node operation with low-latency connections (e.g., optical fibers) between the macro and Phantom Cells. Therefore, more flexible network architectures should be investigated to allow for relaxed backhaul requirements between macro and Phantom Cells and to support a distributed node deployment with separated network nodes for each (i.e., inter-eNB CA).


Tuesday, 5 March 2013

Technologies from Mobile World Congress 2013 (#MWC13)

If you liked the Gadgets roundup from yesterday then you would like this one as well:



You can read more about this topic here.



You can read more about this here.











You can read more about this here.


Finally:

Tuesday, 11 September 2012

New Carrier-Aggregation Proposed Bands

Carrier Aggregation (CA) the promised feature of LTE-A that will make it compatible to IMT-A is not fully exploited in Rel-10. There are only 2 bands supported for CA in Rel-10 and the same for Rel-11. The following are the bands for Rel-10

And the following for Rel-11

Unfortunately these are not enough for all the operators launching LTE/LTE-A. As a result there is currently a study on lots of other bands ongoing within 3GPP. Here is my understanding of the bands that would be needed and the region where they would be needed. Interested in knowing if there are other operators/regions where other bands need to be included.