A crash course in GSM, GPRS, EDGE, UMTS, HSPA, LTE and WiMax


This is almost a crash course in fundamentals on mobile standards. It does not matter if you are just a common man trying to understand the jargon or a professional who is trying to get a grip of things. This article i hope will help you started off :-) Please leave a comment if you don't understand any topic. I am very happy to clarify.





To understand Timeslots and frequencies you can read here!!


GSM stands for Global System for Mobile Comm. This is the most popular 2G protocol standard in the world. It is by law the only system deployed in Europe and is used in many other locations around the world. As a digital standard, GSM can carry both voice and data, although the maximum data rate per channel is only 14kbps. North America, Korea, and pockets worldwide use another 2G standard based on CDMA technology; this protocol, CDMAOne, was developed by Qualcomm and is also known as IS-95 or, more commonly, CDMA. GSM is based on time-division multiple access (TDMA) technology, in which a single frequency is divided into eight time slots, with each caller using a particular slot. Most GSM networks operate in two frequency bands: 900MHz and 1,800MHz. In North America, however, the allocated frequency bands are 850MHz and 1,900MHz. Thus, to support global roaming, a handset must support all four GSM bands. The frequencies in each band are assigned to either the downlink direction (from the base station to the user) or the uplink direction (from the user to the base station). Each band supports 124 carrier frequencies in each direction (uplink and downlink).

GPRS stands for General Packet Radio Service. This is a 2.5G protocol standard which allows a single handset to use up to four slots for the downlink and four for the uplink, thus consuming the entire frequency. Using a more efficient encoding than GSM, GPRS can transmit 20kbps per slot for a maximum of 80kbps in each direction using four slots. A later enhancement, EDGE, increases the data rate to a theoretical maximum of 384kbps, although the most bandwidth supported by any chip vendor or carrier is 240kbps.

EDGE stands for Enhanced Data GSM Environment is a 2.75G protocol standard, which increases the bandwidth of each time slot to 48kbps. Baseband processors commonly support either Class 10 or Class 12, which allow a maximum of four slots (192kbps) on the downlink.

UMTS stands for Universal Mobile Telecommunications Service which is a 3G standard and is a follow-on to GSM, created by ITU. (Japanese carrier NTT DoCoMo uses a pre-standard version of UMTS known as FOMA.) UMTS uses new spectrum at 2GHz and new air interfaces that can carry more data, and therefore a greater number of digital voice calls, than can 2G technologies. UMTS delivers symmetric data rates as high as 384kbps for handsets. Unlike earlier standards, UMTS supports simultaneous voice and data services (dual-transfer mode). With tremendous growth in cell-phone usage during the 1990s, vendors sought to use new frequency bands and new technologies to increase capacity. The term 3G indicates the generational leap involved in this major change. The first 3G network was deployed by NTT DoCoMo in Tokyo in 2001. Today, 3G is broadly deployed by operators around the world. Most operators, however, have not upgraded their entire networks, so 3G devices must include 2G compatibility to have the widest service area.

Qualcomm has continued to develop its own CDMA2000 air interface, thus providing its operators with an upgrade path. The 3G version, known as EV-DO, was first deployed in Korea in 2002. Since then, it has been broadly deployed in North America and other locations. The initial version, called Revision 0 (zero), supports data rates up to 2.4Mbps. Approved by the ITU in 1999 and officially adopted by China in January 2006, TD-SCDMA is a 3G standard deployed primarily by China Mobile, starting in 2008. As the name implies, this air interface combines TDMA and CDMA techniques, but the general characteristics and data rates are similar to those of UMTS. The TDMA aspect of the standard enables use of the same spectrum for both the uplink and downlink, thus providing some flexibility. TD, as the TD-SCDMA standard is sometimes called, provides aggregate data rates of 2Mbps.

HSPA stands for High-Speed (Uplink) Packet Access which is a 3.75G standard. This combine both HSDPA and HSUPA as explained in the next oaragrapgh. As with 2.5G technologies, new technologies enhance the data rates of UMTS while maintaining radio compatibility. The first to ship was HSDPA, which was first deployed in late 2005. HSDPA reserves a portion of the UMTS spectrum and converts it into a new high-speed downlink band. This 14.4Mbps band is shared by all users that are actively downloading data; as with any shared medium, actual bandwidth depends on how many users are simultaneously sharing the downlink band. The amount of data that each handset can accept may be limited.

HSUPA addresses the uplink. This direction is of concern for handset users wishing to transmit high-resolution photos or video. HSUPA raises uplink speed as high as 5.76Mbps. Initial commercial deployments began in early 2007. By pushing peak data rates to several megabits per second, HSDPA and HSUPA (together called HSPA) can also be used to deliver cellular broadband services. The data bandwidth using these technologies is similar to what older DSL and cable modems deliver.


HSPA+ further boosts data rates using two approaches. One uses a higher-order modulation to pack more bits into the signal; the second adds MIMO (multiple input, multiple output) capability, which can double throughput by transmitting two streams at once. To do so, MIMO requires two antennas at the base station and two antennas on the handset. The two approaches can be used separately or can be combined to achieve 42Mbps.

The TD-SCDMA standard can be extended to support faster downlink and uplink speeds using the same techniques that are defined in HSPA. The enhanced protocols are referred to as TD-HSDPA and TD-HSPA. Advancing CDMA2000, Qualcomm developed EV-DO Revision A, which boosts data rates as high as 3.1Mbps on the downlink and 1.8Mbps on the uplink. The new EV-DO Revision B supports 14.7Mbps on the downlink and 5.4Mbps on the uplink; these data rates are similar to those of HSPA. Qualcomm sampled the first EV-DO Rev B chips in late 2008.

LTE - Long Term Evolution
The UMTS camp has developed a 4G technology called Long-Term Evolution (LTE). The specification was completed in January 2008. In December 2009, TeliaSonera deployed the first commercial LTE network in Norway and Sweden. LTE uses a new modulation technique, OFDM (orthogonal frequencydivision multiplexing), and wider (20MHz) channels to deliver a peak data rate of 100Mbps. Optional MIMO support raises the peak rate to 326Mbps in a four-antenna configuration. Because of the space required for multiple antennas, high-end handsets and data cards are likely to use one or two antennas, whereas fixed broadband modems may use four (assuming the carrier supports that mode at the base station). The peak uplink rate is 86Mbps.

As a result of these changes, LTE provides about three times the spectral efficiency of HSPA, meaning that an operator can triple the data rate (or the number of voice calls) using the same set of frequencies. Thus, LTE should eventually reduce the cost of data services significantly. Deploying new base stations and bringing down the cost of LTE modems and handsets will require several years, however.

Another 4G technology is WiMax. Originally developed by Intel for fixed wireless broadband, WiMax is being used by some mobile service providers. WiMax is defined by the IEEE as 801.16. An industry group, the WiMax Forum, promotes the standard and certifies products for interoperability. Originally conceived as a data standard, WiMax can be used for voice as well. Like LTE, WiMax uses OFDM with channels widths of up to 20MHz. WiMax also supports MIMO. WiMax has a theoretical maximum capacity of 75Mbps, but mobile users will receive no more than 25Mbps—a far lower rate than that provided by LTE. For fixed WiMax, the practical peak rate is 45Mbps. An important difference is that WiMax, unlike LTE, is not optimized for power consumption on the uplink, making it less power efficient for handheld devices. According to the ITU, 4G technologies must deliver data rates of at least 1Gbps. Neither the first generation of LTE nor the initial mobile WiMax deployments meet this criterion, but both are generally considered to be 4G technologies because they use OFDM. As a follow-on to LTE, LTE Advanced is expected to be the first cellular standard to meet the ITU’s 1Gbps goal.

+++++++++++++++++++++++++++
Advertise on this Space/Blog!
For more information contact us at ads@digitalelectronics.co.in
+++++++++++++++++++++++++++

Apple launches iPad Air, newer iPad Mini, MacBook Pro and Free OS X Mavericks


In its annual pre-holiday unveiling event, Apple Inc has announced the iPad Air its fifth-generation iPad, iPad Mini and MacBook Pro.



The iPad Air is Thinner and lighter with a powerful processor. The 9.7-inch Retina Display with other added features brings some design and performance enhancements to the best-selling tablet. The Touch ID finger print sensor is missing which would have been a great addition. A new A7 chip inside makes it 8 times faster than the iPad 4, according to Apple. This same 64-bit chip also in the iPhone 5S, the Air's A7 also comes with the M7 motion co-processor, which promises graphics that render at twice the rate of the previous iPad without sucking more juice than the previous gen. Though the slimness and weight are the two significant features, overall from my point of view it is a delicate high tech piece of junk.


The iPad Mini has the same A7 processor as the iPhone 5S and iPad Air, packs in as many pixels as the Retina display on the full-size iPad Air. The new iPad Mini has a higher pixel density on its display than its big brother, at 326 pixels per inch. Can your eyes spot the difference at this form factor? Apple has boasted that the 7.9-inch Retina display on the iPad mini offers a 35 percent larger area than screens with 7-inch tablets. It is also the only small tablet to deliver Apple's full iOS ecosystem and App Store. The new Retina iPad mini features two antennas to support Multiple-In-Multiple-Out (MIMO) technology, bringing twice the Wi-Fi performance at 300Mbps. Cellular models also come with expanded LTE coverage to accommodate even more LTE networks worldwide, while continuing to deliver comprehensive support for other fast cellular technology around the world (DC-HSDPA, HSPA+), all in a single model.


The new MacBook Pros have slimmed down for the 13-inch version, which is now only 0.71 inches thick. They got significant spec bumps, however, including new Haswell Core i5 and i7 processors and next-generation integrated graphics from Intel. Among others, both the 13- and 15-inch MacBook Pro models received PCIe-based flash storage with up to 60 percent faster read speeds than previous models. In addition, the laptops were brought in line with the MacBook Air lineup and now feature 802.11ac Wi-Fi connectivity. Battery life has been boosted as well, with the smaller model now lasting up to nine hours, while the 15-inch Pro can run for eight hours on a single charge.


Finally, Apple has officially released its latest operating system, OS X Mavericks for free. Mac users can install it immediately.


+++++++++++++++++++++++++++
Advertise on this Space/Blog!
For more information contact us at ads@digitalelectronics.co.in
+++++++++++++++++++++++++++

LG G2 is one of the Fastest Android Smartphones On the Market


In the ever-expanding smartphone war, the only two mobile phone manufacturers making any notable profits at present are Apple (with iOS) and Samsung (with Android). Despite Android togather with Samsung dominating the global market share, players such as LG, HTC, Pantech, and Sony are scrapping for market share as well.




The LG G2 is the follow-up to LG's Optimus G Pro.
It is one of the few smartphones on the market powered by Qualcomm's Snapdragon 800 quad-core SoC.
The G2 sports a 5.2-inch 1080p display, 2GB of RAM and up to 32GB of on board storage. However, the 2.26GHz quad-core Snapdragon 800 chip on board also has Qualcomm's Adreno 330 GPU that even gives NVIDIA's Tegra 4 a run for its money in gaming and graphics performance.

Though the G2 has a rather unorthodox volume rocker and power button assembly on the back of the phone, once you get used to the location, it's actually a pretty comfortable system.

What's pretty impressive though is the G2's performance combined with its 3000mAh battery that offers a solid balance of horsepower and battery life and rivals flagship phones like the Samsung Galaxy S4 and Apple's iPhone 5S.


Specifications and features:

Processor and memory
2.26GHz quad-core Qualcomm Snapdragon 800 CPU
2 GB RAM
16GB or 32 GB internal memory

Operating System
Android 4.2.2 (Jelly Bean)

Connectivity
UMTS: Band I (2100);UMTS: Band IV (AWS)
UMTS: Band IV (1700/2100);Band II (1900);Quad Band GSM;LTE
802.11a/b/g/n (Dual-Band) Wi-Fi
Mobile Hotspot
Bluetooth 4.0 LE+EDR
aGPS
USB 2.0

Ports and expansion
3.5 mm audio jack
micro-SIM
micro-USB 2.0

Display
5.2-inch Full HD IPS (1,920 x 1,080) Display

Size and weight
5.45 x 2.79 x 0.35 inches (HxWxD)
5.04 ounces

Cameras and multimedia
2.4 MP HD Front-Facing Camera
13 MP Rear-Facing Autofocus Camera, Full HD Video Recording

Other features: Rear Volume + Power Toggles; Google Now; QSlide

Battery
3,000 mAh Li-Polymer

Super Deal: Nexus 7 Tablet for just $121 or INR7649 at Flipkart


Here comes the festival season and there is no better time for fabulous electronics deals. Nexus 7 is one such and the Indian retailer Flipkart is offering the Nexus 7 2012 version for just Rs 8999 and additional 15% off if you shop using your standard chartered credit card. The time is running out as the deal closes in less than half a day.

This offer has expired!!!!!





NEXUS 7 TABLET (WI-FI, 16 GB) PRICE: RS.8999
Key Features
7-inch HD Display with 216 ppi
16 GB Internal Storage
1.2 MP Front Facing Camera
Android v4.2 (Jelly Bean) OS
NVIDIA Tegra 3 Quad Core Processor
NFC (Android Beam)
Wi-Fi Enabled

Beautiful in a way the world has yet to see, Google captures the essence of all its expertise in technology and design in a tablet that is crafted to woo your heart and mind - the Nexus 7.

Changing The Way You See
With sharp images that change the way you will look at life, the 7 inch LCD IPS screen of the Nexus 7 with capacitive touch will transport you into another plane of clarity and brightness that adds a smoother dimension to everything that you use the tab for - be it playing your favorite game with amazing responsiveness from the tablet or reading the latest from your favorite author or even just chilling with a bit of jazz playing in the background - even videos come alive in full HD. With a pixel density of 216 ppi, the letters and photos are sharper and crisper than real print itself.

Serious Power
The Google Nexus 7 discreetly packs an NVIDIA Tegra 3 Quad Core processor with four cores and a backup of 1 GB of RAM to blow your mind away regardless of what you are doing - from taking down a grocery list, to watching a favorite movie, to launching Zomato to find a new brunch place to even playing a graphic heavy game, life is super fast with the Nexus 7.

Wherever you go
With a simple design complemented by a slim body and bestowed with a massive battery backup of 8 whole hours, the wi-fi enabled Nexus 7 comes with enough juice to get you through the day - especially handy when it comes to long commutes or boring waits.

Share and Have Fun
With the latest Android v.4.2 Jelly Bean operating system powering the tablet, the Nexus 7 from Google grants you a smooth yet simple interface that you could easily get addicted to. You can also share the tablet with the entire family with individual settings for each person. What’s more, with the Play Store at your disposal, you will never be in need for any apps.

Capturing Memories
A 1.2 megapixel camera with auto focus is what the Nexus 7 has on offer enabling you to capture every worthwhile moment with great clarity and perfection to relive when you feel like, later. The tablet also supports HD video recording that ensures that the best day of your life is captured and immortalized in the best possible way.

Who says technology is not art?
The Google Nexus 7 strives to prove otherwise.

A cheap mains operated led light circuit


An idea for the festival season. This basic circuit can be easily modified for 120v operation and more LEDs can be added as well.



Please use extreme caution while handling this circuit since the mains is not isolated and so there is a risk of heavy electric shock.

Broadcom begins layoffs of its LTE team


Post Japan based Renesas Electronics aquisition, the hatchet is on its own LTE design teams across the globe. The layoff started last week in San Diego, as well as in New Jersey, Colorado and India, sources say.



The figure could go substantially higher because the company expects to cut roughly $45 million in operating expenses relating to the deal between now and the next 12 months.

+++++++++++++++++++++++++++
Advertise on this Space/Blog and see your business grow!
For more information contact us at ads@digitalelectronics.co.in
+++++++++++++++++++++++++++

The Economics of Smartphone Damage


A cell phone that is fed with beer at your favorite watering hole is likely not much useful. The following infographic provides an insight into the type, cause and cost of damages .






Open access shared folder is now active to share your files


Any reader can contribute files to the shared web folder.




This can be a document you created or just reference to some non-copyrighted files which you have come across. There is no registration required and neither do we have to invite anyone as a contributor. Just use the "SHARED" URL above and you have full access – including delete permissions – to the files in that folder.

Please give "5 Seconds for it to load fully :-)"

Apple CEO Tim Cook reflects on anniversary of Steve Jobs’ passing in letter to employees


On the eve of the second anniversary of the passing of Apple co-founder Steve Jobs, CEO Tim Cook reflects on the moment in a company-wide email.




Apple also has honored Jobs with a tribute video on its homepage.

Nexus 5 is revealed in a leaked Service Manual


LG’s New Nexus Phone Gets Detailed In Leaked Service Manual.



The new Nexus from LG will likely feature the inclusion of a 4.95-inch display, 1080p IPS screen, a 2.3GHz Qualcomm Snapdragon 800 with 2GB of RAM, 16/32GB variants, LTE radio and an 8-mp camera with optical image stabilization. Wireless charging and NFC are the likely new additions with no juice boost in the battery.

Contact Us


Thank you for taking the time to contact The Digital Electronics Blog




Please use this form for Advertising Information, Consulting Request, custom Technical Information Request, Career Tips (Career Counselling), Tech Talk Invitation, Solution to problems, Gadget Reviews, Report Broken Link, Site Errata, suggestions, concerns or any other sort of feedback. We do read and consider anonymous feedback, but it will be very helpful if you identify yourself. If you would like a response back, don't forget to leave your email.