Reliable delay-sensitive spectrum handoff management for re-entrant secondary users

Opportunistic data transmissions in cognitive radio networks is an effective data transmission mechanism which reduces the limitations of fixed spectrum allocations. In cognitive radio networks secondary users (SUs) can transmit over the available spectrum when the primary users (PUs) are inactive. However, a SU may get interrupted over multiple times when the PU re-appear on that channel for data transmission. For an interrupted SU, efficient spectrum hand-off management is vital to complete the data transmission. Efficient spectrum hand-off necessitates greatly for delay sensitive data transmissions (e.g. time critical remote monitoring applications). For such data transmissions, delay sensitive spectrum hand-off mechanisms are necessary. However, the existing sensed spectrum hand-off management methods do not consider delay bounded repeated attempts for spectrum reallocation when there are multiple interruptions. In this paper a delay sensitive spectrum hand-off management for the re-entrant SUs due to multiple interruptions is proposed. Compared to the existing solutions, the proposed spectrum allocation strategy offers more reliable delay-tolerant opportunities for accessing the spectrum for the re-entrant SUs.