All questions of Mobile Technologies for Class 10 Exam

Answer:

Number of Users/Voice Channels Supported for Each 200 KHz Channel in GSM

GSM (Global System for Mobile Communications) is a digital cellular technology widely used for mobile communication around the world. The GSM system uses a frequency-division multiple access (FDMA) technique to divide the available radio spectrum into frequency channels and time slots.

The number of users or voice channels supported for each 200 KHz channel in GSM is:

- Eight

Explanation:

The GSM system uses a frequency band of 25 MHz, which is divided into 125 frequency channels of 200 KHz each. Each channel can support eight time slots, and each time slot can carry one voice channel or data channel. Therefore, each 200 KHz channel can support up to eight users or voice channels simultaneously.

In other words, the maximum capacity of a GSM cell is determined by the number of available frequency channels and the number of time slots per channel. The more frequency channels and time slots a cell has, the more users or voice channels it can support.

Conclusion:

In summary, each 200 KHz channel in GSM can support up to eight users or voice channels. This is due to the FDMA technique used by the GSM system to divide the available radio spectrum into frequency channels and time slots, allowing multiple users to share the same frequency band.

3G Evolution of GSM, IS-136, and PDC systems

Introduction:
The 3G evolution of GSM, IS-136, and PDC systems refers to the transition from second-generation (2G) technologies to third-generation (3G) technologies in these respective systems. The advent of 3G brought significant advancements in terms of data transfer speeds, capacity, and multimedia capabilities.

Explanation:
The correct option among the given choices is option 'A', which is W-CDMA (Wideband Code Division Multiple Access). W-CDMA is the technology that led to the 3G evolution of GSM, IS-136, and PDC systems. Here is a detailed explanation:

1. GSM (Global System for Mobile Communications):
GSM is a 2G digital cellular technology that was widely used for voice communication. However, it had limited data transfer capabilities. To enhance data transfer speeds and introduce multimedia capabilities, GSM evolved into 3G using W-CDMA technology.

2. IS-136 (Interim Standard-136):
IS-136, also known as D-AMPS (Digital Advanced Mobile Phone System), is a 2G TDMA (Time Division Multiple Access) technology used primarily in North America. Similar to GSM, IS-136 systems also needed an evolution to support higher data rates and multimedia applications. W-CDMA provided the necessary upgrade to enable 3G capabilities.

3. PDC (Personal Digital Cellular):
PDC is a 2G TDMA technology used in Japan. As with GSM and IS-136, PDC systems also required an upgrade to meet the growing demand for faster data transfer and multimedia services. W-CDMA was the chosen technology for the 3G evolution of PDC systems.

4. W-CDMA (Wideband Code Division Multiple Access):
W-CDMA is a 3G technology that uses a wider bandwidth and a different modulation scheme compared to 2G technologies like GSM, IS-136, and PDC. It provides higher data transfer rates, improved capacity, and better support for multimedia applications. W-CDMA was standardized by the International Telecommunication Union (ITU) for the 3G evolution of various 2G systems worldwide.

Conclusion:
In conclusion, the 3G evolution of GSM, IS-136, and PDC systems was achieved using W-CDMA technology. W-CDMA provided the necessary enhancements in terms of data transfer speeds, capacity, and multimedia capabilities, allowing these 2G systems to transition into the 3G era.

IS-95
IS-95, also known as cdmaOne, is a second-generation CDMA standard used for digital cellular networks. It was developed by Qualcomm and adopted by many mobile operators around the world.

Key Points:
- IS-95 stands for Interim Standard 95.
- It was the first CDMA standard to be widely deployed and commercialized.
- IS-95 provided better call quality, increased capacity, and improved data services compared to the previous analog systems.
- The standard was capable of supporting voice and data services simultaneously.
- IS-95 paved the way for the evolution of CDMA technology and set the stage for further advancements in mobile communications.

In contrast, IS-136 is a TDMA-based standard, ETACS is an analog cellular standard, and EDGE is a 2.5G technology that enhances GSM networks with higher data rates.