802.11n and 4G...

IEEE 802.11n is a proposed amendment to the IEEE 802.11-2007 wireless networking standard to significantly improve network throughput over previous standards, such as 802.11b and 802.11g, with a significant increase in raw (PHY) data rate from 54 Mbit/s to a maximum of 600 Mbit/s. Most devices today support a PHY rate of 300 Mbit/s, with the use of 2 Spatial Streams at 40 MHz. Depending on the environment, this may translate into a user throughput (TCP/IP) of 100 Mbit/s.

According to the book "WI-Fi, Bluetooth, Zigbee and Wimax":

802.11n is the 4th generation of wireless lan technology.

• First generation (IEEE 802.11) since 1997 (WLAN/1G)
• Second generation (IEEE 802.11b) since 1998 (WLAN/2G)
• Third generation (802.11a/g) since 2000 (WLAN/3G)
• Fourth generation (IEEE 802.11n) (WLAN/4G)

The distinguishing features of 802.11n are:

• Very high throughput (some hundreds of Mbps)
• Long distances at high data rates (equivalent to IEEE 802.11b at 500 Mbps)
• Use of robust technologies (e.g. multiple-input multiple-output [MIMO]and space time coding).

In the N option, the real data throughput is estimated to reach a theoretical 540 Mbps (which may require an even higher raw data rate at the physical layer), and should be up to 100 times faster than IEEE 802.11b, and well over ten times faster than IEEE 802.11a or IEEE 802.11g. IEEE 802.11n will probably offer a better operating distance than current networks. IEEE 802.11n builds upon previous IEEE 802.11 standards by adding MIMO. MIMO uses multiple transmitter and receiver antennae to allowfor increased data throughput through spatial multiplexing and increased range by exploiting the spatial diversity and powerful coding schemes. The N system is strongly based on the IEEE 802.11e QoS specification to improve bandwidth performance. The system supports basebands width of 20 or 40MHz.

Note that there is 802.11n PHY and 802.11n MAC that will be required to acheive 540Mbps.

To achieve maximum throughput a pure 802.11n 5 GHz network is recommended. The 5 GHz band has substantial capacity due to many non-overlapping radio channels and less radio interference as compared to the 2.4 GHz band. An all-802.11n network may be impractical, however, as existing laptops generally have 802.11b/g radios which must be replaced if they are to operate on the network. Consequently, it may be more practical to operate a mixed 802.11b/g/n network until 802.11n hardware becomes more prevalent. In a mixed-mode system, it’s generally best to utilize a dual-radio access point and place the 802.11b/g traffic on the 2.4 GHz radio and the 802.11n traffic on the 5 GHz radio.

A lot of phones are coming with inbuilt WiFi (or 802.11 a/b/g) and this WiFi is a must on Laptops or they wont sell. The main difference in 802.11n, compared to previous generation of 802.11 is that there is a presence of MIMO. 802.11 family uses OFDM which is the same technology being adopted by LTE. The new LTE handsets will have advantage of easily integrating this 802.11n technology and the same antennas can be reused. In fact the same is applicable for WiMAX as it supports MIMO and OFDM. Ofcourse we will have problems if they are using quite different frequencies as the antennas ore optimised to range of frequencies, this is something that has to be seen.

In the news:

MIT and a medical center based in Alabama are beginning to deploy faster wireless 802.11n access points from Cisco Systems Inc. In more than 100 buildings on MIT's Cambridge, Mass., campus, as many as 3,200 access points running older 802.11a/b/g protocols will be replaced with 802.11n devices in the next 12 to 16 months, said Chris Murphy, a networking engineer at the university. Murphy said MIT, with more than 10,000 students and 11,000 staff members, has a "very, very wide variety" of client devices, from handhelds to laptops. Many of the laptops probably support the 802.11n protocol, he said. Some MIT staffers have been using voice-over-IP wireless handsets and have experienced poor coverage with the older Wi-Fi technology, but they said they have had full signal strength within the range of the new 802.11n access points, he added. With 802.11n, the university could eventually provide IP television, which requires a lot of bandwidth, Murphy said.

Using 802.11n technology, Lapham said he was able to transmit a gigabyte of data in less than two minutes. Currently, the 370-bed medical center has about 450 access points on older protocols. Devices used on the wireless network include 180 laptops, which are used primarily for transmitting bedside patient data. The hospital also supports 100 VoIP wireless phones and a various medical devices.

Wi-Fi is expected to be available in 99 per cent of North American universities by 2013, according to research released by industry analyst ABI Research this week. Much of that penetration will be in the form of 802.11n equipment: higher education is clearly the number one market for early adopters of 802.11n, the company said.

ABI Research expects 802.11n uptake – which is today fairly small in the education market – to ramp up steeply to quite a high rate of penetration," said ABI Research vice president Stan Schatt. There are several reasons for this. ABI said many students now assume a campus Wi-Fi network as a given, and many of their shiny new laptops will be 'n'-compatible. Universities also have great bandwidth demands, as lecture halls may need to serve a large number of users with multimedia contention at any given time and 802.11n's greater speed and capacity can address that need. Moreover, said Schatt, "Universities are breaking new ground by using video over Wi-Fi in a number innovative ways. This is driving the adoption of high speed 802.11n. Students in the near future (at least the diligent ones) will be just as likely to watch their favourite professor's lectures on their laptops as they will be to view 'America's Next Top Model'."

You may also be interested in reading:

• Wireless Handheld Devices--The 802.11n Advantage - Embedded.com
• 802.11n delivers developing ecosystem - EE Times
• Emerging Technologies in Wireless LANs - Benny Bing

Revised paper on “4G” by 3G Americas

3G Americas have published a revised paper on Defining “4G”: Understanding the ITU Process for IMT-Advanced.

3G Americas initially created this white paper one year ago to provide clear understanding regarding the work-in-progress by the ITU, the sole organization responsible for determining the specifications for IMT-Advanced. The current paper updates the considerable progress made by the ITU, establishing a basis for what should be included in an IMT-Advanced system.

While speculation has been going on about 4G technologies, ITU is close to releasing a full set of documentation for this definition. It has held ongoing consultations with the global community over many years on this topic in Working Party 8F under the scope of a work item known as Question ITU-R 229-1/8 “Future development of IMT-2000 and systems beyond IMT-2000.” Following a year-end 2007 restructure in ITU-R, this work is being addressed under the new Study Group 5 umbrella (replacing the former Study Group 8) by Working Party 5D which is the new name for the former WP 8F.

This work in WP 8F, and now WP 5D, has woven together a definition, recipe, and roadmap for the future beyond 3G that is comprised of a balance among a Market and Services View, a Technology View, and a Spectrum View. These, along with Regulatory aspects, are the key elements for business success in wireless.

By mid-2008, ITU-R advanced beyond the vision and framework and developed a set of requirements by which technologies and systems can, in the near future, be determined as a part of IMT- Advanced and in doing so, earn the right to be considered 4G.

During 2008 and though 2009, ITU-R will hold an open call for the “first invitation” of 4G (IMTAdvanced) candidates. Subsequent to the close of the submission period for the “first invitation” an assessment of those candidates' technologies and systems will be conducted under the established ITU-R process, guidelines, and timeframes for this IMT-Advanced ‘first invitation.” The culmination of this open process will be a 4G, or IMT-Advanced family. Such a 4G family, in adherence to the principles defined for acceptance into this process, is globally recognized to be one which can grow to include all aspects of a marketplace that will arrive beyond 2010, thus complementing and building upon an expanding and maturing 3G business.

The paper is available to download from here.

The ITU-R Radiocommunication Bureau has established an “IMT-Advanced” web page (http://www.itu.int/ITU-R/go/rsg5-imt-advanced/) to facilitate the development of proposals and the work of the evaluation groups. The IMT-Advanced web page provides details of the process for the submission of proposals, and will include the RIT and SRIT submissions, evaluation group registration and contact information, evaluation reports and other relevant information on the development of IMTAdvanced.

4G: Where are we now.

Last month i read this news about WiMAX leading the world of 4G and last week I read about an American carrier selecting LTE as its choice of 4G technology. Since ITU has decided that they wont be using the term 4G in future and rather use IMT-Advanced or LTE-Advanced, I guess 4G is up for grabs.
The main driver for '4G' is data. Recently carriers have become agressive and started offering some decently priced 'Wireless Broadband' data plans. Rather than confuse people with HSDPA, etc., they have decided to use the term 'Wireless Broadband' or 'Mobile Broadband'. Personally both the terms have managed to confuse some people who associate Mobile Broadband with Internet access on Mobile and Wireless Broadband as broadband on WiFi.

Andrew Seybold makes some valid points in an article in Fierce Wireless. One of the things that he points out is that LTE may tout on higher data rates as compared to others, that is only possble in 20MHz of spectrum. In real world this kind of spectrum is near impossible to obtain. If the spectrum flexibility is removed than HSPA+, LTE, EV-DO Rev B and WiMAX have nearly the same data rates and performance.

For HSPA+ the existing infrastructure can be reused and a software upgrade would suffice whereas for LTE new infrastructure would be required. NTT DoCoMo has fully committed to being the first LTE network operator and others are raising their hands. He thinks that nationwide LTE networks would only be available around 2014.

While I agree with this analysis completely, I think what is going to dictate this transformation from 3G+ to LTE for the operators will be the uptake of data on a network. The biggest advantage of LTE is that it is able to operate in TDD and FDD mode. Operators that have been traditionally using FDD mode of operation will change their loyalty to TDD mode so that they can use asymmetric data transfer. This can provide more capacity in case of some special event taking place (Football finals, Reality show results, etc.) where the users are just interested in receiving information rather than sending any. For operators with paired spectrums, they can use both the band seperately in TDD modes.

Gigaom has list of American operators that are involved in 4G and the list is quite interesting:

• AT&T: USA's largest network in terms of subscribers, AT&T plans to use LTE to upgrade to 4G, but not for a long, long time. For now it’s content with its current 3G network. It will upgrade to HSPA+ in 2009 and 2010. Eventually it will go to LTE, but won’t begin testing until 2010 or 2011 with full deployment coming after that.
• Verizon Wireless: Verizon is already testing LTE equipment from several vendors, with plans to roll out the network in 2010 and have most of the country covered by 2012; Verizon’s would likely be the first full U.S. deployment of the LTE technology.
• Sprint-Nextel: The outlier in the whole transition to 4G, Sprint is going with WiMAX rather than LTE. After a number of delays, the company is set to launch its network in September. By the end of the year it will join with Clearwire to operate a nationwide WiMAX network under the Clearwire brand.
• T-Mobile: T-Mobile is still launching its 3G coverage, so its 4G networks may take a while to come to fruition. The carrier’s German parent appears to favor LTE.
• Metro PCS: This budget carrier plans to use LTE but it doesn’t yet have a time frame for deployment, pointing out that its customers aren’t heavy data users yet.
• U.S. Cellular: The company is unsure of its deployment plans but it would likely choose to follow the rest of the industry with LTE. As for deployment, the time frame isn’t set.
• Leap Wireless: Recently said it had not made a decision or public comment about its 4G plans.

The picture is a bit different here in UK because all the operators are going to LTE. There may be some ISP's that may be tempted to move to WiMAX as they would get economy of scale. There is also the news of BT (the largest landline phone provider) planning to roll out nationwide WiMAX network in the 2.6GHz spectrum. If BT is able to fulfil its ambition that it could be a big win for the people.

LTE-Advanced = IMT-Advanced = 4G(or 5G?)

The 3GPP TSG RAN workshop on IMT-Advanced was held (in the week after the RAN WG meetings) on April 7-8, 2008 in Shenzhen, China hosted by ZTE Corporations. The main conclusions from the workshop are:

• LTE Advanced shall be an evolution of LTE.
  o LTE terminal shall be supported in LTE-advanced networks.
  o An LTE-Advanced terminal can work in an LTE part of the network.
  o Primary focus of LTE-Advanced is low mobility users.
• All requirements/targets in TR25.913 apply to LTE-Advanced.LTE-Advanced requirements shall fulfill IMT-Advanced requirements within the ITU-R time plan
• For LTE-Advanced:
  o Same inter-RAT interworking capability with at least same performance as in LTE Release 8
  o Intra-RAT handover performance shall be same or better than LTE Release 8
• As a way forward for LTE-Advanced it was agreed:
  o TSG RAN email reflector for LTE-Advanced will be established (the new reflector is called 3GPP_TSG_RAN_LTE_ADVANCED and it is available since 21.04.2008)
  § Email discussions on LTE-Advanced requirements will be started on this reflector (moderator: Takehiro Nakamura, NTT DoCoMo, LTE-Advanced SI rapporteur).
  o A new TR will be created (after the workshop it was decided to create TR 36.913 "Requirements for LTE-Advanced") to include LTE-Advanced requirements and updated by RAN WG meetings in May 2008 referring to structure of 25.913 and outcome of the workshop.(note: Allocation of the TR number 36.xyz was done after the workshop.)
  o Review of the outcome of this workshop and kick-off of discussions about LTE-Advanced requirements and technical solutions in RAN WG meetings in May 2008 in Kansas City.The goal is to complete LTE-Advanced requirements at RAN #40 in Prague end of May 2008 according to agreed work plan (i.e. TR 36.913 will be provided to RAN #40).

How to sell report using the numbers game

Came across this press release by Research and Markets with title, "4Q07 Global 3G/4G Deployments & Subscribers Tracker ". In this it seems that they have indicated LTE as 4G. LTE standards has not yet been finalised and the technology is not in operation anywhere but this makes the report sound better. Good way of sexing up the report ;)

By the way, if you want to know the bottomline:

3G/4G subscribers (i.e., those subscribers to WCDMA/HSPA, EV-DO, TD-SCDMA, Mobile WiMAX, and LTE networks) grew 91% over the course of 2007, and we expect a 63% growth rate over the course of 2008, with subscribers expected to rise from 230 million in 2007, to 375 million in 2008.

Nortel's 4G cocktail at MWC 08

Nortel is busy demo-ing 4G technologies at the Mobile World Congress (MWC ... formerly 3GSM) 2008.

"Today, at home or at the office, your network is just there - putting the world at your fingertips. But if you are out on the move, whether it be for meetings, running errands, or traveling around the world, your communications experience becomes very, very complicated," said Scott Wickware, vice president of marketing and strategy for Carrier Networks, Nortel. "You can e-mail, but you can't send or open certain files. You can surf the net, but you have to wait ages for pages to load and forget about watching a video. Your other option is to search out a WiFi hot spot where you'll then have to pay yet another connection fee. When you go mobile, all of a sudden you are forced to pay attention to the network and you shouldn't have to."
The demand for better connections and the need for the experience to be simple are what drive the next level of innovation in our networks. For wireless networks, that next level of innovation is 4G mobile broadband, which includes LTE and WiMAX. 4G can extend the quality experience that users get from their fixed connections into the mobile world. Nortel has all the elements needed to bring carriers successfully into the 4G world: innovation in WiMAX and LTE, a strong ecosystem, all IP-core, and a deep understanding of what consumer and business users are looking for from their wireless experience.

Nortel's 4G Mobile Broadband website says:

4G delivers true mobile broadband for the masses with a superior user experience. Nortel is boosting the adoption of mobile multimedia and the delivery of a true mobile broadband experience through our leadership in 4G-enabled technologies (WiMAX, LTE (Long Term Evolution), UMB (Ultra Mobile Broadband), and IMS (IP Multimedia Subsystem). 4G mobile broadband provides improved performance, lower total cost of ownership and enables a new era of personalized services. 4G networks are IP-based and flatter with fewer nodes to manage. The benefits are significant and can make 4G mobile broadband a truly disruptive and game-changing technology.

If Nortel calls this 4G then this is 4G ;)

In 4G we trust

So we have this again, LTE is being referred to as 4G. Firstly, this is not really news because i mentioned this in September. Check the post here. Also Verizon is not the first operator to commit to LTE future. AT&T has said the same before them. Regarding the terminology i said earlier that LTE is 3.9G, see here. But 4G sounds better than 3.9G and will confuse ordinary people less so...

Anyway, an article titled "3G bad; 4G better be better" came to my attention:

Not surprisingly, tech-savvy young adults are frustrated by the speed and connectivity limitations of 3G networks and expect both better speed and more reliable connectivity when 4G arrives, according to focus groups in the U.S. and Japan queried by Nortel and the consultant firm CSMG ADVENTIS.

“There was uniform dissatisfaction with today’s UMTS or 3G networks, whether that was because the feeds just weren’t good enough, the applications that they were running, like video, just weren’t good enough.

They look forward in the next generation of technologies to something that can deliver their expectations for these applications in ways that are easy, friendly and useful,” said Scott Wickware, vice president of wireless networks for Nortel.

Wickware said that the focus groups, based in New York City, Seattle and Washington, D.C. in the U.S. and Tokyo and Osaka in Japan, had similar unhappy feelings about their 3G wireless services.

“We expected the Japanese to have a different perspective on this because they’re perceived to be the most tech-savvy nation on the planet, but 25-year-old businesspeople in both countries seem to want the same thing,” Wickware said.

Not coincidentally, what they want is what Nortel has been preaching: “this hyper-trend called mega-connectivity that says everything that could be connected to the network and would be beneficial to the network will be connected to the network,” Wickware said. “We couldn’t have scripted it any better because the feedback came back almost universally saying the same thing.”

The feedback also indicated that users did not necessarily want a single multi-use device but preferred multiple devices connected to the network.
“They don’t want just the mobile phone connected to the network or their PC, they want their camera, their MP3 player, their vehicle, they want everything. I think the trending is a single or dual-purpose device is what a lot of people want,” he said.

Overall, he said, respondents are looking for more from future network services.

“We asked them a wide variety of questions about what they wanted from 4G. We didn’t define 4G for them and lead them down the path to see what they had to say, but left it pretty wide open so we were getting top-of-mind stuff that wasn’t influenced by our views,” he said.

Long time back i remember being so happy with Dial up Internet Connection but now i am not too happy with my 8M broadband. So i suppose the same goes for other technologies.

WiMAX on display

Vodafone has deployed WiMAX technology in Malta. The island (population 400,000) is one of Vodafone's smallest markets.

The supplier of the network, Airspan, announced in June that Vodafone Malta had deployed its HiperMAX 80216d 'fixed' WiMAX base stations and CPE to offer bundled mobile, fixed voice, and data services to residential and business customers. Since that announcement was made, Vodafone has joined the lead industry organisation promoting and steering WiMAX development, the WiMAX Forum.

According to Pyramid research, "Vodafone, owing to its scale, is an agent of change in the operator community and we expect others to follow its trajectory. With operators present in different markets and looking for new revenue sources, there is no 'one-size-fits-all' technology, but the wrong technology can set an operator back years."

The research firm adds that "in catering to the needs of different markets and customer segments, operator networks will comprise diverse access technologies, each optimised for certain geographies, demographics, and services. For the WiMAX champions this is good news; for LTE backers it is a strong warning that should lead to increased R&D budgets for the next few years—in both camps.


In other news, Samsung Electronics will demonstrate the next generation telecommunications technologies at its annual international forum, which will shed light on what they call as global 4G technologies and gadgets.

This year’s Samsung 4G Forum will draw more than 130 influential industry leaders and service providers from 26 countries. It will mark the first time that all three candidate 4G technology _ IEEE 802.16m (Mobile WiMAX), 3GPP2 Ultra Mobile Broadband (UMB) and 3GPP Long Term Evolution (LTE) _ will be seen with each other.Each of the 4G technologies has a head cheerleader, with Intel supporting WiMAX, Ericsson touting LTE and Qualcomm preferring UMB. IEEE 802.16m WiMAX, UMB and LTE are expected to be initially implemented in 2010.

I think for companies like Samsung to break into new markets, its very important to use the term 4G. Lets hope that they all succeed.

Is UMB the same as LTE

Recently i have come across press releases trying to sell UMB (Ultra Mobile Broadband) as 4G technology. This is the same as trying to sell LTE and mobile -WiMAX as a 4G technology.

IMT has taken a clever approach and instead of calling the successor of 3G as 4G, they are calling it IMT-Advanced.

The main requirements for 4G are as follows:

• Peak data rate of 100Mbps for high mobility applications such as mobile access
• Approx. 1Gbps for low mobility applications such as nomadic/local wireless access

Doing some digging on the UMB topic, i realised that it is the same as LTE but an evolution from CDMA2000. This is being standardised by 3GPP2.

Some of the key features (and comparing it with LTE) includes:

• It used OFDMA based air interface (same as LTE)
• It supports FDD (LTE supports FDD and TDD and a combination of them so i am not sure if UMB only supports FDD)
• Scalable b/w of 1.25MHz to 20MHz (same as LTE)
• MIMO and Beamforming (Same as LTE but UMB also supports 4x4 antennas whereas LTE supports 2x2)
• Data speeds upto 275Mbps in DL and 75Mbps in UL (LTE has 144Mbps in DL and 57Mbps in UL but that is because of 2x2 MIMO)

Since the term 4G is already being abused so much, one option is to let people use 4G as they wish and then when IMT-Advanced is available, start calling it 5G. What do you think?

Prepare for WiMAX 2.0

I was completely unaware of IEEE 802.16m which is promising speeds upto 1Gbps. Only when someone asked me what my opinion was on this i did some digging in this.


IEEE 802.16m promises to deliver speeds up to 1Gbps and be backward compatible with 802.16e-2005 (mobile WiMAX) solutions. The 802.16m group should wrap up the technology development phase in 2007. Similar to existing mobile WiMAX, 802.16m will use multiple-input/multiple-output (MIMO) antenna technology. The idea with 802.16m, though, is to increase bandwidth by using larger MIMO antenna arrays.


The 802.1m group is targeting ratification and finalization of the standard by late 2009. So, we’re still a couple of years (or more) from having a gigabit version of WiMAX. As compared to other IEEE 802 standards development, such as 802.11, this is an aggressive schedule. In my opinion, these will be difficult dates to hit, especially with the requirement for being backward compatible with 802.16e-2005.


The advantage of 802.11m to cellular companies is that it could allow the convergence of 3G and 802.16 into a single 4G technology for mobile and fixed applications. This would enable cellular companies to offer service, such as IPTV and VoIP, as effectively over wireless connections as they are today on wired networks. This would lead to competition with existing fixed wireless broadband services currently delivered over cable and telephone lines.


Many vendor sources however, have expressed some skepticism about the speed with the work can be completed (the end of 2009 is being mooted as a baked date) and the chances of maintaining backwards compatibility with mobile 802.16 technology. Some folks worry that carriers have unrealistic expectations on how fast new WiMax profiles and interfaces can be developed. "They just walk in, snap their fingers, and expect it to happen," one industry source told us on the show floor yesterday. After all, it took several years for the IEEE to arrive at a satisfactory fixed broadband wireless specification in the form of 802.16d and even longer for the WiMAX Forum to certify interoperability between products using the technology.


Martin has some interesting analysis on his Mobile technology page:


Between today and WiMAX II, there's systems such as WiMAX and LTE which promise faster data rates than those available today by mainly doing the following:

• Increase the channel bandwidth: HSDPA uses a 5 MHz channel today. WiMAX and LTE have flexible channel bandwidths from 1.25 to 20 MHz (Note: The fastest WiMAX profile currently only uses a 10 MHz channel today for the simple reason that 20 MHz of spectrum is hard to come by). So by using a channel that is four times as broad as today, data rates can be increased four times.
• Multiple Input, Multiple Output (MIMO): Here, multiple antennas at both the transmitting and receiving end are used to send independent data streams over each antenna. This is possible as signals bounce of buildings, trees and other obstacles and thus form independent data paths. Both LTE and WiMAX currently foresee 2 transmitting and 2 receiving antennas (2x2 Mimo). In the best case this doubles data rates.
• Higher Order Modulation: While HSDPA uses 16QAM modulation that packs 4 bits into a single transmission step, WiMAX and LTE will use 64QAM modulation under ideal transmission conditions which packs 6 bits into a single transmission step.

By using the techniques above, LTE and WIMAX will be able to increase today's 2 MBit/s to about 20-25 MBit/s. That's still far away from the envisaged 1.000 GBit/s. To see how to get there let's take a look at what NTT DoCoMo is doing in their research labs, as they have already achieved 5 GBit/s on the air interface and have been a bit more open at what they are doing (see
here and especially here):

• Again increase of the channel bandwidth: They use a 100 MHz channel for their system. That's 4 times wider than the biggest channel bandwidth foreseen for LTE and 20 times wider than used for today's HSDPA. Note that in practice it might be quite difficult to find such large channels in the already congested radio bands.
• 12x12 MIMO: Instead of 2 transmit and receive antennas, DoCoMo uses 12 for their experiments. Current designers of mobile devices already have a lot of trouble finding space for 2 antennas so a 12x12 system should be a bit tricky to put into small devices.
• A new modulation scheme: VSF spread OFDM. This one's a bit mind bogelling using CDMA and OFDM in combination. Wikipedia contains a description of something called VSF-OFCDM which might be a close brother.

More Information available at IEEE 802.16 Task Group m (TGm) page.

China trying to catch up on 4G

In a move to improve the nation's research and development (R&D) capability, top mobile phone operator China Mobile will promote more self-developed next-generation mobile network technologies that match international standards, an official at its research institute disclosed.

The Research Institute of China Mobile has started several projects for the next generation of mobile network technology.

Wireless internet protocol on internet service environment (WIISE), a technology designed to let mobile networks better manage their bandwidth capacity, is among the institute's key research projects. It is funded by the State.

"We do want to do more on this WIISE technology in the next two years with our proprietary intellectual property rights. We do also want to push this self-developed technology internationally," said Wang Xiaoyun, a deputy manager of the institute yesterday.

Ms Wang explained that the WIISE technology is not designed for present mobile technology but will be applicable to so-called 4G technology or technology even more advanced. "We do want to increase the network management power, which could lead to better use of our network resources," she said.

The Chinese government, in the form of its Ministry of Science and Technology, is also reported to be collaborating with its Swedish counterpart, in the form of the VINNOVA agency for innovation, in a 4G research project initially funded at nearly US$8mn. Public details of that collaboration are minimal (that is, none at this juncture).

China Mobile will host a conference jointly with the government later this year to discuss the issue of advanced technology.

The 4G mobile technology is expected to be in the market by 2010, with Japanese mobile operator NTT DoCoMo having taken the lead in its development. The 4G systems are expected to be able to handle a wide range of data-supported rates of up to about 100 megabits per second for high mobility networks.

China Mobile would like to strengthen its network management system in the next-generation network as demand for bandwidth is increasing.
"The new mobile technology will be more compatible with the use of the internet on the move, whereas the existing 3G technologies still have some weakness with internet applications," Ms Wang said.
Some internet-based applications that occupy a lot of network capacity, such as the peer-to-peer (P2P) network, will be migrated to the mobile network in the future, she said.

As the world's largest mobile operator, China Mobile is bent on developing technology to enhance the mobile internet experience with a cost advantage.

Source: China Daily

Defining 4G (I mean IMT-Advanced)

3G Americas published a new white paper entitled "Defining 4G: Understanding the ITU Process for the Next Generation of Wireless Technology". The white paper provides the factual description of how IMT-Advanced or 4G will someday be defined by the International Telecommunications Union (ITU). ITU is the internationally recognized authority that will produce the official definition of the next generation of wireless technologies beyond IMT-2000 or 3G.

Chris Pearson, President of 3G Americas, stated, "The ITU is currently establishing criteria for IMT-Advanced and will be screening various technologies for inclusion in the IMT-Advanced family. Only then will we understand what is and can be rightly and credibly called 4G.” He continued, "Any claim today that a particular technology is a so-called ‘4G technology’, in reality, is simply a marketing spin, creating market confusion and deflating the importance of the telecommunications industry standards. Technologies should be verified against a set of agreed-upon requirements in order to qualify as 4G, and this will happen in the future when the requirements are outlined by the ITU."

Significant progress has been made by the Radiocommunication Sector of the ITU (ITU-R) in establishing an agreed and globally accepted definition of 4G wireless systems, and ITU-R is close to releasing a full set of documentation for this definition. Working under a mandate to address systems beyond 3G, ITU-R has progressed from delivering a vision of 4G in 2002 to establishing a name for 4G in 2005 (IMT-Advanced). In 2006, ITU-R set out the principles for the process of the development of IMT-Advanced. The work of the ITU encompasses the important elements of business success in the wireless industry, especially the balance of a market and services view, a technology view, a spectrum view and regulatory aspects. In early 2008, ITU-R will translate the vision into a set of requirements by which technologies and systems can, in the near future, be determined a part of IMT-Advanced and in doing so, earn the credible right to be considered 4G.

During 2008 and 2009, ITU-R will hold an open call for 4G (IMT-Advanced) candidates as well as an assessment of those candidates' technologies and systems. The culmination of this open process will be a 4G, or IMT-Advanced family of technologies. Such a 4G family of technologies, in adherence to the principles defined for acceptance into this ITU process, is globally recognized to be one which can grow to include all aspects of a marketplace that will arrive beyond 2010.

“Third generation technologies are growing immensely in the marketplace, but they too once started out with a vision and requirements from ITU,” stated Pearson. “The evolving wireless marketplace and its customers will be well served by the current ITU process for the next generation of wireless services.”

As can be seen in the picture above, the main requirements for 4G are as follows:

• Peak data rate of 100Mbps for high mobility applications such as mobile access
• Approx. 1Gbps for low mobility applications such as nomadic/local wireless access

A very important point in the report is what i have been saying for years:

The communications industry is witnessing significant posturing about wireless technologies and systems that are claiming to be “4G.” Any claim that a particular technology is a 4G technology or system today is, in reality, simply
a market positioning statement by the respective technology advocate. Such claims must be verified and substantiated against a set of requirements in order to qualify as 4G.

300 Mbps with 'Super-FOMA'

NTT DoCoMo, Inc. announced that this month it began testing an experimental Super 3G system for mobile communications. With this experiment, DoCoMo will seek to achieve a downlink transmission rate of 300Mbps over a high-speed wireless network.

For people who are unaware, LTE is being branded as Super-3G as this term is more appealing as compared to LTE which would mean nothing to ordinary people.

DoCoMo will begin with an indoor experiment to test transmission speed using one transmitting and one receiving antenna. The company will then expand the experiment to examine downlink transmission by employing up to four Multiple-Input Multiple-Output (MIMO) antennas for both the base station (transmission side) and mobile station (receiving side); the goal is to achieve a downlink transmission speed of 300Mbps. MIMO is an antenna technology for wireless communications in which different data streams are spatially multiplexed using multiple antennas for both transmission and reception on the same frequency. Also to be examined is the "handover function" — switching of the connection between two base stations.

NTT DoCoMo's Super-3G timetable is available here

The reason i am calling this setup as Super-FOMA is because going back to when 3G was being introduced, DoCoMo wanted to be the first with 3G. As a result, they adopted a 3GPP Release version that wasnt stable and released it as FOMA. Now they are doing the same with LTE. LTE wont be stable in that timeframe so they might end up with Super-FOMA instead of Super-3G.

The company has also been aggressively pursuing 4G system development. In late December, the carrier came close to hitting a 5Gbit/sec. data transmission speed from an experimental 4G system to a receiver moving at 10 kilometers per hour.

Possibly it may be the first one with a 4G system and it might end up as Hyper-FOMA :)

(3G) Civil War in US?

Interesting article from Telecom Magazine

In US Sprint Nextel and Verizon Wireless fly the flag for CDMA2000, while AT&T and T-Mobile USA spearhead the W-CDMA charge.

So far, CDMA2000 clearly has taken the high ground. Verizon laid claim to about 60.7 million CDMA2000 customers by the end of March 2007, while Sprint Nextel said it had captured 53.6 million. The W-CDMA operators, by comparison, could muster just 2.5 million customers between them.

The CDMA Development Group (CDG), which lobbies for CDMA2000, attributes this gulf to a technology lead. CDMA2000 operators, it notes, have deployed enhancements like EV-DO Revision A, which can deliver speeds of up to 3 Mbps for VoIP and multimedia applications. W-CDMA, in stark contrast, is still unavailable in many parts of the U.S. Even where it has been deployed, it typically is capable of a far less impressive 384 kbps.

W-CDMA, however, is definitely on the march. AT&T and T-Mobile USA are planning rollouts using HSDPA, a W-CDMA enhancement that offers speeds of up to 3.6 Mbps. More importantly, while W-CDMA’s customer base of 2.5 million appears low when judged alongside CDMA2000, it has grown from just 350,000 late last year.

“AT&T uses a higher frequency [than its CDMA2000 competitors], which is a disadvantage,” explains Allen Nogee, a principal analyst with In-Stat.
Generally, U.S. operators have deployed CDMA2000 using spectrum in the 800 MHz or 1900 MHz bands, while AT&T is rolling out W-CDMA using 2100 MHz spectrum. The lower frequencies have better propagation characteristics, allowing CDMA2000 operators to serve a wider area using fewer base stations.

“AT&T is also in a transitional phase,” Nogee adds. “Although it can advertise its new HSDPA network, that network has not been rolled out everywhere yet.”

Meanwhile, T-Mobile USA, the fourth largest operator in the U.S., plans to launch a W-CDMA service using the 2110 MHz to 2155 MHz spectrum it purchased in last year’s auction for advanced wireless services. Although it did not respond to requests for an interview, T-Mobile USA previously issued a statement on its 3G intentions in which it says the company will transition to a next-generation technology, which may include W-CDMA/UMTS with HSDPA, in the next two-to-three year timeframe.

And finally we cannot have a discussion without looking at the future (4G?):

Although W-CDMA is still in its early days in the United States, operators already are thinking about the next generation of mobile technology.
While a 4G standard is not yet defined, marketing departments are applying the label to some technologies already in development.

For W-CDMA operators such as AT&T and T-Mobile USA, the technology typically viewed as 4G is called long-term evolution, or LTE. It represents the destination on their journey through upgrades to HSPA, but will use a different air interface called OFDMA and require more work. Theoretically LTE will deliver downlink speeds of 100 Mbps and uplink speeds of 50 Mbps.

CDMA2000 operators also have 4G in their sights in the shape of EV-DO Revision C. Like LTE, Revision C promises vast improvements over the current crop of wireless standards. Allen Nogee, a principal analyst with In-Stat, thinks both LTE and Revision C could see commercial deployment by 2010.

In the meantime, Sprint Nextel has been vocal about another 4G technology. Last year, it earmarked US$2.5 bn for investment in a nationwide deployment of WiMAX, using 2.5 GHz spectrum it already owned. WiMAX proponents have made some bullish claims about its capability (promising up to 70 Mbps on the downlink), but the technology has not evolved from other standards—unlike LTE and Revision C—and will lack any scale economies when it is launched next year.

Chris Pearson, president of 3G Americas (a lobby group for W-CDMA), is unconvinced by the WiMAX business case. “It’s a wild card. In our view, most subscribers will be using W-CDMA and EV-DO for years to come.”

OFDM and OFDMA: The Difference

I was curious as to why IEEE 802.16d (fixed service) uses Orthogonal Frequency Division Multiplexing (OFDM). IEEE 802.16e (mobile) uses Orthogonal Frequency Division Multiple Access (OFDMA). So, what’s the difference between the two, and why is there a difference?

Lets first look at FDM:

In FDM system, signals from multiple transmitters are transmitted simultaneously (at the same time slot) over multiple frequencies. Each frequency range (sub-carrier) is modulated separately by different data stream and a spacing (guard band) is placed between sub-carriers to avoid signal overlap.

OFDM is sometimes referred to as discrete multi-tone modulation because, instead of a single carrier being modulated, a large number of evenly spaced subcarriers are modulated using some m-ary of QAM. This is a spread-spectrum technique that increases the efficiency of data communications by increasing data throughput because there are more carriers to modulate. In addition, problems with multi-path signal cancellation and spectral interference are greatly reduced by selectively modulating the “clear” carriers or ignoring carriers with high bit-rate errors.

Like FDM, OFDM also uses multiple sub-carriers but the sub-carriers are closely spaced to each other without causing interference, removing guard bands between adjacent sub-carriers. This is possible because the frequencies (sub-carriers) are orthogonal, meaning the peak of one sub-carrier coincides with the null of an adjacent sub-carrier.

In an OFDM system, a very high rate data stream is divided into multiple parallel low rate data streams. Each smaller data stream is then mapped to individual data sub-carrier and modulated using some sorts of PSK (Phase Shift Keying) or QAM (Quadrature Amplitude Modulation). i.e. BPSK, QPSK, 16-QAM, 64-QAM.

OFDM needs less bandwidth than FDM to carry the same amount of information which translates to higher spectral efficiency. Besides a high spectral efficiency, an OFDM system such as WiMAX is more resilient in NLOS environment. It can efficiently overcome interference and frequency-selective fading caused by multipath because equalizing is done on a subset of sub-carriers instead of a single broader carrier. The effect of ISI (Inter Symbol Interference) is suppressed by virtue of a longer symbol period of the parallel OFDM sub-carriers than a single carrier system and the use of a cyclic prefix (CP).

The OFDM spread-spectrum scheme is used for many broadly used applications, including digital TV broadcasting in Australia, Japan and Europe; digital audio broadcasting in Europe; Asynchronous Digital Subscriber Line (ADSL) modems and wireless networking worldwide (IEEE 802.11a/g).

Like OFDM, OFDMA employs multiple closely spaced sub-carriers, but the sub-carriers are divided into groups of sub-carriers. Each group is named a sub-channel. The sub-carriers that form a sub-channel need not be adjacent. In the downlink, a sub-channel may be intended for different receivers. In the uplink, a transmitter may be assigned one or more sub-channels.

Subchannelization defines sub-channels that can be allocated to subscriber stations (SSs) depending on their channel conditions and data requirements. Using subchannelization, within the same time slot a Mobile WiMAX Base Station (BS) can allocate more transmit power to user devices (SSs) with lower SNR (Signal-to-Noise Ratio), and less power to user devices with higher SNR. Subchannelization also enables the BS to allocate higher power to sub-channels assigned to indoor SSs resulting in better in-building coverage.

Subchannelization in the uplink can save a user device transmit power because it can concentrate power only on certain sub-channel(s) allocated to it. This power-saving feature is particularly useful for battery-powered user devices, the likely case in Mobile WiMAX.

The WiMAX forum established that, initially, OFDM-256 will be used for fixed-service 802.16d (2004). It is referred to as the OFDM 256 FFT Mode, which means there are 256 subcarriers available for use in a single channel. Multiple access on one channel is accomplished using TDMA. Alternatively, FDMA may be used.

On the other hand, OFDMA 128/512/1024/2048 FFT Modes have been proposed for IEEE 802.16e (mobile service). OFDMA 1024 FFT matches that of Korea’s WiBRO. OFDM 256 also is supported for compatibility with IEEE 802.16d (fixed, 2004).

IMT Advanced = 4G

In this story on Telecom TV, is says:

Working under a mandate to address "systems beyond 3G", the working party has now come up with a name for the future mobile systems. Thankfully, they are veering away from 4G and are calling it 'IMT-Advanced'.

A simple search on Google returned some useful information from Telecom ABC:

International Mobile Telecommunications - Advanced (IMT-Advanced) is a concept from the ITU for mobile communication systems with capabilities which go further than that of IMT-2000. IMT-Advanced was previously known as “systems beyond IMT-2000”.

It is foreseen that the development of IMT-2000 will reach a limit of around 30 Mbps. In the vision of the ITU, there may be a need for a new wireless access technology to be developed around the year 2010 capable of supporting even higher data rates with high mobility, which could be widely deployed around the year 2015 in some countries. The new capabilities of these IMT-Advanced systems are envisaged to handle a wide range of supported data rates according to economic and service demands in multi-user environments with target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access.

To support this wide variety of services, it may be necessary for IMT-Advanced to have different radio interfaces and frequency bands for mobile access for highly mobile users and for new nomadic/local area wireless access.

Together with the introduction of the name IMT-Advanced, the ITU introduced the generic root name IMT. The generic root name IMT covers the capabilities of IMT-2000, including future development of IMT-2000, and IMT-Advanced.

Meanwhile a story in ChinaTechNews is suggesting that Datang Telecom has already written a Draft on 4G and is working on 3G&4G convergence. Cannot find much more on this right now.

For more on 4G technologies, either read this story on Network World or 3G4G website.

3G -> 3.9G

There seems to be confusion when people discuss terms like 3.5G, 3.75G so i decided to define them. I am sure people who have objections will comment.

Lets first start with 2G systems:

2G = GSM

2.5G = GPRS

2.75G = EDGE

Then moving onto 3G systems:

3G = WCDMA, R99 (i am not looking at other technologies but similar mapping will apply)
3.5G = HSDPA

3.75G = HSUPA

3.8G = HSPA+ (HSPA Enhancements)

3.85G = 'HSPA+' + MIMO
3.9G = LTE

4G = NOT WiMAX

More 4G and WiMax

In a recent article in EE Times, the author is stressing that "Mobile WiMax opportunities will be the next big growth engine for personal broadband and next-generation cell phone networking equipment vendors and for the communications industry in general". A good point raised though is that there are many people who have comitted to WiMax:

In US, global communications carriers like Sprint have announced plans to deploy large-scale mobile WiMax services by mid-2008. In some cases, entire countries have committed to WiMax as their fourth-generation standard of choice. Two such examples are Korea, with the early WiBro predecessor to mobile WiMax, and Taiwan, with the "M-Taiwan" national initiative.

What other thing the author is trying to stress is that WiMax is 4G but i do not agree.

Sony Ericsson is another high profile name that recently announced joining of WiMax forum. According to MacNN, no hardware updates or new products have been announced, but it's likely that Sony-Ericsson will begin to upgrade their products to take advantage of faster speeds.

According to another article in ARN today:

Unlike 3G, no specific standards spell out what a 4G service, network or technology is today. Analysts say these specifications are to come, but today "4G is more of a marketing idea," says Phil Redman, a research vice president at Gartner.

There is a mobile WiMAX standard -- the IEEE's 802.16e standard -- on which Sprint Nextel is basing its US$3 billion investment. But Redman says mobile WiMAX is not 4G, "although the WiMAX folks would love for that label to catch on."
Still, WiMAX and other technologies may be part of a forthcoming 4G specification. "There's no doubt that existing technologies like WiMax and other technologies such as [Orthogonal Frequency Division Multiple Access] and [multiple input multiple output] will be included in 4G," Redman says. "But no one technology will be 4G."

"These things tend to run in 10-year cycles," Redman says. "2G came out in 1995, 3G in 2004. There will not be a 4G standard before 2015."
In the meantime, a number of players have attempted to spell out what 4G should look like. The World Wireless Research Forum (WWRF) says 4G will run over an IP infrastructure, interoperate with Wi-Fi and WiMAX, and support fast speeds from 100Mbps to as high as 1Gbps.

It's also key that next-generation wireless includes QoS metrics and the ability to prioritize traffic, says Lisa Pierce, a vice president at consulting firm Forrester Research. "Lack of prioritization is preventing businesses from using current EV-DO services as their primary data connection."

WWRF expects 4G will be a collection of technologies and protocols, not just one single standard. That's similar to 3G, which today includes many technologies such as GSM and CDMA that meet specific criteria.

To help move the standards process along, WWRE -- whose members include Ericsson, Huawei Technologies and Motorola -- contributes to standards work done within groups such as the International Telecommunications Union (ITU), the group that defined 3G wireless specifications, and the IETF.

4G's predecessor, 3G wireless, is still taking off. The fourth-largest wireless-service provider, T-Mobile,launched its 3G network this year. So if 3G is just getting going, what does that mean for 4G?

Opinions on when 4G services might be available differ. The Next Generation Mobile Networks (NGMN) group says commercial services beyond 3G could launch as early as 2010. KPN Mobile, Orange, Sprint, T-Mobile International, Vodafone, China Mobile and NTT DoCoMo make up NGMN. The goal of the group, similar to the WWRF, is to work with standards bodies in developing next-generation specifications.

But if standards don't come before 2015, as Gartner's Redman predicts, true 4G services could come only after 2015.

Qualcomm, OFDM and 4G (17/05/07)

Qualcomm is the pioneer of next generation wireless technologies. To stregthen their position further, they have also bought over some smaller companies to give them access to all their IPR, etc. Yesterday i read an interview of Bill Davidson, senior vice president of investor relations and international marketing at Qualcomm and IDG news service. Here are some interesting points:

IDGNS: Is OFDM a new area of development for Qualcomm?
Davidson: If you go back to the beginning of Qualcomm, OFDM was considered a path instead of CDMA. The company ended up going down the CDMA route because CDMA was better able to handle all the things you want to do on a wide-area wireless network. We believe that to this day.

IDGNS: Are you planning any more acquisitions of companies with OFDM technology?
Davidson: In the last couple of years, our acquisition activity has stepped up. Flarion was clearly the largest deal of the last few years.

IDGNS: Do intellectual property rights play a big role in your acquisition strategy?
Davidson: They can and, clearly in the case of Flarion, there was a double benefit. First and foremost, we got the only team -- to this day -- to deploy a working mobile OFDM system. We also got the intellectual property rights that came along with the business. Our acquisitions are focused on accelerating time to market on a build-versus-buy decision and augmenting engineering resources more than we're out trying to grab patents.

IDGNS: What's driving all the interest in OFDM?
Davidson: We're seeing interest in OFDM because spectrum is becoming available in the 10MHz blocks and wider. From an efficiency standpoint, there's not really a benefit for OFDM over CDMA. But when you get into wider branches of spectrum, it can be a little less complex to implement.

IDGNS: But isn't 4G -- in which OFDM will play a big role -- all about newer, faster services?
Davidson: I think OFDM is really just a spectrum play. And frankly, we don't subscribe to the "4G" term. The applications that I've heard discussed aren't a whole lot different from what is being enabled over 3G today.

IDGNS: Isn't 4G supposed to be a lot faster than 3G?
Davidson: Many are talking about data rates that we don't even get on landline systems today. Yes, you can enable HDTV over these enormously wide pieces of spectrum. But what is the practical cost to the end-user?

IDGNS: So do we really need 4G?
Davidson: There is an existing roadmap within existing 3G technologies that provide the very same and, in most cases, better performance than some of the new technologies being proposed by other groups.

IDGNS: So WiMax and LTE aren't necessary?
Davidson: I look at LTE and UMB as being comparable; WiMax is not comparable to those technologies in terms of performance. There is a mistake in the premise that whatever comes along -- what people are calling 4G -- will be something that supplants the existing networks. We've been saying for several years that it will be about multiple airlinks existing in the market and making them work effectively together.

IDGNS: Let me come back to WiMax: Why isn't it comparable to LTE?
Davidson: Because its original legacy is borne out of the fixed environment, there are immediate engineering trade-offs and performance issues that you come up against. There is this concept of link budget, or how effective a technology is over the airlink. WiMax suffers from poor spectral efficiency because of its heritage as not being a mobile standard.

IDGNS: Do you see any intellectual property rights issues with 4G?
Davidson: We believe that our OFDM, OFDMA, and MIMO portfolio is among the strongest out there and clearly believe that it's applicable to any OFDM/OFDMA systems. Unfortunately, those who are supporting WiMax are trying to make it sound that the IP (intellectual property) picture with this technology is very clear and that it's going to be simple. The IP picture in 3G is much clearer today than what exists in WiMax. The number of companies claiming IP that can be contributed to WiMax is enormous.

IDGNS: Will Qualcomm be active in WiMax in any way?
Davidson: As we said several years back when many were trying to say that Wi-Fi would come and kill 3G, to the extent that our customers want the integration of Wi-Fi into our chipsets, we'll accommodate that. We've said the same about WiMax. We're being pragmatic and view that it will be in the market.

IDGNS:
Nokia CEO Olli-Pekka Kallasvuo said at the company's recent shareholders' meeting that the Finnish manufacturer can't give one company, Qualcomm, a chance to dictate rules for the whole industry. He said the issue is not Qualcomm versus Nokia but rather it's more about Qualcomm versus the rest of the industry. And your opinion?
Davidson: It's amusing to me that Nokia seems to think it's holding up the banner for the entire industry. If not for Qualcomm, there would be far fewer handset manufacturers for them to deal with as competitors and potential competitors. Our business model gives consumers a lot more choice so that Nokia can't dictate pricing into the market. Because we hold intellectual property, Nokia wants to paint us controlling the industry. We enable a lot of competition that causes them a lot of concern -- hence why we're being attacked by them.

The last point is amusing and i tend to agree with Qualcomm on this. Nokia has been dominating the market for long time and its about time other players get in the game.