Mobile Technology Questions

- Packet data speed is higher in 3G, and it is up to 384 KBPS
- Voice and sms speed is also 384 KBPS in 3G
- 2G utilizes different switching techniques for voice and data, where as  3G uses single switching, irrespective of data
- 3G has at least 2MB of data link of a mobile, where in 2G the data rate is in KBPS
- 3G has WiMAX facility for faster VOIP and internet
- 2G uses GSM TDMA technology with narrowband 200Khz.
- 3G uses CDMA technology with broadband 5Mhz, with same frequency carrier and time.

BlackBerry Enterprise Server: The BlackBerry handhelds are integrated into the e-mail system of the organization through software BlackBerry Enterprise Server. The BES versions are available for MS Exchange, Novell GroupWise and Lotus Domino. A connector was made by Google for BES for making BES available for Google Apps. A new feature is added which enables to track the current location of an individual through trailateration.

BES provides handhelds with the connectivity of TCP/IP which can be accessed through a component known as “Mobile Data Service – Connection Service – MDS-CS. This allows the development of custom application development using data streams on BlackBerry devices which are based on the Sun JME platform.

BES also provides network security in the form of Triple DES or AES encryption standard of all data including e-mail and MDS traffic, which travels between the BlackBerry hand held devices and a BES.

- GPRS provide gross data rate of 22.80 KBPS / time slot
- Voice uses only 13KBPS/ time slot and the rest is consumed by Error Correction Code
- Error connection code is utilized for detecting and correcting the transmission errors
- As voice is compressed, the usage of Error connection code is mandatory

- GPRS uses 2.5 generation of GSM signals
- The radio interface is the same that of GSM
- GPRS uses 900 / 1800 Mhz, frequency band and GMSK modulation
- The bit rates are EGPRS, similar to EDGE
- Separate hardware and ports need to be added and availed.

- The maximum data rate supported by a GSM system is 9.6 kbps.
- However there are extensions to GSM standard to improve throughput.
- GPRS is one of the extended GSM service.
- The extended standards of GSM allows theoretical data rates on the order of 114 Kbit/s, but with throughput closer to 40Kbit/s in practice.

Android Application Architecture has the following components:
* Services – like Network Operation
* Intent - To perform inter-communication between activities or services
* Resource Externalization - such as strings and graphics
* Notification signaling users - light, sound, icon, notification, dialog etc.
* Content Providers - They share data between applications

Definition: 3G, known as 3rd Generation, is a standard for mobile / cellular phones. It provides the services that fulfill the International Telecommunication Union specifications.

The application services of 3G include wireless voice telephone, mobile internet access, video calls and mobile television – all in a mobile environment.

3G allows simultaneous use of speech and data services
3G provides peak data rates of at least 200 KBits according to the IMT-2000 specification.
Mobile broadband access of several MBits to laptop computer systems, smart phones is provided by latest 3.5G, 3.75G versions.

3G standards:

UMTS:

  -  Universal Mobile Telecommunications System – One of the 3G mobile telecommunications technologies, also being developed into a 4G technology.
  -  Most common form of UMTS uses W-CDMA as an underlying air interface.
  - UMTS also covers Radio Access Network – UMTS Terrestrial Radio Access Network (UTRAN), and Mobile Application Part (MAP).
  -  Users are authenticated via USIM cards (Universal Subscriber Identity Module).

CDMA2000

   -  Also known as IMT Multi-Carrier (IMT-MC), uses CDMA channel access for sending voice, data and signaling data between mobile phones and cell sites.
   -  The standards are CDMA2000 IX, CDMA2000 EV-DOR Rev.0, CDMA2000 EV-DO Rev.A and CDMA2000 EV-Rev.B. They are approved radio interfaces for the ITU’s IMT-2000.

Advantages of 3G:

- Overcrowding is relieved in existing systems with radio spectrum
- Bandwidth, security and reliability are more
- Provides interoperability among service providers
- Availability of fixed and variable rates
- Support to devices with backward compatibility with existing networks
- Always online devices – 3G uses IP connectivity which is packet based
- Rich multi media services are available

Disadvantages of 3G:

- The cost of cellular infrastructure , upgrading base stations is very high
- Needs different handsets.
- Roaming and data/voice work together has not yet been implemented
- Power consumption is high
- Requires closer base stations and are expensive
- Spectrum-license costs, network deployment costs and handset subsidies subscribers are tremendous.