Fundamental difference between HSDPA and HSUPA

It has been long time since HSDPA and HSUPA came into existence. Untill now we have read and implemented many features related to HSDPA and HSUPA. However following are the basic difference between HSDPA and HSUPA:

• In the downlink, the shared resource is transmission power and the code space, both of which are located in one central node, the NodeB. In the uplink, the shared resource is the amount of allowed uplink interference, which depends on the transmission power of multiple distributed nodes, the UEs.
• The scheduler and the transmission buffers are located in the same node in the downlink, while in the uplink the scheduler is located in the NodeB while the data buffers are distributed in the UEs. Hence, the UEs need to signal buffer status information to the scheduler.
• The WCDMA uplink, also with Enhanced Uplink, is inherently non-orthogonal, and subject to interference between uplink transmissions within the same cell. This is in contrast to the downlink, where different transmitted channels are orthogonal. Fast power control is therefore essential for the uplink to handle the near-far problem. The E-DCH is transmitted with a power offset relative to the power-controlled uplink control channel and by adjusting the maximum allowed power offset, the scheduler can control the E-DCH data rate. This is in contrast to HSDPA, where a (more or less) constant transmission power with rate adaptation is used.
• Soft handover is supported by the E-DCH. Receiving data from a terminal in multiple cells is fundamentally beneficial as it provides diversity, while transmission from multiple cells in case of HSDPA is cumbersome and with questionable benefits as discussed in the previous chapter. Soft handover also implies power control by multiple cells, which is necessary to limit the amount of interference generated in neighbouring cells and to maintain backward compatibility and coexistence with UE not using the E-DCH for data transmission.
• In the downlink, higher-order modulation, which trades power efficiency for bandwidth efficiency, is useful to provide high data rates in some situations, for example when the scheduler has assigned a small number of channelization codes for a transmission but the amount of available transmission power is relatively high. The situation in the uplink is different; there is no need to share channelization codes between users and the channel coding rates are therefore typically lower than for the downlink. Hence, unlike the downlink, higher order modulation is less useful in the uplink macro-cells and therefore not part of the first release of enhanced uplink.

Femtocells in India: No thank you.

So many people ask me if Femtocells will be big in India but I am not sure if I know the answer to that. Honestly I will be surprised if any Indian operators have any plan of Femtocells and even if they are rolled out people might not be tempted.

In a post last month, David Chambers gave an interesting overview of facts and statistics of mobile and internet users in India:

First some details on the current situation in India:

- Population: 1.1 Billion

- 80% live in rural areas and survive on agriculture

- 39% are illiterate

- 27% live below the poverty line

- 77% live on less than US$0.50 per day

- The economy is growing at around 8-9% annually (and has done so for a few years), similar to China, but is still far behind in infrastructure – traffic congestion is throttling and there is not yet a metro/underground in the main cities, although some are being built.

- 2% PC penetration

And from a mobile phone perspective:

- It’s all 2G. No 3G licences have yet been awarded.

- It’s GSM. Both the CDMA technology operators (Reliance and Tata) who have a combined share of around 20% are said to be planning GSM technology rollouts, because the technology is cheaper and there is a wider range of handsets.

- It’s growing faster than anywhere else. Over 9 million new subscribers every month, with around 180million subscribers reported today. That’s still a huge growth to catch up with China, which has almost 500M subscribers, increasing by some 4M/month.

- Around 200,000 towers, with around 20% of towers hosting more than one operator’s basestation equipment.

- ARPU figures vary, with a lot of the newer subscribers probably in the US$ 2-4/month bracket, although overall the industry makes around $8/month

- Call rates are in the order of US 2 cent/minute.

- Yankee reports operator share of Bharti 30%, BSNL 18%, Reliance 17%. Vodafone (formerly Hutch) is growing quickly.

- 2G cellular data cards, using fixed price data plans, are becoming popular in a similar way to 3G cards/USB dongles promoted in developed countries. The data rates and capacity are more limited.

Yet from a wired broadband internet position:

- 3 million broadband DSL subscriptions

- 8 million copper loops capable of delivering broadband.

- 10 million dialup internet users.- Fibre is being laid across the country, but fibre-cuts remain a regular fault

So if we look at the potential for 3G femtocells, we find there is little comfort:

- No 3G licences available yet – this is probably some years off, whilst the country focuses on basic 2G voice/text rollout.

- Virtually no wired broadband to support significant volumes.

- Any 2G femtocells would likely conflict with the tight spectrum reuse and frequency planning of the macro network, so would be discouraged except where deployed and managed directly by the operator in extremely high capacity locations.

- The business case for coverage fill-in doesn’t stack up – broadband is unavailable in areas which don’t have cellular coverage.

- The business case for data in the home is even more difficult, with relatively low levels of domestic computer penetration. There is more likely demand for mobile broadband access via macrocells, using the new HSPA, HSPA+ and LTE technologies when 3G spectrum is made available.

So it’s not a question of deployment of 3G femtocells in the Indian market coming a few years after the developed world. The complete lack of copper loops, and the changing technology that makes it more feasible to deploy wireless broadband than dig up and lay new copper loops. The services that femtocells would offer are therefore more likely to be delivered over the macrocellular network (with microcellular support) in the medium and long term for any developing country. There is some interest in 2G picocells which would be deployed by the operator in enterprise situations to handle high traffic concentrations, but this is a different application, technology and market segment from the 3G proposition.

A similar view is reflected in this article here:

Bharti Airtel, Reliance Communications and Vodafone, all became members of Femtoforum about two years back but don't have any deployment of femtocell in the country. Femtoforum is a not-for-profit membership organization founded in 2007 to promote femtocell deployment worldwide. According to some media reports Bharti Airtel is conducting pilot projects for femtocells. The same is true for Reliance Communications and Vodafone, both are members of Femtoforum but are doing nothing about femtocell deployment in the country. Despite repeated attempts none of the service provider is forthcoming about femtocells deployment status.

In my recent visit to India I found that people have a different perspective of mobiles. For instance people couldnt understand why we use SMS so frequently and as a medium for communication (between friends, couples). India may probably have lowest tariff for voice and that is one of the reasons people use mobiles for. Many people have removed their landlines and use mobiles only, for their calls. Another most common use of the mobiles is to be reachable wherever you are. People havent learnt to switch their phones of silent and hence many places of worship in India are installing Jammers to stop mobiles working while you are thinking about God.

Similarly, people are not too bothered about the internet. They would generally use it on the weekends to write to their, friends, etc. If there is free net available in the office then its a different thing. The net speeds are also not very good and the link is not too reliable. One of the most popular application is Skype follwed by chatting applications.

I met many people who had Iphones or latest Nokia's/Samsung's but when I asked them if they did any data usage on their phones they all drew blank. I found one guy very actively using net on his E71 but he was connected via WiFi.

In this kind of situation, Femtocells may not be of much use to people. Femtocells would be useful as voice boosters but would that justify its cost. I dont think so. The main reason for surge in Mobile takeup is because its very cheap to make calls. You get some very good call bundles at really low cost. There are off peak rates which is 1/5th the normal rate. If the reception of a network is not good in somebody's house, he would change to a different network. In fact even now Mobile Number Portability is not available in India. As a result some people change mobile numbers every year.

With all these things in mind, Femtocells would be hard sell in India.

Coin operated 'Credit Crunch Mobile'

Bizarre concept, but I have already started liking it.

The following is from dialaphone website:

Following our brief earlier coverage of the phone set to challenge the Credit Crunch, we’re very excited to have the first artist’s impression of this new handset, codenamed the 100-F from a Latvian manufacturer, new to the mobile phone market, called Lirpa. It seems bizarre, but the phone design has been inspired by the global credit crunch (which must have reached Latvia too), and works as either a coin-operated or credit/debit card mobile. The UK variant will have a £1 coin slot for calls and a 10p slot for texts (not a bad price for a PAYG text) as well as a card slot (for which you’ll need to enter your PIN). It sounds like it will be quite bulky, maybe comparable with some of the smartphones around, and features will be limited - no camera or MP3 player as the components would take up too much valuable coin space.

Here are some of the 100-F features:
Colour screen - No
Bluetooth - No
Weight - 110g empty, 400g full
Available colours - Midnight Black, Dirty Grey and Grey Black
Card slot - Visa, Mastercard, Electron
Messaging - SMS, MMS, IOU
Ringtones - Built-in, Vibrate, Jangle

The idea behind this phone is obviously to make you think about how much you spend on calls, and we understand there’s another twist on this - users will be able to opt for having no access to the coin box, in which case they will have to take the phone to one of their network provider’s shops to have it emptied. None of the UK networks have commented on this as yet.

Dont forget to checkout the pre-order offers here.

Prisoners need mobiles too :)

Looks like there is a worldwide problem of Mobiles in the jails. Nearly everywhere mobiles are illegal in jails but people somehow manage to sneak them in.

First, this news from India about an inmate found with a mobile inside the prison. Apparently these phones are used by inmates to create co-ordinated attacks, etc. Sneaking a mobile in India is probably not too difficult because you bribe the policeman and he will get one for you ;)

In Brazil, it difficult to probably get a phone by bribing the policemen. That is why the prisoners have to ask someone to send mobiles using pigeons as carriers. Pigeons are carrying parts of mobiles which are being used by the inmates to assemble and create working mobiles. Maybe they can fix my old Nokia 6280 as well. Unfortunately couple of pigeons were recently caught and thats how authorities found out about them.

The Australian authorities in New South Wales have already passed a law stating that if someone is found smuggling mobiles in prison then they will face 2 years jail and $2200 fine. They are training dogs to sniff out mobiles.

In India a member of public (normal human being like most of us) has demanded that 'rude' mobile users should go to prison:

A petition filed by Gurjit Singh, a member of the public, demands that carrying mobiles at funerals and temples should be made illegal and the installation of mobile phone jammers on school buildings to block students from making calls mandatory.

Mr Singh also wants phone companies to roll-out apparatus would disable mobiles on the roads to avoid traffic accidents, and a law under which civil servants could be imprisoned if they make personal calls on their handsets during office hours.

His final demand is that mobile phones fitted with cameras be outlawed “for the safety of women”.

The measures may appear extreme, but have already won significant backing, including from The Times of India, the country’s most-read English language newspaper. “Mobile phones have made us less considerate for each other,” it said.

The newspaper went on to admit – somewhat ruefully – that banning mobile phones outright was not an option, but added: “The problem will only get worse, unless the parliamentary panel’s observations are taken seriously.”

India’s mobile phone market is one of the few corners of the global economy to have remained impervious – so far – to the effects of the credit crunch. In January, the country added a record 15 million subscribers, making it the world’s fastest growing, with customers from the country's poor rural areas driving the surge.

The industry's success has a dark side, however: in cinema theatres across India audience members can often be heard chatting on their new handsets, discussing the plot of the film as it unfolds on screen.

While even doctors commonly answer calls while treating patients.

The problem is made worse as the phone companies force as many conversations as possible through a limited amount of infrastructure, a cost-cutting measure that executives privately admit lessens the clarity of calls and means users often have to shout to make themselves heard.

There are, however, doubts over whether tough new penalties would work, especially when laws banning other public nuisances such as spitting have failed. A spokesman for RCom, India’s fastest growing mobile provider, insisted that while the industry takes the etiquette issue seriously there is a limit to what it can do. “This is really a matter of personal responsibility,” he said.

My solution for the Indian government is that mobiles should be allowed only in prisons :-)

ICE: In case of emergency

In case of emergency (ICE) is a program that enables first responders, such as paramedics, firefighters, and police officers, to identify victims and contact their next of kin to obtain important medical information. The program was conceived in the mid-2000s and promoted by British paramedic Bob Brotchie in May 2005. It encourages people to enter emergency contacts in their cell phone address book under the name "ICE". Alternately, a person can list multiple emergency contacts as "ICE1", "ICE2", etc. The popularity of the program has spread across Europe and Australia, and has started to grow into North America.

Implementation of CQI Reporting in HSPA

In HSDPA the channel quality indicator is a measure of the mobile channel which is send regularly from the UE to the Node B. These measurements are used to adapt modulation and coding for the corresponding UE and it can be also used for the scheduling algorithms.

The CQI measurement is implemented in the HSPA module and the measurement interval as well as the influence of measurement errors can be parameterised. The results can be given in form of maps or in a statistical manner as histogram for each cell.

Information about the instantaneous channel quality at the UE is typically obtained through a 5-bit Channel-Quality Indicator (CQI) in HS-SCCH, which each UE feed back to the NodeB at regular intervals. The CQI is calculated at the UE based on the signal-to-noise ratio of the received common pilot. Instead of expressing the CQI as a received signal quality, the CQI is expressed as a recommended transport-block size, taking into account also the receiver performance.

The reason for not reporting an explicit channel-quality measure is that different UEs might support different data rates in identical environments, depending on the exact receiver implementation. By reporting the data rate rather than an explicit channel-quality measure, the fact that a UE has a relatively better receiver can be utilized to provide better service (higher data rates) to such a UE. It is interesting to note that this provides a benefit with advanced receiver structures for the end user.

This is appropriate as the quantity of relevance is the instantaneous data rate a terminal can support rather than the channel quality alone. Hence, a terminal with a more advanced receiver, being able to receive data at a higher rate at the same channel quality, will report a larger CQI than a terminal with a less advanced receiver, all other conditions being identical.

Each 5-bit CQI value corresponds to a given transport-block size, modulation scheme, and number of channelization codes. Different tables are used for different UE categories as a UE shall not report a CQI exceeding its capabilities. For example, a UE only supporting 5 codes shall not report a CQI corresponding to 15 codes, while a 15-code UE may do so. Therefore, power

offsets are used for channel qualities exceeding the UE capabilities. A power offset of x dB indicates that the UE can receive a certain transport-block size, but at x dB lower transmission power than the CQI report was based upon. UEs belonging to category 1–6 can only receive up to 5 HS-DSCH channelization codes and therefore must use a power offset for the highest CQI values, while category 10 UEs are able to receive up to 15 codes.

The CQI values listed are sorted in ascending order and the UE shall report the highest CQI for which transmission with parameters corresponding to the CQI result in a block error probability not exceeding 10%.

Specifying which interval the CQI relates to allows the NodeB to track changes in the channel quality between the CQI reports by using the power control commands for the associated downlink (F-) DPCH. The rate of the channel-quality reporting is configurable in the range of one report per 2–160 ms. The CQI reporting can also be switched off completely.

In addition to the instantaneous channel quality, the scheduler implementation in the NodeB should typically also take buffer status and priority levels into account before finalising the data rate for the UE. Obviously UEs for which there is no data awaiting transmission should not be scheduled. There could also be data that is important to transmit within a certain maximum delay, regardless of the channel conditions. One important example hereof is RRC signalling, for example, related to cell change in order to support mobility, which should be delivered to the UE as soon as possible. Another example, although not as time critical as RRC signalling, is streaming services, which has an upper limit on the acceptable delay of a packet to ensure a constant average data rate. To support priority handling in the scheduling decision, a set of priority queues is defined into which the data is inserted according to the priority of the data. The scheduler selects data from these priority queues for transmission based on the channel conditions, the priority of the queue, and any other relevant information.

LTE UE Categories

Five different UE categories have been defined for LTE. These UE categories are often referred to as UE classes. As can be seen in the table above, the low end UE does not support MIMO but the high end UE will support 4x4 MIMO. It is also worth noting that UE class 1 would be inferior to that of the best HSPA UE. It is important to note that regardless of whatever category a UE belongs to, it has to be capable of receiving transmissions from upto four antenna ports. This is because the system information can be transmitted on upto four antenna ports.

It should be noted that some of the capabilities are outside the UE category info. For example the Inter-RAT capabilities like the support of EV-DO or GSM, etc is not specified as part of the UE categories. Similarly the support of duplexing schemes and the support of UE-specific reference signals are outside the scope of this.

Reference:3GPP TS 36.306 - E-UTRA User Equipment (UE) radio access capabilities

Orange to launch Exposure2

Orange this week launches Exposure 2, the second Exposure research survey commissioned to reveal the role of mobile media usage within the broader media landscape. Exposure 2 consists of independent qualitative and quantitative research, following a survey of more than 2,000 mobile media users from across all UK mobile networks. The survey focuses on consumer consumption of mobile media, and attitudes towards it when used as a marketing channel - particularly in comparison to other traditional and digital media.

Key Findings

Mobile Media Consumption

A mobile media user for the Exposure2 study is anyone who has used their mobile handset to do one of the following:

• Watch Mobile TV
• Use the mobile internet
• Use Bluetooth
• Send & receive mobile videos / MMS
• Send & receive pictures / MMS
• Send & receive emails
• Search the internet
• Play games
• Listen to the radio
• Listen to music
• Find local information
• Download wallpapers/pictures
• Download screen logos
• Download ringtones
• Download music
• Download games

Mobile media usage patterns differ greatly depending on a consumers location, with the strongest usage of mobile media being in the home: 67% of participants who used their mobile for email did so in their home and 56% for mobile internet browsing. Downloading, mobile content was also revealed as significantly more likely to be performed at home, with speed, convenience and alleviating boredom, cited as the key reasons for usage.

Meanwhile, high use of mobile media on public transport centred around entertainment services, such as TV, music and games, whereas services used most when out and about, such as local information and internet search, tend to facilitate movement.

Other key findings on mobile media usage included:

• The average age for mobile media users is 36, and 81% use mobile media more than once a week with 46% using it daily
• Men generally use mobile media more, although women are much more likely to use picture messaging
• The mobile internet pages viewed most often are search engines, email, news, music and film although, interestingly, a high proportion (55%) of people browse the mobile internet with no specific agenda, providing an opportunity for marketers to attract their attention

Attitudes to Mobile Media as a Marketing Channel

Research participants were asked to rate traditional and digital broadcast and print media on a number of attributes. Mobile media was overwhelmingly viewed as the most personal and innovative media, providing it with a unique place in the marketing mix.

The research revealed that people are very much open to mobile marketing and contained some important insights for brands looking to engage with consumers using the media:

• Short SMS codes remain a popular marketing mechanic, having been used by two-thirds of participants
• 70% of participants are attracted more by interactive marketing formats, such as sponsorship, coupons or picture messaging mechanics
• In general, consumers viewed marketing formats with perceived value as the most appealing, such as coupons offering discounts and sponsored games available for free download
• When clicking on adverts on the mobile internet, the next stages which are most popular are: adverts which click straight through to the brand’s website (favoured by 47%); voucher code or coupon (43%); click through to another area of the site (36%); entered in a competition (34%)
• Icons letting users know what to expect from mobile advertising were received positively by 76% of participants
• 82% of respondents have the operator’s portal as their mobile internet home page, making this page an extremely valuable piece of marketing estate

Steve Heald said: “Exposure 2 provides some terrific insights into how exactly brands can go about engaging consumers through mobile. The public is looking for campaigns that reflect their perceptions of mobile as unique and innovative and that entices and excites them with clever interaction. There’s also a clear signal that brands need to be clear on what consumers can expect from mobile campaigns.”

Difference between SDU and PDU

This question keeps propping up in many discussions so here is an explanation for the difference between PDU and SDU.




Going back to the basics, a protocol stack consists of many different individual protocols. Protocols can be simply described as set of rules that allow communication between peer entities or they can also be described as set of rules that facilitate horizontal communication. Now these protocols are arranged in layers as can be seen in the figure above. In the transmitter side, a layer N receives data from layer N+1 and this data is called the SDU or Service Data Unit. This layer will modify the data and convert it into a PDU or a Protocol Data Unit. The peer entity in the receiver is only able to understand this PDU.

In simplest form, this modification by layer N of the layer N+1 SDU contains encapsulation. In encapsulation, the SDU is preserved as it is and an additional header is added by the layer N protocol. The modification can also perform concatenation (where more than one SDU is combined in a single PDU), segmentation (where a SDU can be split so that different parts of it end up in different PDU) and padding (where SDU is so small that filler bits are added in the end to complete the PDU).

In the receiver side, the peer entity receives the PDU from layer N-1 (its actually layer N-1 SDU) and convert it back into SDU(s) and passes it to layer N+1.

The figure above shows an example of RLC SDU and PDU. The SDU's are received from higher layer, which is from PDCP in case of LTE. These SDU's have to be converted to PDU's so they undergo segmentation and concatenation and suitable RLC headers are added to form the RLC PDU's.

First Figure Source: The TCP/IP Guide

Second Figure Source: 3G Evolution - HSPA and LTE for Mobile Broadband, Erik Dahlman et al.

Bankrupt Nortel pays hefty bonuses to executives

Nortel Networks, as it continues to wade through bankruptcy protection, posted a $2.14 billion loss in the fourth quarter and a $5.8 billion loss for all of 2008.

The above news obviously paints picture where the restructuring and job losses will be normal activity at Nortel. However the news which I got to read today and which is not at all normal is that Nortel is going to pay $7.3 million as a bonuses to it’s executives.

This is quite extraordinary for me specially when employees at the bankrupt company were forced to decide between severance pay and their pension plans.

An Ontario Superior Court Judge Geoffrey Morawetz has allowed Nortel Networks Corp. to pay these bonuses to some Canadian senior executives as part of an incentive plan to keep them with the company to drive reorganization as it tries to emerge from bankruptcy protection.Earlier this month, a U.S. court overseeing Nortel's bankruptcy allowed the company to pay $22 million in bonuses the company said it needed to keep 880 employees worldwide.

All the amounts mentioned above do not include any payments to CEO Mike Zafirovski. This becomes quite apparent that whatever compensation Zafirovski receives will come from a separate pot.

It’s reported that under the terms of the key executive incentive plan, the top executives could get cash incentives of 100 per cent to 183 per cent of base salaries where the salaries are thought to in the $1-million U.S. annual range.

These new payments in terms of bonuses has not gone down well and there are vociferous protests specially from a lawyer representing a group of Nortel workers who have been fired but have not received severance pay.

For me this situation is like there is a guy who refuses to pay his debts but then spends £10,000 for a car. These are tough times and it should apply fairly to everybody.

Nortel has offered to give fired employees early access to pension plans and provide medical benefits to retirees under the condition that they drop their claims for severance pay in bankruptcy court.

The telecom equipment giant filed for bankruptcy protection in mid-January and has until May to restructure. Since filing the bankruptcy, Nortel’s revenue declined 15 percent year-over-year in the fourth quarter, down to $2.72 billion.

As a part of restructuring process Nortel may offload some of its major units, including its wireless equipment business, instead of trying to remain a whole company.