Cooperative transmission techniques for smart cities data sensing collection

Project leaders

Alberto Zanella, Ghassane Aniba

Agreement

MAROCCO - CNRST - Centre National pour la Recherche Scientifique et Technique

Call

CNR/CNRST 2016-2017

Department

Engineering, ICT and technologies for energy and transportation

Thematic area

Engineering, ICT and technologies for energy and transportation

Status of the project

New

Research proposal

The impetuous development of ICT solutions is enriching our homes and public buildings of devices and other manufactures equipped with sensing and computation capabilities. The main aim of such devices is the collection and processing of information from the environment to allow a more efficient use of the resources (for instance, power and materials) and increase quality of life. Among the possible applications, demand-side management (DSM) is gaining interest in the context of smart grid design and requires the real time transmission of power consumption information of each electric component in the building towards a suitable processing center. In this scenario the concept of "smart city" is merged with the paradigm of "internet of things" where thousands of devices exploit the network infrastructure for control and/or monitoring purposes. In our scenarios, we focus on the problem of how to send efficiently the data collected by the various sensing elements of the buildings to remote data fusion centers where the information is conveyed and processed. It is worth noting that several solutions are possible to handle data transmission from the buildings to the data fusion centers : a) fixed internet connections; b) cellular networks; c) specific wireless technologies. The first solution exploits the presence of an existing infrastructure in most of the towns but has the disadvantage that the fixed internet connections are asymmetrical and the data rate of the flow from the host to the center of the network (upload) is typically lower than that from the center to the host (download). This solution is not very flexible and requires higher costs for maintenance and upgrade. The cellular network solution is less expensive than the previous one but the huge amount of data to be transferred, especially in large urban areas, could overload the whole system. The solution of constructing a specific wireless architecture is more challenging from the technical point of view but it is potentially more scalable and resource efficient. For these reasons we will focus on the latter solution.
Starting from the necessity to develop a suitable wireless network, our reference scenario is based on the following technical assumptions:
i) the use of, low cost, conventional antennas for TV broadcasting, already installed at the top of the large majority of the buildings as transmitters. This solution has the great advantage that it does not requires expensive hardware for the realization of the transceivers.
ii) data fusion centers can broadcast pilot messages to the buildings to allow channel state information at the transmitter sides;
iii) we exploit the fact that some frequency bands, originally allocated for TV broadcasting are no longer used (white spaces). This assumption allows us to reuse the TV antennas for transmission purposes without additional radio frequency front-end.
iv) the use of the same band, adopting the concept of single frequency network (SFN), for all the transmissions. This choice has the advantage of reducing the band occupation but requires the development of suitable techniques to limit the amount of interference;
v) strategies of cooperation between buildings to help the transmission of data towards the fusion centers will be also considered, by implementing the paradigm of virtual multiple-input multiple-output (V-MIMO) to increase diversity gain and to reduce the impact of co-channel interference. To exploit the channel state information at the transmitter site, made available by point ii), we adopt beamforming techniques.
The previously mentioned assumptions lead to several open questions. In particular:
a) Is SFN solution suitable for this service in large urban areas?
b) How many data fusions are necessary for a given distribution of building in an urban area?
c) Where should these data fusion be located?
d) The cooperation procedures foreseen in point v) requires an exchange of data and channel state information between buildings. What is the best technology to provide such information?
e) Can suboptimal techniques (i.e. limited feedback approaches) be applied?
f) Is there an optimal size for the cluster of buildings as a tradeoff between amount of information to be exchanged by buildings and performance of the buildings-to-data fusion transmission?
g) How can the communication protocols between buildings and data fusion centers be realized?

To answer these questions we will implement a complete simulation environment taking both the geographical layout of a town and the realistic position of the buildings into account. From the quality of the transmission point of view, we will investigate the tradeoff between having a large number of clusters of cooperating buildings, which makes the beamforming technique more efficient, and the amount of information to be exchanged within the cluster, which increases as the cluster size increases. We will also derive some guidelines and basic rules for the planning of the data fusion centers (number and position).
As far as the quality of the consortium is concerned. The two research groups have a large experience in the field of wireless communications. In particular, the main skills of CNR group are in the detailed simulation of wireless scenarios and network aspects analysis, whereas CNRST has a large experience in Physical layer design and signal processing aspects. These skills are complementary and allow us to cover all the topics of the research project.

Research goals

This project addresses a smart city scenario where buildings are equipped with a large number of sensing devices and the data collected are transmitted to some data fusion center for further processing. To this aim a transmission scheme which make use of conventional TV antenna systems is considered to reduce the burden we would obtain by using fixed internet lines of cellular technology. The main objectives of this project are:
a) to device a communication system to allow the data transmission in urban areas characterized by a large density of buildings;
b) characterize the most important causes of performance degradation;
c) check the feasibility of such low cost scheme by studying a complex scenario characterized by a realistic layout of streets and buildings;
d) identify the suitable number of data fusion center and their position in order to maximize the tradeoff between installation costs and reliability of the data transmission.
The main outputs of this research projects will be research papers to be presented at international conferences and journals.

Last update: 04/10/2024