A. Sensing
B. Decision
C. Mobility
D. Repair

A. Spectrum analysis
B. Spectrum decision
C. Spectrum mobility
D. Spectrum sharing

A. Detect spectrum holes
B. Gather information about available spectrum bands
C. Vacate spectrum band
D. Monitor spectrum band

A. Detect spectrum holes
B. Prevent collision between multiple users
C. Match spectrum bands with user requirements
D. Listen for the arrival of the primary user

A. Distance between the primary transmitter and xg user
B. Amount of interference at the primary receiver
C. Amount of interference at xg user
D. Distance between the primary receiver and xg user

A. Transmission range at higher frequencies is maintained
B. Path loss is increased
C. Interference is increased
D. Transmission range at lower frequencies is maintained

A. Encoding techniques
B. Modulation scheme
C. Channel capacity
D. Access techniques

A. Selection of appropriate protocol
B. Selection of routing path
C. Packet generation
D. Frame generation

A. The duration required to identify a spectrum hole
B. The duration available after the arrival of the primary user to vacate the spectrum band
C. The duration over which the xg user can use the licensed spectrum band
D. The duration over which the xg user can use the unlicensed spectrum band

A. Asynchronous sensing
B. Multiple spectrum band operation
C. Availability of non-contiguous spectrum bands
D. Reconfiguration