The Technology
As we saw, the 3.5 G standard used in HSDPA is an improvement upon the 3G protocol used in W-CDMA technology. With HADPA, the data transfer rate improves over W-CDMA by a factor of at least five. Theoretically speaking, it is possible to reach data transmission speeds of 8-10 Mbps with HSDPA. Therefore HSDPA is touted as highly favorable for transmission areas like video and streaming music where high data transfer rates are required.
Now the question is, in what way HSDPA has improved upon WCDMA. HSDPA employs different techniques for modulation and coding by creating a new channel within W-CDMA. This channel is called High Speed Downlink Shared Channel, or HS-DSCH. This channel is created in such a way that it makes higher downlink speeds possible. However this channel enables only downlinks, which means that the source can send data to the receptor but not vice versa. You cannot send data from your phone to the source using HSDPA. The HS-DSCH channel is shared among users, allowing the most efficient use of radio signals and thus helping faster download speeds. HSDPA uses 5 MHz bandwidth. The technology upgrade has enabled a smooth transition for Universal Mobile Telecommunications System (UMTS).
In the HS-DCH channel, the variable spreading factor and fast power control of the WCDMA channels are done away with. The new technology uses Adaptive Modulation and Coding (AMC), fast packet scheduling at the Base Station and fast retransmissions from the Base Station. The retransmissions are done through Hybrid Automatic Repeat Request (HARQ), where the concept of incremental redundancy comes into play. Here, the retransmissions have different codes of the data against the codes of the original transmission. In other words, the data received at the base station is ‘processed’ to manage any corruption the data may have gone through at the time of the original transmission. The net result of this process is that the user device can receive error free packets, thus ensuring better quality to the video and sound.
Is HSDPA Here to Stay?
Well, only time can answer that question. Many mobile telecommunication companies are working to deploy 3G (WCDMA) networks and this is a positive indication. It would be easy to upgrade to 3.5 G once a 3G network is in place. Some companies are expected to deploy HSDPA by the end of 2006. However the downlink speeds in reality at this moment are going to be much lower at 1.8-3.6 Mbps, than the theoretical potential of 8-10 Mbps.
The success of HSDPA will also depend on many other factors. There are other technologies like CDMA2000, 1xEV-DO and WiMAX that promise high data transmission speeds. Further, HSDPA is an improvement upon the W-CDMA standard, so it can gain acceptance only in places where W-CDMA has been deployed successfully.
By: Riktesh Srivastava
High Speed Downlink Packet Access
March 7th, 2010 by admin No comments »Samsung S8300 Tocco Ultra – Extremely Advanced
March 5th, 2010 by admin No comments »
Samsung is releasing many firsts in mobile phone industry recently, like first 8MP phone, then Omnia and Tocco. Samsung Tocco is one of the most successful phones of the 2008, to continue the legacy of the phone, Samsung has released the new superior edition, called Samsung S8300 Tocco Ultra with some cool and fantastic features for advanced users of the phones.
It comes with some hottest new and exciting features like 8MP camera, touch screen interface, 3X4 keyboard in a thin body. The thickness of the phone is 12.7mm, just above the 1cm. The new AMOLED touchscreen with touchwiz 1.5v gives it a easy to navigate feel. The screen of 2.8″ with 16 million colours gives it bright clarity for images and videos.
The 8MP camera is more than enough for good quality photographs and with 30fps video recording makes it one of the best gadgets for mobile photographer in the town. Camera of the device is comes with auto focus, face detection and geo tagging features. There is inbuilt photo and video editor for trimming video, audio dubbing, adding subtitle, live dubbing and other exciting features.
Nowadays, mobile phones are becoming mobile computers for accessing mails, messenger services, blog etc. Tocco Ultra has one of the best web features found in Samsung phones. Photo blogging, GPS, online widgets are present in the phone. It supports 7.2 Mbps HSDPA internet access service for fast downloading and uploading of the data.
Music features are also there, you can play all the popular formats like MP3, AAC and more with the phone. Samsung S8300 Tocco Ultra has a decent memory of 16 GB, so there is plenty room for your digital library.
By: Lucy Brightly
Mini Laptop Speakers and Other Netbook Accessories
March 5th, 2010 by admin No comments »
Netbooks have three main selling points – small, light and cheap. Mini laptop speakers and other netbook accessories like USB optical disc drives, USB keyboards and laptop cases add to the overall product. Here’s a guide of products to make your netbook even better.
Keyboards and Mouses
With mini laptops, the space for the interface is very small. Although there are some gems which have excellent typing surfaces like the HP mini 1000 and Sony VAIO TT , several keyboards available are somewhat more compromised in there practicality. A simple USB keyboard is portable, and can offer a typing experience equivalent to a PC. Some are capable of folding up. USB mouses are also available.
Batteries
Most netbooks come as standard with a 3-cell battery which generally gives around 3 hours battery life. Larger batteries, whilst heavier allow for huge amounts more mobile computing time, with the Acer Aspire One getting up to 9 hours 40 minutes on it’s new 9-cell battery option.
Mini laptop speakers
Inbuilt mini laptop speakers in general are pretty average. For those you like to listen to music or play games from your netbook, portable mini laptop speakers offer an affordable and practical means of boosting sound quality whilst on the move.
Optical Disc Drive – aka. CD/DVD-ROM
Netbooks come without an optical disc drive, so you can’t play CD/DVD-ROMs. However, you can get a USB optical disc drive so you can load your own games, play CDs, DVDs and more.
Cases
Like most electronics, you need something to carry them around in and keep them in one piece. Cases vary in quality and style from coloured pouches to smart leather briefcases to pink polka dot bags. Cases are particularly useful if you’re travelling around a lot.
Chargers
New mini laptops should always come with a mains charger, but it can be helpful to have a second or a car charger to remain flexible. It can also help to have chargers for foreign countries if you travel around a lot.
Mobile Broadband USB Modem
Wifi and Bluetooth have their limitations in having to be near hotspots or local networks. With 3G Mobile Broadband (or HSDPA) you can receive internet connection wherever there is a phone signal. Mobile Broadband can be purchased from network providers on contract or on prepay USB sticks.
Screen Protector
Screen protectors help prevent scratches and imperfections on your screen. Some can also limit viewing from other angles to prevent people looking at your work, particularly useful in confined spaces such as a plane or a train. Remember to use an old credit card or similar to squeeze out the bubbles which inevitably get trapped between the screen protector and the screen itself.
By: Ed Fry
