Wireless & Mobile Communications Multiple Choice Questions on “Wireless Data Services”.
1. US cellular standard CDPD stands for _________
a) Cellular Digital Packet Data
b) Cellular Digital Packet Data
c) Cellular Digital Pocket Data
d) Cellular Discrete Pocket Data
Answer: a
Clarification: US cellular standard CDPD stands for Cellular Digital Packet Data. In 1993, US cellular industry developed CDPD to coexist with the conventional voice only cellular system.
2. CDPD is data service for third generation US cellular systems.
a) True
b) False
Answer: b
Clarification: CDPD is a data service for first and second generation US cellular systems and uses a full 30 kHz AMPS channel on a shared basis. CDPD provides mobile packet data connectivity to existing data networks.
3. Which of the following is true for CDPD?
a) Expensive to install
b) Uses different infrastructure
c) Complex
d) Inexpensive to install
Answer: d
Clarification: CDPD directly overlays with existing cellular infrastructure and uses existing base station equipment, making it simple and inexpensive to install. CDPD does not use the MSC, but rather has its own traffic routing capabilities.
4. CDPD channel is _________
a) Simplex
b) Complex
c) Duplex
d) Expensive
Answer: c
Clarification: Each CDPD channel is duplex in nature. The forward channel serves as a beacon and transmits data from the PSTN side of the network, while the reverse channel links all mobile users to the CDPD network and serves as the access channel for each subscriber.
5. CDPD transmissions are carried out using ________ blocks.
a) Fixed length
b) Variable length
c) Long
d) Short
Answer: a
Clarification: CDPD transmissions are carried out using fixed length blocks. User data is protected using a Reed-Solomon (63, 47) block code with 6 bit symbols.
6. MDLP is _________
a) Layer protocol used in CDPD
b) Layer protocol used in GSM
c) Layer protocol used in ARDIS
d) Layer protocol used in CDMA
Answer: a
Clarification: MDLP (Mobile data link protocol) is a lower layer protocol of CDPD. It is used to convey information between data link layer entities (layer 2 devices) across the CDPD air interface.
7. The layer protocol, RRMP stands for _________
a) Radio Resource Management Protocol
b) Radio Resource Mobile Protocol
c) Radio Rate Management Protocol
d) Radio Rate Mobile Protocol
Answer: a
Clarification: The radio resource management protocol (RRMP) is a higher, layer 3 protocol used to manage the radio channel resources of the CDPD system and enables an M-ES to find and utilize a duplex radio channel without interfering with standard voice services.
8. ARDIS is a public network service.
a) True
b) False
Answer: b
Clarification: ARDIS (Advanced Radio Data Information Systems) is a private network service provided by Motorola and IBM. It is based on MDC 4800 and RD-LAP protocols developed at Motorola.
9. RMD is a _______ and ________ data service.
a) Private, two way
b) Public, one way
c) Public, two way
d) Private, one way
Answer: c
Clarification: RAM Mobile Data (RMD) is a public, two way data service based upon the Mobitex protocol developed by Ericsson. RAM provides street level coverage for short and long messages for users moving in an urban environment.
10. The MSC provides subscriber access to the PSTN via the _______
a) Signalling transfer points
b) Service management system
c) Database service management system
d) Switching end points
Answer: d
Clarification: The MSC provides subscriber access to the PSTN via the switching end points (SEPs). The SEP implements a stored program control switching system known as the service control point (SCP).
11. ________ controls the switching of messages between nodes in the CCS network.
a) Signalling transfer points
b) Service management system
c) Database service management system
d) Switching end points
Answer: a
Clarification: The signalling transfer point (STP) controls the switching of messages between nodes in the CCS network. For higher reliability of transmission, SEPs are required to be connected to the SS7 network via at least two STPs.
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