Optimal Gateway Placement For Hybrid Banets-Sensor Networks In Urban Areas

For a given urban area, we apply the existing bus-based ad hoc networks (BANETs) to collect and transmit information, monitored by wireless sensor networks (WSNs), from subareas to the data center. Sensors are well deployed in each subareas divided by streets. WSNs and BANETs are heterogeneous and minimal gateways are required to connect the both kinds of networks. In this paper, we provide two gateway placement problems" minimum gateways placement and minimal gateways placement with minimum average delay. We present two constant algorithm MGPPA and MADGPPA to solve the two problems, respectively. Theoretical analysis demonstrates that MGPPA is a (1 + In lambda)-approximation algorithm and MADGPPA is a lambda-approximation algorithm correspondingly, where lambda is the maximum number of subareas covered by a gateway candidate. In the geometric topology of the grid urban area, lambda <= 4. Extensive comparison simulation show the performance of minimum gateways and minimal gateways with minimum average delay achieves significantly.