HSDPA Code Tree

How often does it happen that people ask you questions you know the answer to but cant recall the complete details. A similar thing happened when a colleague asked me about why only 15 codes why HS-PDSCH and what happens to the 16th code.

Here is a picture which is from Qualcomm Whitepaper (available here) which is self explanatory.

Mobile Phone Batteries: Past, Present and Future

Forty-five years ago, when, to most people at least, chips only ever came with fish, a man called Gordon Moore wrote a paper in which he said the number of transistors that could be squeezed on to an integrated circuit doubles about every two years. Three years later, Moore co-founded Intel, whose computer chips have, to this day, developed almost exactly at the dizzying pace he predicted. Today, an Intel microprocessor boasts more than a billion transistors packed so densely that you could fit two million of the things on the full-stop at the end of this sentence. What became known as Moore's Law has driven exponential growth in the digital revolution – the more transistors you can pack into a circuit, the faster and more powerful its chips can run while remaining cheap. But the batteries keeping those circuits pinging are not digital and still work according to basic principles developed more than 200 years ago.

In the 1780s, Italian physicist Luigi Galvani discovered that a dead frog's leg would spring to life when he applied two pieces of metal. Galvani had created a crude circuit and the phenomenon was taken up by his friend, the aristocrat professor, Alessandro Volta. His voltaic pile swapped frogs for brine-soaked paper and pieces of metal for a stack of alternating zinc and copper disks. Volta had created the world's first modern battery.

A battery remains, by its simplest definition, a device that turns stored chemical energy into electrical energy. A chemical reaction takes place within a series of cells with negative and positive electrodes separated by conductive electrolyte. When you hook up the battery, positively charged ions "swim" from the negative to the positive electrode, prompting negatively charged electrons to power the bulb of a torch or the screen of your iPhone. It's a chemical process and, up to a certain point, you can't shrink chemistry. Peter Bruce, a professor of chemistry at the University of St Andrews, says that while computer performance has effectively doubled every two years, the energy density in batteries has increased five times in about 100 years. "If you want to store more energy you really have to develop new materials and new concepts," he says. "It's not just making the same things smaller."

Bruce is among a host of scientists racing to get more out of the modern battery. He owes a debt not only to Volta but also to the man whose work in the 1970s gave us the modern rechargeable battery that powers nearly all our gadgets. Stan Whittingham, a British-born American chemist who studied at Oxford in the 1960s, was working at the research division of the oil giant, Exxon, when he realised that the excellent energy-storing properties of the element lithium made it an ideal material to be used in rechargeable batteries. "A lithium-ion battery holds about five times as much energy as a lead one," Whittingham says on the phone from Binghamton University in New York, where he's a professor of chemistry. "It got a lot of people excited because it was really a technology-changing idea. Without lithium-ion batteries, you wouldn't have your iPod or your mobile phone. They've given us so much but of course people want more and more."

Bruce is taking up that challenge with his "air-fuelled" rechargeable lithium battery. Put very simply, the Stair cell (St Andrews air cell) uses nothing more complicated than air as a reagent in a battery instead of costly chemicals. By freeing up space and exploiting one of the few elements that is free, Bruce's cells can squeeze more power into a smaller space at a reduced cost. "By using air in the cell we can get much higher energy storage up to a factor of 10," Bruce says. "That's exciting because it's difficult to improve the lithium ion battery beyond a factor of two."

A battery with 10 times the storage of the one powering your phone would see a return to the days of weekly phone charging. Meanwhile, other scientists are working to solve that other great problem of the modern battery – the time it takes to recharge. Gerbrand Ceder at the Massachusetts Institute of Technology (MIT) has been looking at improving the way the lithium ions themselves move through batteries – the faster they "swim", the more quickly they charge the battery. Ceder and his team manipulated the materials inside batteries to make the ions' passage smoother and watched as they travelled at incredible speeds. Ceder estimates that a prototype battery made using the process could be charged not in hours or even minutes but seconds. "If we could cut charging time from, say, two hours to one hour, you would probably still do it overnight," he says. "But if it's one minute, you would stand by and wait – it would be like filling your car or getting a cup of coffee."

Ceder has also worked with a team that has used genetically-engineered viruses to build the positively and negatively charged ends of a lithium-ion battery. The new batteries would be more flexible and efficient than existing technology but, like MIT's fast-charging battery and Bruce's Stair cell, they are very much on the laboratory drawing board.

It's a measure of both the greatness of the modern battery and the challenges faced by developers that, as Whittingham puts it (perhaps with a degree of pride): "For the next five years at least it's just lithium." In the meantime, manufacturers are racing to launch energy-efficient screens and hardware that place less demand on batteries. But with so much riding on the next big breakthrough, it's only a matter of time before we get batteries fit to power the next generation of gadgets and cars. For those of us increasingly shackled to our phone chargers, that time can't come soon enough.

Via: The Independent

LTE/EPS Security Starting point

Recently a colleague wanted to know from where should he start reading about LTE/SAE security. The obvious answer was 3GPP TS 33.401 which is the specification and provides complete details. It seems that some people get scared when they start looking at the specs and in that case it is preferable to have a book chapter or something similar that could provide useful information.

Agilent, the T&M manufacturers released a book last year on LTE and the chapter on the Security is freely available on the web which I have also stored on the 3G4G website. It is a good starting point and provides basic details that technically minded people may find useful.

You can have a look at the Security chapter here.

LG cementing its LTE handset leader position

LG has been in news recently for showing off their LTE preparedness:

LG Electronics MobileComm U.S.A., Inc. revealed at this year’s CES the advanced capabilities of Long Term Evolution or LTE technology. The company showcased LTE download speeds of 100MBps. Long Term Evolution is also known as the next generation mobile communication service technology.

LG conducted real-time demonstrations of video conferences, full HD video files and web-surfing at speeds up to 50Mbps for uploads and 100Mbps for downloads. All this was executed by connecting to the LTE USB Modem from LG. The offering gives extremely high data download speeds.

The company also unfurled to the CES attendees the ‘handover’ technology. This offering executes hindrance-free network conversion between LTE and CDMA networks. LG displayed endless data transmissions taking place between LTE and CDMA antennas which enables video file downloads, internet calling and web surfing. All this was done via the sleek version of the 4G LTE device which is an LG proprietary product fashioned for the Handover just last August.

LG has also teamed up with Verizon wireless to demonstrate the applications and capabilities that are possible with LTE networks. At the recently held event, the Verizon Wireless Innovation Center demonstrated many applications with Innovation Center member LG Mobile Phones being its main participant.

LG demonstrated LTE network and joined forces with other companies for formulating Home monitoring solutions, an indoor/outdoor IP security camera and a video conferencing product.

Alcatel-Lucent and LG Electronics have completed a successful handoff of an end-to-end data call between Long Term Evolution, or “LTE,” and CDMA mobile networks. The live, over-the-air handover consisted of an uninterrupted streaming video session conducted over Alcatel-Lucent's end-to-end commercial LTE and CDMA/EV-DO infrastructure using an LG Electronics CDMA and LTE dual mode device.

The handoff is compliant with the standards established by the Third Generation Partnership Project, or “3GPP.” According to Ken Wirth, president of 4G and LTE Networks at Alcatel-Lucent, since existing networks were designed primarily with voice in mind, the current explosion in data traffic is creating a challenge for service providers. The successful handoff demonstrates Alcatel-Lucent's readiness to deliver LTE to CDMA operators. LTE provides operators with the opportunity to deploy a system designed specifically to support data.

LG's M13 CDMA/LTE device incorporated for the testing is the world's first modem chipset for 4G LTE devices. It was created with commercial grade components and released in December 2008. The technology behind LG's M13 CDMA/LTE terminal is important in enabling LTE networks to operate transparently with existing CDMA networks.

According to In-kyung Kim, vice president of 4G development at LG Electronics Mobile Communications Company R&D Center, LG's M13 terminal will be an important device in enabling CDMA network operators to deploy a LTE network incrementally over a national CDMA network.

An article in Fierce Broadband Wireless summarises their leadership in these words:

LG has an impressive LTE track record: an LTE demo at Mobile World Congress 2008; the announcement of the world's first LTE chipset and modem prototype in November 2008; the first LTE-enabled mobile device Live Air Demo at Mobile World Congress 2009; the first FCC LTE Device certification built around LG's LTE chipset in June 2009; the first dual-mode LTE/eHRPD in-call handover in August 2009; and a 100 Mbps maximum throughput Live Demo at CES 2010.

3GPP Release8 June 2009 compliance, multiple band support (2.1 GHz Band1 or 700 MHz Band13), various system bandwidth, from 5 MHz to 20 MHz and max throughput with up to 100 Mbps downlink and 50 Mbps uplink, are among the main features supported by the dual-mode LTE/CDMA Vd13 device and LTE-only LD100U device.

In Las Vegas, LG executives recognized that the two devices recently unveiled are intended more to demonstrate their LTE development leadership and, likely, will not be launched as commercial devices. Although they didn't outline their exact plan, they disclosed that their own LTE modem will eventually be integrated into a netbook or notebook, meaning that a more integrated chipset solution will hit the market soon.

Known for its 2G and 3G handset line, LG relied on mature merchant chipset solutions such as Qualcomm, ST-Ericsson or Infineon chips, not LG technology. We can elaborate different scenarios to explain their new positioning as an LTE market driver. Gaining ground in all cellular technologies and capturing more than 10 percent of the total handset market as year-end 2009, leading them to third position worldwide, LG has decided to invest significantly into chipset development in order to become technology independent.

On top of the LTE modem, they will now introduce phones based on their own 2G/3G/4G intellectual properties to save cost and stay ahead. We could also speculate that LG wants to broaden their essential patents portfolio, driving 3GPP groups and initiatives to better compete with their current chip suppliers. In this case, once the LTE market matures and reaches a critical mass, LG will switch to third party players just as they have in the past. One more scenario has to be considered: following Nokia's early strategy, LG could license its LTE modem IP to partners that will manufacture the chipset solution and sell it back to them.

It's difficult to predict LG's long-term strategy in terms of chipset development at this point. The company has the scale to succeed, scale that small WiMAX players who recently announced parallel WiMAX/LTE roadmaps lack. In the new research report released by Maravedis in partnership with Reveal Wireless, entitled "WiMAX Wave2 Subscriber Station Chipset Vendors Competitive Analysis," we have identified the WiMAX chipset companies who have shifted to LTE by offering a flexible programmable base-band solution.

The LTE base-band chipset market is already crowded: incumbent manufacturers who ship in large volume (Qualcomm, ST-Ericsson, and Nokia), new entrants who traditionally relied on merchant solutions (LG and Samsung Electronics), and newcomers who leverage their OFDM expertise, WiMAX chipset background, and WiMAX ecosystem experience (Altair, Comsys, Sandbridge, Sequans and Wavesat) are committed to playing a significant role in the LTE baseband landscape. With Mediatek, Infineon, Marvell, and likely giant Intel poised to enter the market eventually, the field will soon be comparable to the aisles of CES 2010... very packed.

One thing I have learned is that initial leadership doesn't guarantee final outcome but we have to appreciate LG's rise in the LTE technology arena.

World Largest Operator helping transform China

Chinese operators have been spending Billions of Dollars building their 3G Infrastructure

China Mobile, the largest wireless carrier in the world with roughly 518 million customers, recently revealed that it has so far invested approximately RMB80 billion (US$11.7 billion) for 3G network construction. The carrier has completed the third phase of the 3G network (based on the home-grown TD-SCDMA standard) deployment in 2009 having covered approximately 70% of the Chinese cities.

The Chinese are becoming more and more mobile savvy.

In a news release Friday, China Internet Network Information Center (CNNIC) announced that China's mobile phone Internet users reached 233 million in December 2009, a growth of 120 million users from 2008. Among these users, 30.7 million accessed the Internet exclusively on their mobile phones.

China's online population reached 384 million as of December 2009, growing 28.9 percent from figures recorded in 2008, said CNNIC in the report.

The country surpassed the United States in 2008 to become home to the world's largest Internet user community.

There is a very interesting piece in The Guardian:

Until just over a year ago, Gong Kangshun spent much of his life trekking over the mountains around his remote village in south-west China. It isn't easy to make a living in Xiuxi, a tiny settlement of 58 families deep in Aba county, Sichuan. Gong grows crops on a small plot and sells rare fungi found on the steep slopes nearby. Many young people, including his brother, leave to find work in the factories and shops of China's east.

But a single purchase has shortened his working hours and sent his income soaring – by helping him to find buyers for his fungi. It has even improved his relationships with family and friends. "I'd panic without my mobile phone," the 35-year-old admits.

Across China, tens of millions have similar tales to tell. Many had never enjoyed phone access until recently. Now, for as little as £20, they can buy a handset, slot in a pre-paid sim card, start calling – and change their lives.

Most, like Gong, can thank one firm: China Mobile. With more than 70% of the domestic market it has 518 million subscribers; more than any other mobile carrier on the planet.

It is the world's largest phone operator by market value and the largest Chinese company listed overseas. Its work on 4G technology and its interest in foreign acquisitions suggest its international profile may soon grow.

Already the company's influence is rippling out across the world, almost unnoticed. The rapid spread of mobiles facilitated by the company's high-speed network roll-out, is both a product of China's aggressive development and a contributor to it – accelerating the pace of life and business, shrinking distances.

Some activists are enthusiastic about the potential for mobiles and the internet to expand the flow of information in a country with heavy censorship. They point to cases where camera phones have captured and shared images of unrest or official abuse.

The authorities certainly seem to be aware of the potential – Chinese social networking sites are strictly controlled and overseas services such as YouTube are blocked. In restive Xinjiang text messaging was turned off after vicious ethnic violence. The authorities also use mobiles for everything from political education to monitoring individuals.

The social and political effects of new technology are rarely straightforward, but for most people, mobiles are simply a part of their life. Whether a highly-paid Shanghai executive, or an independent farmer-cum-trader such as Gong, no one can afford to be without a phone – or a signal. China Mobile's 500,000 base stations now cover 98% of the population. You can call home from city subway trains, distant fields, or the peak of Mount Everest.

"If you have a requirement, we will have coverage," pledged the firm's chairman and chief executive Wang Jianzhou, who has more than three decades of experience in the sector.

"When we started this business we thought very few people would usemobile phones – only the rich," he said. Now he is dissatisfied with a penetration rate of 57%. "I think every adult should have at least one mobile … they are an extension of human ears, eyes and mouths."

Before the network reached Xiuxi, in late 2008, Gong used the phone perhaps twice a month. Each time he would walk for an hour to the nearest landline to call traders interested in buying the valuable "caterpillar" and "sheep stomach" fungi used in Chinese medicine.

"Now, on a busy day, I might make 20 calls," he said. "I can contact buyers in Chengdu and Shanghai. I can do business sitting at home and buyers can reach me, too."

His income has risen 50%, to 20,000 yuan (£1,820). And instead of walking seven hours a day to find the fungi collectors, he can call and ask them to deliver.

In his spare time, he chats to his younger brother, a chef in Zhejiang province who comes home at most once a year. Villagers hear a lot more news from the outside world these days – even Gong's 14-year-old son has his own phone. In 1997, there were just 10 million mobile users in China; by 2005, China Mobile had 240 million. Since then it has more than doubled.

The government pushes all carriers to serve the poorest. But since taking charge at China Mobile in 2004, Wang has shown sceptics that focusing on rural areas is a viable business strategy.

"Many analysts and investment bankers told me: never go to rural areas because they are low revenue. You will not make a profit," Wang said, in an interview at his spacious but low-key office in the company's headquarters on Beijing's Financial Street.

"I didn't believe that … with fixed lines, providing rural services is very, very difficult and expensive. [We have] low average revenue per user – but also low costs."

With a penetration rate of just 37%, there is plenty of room for growth among China's 700 million rural population. And there is plenty of demand. In Yangcun county, close to Beijing, Chen Fengmei anxiously scrolls through her latest text message: advice from officials on how the day's weather will affect her tomato crop. Another villager, Li Chunyu, checks the latest market prices for his pigs, no longer needing to trust middlemen or to give them a cut of his profits. "I never need to go anywhere. I can stay on the farm and find out everything," he said.

Continue reading the complete article here.

Top 10 paid iPhone apps

Interesting collection of paid iPhone Apps from The Independent.

1. Doodle Jump: £0.59 Jumping game featuring different platforms and obstacles to overcome.

See here for details. Official website here.

2. Where's Wally (Where's Waldo in USA). £1.79 The striped-jumper sporting explorer leaves the page and enters the iPhone in this hidden-object game.

More details here. Official website here.

3. MOTO X MAYHEM £0.59 Jump, lean and race through 14 levels of motocross action in this side-scroller.

More details here. Official website here.

4. CRASH BANDICOOT £1.79 High-octane 3D kart racing.

More details here. Official website here.

5. BEJEWELED 2 £1.79 The simple but compelling gem-swapping action puzzle.

More details here. Official website here.

6. WHO WANTS TO BE A MILLIONAIRE? £2.99 Although you can't win the ultimate cash prize, this game lets you experience the 'Millionaire' quiz questions.

More details here. Official website here.

7. THE SIMPSONS ARCADE £2.99 Help Homer round up the delicious doughnuts that are located around Springfield.

More details here.

8. TETRIS £1.79 The block-dropping classic.

More details here. Official website here.

9. NEED FOR SPEED SHIFT £3.99 With 20 supercars and 18 tricky tracks to master, this title, currently reduced, is a winner.

More details here.

10. IVIDEO CAMERA £0.59 No 3GS? No worries with this video camera app.

More details here.

Mobile Phones transforming Africa

Interesting article from The Guardian:

The mobile phone is turning into Africa's silver bullet. Bone-rattling roads, inaccessible internet, unavailable banks, unaffordable teachers, unmet medical need – applications designed to bridge one or more of these gaps are beginning to transform the lives of millions of Africans, and Asians, often in a way that, rather than relying on international aid, promotes small-scale entrepreneurship.

While access to a fixed landline has remained static for a decade, access to a mobile phone in Africa has soared fivefold in the past five years. Here, in one of the poorest parts of the globe, nearly one in three people can make or receive a phone call. In Uganda, almost one in four has their own handset and far more can reach a "village phone", an early and successful microfinance initiative supported by the Grameen foundation.

One recent piece of research revealed how phone sharing, and the facility for phone charging, has been an engine of this small-business revolution. Particularly in rural areas, a small investment in a phone can first create a business opportunity, then maximise its reach by overcoming the possible limitations of real or technological illiteracy – because the phone operator can make sure the call gets through, and can cut off the call at exactly the right moment to avoid wasting any part of a unit. And what a difference a phone call can make.

Often the mere fact of being able to speak to someone too far away to meet with easily can be a transforming experience. For fishermen deciding which market is best for their catch, or what the market wants them to fish for, a phone call makes the difference between a good return on the right catch or having to throw away the profit, and the fish, from a wrong catch. For smallholders trying to decide when or where to sell, a single phone call can be an equally profitable experience.

But establishing market conditions is just the start. Uganda has pioneered cash transfers by phone through the innovative Me2U airtime sharing service, which allows a client to pay in cash where they are and transmit it by phone to family or a business associate hundreds of miles away. They receive a unique code that they can take to a local payment outlet to turn into cash.

But the market leaders are M-PESA, a mobile money system set up by Safaricom, in its turn an affiliate of Vodafone, in Kenya (although it operates in Uganda now too). Less than three years old, it has 7 million customers and, according to some sources, processes as much as 10% of Kenya's GDP.

At a recent International Telecommunications Union session, Nokia's Teppo Paavola pointed out that there are 4 billion mobile phone users and only 1.6 billion bank accounts. The huge scope for providing financial services through mobile phones represented by that differential is a tempting prospect for the big players.

But, as one British contender, Masabi, has discovered, it is one thing to develop a secure mobile payment system like their Street Vendor - which works on old handsets and in most scripts – and quite another to get a deal with the international financial regulators that police cross-border cash flows.

Masabi has worked with another UK company, Kiwanja.net, that aims to help NGOs and other not-for-profit organisations use mobile technology.

Ken Banks, founder of Kiwanja.net (Kiwanja means "earth" in Swahili) has pioneered a two-way texting system called FrontlineSMS that allows mass texting from a single computer-based source to which individual subscribers can reply.

So for example, health workers attached to a hospital in Malawi can "talk" to their base to seek advice, pass on news of patients' progress or ask for drug supplies. The data can be centrally collected and managed. All that's needed is a mobile signal – far more available than an internet connection.

FrontlineSMS is a free download: the aim is not to tell users what to do, but to help them work out how to apply the technology to their own problem.

The only barrier to even greater mobile use, apart from international financial regulations, are the taxes levied by national governments that can make the cost prohibitive. According to one recent report, despite exponential growth in countries like Uganda there is growing evidence that what for millions is a life-changing technology risks leaving out the poorest.

Mobile Trends in 2020

Mobile Trends 2020

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2.6 GHz LTE Spectrum Band Report

The licensing of the 2.6 GHz band will be critical to unlocking the benefits of global scale economies in the Mobile Broadband market, according to a new report* by US-based research firm Global View Partners in partnership with the GSMA. The research found that the 2.6 GHz spectrum, which has been identified globally by the ITU as the ‘3G extension band’, will be vital in satisfying the demand for greater capacity for Mobile Broadband and launching next-generation networks such as LTE, which will start to be deployed commercially around the world this year.

“There is clear evidence that the volume of data flowing over mobile networks is growing rapidly and is being accelerated by the popularity of smart phones and the growth in music and video downloads,” said Tom Phillips, Chief Regulatory Affairs Officer at the GSMA. “The report highlights that the 2.6 GHz band will allow operators to address rapidly increasing traffic volumes in an efficient and harmonised way. Recent licensing of this band in Hong Kong, Norway, Finland and Sweden, for example, has highlighted that there is more demand for paired (FDD) than unpaired spectrum (TDD) and that the ITU’s recommended Option 1** plan is the best structure to stimulate market growth in a technology-neutral and competitive environment.”

In Europe, measurable progress has been achieved towards the allocation of the 2.6 GHz frequency, as specified in the ITU Option 1 plan. There is widespread agreement at the member state and European Union level that this objective will best be fulfilled in a manner that is harmonised and coordinated across all countries in the region. The research suggests that leaving the band unstructured for auctions or with a diverse mix of non-harmonised FDD and TDD allocations should be avoided. Potential challenges include interference management, resulting reductions in usable bandwidth and loss of coverage in border regions, as well as higher costs and delayed equipment availability.

The research also points out that in many cases, the 2.6 GHz frequency will be the first opportunity for mobile operators to acquire 2x20 MHz of contiguous spectrum, enabling them to operate high-speed LTE services at optimum performance. LTE is the next-generation Mobile Broadband technology for both GSM and CDMA operators, and will leverage new and wider bandwidths to significantly increase data capacity in high demand zones such as dense urban areas. The 2.6 GHz spectrum is the ideal complement to the 700 MHz spectrum, also known as ‘digital dividend’, and will enable the most cost-effective nationwide coverage of Mobile Broadband across both rural and urban environments.

Governments in most Western European countries as well as in Brazil, Chile, Colombia, and South Africa are planning to award 2.6 GHz frequencies within the next two years.

The Report is available HERE.

Temporary Identities in LTE/SAE - 2: RNTI's

Last year I covered some information on temporary identities but never got a chance to continue on it. Here is one on RNTI's

RNTI or Radio Network Temporary Identifier(s) are used primarily by eNB Physical Layer for scrambling the coded bits in each of the code words to be transmitted on the physical channel. This scrambling process in PHY happens before modulation. There is a sequence followed for scrambling, calculation of which depends on the RNTI(UE specific for channels like PDSCH,PUSCH) and cell specific (for broadcast channels like PBCH). Details could be found in [2].

The following table lists different kinds of RNTI's:

Lets look at some of these in slightly more detail:

P-RNTI (Paging RNTI): To receive paging messages from E-UTRAN, UEs in idle mode monitor the PDCCH channel for P-RNTI value used to indicate paging. If the terminal detects a group identity used for paging (the P-RNTI) when it wakes up, it will process the corresponding downlink paging message transmitted on the PCH.

SI-RNTI (System Information RNTI): The presence of system information on DL-SCH in a subframe is indicated by the transmission of a corresponding PDCCH marked with a special System Information RNTI (SI-RNTI). Similar to the PDCCH providing the scheduling assignment for ‘ normal ’ DL-SCH transmission, this PDCCH also indicates the transport format and physical resource (set of resource blocks) used for the system-information transmission.

M-RNTI (MBMS RNTI): Used in Rel-9 for MCCH Information change notification.

RA-RNTI (Random Access RNTI): The RA-RNTI is used on the PDCCH when Random Access Response (RAR) messages are transmitted. It unambiguously identifies which time-frequency resource was utilized by the UE to transmit the Random Access preamble. If multiple UEs had collided by selecting the same signature in the same preamble time-frequency resource, they would each receive the RAR.

C-RNTI (Cell RNTI): The C-RNTI to be used by a given UE while it is in a particular cell. C-RNTI allocation and details are too complex to explain in the blog so please refer to Nomor newsletter here.

TC-RNTI: When the UE does not have allocated C-RNTI then Temporaru C-RNTI is used. A temporary identity, the TC-RNTI, used for further communication between the terminal and the network. If the communication is successful then TC-RNTI is promoted eventually to C-RNTI in the case of UE not having a C-RNTI.

SPS-C-RNTI (Semi-Persistent Scheduling C-RNTI): For the configuration or reconfiguration of a persistent schedule, RRC signalling indicates the resource allocation interval at which the radio resources are periodically assigned. Specific transmission resource allocations in the frequency domain, and transmission attributes such as the modulation and coding scheme, are signalled using the PDCCH. The actual transmission timing of the PDCCH messages is used as the reference timing to which the resource allocation interval applies. When the PDCCH is used to configure or reconfigure a persistent schedule, it is necessary to distinguish the scheduling messages which apply to a persistent schedule from those used for dynamic scheduling. For this purpose, a special identity is used, known as the Semi-Persistent Scheduling C-RNTI (SPS-C-RNTI), which for each UE is different from C-RNTI used for dynamic scheduling messages. - Source: LTE, The UMTS Long Term Evolution: From Theory to Practice By Stefania Sesia, Issam Toufik, Matthew Baker

TPC-PUCCH-RNTI (Transmit Power Control-Physical Uplink Control Channel-RNTI) and TPC-PUSCH-RNTI (Transmit Power Control-Physical Uplink Shared Channel-RNTI): The power-control message is directed to a group of terminals using an RNTI specific for that group. Each terminal can be allocated two power-control RNTIs, one for PUCCH power control and the other for PUSCH power control. Although the power control RNTIs are common to a group of terminals, each terminal is informed through RRC signaling which bit(s) in the DCI message it should follow.

The following table lists the values that are assigned to different RNTI's in MAC:



[1] 3GPP TS 36.321 - Evolved Universal Terrestrial Radio Access (E-UTRA) Medium Access Control (MAC) protocol specification
[2] 3GPP TS 36.211 - Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation