Wireless & Mobile Communications Questions and Answers for Freshers on “Bluetooth and Personal Area Networks (PANs)”.
1. Which of the following is not an open standard?
a) Bluetooth
b) WWW
c) HTML
d) VPN
Answer: d
Clarification: An open standard is a standard that is publicly available. It has various rights to use associated with it. Bluetooth is an open standard that has been embraced by over thousand manufacturers of electronic appliances. VPN (Virtual Private Network) is a private network.
2. What is the nominal range of Bluetooth?
a) 1 Km
b) 10 m
c) 1 m
d) 10 Km
Answer: b
Clarification: The power of the transmitter governs the range over which a Bluetooth device can operate. Generally, Bluetooth devices are said to fall into one of three classes. The most common kind is class 2, and it operates in 10 m range.
3. Bluetooth standard is named after ___________
a) King Ronaldo Bluetooth
b) Pope Vincent Bluetooth
c) King Herald Bluetooth
d) Pope Francis Bluetooth
Answer: c
Clarification: Bluetooth standard is named after King Harald Bluetooth. He was the 10th century Viking who united Denmark and Norway. The Bluetooth standard aims to unify the connectivity chores of appliances within the personal workspace of an individual.
4. Bluetooth operates in which band?
a) Ka Band
b) L Band
c) Ku Band
d) 2.4 GHz ISM Band
Answer: d
Clarification: Bluetooth is a radio technology operating in 2.4 GHz frequency band. Bluetooth is best suited for low-bandwidth applications like transferring sound data with telephones (i.e. with a Bluetooth headset) or byte data with hand-held computers (transferring files) or keyboard.
5. Which of the following scheme is used by Bluetooth?
a) Frequency hopping TDD scheme
b) Frequency hopping FDD scheme
c) DSSS TDD scheme
d) DSSS FDD scheme
Answer: a
Clarification: Frequency hopping TDD (Time Division Duplexing) scheme is used by Bluetooth. Frequency hopping provides a form of multiple access among co-located devices in different piconets.
6. What is the range of time slot in Bluetooth?
a) 120 milliseconds
b) 625 microseconds
c) 577 microseconds
d) 5.7 seconds
Answer: b
Clarification: Bluetooth uses a timeslot of 625 microseconds. A data channel hops randomly 1600 times per second between 79 RF channels. Thus, each channel is divided into time slots 625 microseconds.
7. Which modulation scheme is used by Bluetooth?
a) DQPSK
b) MSK
c) GFSK
d) BPSK
Answer: c
Clarification: Bluetooth uses GFSK (Gaussian Frequency Shift Keying). When GFSK is used for Bluetooth modulation, the frequency of the carrier is shifted to carry the modulation. By doing this the Bluetooth modulation achieves a bandwidth of 1 MHz with stringent filter requirements to prevent interference on other channels.
8. What is the channel symbol rate in Bluetooth for each user?
a) 270.833 Kbps
b) 1 Gbps
c) 100 Mbps
d) 1 Mbps
Answer: d
Clarification: Each user in Bluetooth uses a radio channel symbol rate of 1 Mbps using GFSK modulation. The frequency hopping scheme of each Bluetooth user is determined from a cyclic code with a length of 1027-1.
9. What is the raw channel bit error rate of Bluetooth?
a) 10-3
b) 10-10
c) 103
d) 10-1
Answer: a
Clarification: Bluetooth has a bit error rate (BER) of 10-3. Bluetooth uses a number of forward error control (FEC) coding and automatic repeat request (ARR) schemes to achieve this bit rate.
10. Which of the following standard committee specifies Bluetooth and other Personal Area Networks (PAN)?
a) IEEE 802.11b
b) IEEE 802.15
c) IEEE 802.11g
d) IEEE 802.16
Answer: b
Clarification: IEEE 802.15 standards committee is formed to provide an international forum for developing Bluetooth and other PANs. PANs are used to interconnect pocket PCs, personal digital assistants (PDAs), cell phones, light projectors and other appliances.