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. 
• It should be mentioned that the target is to reach 300 million subscribers by end of 2015.
• 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.

Case Study: Migrating from WiMAX to TD-LTE

I was glad to hear this case study by Mike Stacey where they have a WiMAX network already deployed and are in process of moving to TD-LTE. Along with the technical issues there are also business and customer issues that need to be taken into account while doing this technology swap. Surprisingly 3.5GHz is also not a very popular band because there are very few deployments in this spectrum. On the other hand, most of the companies worldwide that have been able to get their hands on this spectrum, generally got a big chunk (60-100MHz) so they would be able to do CA easily (bar the technical issues of Intra-band interference).

Anyway, the presentation is embedded below. Hope you find it useful. If you know of similar experiences, please feel free to add them in the comments.

Overcoming Interference Challenges when migrating from WiMAX to LTE from Zahid Ghadialy

Spectral Efficiency Comparison

From the 4G Americas presentation

800MHz to be reserved for LTE and WiMAX in Europe

We were having a discussion in the LTE Linkedin group couple of days back about when devices would be ready in bands other than 2.6Gz. The 2.6GHz band has become a de facto standard for LTE but there are other bands at much lower bands that are gaining interest as well.

Here is something from Cellular News today:

The European Commission has adopted a Decision establishing harmonised technical rules for Member States on the allocation of radio frequencies in the 800 MHz band that contribute to the deployment of high-speed wireless internet services by avoiding harmful interference.

In several Member States the 800 MHz frequencies are being freed up as part of the so-called "digital dividend" resulting from the switchover from analogue to digital television broadcasting. If Member States decide to change the existing frequency allocation (for broadcasting) they must immediately apply the harmonised technical rules laid down by the Decision to make these frequencies available to wireless broadband applications. Today's decision does not itself require Member States to make available the 790-862 MHz band for electronic communication services. However, the Commission is considering such a proposal in the forthcoming Radio Spectrum Policy Programme.

The Commission strongly supports the use of the 790-862 MHz band (currently used for broadcasting in most Member States) for electronic communication services and wants EU countries to act quickly, as coordinated management of this spectrum could give an economic boost of up to EUR44 billion to the EU's economy and help to achieve the EU 2020 Strategy target of high-speed broadband for all by the end of 2013 (with speeds gradually increasing up to 30 Mbts and above in 2020).

The new Commission Decision stipulates that all Member States which decide to make available the 790-862 MHz spectrum band (the so-called 800 MHz band) for services other than broadcasting should apply the same harmonised technical rules when they do so. These technical rules will ensure that radio communications equipment, like handsets or base stations using the 800 MHz band, can be used efficiently for wireless broadband networks, such as LTE or WiMAX.

Telecoms industry experts estimate that infrastructure to provide mobile broadband coverage using the 800 MHz band will be around 70% cheaper than through using the radio frequencies currently used by 3G networks. The lower costs involved in rolling out such networks will make these investments more attractive for operators, which should improve the geographic coverage of wireless broadband services. Application of the technical rules for frequency allocation foreseen by this Decision will substantially increase the potential economic benefits of the digital dividend by giving a new impetus to wireless internet services.

Until now, the 800 MHz band has been used for terrestrial TV broadcasting in most Member States. The new rules laid down in the Decision set out conditions for allocation of nearly one quarter of the frequencies that will become available when Member States switch from analogue to digital broadcasting (due by end 2012). The Commission is currently working on a Radio Spectrum Policy Programme that will take into account the other elements of the digital dividend and may also include a common date by which all Member States must make the 800 MHz band available.

Also read this post.

The WiMAX taxis of Taiwan

LTE wont be coming to Taiwan until 2017. In fact, I am hoping that LTE-A would be available by then and Taiwan can skip LTE completely.

Taiwan is pushing WiMAX as a lot of small manufacturers based in Taiwan jumped in the WiMAX bandwagon at its peak. The main advantage with WiMAX being that there is no legacy GSM/UMTS baggage so the things are relatively simple. Having said that, this is also the main reason operators have not embraced the WiMAX technology.

See the Video above before reading the report from Telecom Asia below:

I’ve been to a number of Wimax conferences in the past few years, but this year’s Wimax Forum Asia show in Taipei marks the first time I could walk out of the conference hall and see a demo of Wimax in action.

As Telecom Asia reported last month, Vmax has launched a Wimax service in the capital, offering connectivity to 1,000 taxis.

I managed to catch one of them. The Wimax set-up featured a GPS-enabled touchscreen MID mounted on the back of the front passenger seat. Among other things, I could access a real-time navigation app that also displayed our driving speed, and – of course – streaming music videos.

The video was the real test, and it was YouTube quality – which is to say, acceptable – for the entire 15-minute trip.

If Vmax chief Teddy Huang is right about the service yielding “much more” than NT$500-NT$600 in ARPU per user, it’s not a bad testament to Wimax’s potential to carve out these kind of B2B niche services.

Or to allow users to come up with their own solutions. Another taxi I rode in had a mounted laptop next to the driver that was running GoogleMaps whilst playing a live local TV channel with good video quality.

All eyes on TD-LTE in India and China

The TD-SCDMA and Long Term Evolution (TD-LTE) network will be massively deployed in China, the world's largest telecommunications country by number of telecoms users, in 2010, globally premier international market research and consulting firm Infonetics Research said in a forecast report.

More and more mobile carriers have started developing the LTE, including Verizon Communications Inc., China Mobile Ltd., and China Telecom Corporation Ltd., Infonetics noted. There will be no more than twenty LTE networks in the world at the end of 2010.

China Mobile Communications, the largest mobile telecom carrier in China, will establish three experimental TD-LTE (time division-long term evolution) networks separately in three coastal cities - Qingdao, Xiamen and Zhuhai - beginning the third quarter of 2010, according to the China-based China Business News Daily.

China's Ministry of Industry and Information Technology (MIIT), the carrier, handset and component makers, and handset solution suppliers in China in late 2008 began to cooperate for the development of TD-LTE in three phases, the report said.

The first-phase trial of technological concepts completed in June 2009, and the ongoing R&D and experiments in the second phase will be finished at the end of June 2010, the report indicated, adding the third phase will begin with China Mobile setting up three trial networks in the third quarter.

China Mobile Communications, the largest mobile telecom carrier in China, on April 15 inaugurated its first experimental TD-LTE network at the site of the 2010 Shanghai World Expo.

The trial network consists of 17 outdoor TD-LTE base stations made by Huawei Technologies completely covering the 5.28km square site and will be used to provide mobile high-definition multimedia services.

ZTE and Datang Mobile Communications Equipment as well as Motorola and Alcatel-Lucent have also set up TD-LTE access points inside a number of pavilions.

Motorola, Inc.'s Networks business has already announced in February that it has successfully deployed a TD-LTE network at the Expo Center for World Expo 2010 Shanghai China, and completed the first indoor over-the-air (OTA) TD-LTE data sessions at the site. These advancements demonstrate another milestone of collaborative industry efforts on TD-LTE commercialization, reaffirming Motorola's commitment to address the future needs of TDD spectrum operators in China and around the world.

These milestones follow the announcement by China Mobile Communications Corporation (CMCC) in 2009, that Motorola was selected as main equipment supplier to provide indoor TD-LTE coverage for pavilions at Shanghai Expo. During the Shanghai Expo, Motorola will provide an advanced end-to-end TD-LTE solution and the world's first TD-LTE USB dongles. Motorola will also leverage its orthogonal frequency division multiplexing (OFDM) expertise with professional services to deploy, maintain and optimize these leading-edge networks. Visitors will be able to experience applications such as high-definition video on demand, remote monitoring and high-speed Internet access services.

Motorola, Inc.'s Networks business announced on April 16th that it showcased an end-to-end TD-LTE demonstration via the world's first TD-LTE USB dongle at the Shanghai Expo site to support the "TD-LTE Showcase Network Opening Ceremony" hosted in Shanghai on April 15. Delegates at the ceremony experienced applications that run over a TD-LTE network via USB dongles, including high-definition video wall (simultaneous 24 video streams), remote monitoring and high-speed Internet browsing applications. This latest advancement demonstrates a major milestone of the collaborative industry efforts in building a healthy TD-LTE device ecosystem, reaffirming Motorola's commitment to TDD spectrum operators around the world.

Motorola, a leading provider of TD-LTE technology, and China Mobile share the same commitment to accelerating TD-LTE commercialization and globalization. "We are very excited to support China Mobile in bringing the world's first TD-LTE USB dongle demonstration enabled by our TD-LTE system," said Dr. Mohammad Akhtar, corporate vice president and general manager, Motorola Networks business in Asia Pacific. "A healthy devices ecosystem has always been critical to the development, commercialization and success of wireless network technologies. We are working closely with partners to drive this ecosystem as demonstrated by the advancement announced today. TD-LTE is now a commercial reality and we are very pleased to see that industry players are joining forces to accelerate TD-LTE globalization."

Interest in TD-LTE continues to grow because of several key factors: the low cost of TDD spectrum that is particularly attractive to emerging and developing markets; operators' continuing need for more capacity and spectrum; and the ability to hand-off between TD-LTE and LTE FDD networks. In effect, this ability to roam between LTE FDD and TD-LTE means operators can use TD-LTE networks to augment their FDD LTE network for more capacity or other applications such as video broadcasting, while operators choosing to use TD-LTE as their "main" network can still offer their subscribers the ability to roam to other operators' FDD LTE networks in different countries. Motorola is one of the few vendors in the industry that has expertise in, and is committed to investing in both FDD-LTE and TD-LTE, as well as WiMAX. By leveraging its orthogonal frequency division multiplexing (OFDM) expertise and WiMAX legacy, Motorola has built up its leadership position in TD-LTE with a number of industry-firsts.

Nokia Siemens Networks has inaugurated a TD-LTE Open Lab at its Chinese Hangzhou R&D facility. TD-LTE smartphone and terminal manufacturers will be able to use the lab to test the interoperability and functionality of their devices across TD-LTE networks.

"The development of terminals and devices has always been a bottleneck in the roll-out of new mobile technology," said Mr. Sha Yuejia, vice president of China Mobile. "We are thus more than happy to see that Nokia Siemens Networks has established a cutting-edge terminal testing environment, an initiative that we support wholeheartedly. After all, a healthy ecosystem needs efforts from all stakeholders."

Nokia Siemens Networks' Open Lab will provide an end-to-end testing environment for verifying the compatibility of terminals and devices with the company's TD-LTE network products and solutions. The lab will also provide consultancy and testing services to device manufacturers. Nokia Siemens Networks' TD-LTE R&D center in Hangzhou is fully integrated into the company's global network of LTE Centers of Competence.

Providing a live TD-LTE experience to operators in the region, Nokia Siemens Networks also recently kicked off a nationwide TD-LTE road show in China. Beginning in Beijing, the road show will cover more than ten provinces in three months, demonstrating the most advanced TD-LTE technology and applications.

In India, Even as the government hopes to raise around $9 billion from the 3G and BWA auctions, foreign telcos waiting in the wings are eager to unfurl a new technology — TD-LTE —which is akin to 4G technology.

US-based Qualcomm and Sweden's Ericcson aim to piggyback on TD-LTE, hoping that it will help them gain a toe-hold in India, the world's fastest growing mobile market. Qualcomm is to participate in the broadband wireless access (BWA) spectrum auction. If it does secure its bid in the auction, India could well become the first country after China to roll out TD-LTE.

TD-LTE, or Time Division Long Term Evolution, caters to peak download speeds of 100 Mbps on mobile phones, compared to the 20 Mbps for 3G and 40 Mbps for Wimax. LTE brings to the table additional spectrum, more capacity, lower cost, and is essential to take mobile broadband to the mass market.

The government has slotted the sale of two 2.3 GHz blocks of spectrum on April 11, providing 20 MHz spectrum in each of the country's 22 telecom circles. The base price has been set at $ 385 million. However, Qualcomm will need an Indian partner for its TD-LTE foray in the country since foreign direct investment is limited to 74%.

The US telco aims to use the 2.3 GHz spectrum band offered for TD-LTE-based BWA services. Sources in the know told TOI that the company would bid aggressively to corner one of the two BWA slots up for sale. There are 11 bidders for the BWA auction.

Asked to comment on the market dynamics, Sandeep Ladda, executive director, PricewaterhouseCoopers (PWC), said: "Though the Indian market is huge, it won't be smooth sailing post auction. We are adding 1 crore customers a month and in January, we added 1.9 crore customers, but the implementation of the new technology has its own cost. And India is a very cost conscious market."

Eager to play by the rules in India, Qualcomm has notified that it would enter into a joint venture with an Indian partner to launch its services and later exit from the joint venture after the network becomes operable.

Meanwhile, The WiMAX Forum has gone on the defensive during the WiMAX Forum Congress Asia in Taipei, Taiwan. The group is speeding up its time table to deliver the next generation of WiMAX--a reaction to heavy data use among WiMAX subscribers as well as the looming threat posed by Qualcomm and Ericsson's lobbying for TD-LTE in India.

Recently, the forum launched a global initiative to accelerate advanced WiMAX features that would double peak data rates and increase average and cell edge end user performance by 50 percent.

Mo Shakouri, vice president with the WiMAX Forum, said enhancements to the current generation of WiMAX weren't on the forum's roadmap, but were brought to the forefront at the urging of several WiMAX operators already facing capacity crunches. The forum reports that the average usage of data on WiMAX networks is close to 10 GB. Clearwire recently reported that mobile users average more than 7 GB of usage per month. In Russia, mobile WiMAX operator Yota sees more than 1 GB per month in data traffic from subscribers using its HTC smartphone. For laptops, it's 13 GB per month.

"Demand for data is moving so fast that we were pushed by many people to add this functionality," Shakouri said.

The WiMAX Forum has also been prodded to announce more detailed plans for 802.16m, and step up the timeline for its development via a new group called the WiMAX 2 Collaboration Initiative, which is made up of vendors Samsung, Alvarion, Motorola, ZTE, Sequans, Beceem, GCT Semiconductor and XRONet. The companies will work in tandem with the WiMAX Forum and WiMAX operators to accelerate the next-generation standard. WiMAX 2, the marketing name for the 802.16m standard, is expected to expand capacity to 300 Mbps peak rates via advances in antennas, channel stacking and frequency re-use.

The forum previously forecast 802.16m would hit in 2012 or 2013. But increasing demands for data--coupled with Qualcomm and Ericsson urging Indian mobile broadband license bidders to go with TD-LTE--motivated the forum to put some stakes in the ground and declare that WiMAX 2 equipment will meet certification by the end of 2011.

"There has been a lot of noise about TD-LTE, and the WiMAX Forum had not specifically given dates regarding timelines for 802.16m," Shakouri said. "Basically our announcement around 802.16m came about because of the noise in India."

The formation of the WiMAX 2 Collaboration Initiative is a marked change from the way the first generation of WiMAX was developed. Sprint Nextel was the entity driving the majority of the standards work as it was eager to get to market and begin building an ecosystem. Vendors are now taking the lead and driving equipment readiness before the 802.16m standard is finalized by the end of this year. Shakouri said the standard is 95 percent finished.

"Those companies are going to take a more active role inside the forum," Shakouri said. "They have all come together to speed up the process."

The group of vendors plans to collaborate on interoperability testing, performance benchmarking and application development before the WiMAX Forum establishes its certification program to narrow the gap between the finalized standard and commercial rollouts.
So how much of a threat is TD-LTE to WiMAX? Shakouri said the answer depends on spectrum decisions. "At this moment, the spectrum we are focusing on is separate, aside from what Qualcomm announced in India," Shakouri said. He also said that a TD-LTE ecosystem is at least two to three years behind WiMAX.

Many analysts speculate that TD-LTE will become the crossover technology that will prompt WiMAX operators to flip to LTE. Clearwire was part of a group of operators and vendors that last month asked the 3GPP standards body to begin working on specifications that would enable TD-LTE to be deployed in the 2.6 GHz band, which Clearwire uses for WiMAX. During the CTIA Wireless 2010 trade show last month, Clearwire CEO Bill Morrow reiterated the company's interest in deploying LTE when the technology catches up to WIMAX. He also called for one standard down the road.

Another initiative the forum is announcing this week is the launch of its Open Retail Initiative, a global program aimed at driving WiMAX into consumer devices sold directly or through retail channels that can be activated by the consumer over the air on the network. If you remember the evangelism of early WiMAX advocates like Barry West, this capability was supposed to be the Holy Grail of the technology.

WiMAX gaining foothold in Japan

Photo Source

From Wireless Watch Japan:

The current state of the mobile network environment such as public wireless LAN and the cellular phone lines and those problems were considered last time. This time, the focus is applied to “Mobility WiMAX” of the new service that solves these problems, and it introduces the difference with an existing mobile network. The 2nd explains the point of the IEEE standard by which the specification of mobile WiMAX has been decided.

Mobile WiMAX that the business service started in July, 2009 is a new mobile network that did “Cousin removing” of public wireless LAN and the cellular phone line. It becomes “Communication method of the world standard using the micro wave (frequency band of 3GHz-30GHz)” with WiMAX if it translates literally by the one that “World Interoperability for Microwave Access” was abbreviated.

It is a word “Communication (Access)” the hope of you attention here. “Line from the telephone office to the terminal” is indicated if it is said, “Access line” in the world on the network. In a word, WiMAX is a method to achieve the same role as the accomplishment of “[Furettsu] light” of ADSL and NTT on a wireless network.

Actually, there is details of having started WiMAX as a network for not the mobile network but fixed wireless telecommunications (FWA: Fixed Wireless Access). FWA is a method to send and receive data to the antenna set up in the rooftop in the communication tower and the building between terminals. FWA up to maximum transmission speed 156Mbps is an opening in Japan in December, 1998.

WiMAX is wireless MAN(Metropolitan Area Network) standard to achieve this FWA. Institute of Electrical and Electronic Engineers (IEEE) has approved WiMAX as “IEEE 802.16″ in December, 2001.

The bandwidth of 2GHz-11GHz was added back though WiMAX used the bandwidth of improving named 10GHz-66GHz at first. And, the specification named maximum transmission speed 134.4Mbps (occupation bandwidth 28MHz time) or 74.81Mbps (occupation bandwidth 20MHz time) was fixed by the maximum in “IEEE 802.16-2004″ that had been approved in June, 2004 communication distance 48km.

It has corresponded to the handover at 120km per hour.
It reaches up to 4.8km at the speed of 40Mbps or less.

Mobile WiMAX equipped in mobile PC is a wireless network method settled on as derivation standard “IEEE 802.16e” of IEEE 802.16.

Mobility WiMAX is that the maximum difference point of fixation WiMAX of IEEE 802.16 and mobile WiMAX corresponds to the handover (succession) that assumes the movable body of 120km per hour.

In a word, mobile WiMAX is to be able to use it in the train and the car running just like the cellular phone because a surrounding base station communicates one after another in “Hand over” according to the communication situation. There is especially no inconvenience if it thinks the communication distance of the cellular phone is several km though the maximum communication distance of mobile WiMAX is 4.8km and fixation WiMAX 1/10.

It differs according to the occupation bandwidth, and if it is 32Mbps, and it is 20MHz if it is 15Mbps, and 10MHz if the occupation bandwidth is 5MHz, the maximum transmission speed of mobile WiMAX is 75Mbps. In UQ communications that develop mobile WiMAX service domestically, it is sung, “It is 40Mbps or less, and is up-loading, and it is download and 10Mbps or less”. It may be expected that the same degree of the speed as wireless LAN in the office will be obtained as long as the condition is avoided.

Another difference between fixation WiMAX and mobile WiMAX is in the size of the terminal side transmitter-receiver. In fixation WiMAX where long distance/high speed has been achieved by a big transmission output, a considerably big as for terminal side device is needed. On the other hand, the transmitter-receiver of mobile WiMAX is being put in several LSI chips small. An external type is the same degree of the size as USB thumb drive.

Moreover, note PC with built-in controller for mobile WiMAX has been released by each vender since the summer of 2009. The “Let’snote S8/N8″ series of Panasonic especially supports WiMAX by the standard in the consumer model (A corporate model is for subject).

Another strong point is a base station. Wide, mobile WiMAX covers the range where the electric wave reaches and even if the number of base stations is not increased too much, can cover the large range at the cellular phone level. Because it is possible to communicate while it moves by in the train and car, it will be able to be said that it will be a very profitable network for the business user who frequently uses the Web application.

The maintenance of the base station is advanced in domestic various places with steady steps now. I hear that it became possible to use in the government-designated major city and major cities across the country at the end of fiscal year 2009 according to UQ communications.

Note, this is machine translation so ignore the errors.

WiMAX Femtocell System Architecture

So what does it take to build a WiMAX Femtocell solution?

WiMAX Femtocell can be visualized as a scaled down version of WiMAX macro-cell solution. In addition to the capabilities of a WiMAX macro-cell, other required features of a WiMAX Femtocell are the following:

• Spectrum: WFAP operates over licensed spectrum using standard WiMAX wireless air interface and protocol.

• Form factor: WFAP can be standalone (similar to WiFi access points) or integrated with DSL or cable modems.

• Transport: WFAP uses transport network of subscribers’ DSL, FTTH or cable-based broadband connection.

• User Capacity: Since WFAP is deployed inside a building; a WFAP needs to support at least 5-6 subscribers.

• Power Output: With a range of roughly 10 meters, power output should be kept very low, no more than a 2.4 GHz WiFi product.

• Deployment Support: Operating in a licensed spectrum a WFAP may face interference from neighboring base stations (femto or macro). Therefore, a WFAP should have the capabilities to automatically adjust to minimize the interference.

• Local Breakout: A WFAP should optionally support the capability to route incoming or outgoing traffic directly to the destination through the Internet Service Provider (ISP) network. This approach will bypass the WiMAX service provider network, thus offloading WiMAX service provider network and reducing the cost of service to the subscriber.

• Performance: A Femtocell solution should fit as per the WiMAX network architecture defined by the WiMAX forum. The deployment should not limit the number of WFAPs that are able to connect with a designated ASN Gateway unless operator specified. A network deployment should allow different ISPs to connect WFAP with ASN Gateway in the core network.

• Hand-over: A Femtocell solution should allow handovers between WFAP and WiMAX macro cells or with other adjacent WFAPs.

• Security: A Femtocell solution should use a secure channel of communication (for both control plane and data plane) with ASN Gateways in the core network. The core network must authenticate and authorize a WFAP before it starts offering services to MS/SS in its coverage area. A WFAP may authenticate the ASN Gateway with which it gets connected. A WFAP should keep its air interface disabled unless it is authenticated and authorized to start communication with the ASN Gateway in the core network. A Femtocell may support close subscriber group (CSG) database i.e. a list of subscribers allowed to access the WFAP, and its management.

• Accounting: For providing different rate plans to subscribers accessing services through WFAP, a WFAP needs to make sure that it is recognized by the core network.

• Location Information: A WFAP should support location identification procedures with the core network. Location information can then be used for emergency services or location based services.

• Air Interface: A WFAP should provide at least 10 meters of coverage area in a residential set up without any exclusion zone around it.

• Network Synchronization: A WFAP should support mechanism to synchronize with external network to provide services that require strict air interface co-ordination. Some of the services are soft-handovers, support for idle mode paging, and multicast-broadcast (MCBCS) services.

• Quality of Service: A WFAP should support marking of incoming/outgoing packets with appropriate DSCP code, as configured by a service provider. This would allow support for defined service level agreements (SLAs) when the service is delivered through a WFAP.

• Manageability: A WFAP should implement DSL forum’s defined TR069 protocol to allow an operator to remotely manage a WAFP. It must allow an operator to remotely disable/enable the air interface service.

The WiMAX network architecture for femtocell systems is based on the WiMAX basic network reference model that differentiates the functional and business domains of NAPs from those of the network service providers (NSPs). The NAP is a business entity that provides and manages WiMAX radio access infrastructure, while the NSP is the business entity that manages user subscriptions, and provides IP connectivity and WiMAX services to subscribers according to negotiated service level agreements (SLAs) with one or more NAPs. A NAP is deployed as one or more access service networks (ASNs), which are composed of ASN gateways and BSs, while the NSP includes a home agent, authentication, authorization, and accounting (AAA), and other relevant servers and databases.

In a WiMAX network supporting a femtocell, a new business entity called the femto-NSP is introduced, which is responsible for the operation, authentication, and management of WFAPs. The femto-NSP is logically separated from the conventional WiMAX NSPs responsible for MSs’ subscriptions, and it includes femto-AAA and femtocell management/self-organizing network (SON) subsystems.

The femtocell management system is an entity to support operation and maintenance (O&M) features of the WFAP based on TR-069 or DOCSIS standards. Because potentially many femto BSs will be deployed in overlay coverage of macrocell BSs and have to support handover to/from macrocell BSs or neighbor femto BSs, the operating parameters of femto BSs have to be well organized and optimized. Femto BS parameter configuration and network performance, coverage, and capacity optimization can be done in an autonomous fashion by using SON functions. A SON server provides SON functions to measure/analyze performance data, and to fine-tune network attributes in order to achieve optimal performance.

A femto-NAP implements its infrastructure using one or more femto-ASNs; an ASN is defined as a complete set of network functions needed to provide radio access to a WiMAX femtocell subscriber. The reference model for a the femto-ASN is defined based on some changes to the conventional ASN to address specific needs of WFAPs, which typically reside at customer premises, and are operated and managed remotely by a femtocell operator over third party IP broadband connection. The femto-ASN reference model includes a WFAP connected to a femto-GW serving as the ASN-GW, through a new entity called a security gateway (SeGW). The SeGW provides IP Security (IPsec) tunnels for WFAPs, and is responsible for authentication and authorization of the WFAPs. The WFAP is connected to a femto-ASN gateway (femto-ASN GW) and other functional entities in the network through this IPsec tunnel. The management system is connected to WFAP through Rm for remote configuration, and it will also include the SON server function, to be defined in the next releases of the femto architecture.

The femto-ASN GW is an entity that controls WFAPs, and performs bearer plane routing to the CSN and Internet as well as control plane functions similar to ASN-GW providing the link to the connectivity service network (CSN) and other ASNs with mobility and security support in the control plane and IP forwarding. In addition to common functionalities of the ASN-GW, the femto-ASN GW supports femto-specific functionalities such as closed subscriber group (CSG) subscriber admission control, femtocell handover control, WFAP low-duty mode management, and femtocell interference management.

Image Reference: WiMAX Femtocell: Requirements, Challenges, and Solutions

The Secret world of WiMAX Femtocell

We have talked of WiMAX femtocells before and since I have mostly been focussing on 3GPP standardised Femtocell, I thought it is wise to focus on WiMAX femtocell and learn more about its terminology and implementation. Whenever possible, I will draw comparisons with the 3GPP femtos and try to provide more insight if I can.

Surprisingly I found it difficult to find the information on WiMAX femtocells. I am sure its not because no one is interested in the technology but its more because of the standards not being available in public domain. An old article on Think Femtocell informs us of the initial players of WiMAX femtocells. I havent tried digging in who is doing what in the WiMAX femtocell world, so if you are aware of potential players, feel free to highlight them via comments.

In WiMAX terminology, femtocells are known as femto base stations (BSs) or WiMAX femto access points (WFAPs). They are intended to serve the same purpose as the 3GPP femtocell that I have mentioned time and again. WiMAX as a technology is intended for data and voice can be an OTT application. In a way its a disadvantage for this technology but can be considered as an advantage as it doesnt have the baggage of old Circuit Switched system.

Another thing that I should clarify here is that WiMAX is intended to operate in licensed spectrum and so are the WFAPs. All femtocells start playing important role when high data rates are required and when the operating frequencies are high. Higher frequencies means lower penetration inside homes and the signal inside the offices can be easily enhanced with femtocells (or for that matter picocells in big buildings).

The WiMAX Forum has commenced the development of femtocell standards in two phases. The first phase is based on IEEE 802.16-2009 (aka 802.16Rev2) and system profile Release 1.0 or Release 1.5, so no change in the air interface standard or legacy MS is required to enable basic femtocell deployments. Some optional software upgradable enhancements in the MS may be used to enable additional femtocell functionalities only for such femto-aware MSs. The network framework to support femtocells in phase 1 is being developed in the WiMAX Forum as part of Network Working Group (NWG) release 1.6. The complete end-to-end femtocell specifications are expected to be finalized by the end of 2009. The second phase of WiMAX femtocell development, which brings additional functionalities and more optimal performance, will be introduced in system profile and network Release 2 based on the 802.16m air interface. The evolution to phase 2, which is expected to be completed by 2011–2012, enables enhanced femtocell systems with 802.16m MSs’ advanced functionalities while continuing the support of phase 1 legacy MSs with basic functionalities. Femtocells are expected to play an important role in terms of cost-effective delivery of new services, such as multimedia, gaming, social networking, and other demanding applications with the high quality of service (QoS) level expected by users in an indoor environment. However, femtocells are in an early stage of development and have some technical challenges to overcome.

Image Reference: WiMAX Femtocells Whitepaper - Aricent

Content Reference: WiMAX Femtocell: Requirements, Challenges, and Solutions

WiMAX Network reference model

Continuing from yesterdays post.

The WiMAX network architecture is designed to meet the requirements while maximizing the use of open standards and IETF protocols in a simple all-IP architecture. Among the design requirements are supports for fixed and mobile access deployments as well as unbundling of access, connectivity, and application services to allow access infrastructure sharing and multiple access infrastructure aggregation.

The baseline WiMAX network architecture can be logically represented by a network reference model (NRM), which identifies key functional entities and reference points over which the network interoperability specifications are defined. The WiMAX NRM differentiates between network access providers (NAPs) and network service providers (NSPs). The NAP is a business entity that provides WiMAX radio access infrastructure, while the NSP is the business entity that provides IP connectivity and WiMAX services to WiMAX subscribers according to some negotiated service level agreements (SLAs) with one or more NAPs. The network architecture allows one NSP to have a relationship with multiple NAPs in one or different geographical locations. It also enables NAP sharing by multiple NSPs. In some cases the NSP may be the same business entity as the NAP.

The WiMAX NRM, as illustrated in Fig. 3, consists of several logical network entities: MSs, an access service network (ASN), and a connectivity service network (CSN), and their interactions through reference points R1–R8. Each MS, ASN, and CSN represents a logical grouping of functions as described in the following:

• Mobile station (MS): generalized user equipment set providing wireless connectivity between a single or multiple hosts and the WiMAX network. In this context the term MS is used more generically to refer to both mobile and fixed device terminals.

• Access service network (ASN): represents a complete set of network functions required to provide radio access to the MS. These functions include layer 2 connectivity with the MS according to IEEE 802.16 standards and WiMAX system profile, transfer of auathentication, authorization, and accounting (AAA) messages to the home NSP (HNSP), preferred NSP discovery and selection, relay functionality for establishing layer 3 (L3) connectivity with MS (i.e., IP address allocation), as well as radio resource management. To enable mobility, the ASN may also support ASN and CSN anchored mobility, paging and location management, and ASN-CSN tunneling.

• Connectivity service network (CSN): a set of network functions that provide IP connectivity services to WiMAX subscriber(s). The CSN may further comprises network elements such as routers, AAA proxy/ servers, home agent, and user databases as well as interworking gateways or enhanced broadcast services and location-based services.

A CSN may be deployed as part of a green field WiMAX NSP or part of an incumbent WiMAX NSP. The following are some of the key functions of the CSN:–IP address management–AAA proxy or server–QoS policy and admission control based on user subscription profiles–ASN-CSN tunneling support –Subscriber billing and interoperator settlement–Inter-CSN tunneling for roaming–CSN-anchored inter-ASN mobility–Connectivity to Internet and managed WiMAX services such as IP multimedia services (IMS), location-based services, peer-to-peer services, and broadcast and multicast services –Over-the-air activation and provisioning of WiMAX devices

• Base station (BS): a logical network entity that primarily consists of the radio related functions of an ASN interfacing with an MS over-the-air link according to MAC and PHY specifications in IEEE 802.16 specifications subject to applicable interpretations and parameters defined in the WiMAX Forum system profile. In this definition each BS is associated with one sector with one frequency assignment but may incorporate additional implementation-specific functions such as a DL and UL scheduler.

• ASN gateway (ASN-GW): a logical entity that represents an aggregation of centralized functions related to QoS, security, and mobility management for all the data connections served by its association with BSs through R6t. The ASN-GW also hosts functions related to IP layer interactions with the CSN through R3 as well as interactions with other ASNs through R4 in support of mobility.

Typically multiple BSs may be logically associated with an ASN. Also, a BS may be logically connected to more than one ASN-GW to allow load balancing and redundancy options. The WiMAX network specification defines a single decomposed ASN profile (ASN C) with an open R6 interface as well as an alternative ASN profile B that may be implemented as an integrated or a decomposed ASN in which R6 is proprietary or not exposed. The normative definitions of intra-ASN reference points (R6 and R8) are only applicable to profile C. Note that in release 1.5 profile A has been removed to reduce the number of implementation options and create a better framework for network interoperability.

Reference: Overview of Mobile WiMAX Technology and Evolution - Kamran Etemad, Intel Corporation

Mobile WiMAX technology and network evolution roadmap.

The Mobile WiMAX Release 1.0 System Profile, based on 802.16e or 802.16-2005, was completed in late 2006, and the radio-level certification of products began in 2007. The certification follows a phased approach to address deployment priorities and vendor readiness. System Profile Release 1.0 includes all 802.16-2005 mandatory features, and also requires some of the optional features needed for enhanced mobility and QoS support. This system profile is based on OFDMA, and enables downlink and uplink multiple-input multipleoutput (MIMO) as well as beamforming (BF) features. The release 1.0 system profile is defined only for the TDD mode of operation, with more focus on 5 and 10 MHz bandwidths in several band classes in 2.3 GHz, 2.5 GHz ,and 3.5 GHz bands, but it also includes 8.75 MHz specifically for Korea.

The WiMAX certification for the release 1.0 profile started with a Wave 1 subset, excluding MIMO and a few optimization features, to enable early market deployments. This was followed by Wave 2, which progressively adds more and more feature tests over time based on vendors and testing tool availability. The early phases of certification were also limited to MAC and PHY layer conformance and interoperability testing, which will be expanded to add networklevel testing.

Meanwhile, the development of WiMAX Forum Network Release 1.0 was completed in 2007, based on which the specific network-level device conformance testing as well as infrastructure interoperability testing projects were initiated. The goal was to ensure e2e interoperability of WiMAX devices with networks and also ensure multivendor plug and play network infrastructure deployments. Release 1.0 defines the basic architecture for IP-based connectivity and services while supporting all levels of mobility. Based on operators’ requirements for advanced services and new market opportunities to be more competitive with evolved 3G systems, the WiMAX Forum initiated interim releases for both the system profile and network without major modifications to the IEE 802.16 standard. The work on network release 1.5 network specifications was started in parallel, aimed primarily at enabling dynamic QoS and provisioning of open retail device and support for advanced network services as well as commercial grade VoIP.

The release 1.5 system profile work item was initiated to enable mobile WiMAX in new spectrum including frequency-division duplex (FDD) bands, address a few MAC efficiency improvements needed for technology competitiveness, and align the system profile with advanced network services supported by network release 1.5. All required fixes and minor enhancements needed to support release 1.5 are incorporated in IEEE 802.16 REV2, which combines the IEEE 802.16-2004 base standard plus IEEE 802.16e/f/g amendments and related corrigenda into one specification document.

Following Release 1.5, the next major release mobile WiMAX, Release 2.0, will be based on the next generation of IEEE 802.16, which is being developed in the 16m technical group (TGm) of 802.16. WiMAX Release 2 targets major enhancements in spectrum efficiency, latency, and scalability of the access technology to wider bandwidths in challenging spectrum environments. Currently the expected timeline for the formal completion of 802.16m and WiMAX Certification of Release 2 products are early 2010 and early 2011, respectively.

In parallel with developments in IEEE on the stage 2 system-level description of 802.16m, the requirements for network release 2.0 are being discussed in the WiMAX Forum, where stage 2/3 specifications are expected to be completed by 2010.

Reference: Overview of Mobile WiMAX Technology and Evolution - Kamran Etemad, Intel Corporation

IMT-Advanced Proposals by 3GPP and IEEE

The proposals for IMT-Advanced that I mentioned about earlier have been put up on 3G4G website.

The 3GPP proposal for LTE-Advanced is here.

The IEEE proposal for 802.16m is here.

On Relay Technology in LTE-Advanced and WiMAX standards

I blogged earlier about Relay technology that is part of LTE-Advanced. In the IEEE Communications Magazine, this month there is a complete article on Relay technology. Here is a brief summary from that paper with my own understanding (and words).

We have mentioned about IMT-Advanced and LTE-Advanced before. International Mobile Telecommunications-Advanced is going to be the first 4G technology and as i discussed earlier, there are two main technologies vying for the 4G crown. I am sure both are as good and both will succeed. From 3GPP point of view, the standards will be part of Release-10 and should be ready end 2010 or beginning 2011. The understanding is that IMT-Advanced systems will support peak data rates of 100 Mb/s in high mobility environment (up to 350 km/h) and 1 Gb/s in stationary and pedestrian environments (up to 10 km/h). The transmission bandwidth of IMT-Advanced systems will be scalable and can change from 20 to 100 MHz, with downlink and uplink spectrum efficiencies in the ranges of [1.1, 15 b/s/Hz] and [0.7, 6.75 b/s/Hz], respectively. There will be a minimum requirement on voice over IP (VoIP) capacities in high- and low-mobility environments of around 30 and 50 active users/sector/MHz. The latency for control and user planes should be less than 100 ms and 10 ms, respectively, in unloaded conditions.


As I mentioned last week, the 3GPP candidate for IMT-Advanced is LTE-Advanced. On the IEEE front, 802.16j group published the relay-based multihop techniques for WiMAX and IEEE 802.16m has been submitted for the IMT-Advanced approval last week. The normal 802.16 WiMAX standard has been approved as 3G standard by the ITU.

So what exactly are Relays. Relay transmission can be seen as a kind of collaborative communications, in which a relay station (RS) helps to forward user information from neighboring user equipment (UE)/mobile station (MS) to a local eNode-B (eNB)/base station (BS). In doing this, an RS can effectively extend the signal and service coverage of an eNB and enhance the overall throughput performance of a wireless communication system. The performance of relay transmissions is greatly affected by the collaborative strategy, which includes the selection of relay types and relay partners (i.e., to decide when, how, and with whom to collaborate).



There are two different terminology used for Relay's. First is Type-I and Type-II and other is non-transparency and transparency. Specifically, a Type-I (or non-transparency) RS can help a remote UE unit, which is located far away from an eNB (or a BS), to access the eNB. So a Type-I RS needs to transmit the common reference signal and the control information for the eNB, and its main objective is to extend signal and service coverage. Type-I RSs mainly perform IP packet forwarding in the network layer (layer 3) and can make some contributions to the overall system capacity by enabling communication services and data transmissions for remote UE units. On the other hand, a Type-II (or transparency) RS can help a local UE unit, which is located within the coverage of an eNB (or a BS) and has a direct communication link with the eNB, to improve its service quality and link capacity. So a Type-II RS does not transmit the common reference signal or the control information, and its main objective is to increase the overall system capacity by achieving multipath diversity and transmission gains for local UE units.

Different relay transmission schemes have been proposed to establish two-hop communication between an eNB and a UE unit through an RS. Amplify and Forward — An RS receives the signal from the eNB (or UE) at the first phase. It amplifies this received signal and forwards it to the UE (or eNB) at the second phase. This Amplify and Forward (AF) scheme is very simple and has very short delay, but it also amplifies noise. Selective Decode and Forward — An RS decodes (channel decoding) the received signal from the eNB (UE) at the first phase. If the decoded data is correct using cyclic redundancy check (CRC), the RS will perform channel coding and forward the new signal to the UE (eNB) at the second phase. This DCF scheme can effectively avoid error propagation through the RS, but the processing delay is quite long. Demodulation and Forward — An RS demodulates the received signal from the eNB (UE) and makes a hard decision at the first phase (without decoding the received signal). It modulates and forwards the new signal to the UE (eNB) at the second phase. This Demodulation and Forward (DMF) scheme has the advantages of simple operation and low processing delay, but it cannot avoid error propagation due to the hard decisions made at the symbol level in phase one.

Relay starts becoming interesting because according to the 3GPP LTE-Advanced and IEEE 802.16j, an RS can act as the BS for legacy UE units and should have its own physical cell identifier. It should be able to transmit its own synchronization channels, reference symbols and downlink control information. So an RS shall have the full functions of an eNB/BS (except for traffic backhauling), including the capabilities of knowing the radio bearer of received data packets and performing traffic aggregation to reduce signaling overhead. There should be no difference between the cell controlled by an RS and that controlled by a normal eNB.

There are much more details and simulation results in the IEEE article. For those interested, can always get hold of the article and dig deeper.

More information also available in the following:

• Future 3GPP Radio technologies for IMT-Advanced
• Initial thoughts on LTE-Advanced for 3GPP Release-10
• Consideration on Technical candidates for IMT-Advanced
  

IMT-Advanced Proposals to be discussed next week

Depending on which camp you belong to, you would have read atleast one press release.

The 3GPP Partners, which unite more than 370 leading mobile technology companies, made a formal submission to the ITU yesterday, proposing that LTE Release 10 & beyond (LTE-Advanced) be evaluated as a candidate for IMT-Advanced. Complete press release here.

The IEEE today announced that it has submitted a candidate radio interface technology for IMT-Advanced standardization in the Radiocommunication Sector of the International Telecommunication Union (ITU-R).

The proposal is based on IEEE standards project 802.16m™, the “Advanced Air Interface” specification under development by the IEEE 802.16™ Working Group on Broadband Wireless Access. The proposal documents that it meets ITU-R’s challenging and stringent requirements in all four IMT-Advanced “environments”: Indoor, Microcellular, Urban, and High Speed. The proposal will be presented at the 3rd Workshop on IMT-Advanced in Dresden on 15 October in conjunction with a meeting of ITU-R Working Party 5D. Complete press release here.

The workshop next week will see lots of announcements, discussions and debates about both these technologies. More details on workshop here. My 3G4G page on LTE-Advanced here.

I am sure there is a place for both these technologies and hopefully both of them will succeed :)

OFDMA Femtocells: A Roadmap on Interference Avoidance

Earlier, I have blogged about LTE femtocells being starting point of LTE and how LTE can be better technology than HSPA. In this months IEEE Communications magazine, there is a series of articles on Femtocells. I will try and cover some of these (unless I wander off in some other direction). The first one is titled 'OFDMA Femtocells: A Roadmap on Interference Avoidance'. At the end of this post, I have provided links to the research and the actual paper (in a legal way ;) so if you are not interested in the post and want to directly jump on the actual paper see the end of this post.

There are all kinds of statistics about the number of Femtocells worldwide. There could be upto 70million by 2012. If this happens the big problem would be the interference between Macro and Femtocells and also between Femtos. OFDMA (used in LTE and WiMAX both) Femtocells can handle the interference better than CDMA (UMTS and CDMA2000) Femtocells due to its Intracell interference avoiding properties and robustness to multipath.

So what are the main problems that the operators will face when deploying femtocells? Lets look at some of them:

• Access method: Three different approaches exist namely, Open access, Closed access and Hybrid access which is a mix of both of them. The first two approach has some problems and I have suggested a solution before ;) but the best solution may be to go for Hybrid approach where limited connectivity is available to non-subscribers of the femto.
• Time Synchronisation is another important aspect of OFDMA Femtos. To minimise multi-access interference and for successful handovers, synchronisation between all the Femtos and between Femto and Macro is a must. This should be acheived without any complicated hardware so as to keep the cost down.
• Physical Cell Idendities (PCI) could be a problem because of limited numbers
• Neighbouring cell list, which is restricted to 32 in LTE, could be a problem if too many Femtos are around
• Handovers could also be a problem if the UE keeps jumping between Femtos and macro. One solution could be the use of HCS.

Interference analysis will definitelty play an important part in the rollouts. If not properly managed, could result in dead zones within Macro. Power control Algorithms and Radio Resource Management strategy will help but effective Spectrum allocation technique is needed as well. The diagram above shows different approaches for subchannel allocation in OFDMA femtocells.


The Femtocells would need to be self-configurable and self-optimising. I tried to explain the SON concept earlier which is similar. Self-configuration comes into picture when the Femto is switched on. Once the parameters are adjusted then Self-Optimisation tries to optimise these defaults into something better and more suited to the current environment. Sensing of the environment plays an important part in this. The diagram above shows different approaches being used by different Femtocells. The cheapest approach would ofcourse be the measurement report approach where the phone is made to report the environment. The only problem being that whichever phone was used (automatically selected) will have considerable amount of its battery power used up :)

The team behind this IEEE paper has been doing some excellent research work in the field of femtocells.

There is a book that is under publication and will be available early next year. At the same time if it interests you, you can look at some of their publications including the IEEE one that has been quoted here. Here are all the necessary links:

• The Centre for Wireless Network Design
• Professor Jie Zhang homepage
• David López-Pérez, Research Fellow, homepage
• Femtocells World Summit presentation on Self-organisation of the Subchannel Assignment in OFDMA Femtocells
• OFDMA Femtocells: A Roadmap on Interference Avoidance - IEEE Communications magazine, Sep. 2009
• ICC 2009: Femtocells panel presentation slides

Hope someone finds all this info useful :)

Wireless Subscribers Forecast 2014

Source: Informa Telecoms & Media, WCIS+, June 2009

Via: 3G Americas Whitepaper, HSPA to LTE-Advanced: 3GPP Broadband Evolution to IMT-Advanced (4G)

Samsung claims First commercial LTE Modem development

Samsung Electronics Co. Ltd., announced that it has developed the first Long Term Evolution (LTE) modem that complies with the latest standards of the 3rd Generation Partnership Project (3GPP), which were released in March 2009. Utilizing Release 8 of the 3GPP, this LTE modem is a significant upgrade from the previous standard that was released in December 2008.

The modem, branded the Kalmia, supports download speed up to 100Mbps and upload speed of 50Mbps within the 20MHz frequency bandwidth. Users of a mobile device equipped with the LTE chipset can download a high-definition movie file (800MB) in one minute at speeds of 100Mbps, while simultaneously streaming four high-definition movies with no buffering.

Samsung also announced it has successfully developed a 3G baseband modem based on the Release 7 standard with an HSPA (High Speed Packet Access) Evolution platform.

This modem, branded the Broom, allows download speeds of up to 28Mbps and upload speeds of 11.5 Mbps. This makes the Release 7 more than twice as fast as the Release 6 HSPA Service, which had a maximum download speed of 14.4Mbps.

Separately, Samsung Electronics has also developed the mobile WiMAX (IEEE 802.16e) modem chip, a product that is already resonating in the mobile market. The company has already adopted the modem into commercial WiBro handsets in Korea. With this new modem, Samsung has delivered WiMAX and LTE model solutions, which are the two major wireless mobile communications systems for the next generation. The company has also demonstrated a full lineup of modems from 2G/3G to modems for the next generation of mobile telecommunication systems with its HSDPA Evolution modems.

Samsung is also strengthening its position as a leader in mobile telecommunication system standards. Samsung currently holds the most chairman seats within the IEEE 802.16 Working Group, a WiMAX standardization association, and also chairs the WiMAX Forum, an affiliate organization. Additionally, Samsung is highly influential in securing many leading positions in other organizations such as the Technology Working Group.

At 3GPP, an association that specifies standards for LTE, Samsung ranks in the top group according to its number of contributions and has four seats in the wireless networking standardization working group executive board. Samsung has also served as the chair for two years in the steering committee of LSTI (LTE/SAE Trial Initiative), an organization that works closely with LTE. The company is also actively participating in various programs for NGMN (Next Generation Mobile Networks), a business association of global and leading mobile operators.