Marco Monti

Hybrid System HAP-WiFi for Incident Area Network

Recent large scale disasters have highlighted the importance of a robust and efficient public safety communication network able to coordinate emergency operations even when existing infrastructures are damaged. The Incident Area Network (IAN) is a self-forming temporary network infrastructures brought to the scene of an incident to support personal and local communications among different public safety end-users. In this work we are interested in investigating how the High Altitude Platform (HAP) can effectively support Multimedia Broadcast/Multicast Service (MBMS) in a scenario wherein the preexistent terrestrial network is not available. To this aim, we propose an efficient policy of Radio Resource Management (RRM) based on cooperation framework between HAP and Mobile Ad-Hoc NETwork (MANET). The proposed solution has been successfully tested through a comprehensive simulation campaign.

Cooperative Mobile User Location for Next-Generation Wireless Cellular Networks

Along with a vision that foresees the fourth generation (4G) as based on a cellular system that will also support short-range communications among its terminals, in this paper we propose an innovative geolocation scheme that exploits such an architecture and combines long- and short-range location information in a novel location algorithm. The simulation results presented in the paper show that our proposed scheme permits to enhance the location estimation accuracy with respect to the actual stand-alone hybrid cellular solutions.

A cooperative localization scheme for 4G wireless communications

Along with a vision that foresees the fourth generation (4G) as based on a cellular system that will also support short-range communications among the terminals, in this paper we propose an innovative geolocation scheme that combines long-and short-range location information, respectively retrieved by mean of a hybrid time of arrival/angle of arrival (TOA/AOA) technique in the cellular segment and a TOA technique in the short-range one, in order to enhance the location estimation accuracy with respect to the actual stand-alone hybrid cellular solutions

Cooperative terminals for Incident Area Networks

Past crises all over the world (09/11, tsunami, etc.) have highlighted the importance of the availability of critical up-to-date information in real-time at the place where required. The key need is, consequently, for reliable communication systems to coordinate emergency operations even when existing infrastructures are damaged. In this case, rapidly deploying ad-hoc networks in the disaster area is a feasible solution. Incident Area Network (IAN), are self-forming temporary network infrastructures brought to the scene of an incident to support personal and local communications among different public safety end-users. This paper aims at defining the system architecture of IANs where the cooperation among terminals is foreseen. Furthermore, several open issues are identified and possible solutions are proposed.

Ad-Coop Positioning System (ACPS): positioning for cooperative users in hybrid cellular ad-hoc networks

In this paper, we propose an innovative solution for positioning determination in fourth generation (4G) wireless networks by introducing the Ad-Coop Positioning System (ACPS). The ACPS is supported by a hybrid cellular ad-hoc architecture, where the cellular network has a centralised control over the ad-hoc connections among pairs of mobiles. Specifically, peer-to-peer (P2P) communications are exploited in a mesh fashion within cellular-established clusters for cooperation-aided localisation purposes (from that, the word ad-coop is derived). The major contribution of this work is the design of the data fusion method for the ACPS which appropriately combines and weights the long- and short-range location information in a non-linear least square (NLLS) minimisation procedure. The numerical results shown in the paper demonstrate that the ACPS enhances the location estimation accuracy with respect to conventional hybrid positioning techniques in cellular networks. Copyright

On the Use of Cooperation to Enhance the Location Estimation Accuracy

In this paper, we propose an innovative solution for positioning determination in 4G wireless networks by introducing the ad-coop positioning system (ACPS). The ACPS is supported by a hybrid cellular ad-hoc architecture, where the cellular network has a centralized control over the ad-hoc connections among pairs of mobiles. Specifically, P2P communications are exploited in a mesh fashion within cellular-established clusters for cooperation-aided localization purposes (from that, the word ad-coop is derived). The major contribution of this work is the design of the data fusion method for the ACPS, which appropriately combines and weights the long- and short-range location information in a non-linear least square (NLLS) minimization procedure. The numerical results show that the ACPS enhances the location estimation accuracy with respect to conventional hybrid positioning techniques in cellular networks.

A collaborative coexistence mechanism for IEEE 802.15.3 and 802.15.4 WPANs

Wireless Personal Area Networks (WPANs) are short-range ad-hoc networks centered around a person that make use of unlicensed bands for data transmission. Two complementary types of standards have been proposed by IEEE working groups for both High Data Rate (HDR) and Low Data Rate (LDR) WPANs. However, because of the unlicensed nature of WPANs, interference issues exist between uncoordinated WPANs. These interference issues are particularly severe when two or more nodes are closely located (e.g. in a multimode LDR/HDR device). This paper proposes a novel collaborative coexistence mechanism named Alternating Wireless Activity (AWA, patent pending) between a HDR WPAN based on the standard IEEE 802.15.3 and a LDR WPAN based on the standard IEEE 802.15.4. The AWA coexistence mechanism does not require any modification to the mentioned standards because it exploits their already available features.

The synergic localization system (SLS)

Along with a vision that foresees the Fourth Gen- eration of Wirless Mobile Communication Systems (4G) as based on a cellular extended short-range architecture, in this paper we propose a GPS-free localization system, named the Synergic Localization System (SLS), and its localization algorithm. Ba- sically, the cellular system supervises the formation of clusters, where each Mobile Station (MS) can measure its relative distance from the other MS members. This information is transmitted to the Cluster Head (CH) and further relayed back to the cellular network, where it will be used in the localization algorithm by the location server, in addition to the information retrieved using ah ybridTime Of Arrival/Angle Of Arrival (TOA/AOA) technique, to obtain the position of each user in the group. As a consequence of the synergy between cellular and short-range communication, the simulation run shows the effectiveness of the SLS in terms of an enhanced accuracy of the location error respect to the actual stand-alone cellular solutions.

Cooperative Mobile Positioning in 4G Wireless Networks

Cooperative mobile positioning is raising up as a promising new branch of wireless location, in which several research directions are being explored. In this chapter, we apply the cooperative mobile positioning framework as an innovative solution for positioning determination in 4G wireless networks by introducing the Ad-Coop Positioning System (ACPS). The ACPS is supported by a hybrid cellular ad-hoc architecture, where the cellular network has a centralized control over the adhoc connections among pairs of mobiles. Specifically, peer-to-peer communications are exploited in a mesh fashion within cellular-established clusters for cooperationaided localization purposes (from that, the word ad-coop is derived). The numerical results exposed in the chapter will show that thanks to the spatial proximity and spatial diversity within a group of cooperative mobiles, our proposal has the potential to enhance the location estimation accuracy with respect to conventional hybrid positioning techniques in stand-alone cellular networks.

Coexistence mechanism for colocated HDR/LDR WPANs air interfaces

This paper addresses the issues of interference management among Low Data Rate (LDR) and High Data Rate (HDR) WPAN air interfaces that are located in close-proximity (up to 10 cm) and eventually on the same multimode device. After showing the noticeable performance degradation in terms of Bit Error Rate (BER) and goodput due to the out-of-band interference of an HDR air interface over an LDR air interface, the paper presents a novel coexistence mechanism, named Alternating Wireless Activity (AWA), which is shown to greatly improve the performance in terms of goodput of the most interference vulnerable air interface (i.e., the LDR air interface). The main difference of the proposed mechanism with respect to other collaborative mechanisms based on time-scheduling is that it synchronizes the transmission of the LDR and HDR WPANs at the superframe level instead of packet level. Advantages and limitations of this choice are presented in the paper. Furthermore the functionalities of the AWA mechanism are positioned in a common protocol layer over the Medium Access Control (MAC) sublayers of the HDR and LDR devices and it can be used with any standard whose MAC is based on a superframe structure.