Virtual channel management for densely deployed IEEE 802.15.4 LR-WPANs

The number of channels specified for IEEE 802.15.4 low-rate wireless personal area networks (LR-WPANs) is too few to operate many applications of WPANs in the same area. To overcome this limit, we introduce virtual channel, a novel concept to increase the number of available channels when various WPAN applications coexist. A virtual channel is basically created via superframe scheduling within the inactive periods in a logical channel preoccupied by other WPANs. To maximize the coexistence capability of WPANs using virtual channels, we propose (1) least collision superframe scheduler (LC-scheduler), (2) less complex heuristics, and (3) virtual channel selector (VCS) to efficiently manage multiple available logical channels. In addition, a simple but practical synchronization method is developed to compensate different time drifts among coexisting WPANs. The simulation results demonstrate that a remarkable improvement on the coexistence capability of the 802.15.4 can be achieved through the proposed schemes