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A mobile terminal moving at a speed of 30 m/sec is receiving a signal with a center frequency of 2 G, having a bandwidth of 5 MHz. The received signal has a delay spread of 2 µsec. The Doppler shift of the received signal is approximately:
1. 200 Hz
2. 400 Hz
3. 0.5 MHz
4. 2.5 MHz
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In a CDMA cellular system, the coverage region of a cell located in a dense urban environment at 5:00 PM (busy hour) is most likely to be:
1. smaller than the coverage of 3:00 AM (dead hour) because of higher cell loading.
2. the same as the coverage at 3:00 AM (dead hour) because propagation remains the same.
3. the same as the cover at 3:00 AM (dead hour) because transmit power remains the same.
4. smaller than the coverage at 3:00 AM (dead hour) because of more signal fading due to more cars on the street.
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A wireless channel has a 10 KHz Doppler spread and a 10 ms delay, and the over-the-air data rate with BFSK modulation is 1 Kbps. Which of the following is the best description of this channel?
1. Fast fading and frequency selective fading
2. Slow fading and frequency nonselective fading
3. Slow fading and frequency selective fading
4. Fast fading and frequency nonselective fading
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In 802.11 using RTS/CTS as an access scheme where the duration of RTS, CTS, and an ACK are all equal to T, the Short Interframe Spacing duration equals S and the data packet duration of the transmitting source is D, the total period allocated to the transmitting terminal and no others is:
1. 3T+2S+D
2. 3T+3S+D
3. 3T+4S+D
4. 3T+S+D
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The choice of a duplexing method depends on the
1. nature of the available spectrum and of the traffic in uplink/downlink.
2. modulation type.
3. chosen multiple access technology.
4. modulation type and the multiple access technology.
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The relationship among the IEEE 802.11 timing parameters is:
1. SIFS‹DIFS‹PIFS.
2. PIFS‹SIFS‹DIFS.
3. SIFS›PIFS›DIFS.
4. SIFS‹PIFS‹DIFS.
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Which of the following OSI layers is responsible for error recovery and reliability?
1. Data link
2. Session
3. Application
4. Physical
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The main function of the TCP (Transmission Control Protocol) in an internet networking environment is to provide:
1. reliable communication for end systems.
2. fragmentation and synchronization services.
3. error recovery between adjacent nodes.
4. a transparent routing among subnets.
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A fundamental architectural difference between Mobile IPv4 and Mobile IPv6 is that:
1. Mobile IPv4 dynamic home agent discovery returns a single reply to the mobile node.
2. Mobile IPv6 provides secure but less optimized routes than Mobile IPv4.
3. Mobile IPv6 does not require Foreign Agent (FA).
4. Mobile IPv6 does not require Home Agent (HA).
