This set of Wireless & Mobile Communications Multiple Choice Questions & Answers (MCQs) focuses on “CDMA Digital Cellular Standard (IS-95)”.
1. US digital cellular system based on CDMA was standardized as ________
Explanation: A US digital cellular system based on CDMA was standardized as Interim Standard 95 (IS-95). It was standardized by US Telecommunication Industry Association (TIA) and promised increased capacity.
2. IS-95 was not compatible with existing AMPS frequency band.
Explanation: Like IS-136, IS-95 system was designed to be compatible with the existing US analog cellular system (AMPS) frequency band. Hence, mobile and base stations can be economically produced for dual mode operation.
3. Which of the following is used by IS-95?
Explanation: IS-95 uses a direct sequence spread spectrum CDMA system. It allows each user within a cell to use the same radio channel, and users in adjacent cell also use the same radio channel.
4. Each IS-95 channel occupies _______ of spectrum on each one way link.
a) 1.25 MHz
b) 1.25 kHz
c) 200 kHz
d) 125 kHz
Explanation: To facilitate graceful transition from AMPS to CDMA, each IS-95 channel occupies 1.25 MHz of spectrum on each one way link, or 10% of the available cellular spectrum for a US cellular provider.
5. IS-95 uses same modulation technique for forward and reverse channel.
Explanation: IS-95 uses different modulation and spreading technique for the forward and reverse links. On the forward link, the base station simultaneously transmits the user data for all mobiles in the cell by using different spreading sequence for each mobile.
6. IS-95 is specified for reverse link operation in _________ band.
a) 869-894 MHz
b) 849-894 MHz
c) 849-869 MHz
d) 824-849 MHz
Explanation: IS-95 is specified for reverse link operation in the 824-849 MHz band and 869-894 MHz for the forward link. The PCS version of IS-95 has also been designed for international use in the 1800-2000 MHz bands.
7. User data in IS-95 is spread to a channel chip rate of ________
a) 1.2288 Mchip/s
b) 9.6 Mchip/s
c) 12.288 Mchip/s
d) 0.96 Mchip/s
Explanation: User data is spread to a channel chip rate of 1.2288 Mchip/s (a total spreading factor of 128) using a combination of techniques. The spreading process is different for the forward and reverse links in the original CDMA specification.
8. _______ are used to resolve and combine multipath components.
c) RAKE receiver
d) Frequency divider
Explanation: At both the base station and the subscriber, RAKE receivers are used to resolve and combine multipath components, thereby reducing the degree of fading. A RAKE receiver exploits the multipath time delays in a channel and combines the delayed replicas of transmitted signal.
9. CT2 was the first generation of cordless telephones.
Explanation: CT2 was the second generation of cordless telephones introduced in Great Britain in 1989. It is used to provide telepoint services which allow a subscriber to use CT2 handsets at a public telepoint.
10. CT2 is analog version of first generation cordless telephones.
Explanation: CT2 is a digital version of the first generation, analog, cordless telephones. When compared with analog cordless phones, CT2 offers good speech quality, and is more resistant to interference.
Sanfoundry Global Education & Learning Series – Wireless & Mobile Communications.
To practice all areas of Wireless & Mobile Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.