Francesco Militano

Coverage analysis of Bluetooth low energy and IEEE 802.11ah for office scenario

In this paper, a coverage analysis of Bluetooth Low Energy (BLE) and IEEE 802.11ah technologies for indoor scenarios is performed. This is of particular relevance when these technologies are deployed as part of capillary networks. The physical layer parameters of BLE and IEEE 802.11ah are modeled, together with a detailed and accurate indoor propagation scenario that accounts for wall losses, ray tracing multi-path, and diffractions. A real case office building scenario is considered for practical evaluation. The minimum density of BLE central devices and IEEE 802.11ah access points that guarantees a predetermined coverage level is derived and compared between the two technologies. It is shown that BLE requires five times the number of central devices than IEEE 802.11ah access points to guarantee 95% coverage. IEEE 802.11ah benefits from the use of lower frequency band, higher transmit power and better receiver sensitivity than BLE, which permits a low cost and effective deployment of Internet of Things applications. Mesh capabilities and range extension for BLE are therefore essential for the success of BLE within the Internet of Things framework.

Reducing signaling overload: Flexible capillary admission control for dense MTC over LTE networks

The increasing adoption of Machine-Type Communication (MTC) applications on existing Long Term Evolution (LTE) brings new challenges for traditional signaling mechanism and system capacity. MTC is related to high number of devices; which represents a challenge when performing control and signaling procedures required for getting resource grant, since these processes are inefficient compared to the actual resource usage for small data transmissions. Solutions based on device grouping propose a static grouping approach, which does not perform well in low load scenario. This paper introduces the notion of a flexible admission/connection that can give granular group device control to Core network. With the proposed approach devices can be grouped for a certain period of time under supervision and control of a gateway and they can be ungrouped when there is no need for grouping them together. In this way, a finer control can be achieved on prioritizing certain services and load balancing. Our simulation results demonstrate significant signaling reduction by using this simple scheme compared to conventional connection procedure.

Topology Formation in mesh networks considering Role Suitability

The paper studies various mesh topology formation techniques that can be used to aid the development of large-scale capillary networks. The work focuses on how mesh networks can be established using Bluetooth Low Energy exploiting the heterogeneous characteristics of the devices in the network. A novel algorithm called Topology Formation considering Role Suitability (TFRS) is proposed aiming to maximize the network lifetime. The algorithm employs a newly introduced metric called role suitability metric (RSM) to assign the best role among master, relay and slave to a participating device. The RSM metric is computed from device characteristics including, but not limited to, energy, mobility and computational capability. We use system-level simulation to evaluate the performance of the proposed algorithm against a reference under a homogeneous deployment scenario consisting of heterogeneous devices. Results show that the network lifetime can be improved significantly when the topology is formed considering the device characteristics for both master role selection and relay selection. TFRS can achieve 20% to 40% higher network lifetime depending on the deployment characteristics over the reference algorithm.