Wednesday 28 October 2009

China proposes TD-LTE-Advanced as its candidate for 4G


The International Telecommunication Union (ITU) has recently received six candidate technology submissions, including China's domestically-developed TD-LTE-Advanced for the global 4G (IMT-Advanced) mobile wireless broadband technology.

China's Ministry of Industry and Information Technology (MIIT) said on October 26 that it will fully support TD-LTE-Advanced in competing to be qualified as global 4G standard technology and promote development of related industries.

TD-LTE-Advanced, which is the intellectual property of China, inherits some of the major technical elements of TD-SCDMA, but will be able to offer an extended bandwidth and higher speed for Internet access.

Currently, 3GPP's LTE-advanced and IEEE's 802.16m are the two major 4G technologies. TD-LTE-Advanced was submitted at the ITU meeting as IMT-Advanced candidate technology, which is supported by major telecom operators and network device manufacturers including France Télécom, Deutsche Telekom, AT&T, NTT, KT, China Mobile, Ericsson, Nokia, Huawei and ZTE.

The selected technologies are expected to be accorded the official designation of IMT-Advanced - to qualify as true 4G technologies - in October 2010.

I was unable to locate more information on TD-LTE-Advanced. Will update once I have some more info.

Tuesday 27 October 2009

Potential "killer apps" for Femtocell in 3G and LTE



Interesting discussion on Linkedin. Too big for me to summarise here but do check it out here.

Sorry, you may have to login :(

Monday 26 October 2009

African Mobile Market grows 550% in 5 years



Africans are buying mobile phones at a world record rate, with take-up soaring by 550% in five years, research shows.

"The mobile phone revolution continues," says a UN report charting the phenomenon that has transformed commerce, healthcare and social lives across the planet. Mobile subscriptions in Africa rose from 54m to almost 350m between 2003 and 2008, the quickest growth in the world. The global total reached 4bn at the end of last year and, although growth was down on the previous year, it remained close to 20%.

On average there are now 60 mobile subscriptions for every 100 people in the world. In developing countries, the figure stands at 48 – more than eight times the level of penetration in 2000.

In Africa, average penetration stands at more than a third of the population, and in north Africa it is almost two-thirds. Gabon, the Seychelles and South Africa now boast almost 100% penetration. Only five African countries – Burundi, Djibouti, Eritrea, Ethiopia and Somalia – still have a penetration of less than 10 per 100 inhabitants.

Uganda, the first African country to have more mobiles than fixed telephones, is cited as an example of cultural and economic transformation. Penetration has risen from 0.2% in 1995 to 23% in 2008, with operators making huge investments in infrastructure, particularly in rural areas. Given their low incomes, only about a quarter of Ugandans have a mobile subscription, but street vendors offer mobile access on a per-call basis. They also invite those without access to electricity to charge their phones using car batteries.

Popular mobile services include money transfers, allowing people without bank accounts to send money by text message. Many farmers use mobiles to trade and check market prices.

The share of the population covered by a mobile signal stood at 76% in developing countries in 2006, including 61% in rural areas. In sub-Saharan Africa, closer to half the population was covered, including 42% in rural areas.

At the end of 2007, there were eight times as many mobile phones as fixed lines in the least developed countries. The number of fixed lines in the world has essentially been frozen around 1.2bn since 2006 and saw a slight decline in 2008.

But a "digital divide" persists in terms of internet access. Australia, a country with 21 million inhabitants, has more broadband subscribers than the whole of Africa. There is also a huge gap in terms of broadband speed. The report warns: "Urgent attention is needed to address this situation and bring the continent more meaningfully online."

Other developing regions often boast a broadband penetration 10 times higher than in Africa, where Algeria, Egypt, Morocco, South Africa, and Tunisia account for 90% of all subscriptions. Broadband access in Burkina Faso, the Central African Republic and Swaziland is the most expensive in the world, costing more than $1,300 (£780) a month.

The report also found that at the end of 2008 there were an estimated 1.4bn internet users around the world. The growth rate of 15% was slightly lower than in 2007. In developing countries, the number of users grew by a quarter and such countries now account for more than half the world's internet users. But while more than half of the developed world population is now online, the corresponding share is only 15% in developing economies and 17% in "transition" economies.

China hosted the biggest number of users (298 million), followed by the United States (191 million) and Japan (88 million). A little over one fifth of the world's population used the internet in 2008.

Sunday 25 October 2009

All eyes on China Mobile TD-SCDMA network


China Mobile plans to spend more on 3G terminal subsidies in 2010.

The outfit has tripled the amount of subsidies from the current year level and is expected to spend $4.4 billion next year. The huge amounts of cash will enable the outfit to push into the 3G space in the worlds largest economy.

China Mobile has 70 per cent of the Chinese wireless market but has been taking a caning from China Unicom. The outfit uses its own TD-SCDMA 3G standard but with that sort of money to spend it is fairly clear that foreign salesmen will be showing up trying to flog the outfit shedloads of 3G gear.

The company recently launched a line of smartphones dubbed Ophones based on the TD-SCDMA technology which uses Google's Android mobile operating system.

All three carriers have commercially launched their 3G networks over the recent months, but take-up has been slow. Market leader Mobile has been hamstrung by the limited number of handsets for the new TD-SCDMA system.

But now with its device range expanding and the network expected to be rolled out to 238 cities by year-end, the market’s 800-pound gorilla appears ready to assert itself.

Analyst firm BDA says China Mobile plans to spend 120 billion yuan on handset subsidies this year, most of it on TD-SCDMA. It laid out 50 billion on subsidizing phones in the first half of the year, with less than 12% going to TD phones.

Now a China Mobile source told has told website C114 that the company would leverage its financial strengths “to stage a price war to resist Telecom’s and Unicom’s 3G” services.

China Mobile has 503 million users, Unicom 142 million and China Telecom 44 million customers. Of these 3G comprises a tiny fraction - China Mobile has 1.3 million using TD-SCDMA, Unicom 350,000 using W-CDMA and China Telecom 1.3 million on its CDMA EV-DO network.


TD-SCDMA is primed to evolve into a global standard: TD-LTE. Granted, TD-LTE's sales pitch is not all that different from its ancestors - i.e. making use of unpaired spectrum to boost capacity in urban environments where FDD macro networks get overloaded. What is different this time around is a bigger ecosystem of vendors developing it - admittedly for just a single market at the moment, but also the biggest single mobile market in the world.

The other key difference is that TDD has always been primarily a data play. But from 2001 up to 2008, 3G cellcos were still primarily in the voice business, and FDD allowed them to continue milking that cash cow. That worked fine when 3G data usage was still mostly ringtones, wallpapers and other walled-garden content.

Then the iPhone happened. Smartphones got smarter and data usage skyrocketed so high that E1 backhaul links became the new bottlenecks. If ABI Research is to be believed, by 2014 mobile users will be transmitting a total of 1.6 exabytes a month (compared to 1.3 exabytes for all of last year).

Hence all the interest in LTE, as well as related technological tricks to offload data traffic and maximize RAN capacity like spectrum refarming in the 900- and 1800-MHz bands and femtocells. TD-LTE is another tool in the toolbox, and by the time we start hitting monthly exabyte levels in five years, its predecessor in China will have been put through the ringer enough to qualify as "seasoned" if not "mature".

Of course, all that depends on a ton of factors over the next five years. Still, TDD is a lot closer to realizing its potential than it was at the start of the decade.

If nothing else, TD-LTE may have the novel distinction of being the quietest evolution the cellular world has yet seen. That will depend on how much progress Qualcomm and other chipset vendors make with dual-mode FDD/TDD chipsets, but once devices are capable of roaming seamlessly between both, TD-LTE may be the first RAN acronym that won't need to be marketed to end-users who don't give a toss what it's called anyway.

ST-Ericsson is creating a strong foothold in the evolving Chinese 3G market, and is powering the first modem for TD-HSPA, which can take advantage of the fastest speeds offered by China Mobile.

The silicon joint venture is working with Chinese partner Hojy Wireless on modules that will turn up in data cards and dongles early next year. China Mobile will hope these will boost uptake of its new network by heavy duty data users, a market where China Telecom's EV-DO system has so far shone more brightly. The M6718 modem could also be included in notebooks, netbooks and smartphones in future, as the market moves beyond data cards.

Mobile broadband modules, for incorporation in a range of devices, are an important part of the broader ST-Ericsson portfolio, with co-parent Ericsson a key customer as it bolsters its module business in 3G and LTE. The M6718 is a dual-mode TD-HSPA/EDGE device, supporting 2.8Mbps downlink and 2.2Mbps uplink.

LTE: moving from a promising technology to real business

Interesting presentation.

Tuesday 20 October 2009

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.

Saturday 17 October 2009

Vodafone Access Gateway (VAG) femtocell setup

I blogged about ALU and Vodafone Femto earlier. Here is an Interesting Video showing unboxing, setting up and using the Femtocell.

Thursday 15 October 2009

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:

Monday 12 October 2009

LTE Stuff

Just added some new material on LTE at 3G4G website. Check the LTE section here. Also started collection FAQ's. See here.

As always, comments, criticisms, suggestions and feedback welcome :)