Home > Spectrum Mobility > Spectum Mobility Challenges

The followings are the open research issues for efficient spectrum mobility in xG networks.

• At a particular time, several frequency bands may be available for an xG user. Algorithms are required to decide the best available spectrum based on the channel characteristics of the available spectrum and the requirements of the applications that are being used by an xG user.

• Once, the best available spectrum is selected, the next challenge is to design new mobility and connection management approaches to reduce delay and loss during spectrum handoff.

• When the current operational frequency becomes busy (this may happen if a licensed user starts to use this frequency) in the middle of a communication
by an xG user, then applications running on this node have to be transferred to another available frequency band. However, the selection of new operational frequency may take time. Novel algorithms are required to ensure that applications do not suffer from severe performance degradation during such transitions.

• Spectrum handoff may occur due to reasons other than the detection of the primary user. Thus, there exist various other spectrum handoff schemes in xG networks. If an xG user moves from one place to another, spectrum handoff may occur just because the available spectrum bands change. Thus the desired spectrum handoff scheme should integrate inter-cell handoff. Apart from this, spectrum handoff between different networks, referred to as vertical handoff is also likely to occur in xG networks. Under such a diverse environment, it is essential that spectrum handoff scheme takes all the above mentioned possibilities into consideration.

• Spectrum mobility in time domain: xG networks adapt to the wireless spectrum based on available bands on the spectrum. Since these available channels change over time, enabling QoS in this environment is challenging. The physical radio should ‘‘move’’ through the spectrum to meet the QoS requirements.

• Spectrum mobility in space: The available bands also change as a user moves from one place to another. Hence, continuous allocation of spectrum is a major challenge. in xG networks.