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					CEFRIEL
Centro per la Formazione e la Ricerca in Ingegneria dell’Informazione

Politecnico di Milano

MESA System Reference Model and Architectures
MESA Meeting #6
Gianni Redaelli CEFRIEL

Via Fucini 2 20133 Milano MI, Italy Ph.:+39-0223954.217, Fax: +39-0223954.254 mailto: gianni.redaelli@cefriel.it http://www.cefriel.it/amwts

Ottawa, 22nd - 25th April 2003

Outline

MESA goal A proposal architecture of the MESA system

Access Network
Network elements

Backbone

Some proposed network architectures for different scenarios

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MESA Project

The project aims at producing specifications for an advanced digital mobile broadband standard much beyond the scope of currently known technologies for
Public Protection and Disaster Relief

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A Proposal of the main MESA System Features In order to fulfil user requirements MESA system should be
flexible
adaptable reconfigurable

self-organizing easy and fast to deploy interoperable broadband able to guarantee the requested QoS reliable secure able to locate nodes, sensors, robots…
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A possible MESA Network Architecture
A solution based on a multi hop mobile ad hoc network can be foreseen

External Networks

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MESA Components and Sub-Systems MESA nodes
transceiver User devices (MSs, PDAs, Notebooks, fax machines, …) Sensors Control robots …

Access network
MESA Access Points

IP Backbone
MESA Router MESA Gateway MESA DBs (User authentication…)
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profile,
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devices

identification,
Ottawa, 22nd - 25th April 2003

Nodes Classification
Mobility each node can be fixed, nomadic or mobile Elaboration capacity e.g. notebook, PDA, smart phones, sensors, control robots… Power capacity different types of nodes are characterized by different power capacity nodes of the same type may have batteries with different power-life Transmitting capacity different types of nodes are characterized by different communication ranges Networking capability a MESA node may or not act as bridge (simple relay) or as a router (store and forwarding)
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Nodes Foreseen Connections
A MESA Node could be able to establish
1.

a wireless peer-to-peer communication with other MESA Nodes
single hop multi hops

2. 3.

a connection with the MESA AP(s) a peer-to-peer or infrastructured connection with external networks
TETRA TETRAPOL TETRA II (?) Project 25 2G/2.5G/3G (?) DVB-T Satellite (?) Fixed and Mobile BWA (?), (LMDS, MVDS, MMDS, 802.16, 802.20…) WLANs (802.11x, HiperLAN/2…) (?) UWB (?)
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Traffic Type

The following modes can be foreseen
Unicast
Multicast

Broadcast

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MESA Access Point
MESA AP provides an alternative way of communication between nodes whereas peer-to-peer communication is not feasible or it is too expensive When adjacent MESA APs communicate (depending on MESA network decisions) a light MESA backbone is built up using MESA APs MESA APs should access to the backbones of other networks only through a MESA router MESA APs can have switching capabilities (cheaper devices) and/or routing functionalities (more expensive) – integrates the MESA router It can be fixed (previously deployed e.g. in hot spots areas) portable mobile
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Backbone
MESA backbone should be able to interoperate with existing network infrastructures As backbone we can consider two classes of network solutions
Terrestrial
MESA backbone MAN WAN

Aerial
Satellite High Altitude Platform

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Terrestrial Backbone: Wired Connections
The wired connection build the fixed MESA backbone Routers are fixed and available at occurrence for allowing nodes/APs to access the backbone Solutions A fiber optic network based on the SDH technology
up to 40 Gbit/s per fiber with current technology guaranteeing very high network availability up to 99.999 % transmission path backed-up and restored within 50 ms in case of optical fiber cut or network card failure

in case it is necessary to improve the network capacity, the Wavelength Division Multiplexing (WDM) technique can be used, where multiple optical channels are multiplexed on the same fibre exploit the existing copper (twisted pair and coaxial cable) infrastructure, when this infrastructure is able to fulfil all services requirements using VDSL, ADSL or SHDSL technologies
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Terrestrial Backbone: Wireless Connections

MVDS
MMDS (Multipoint Microwave Distribution Systems)

IEEE 802.16 Wireless MAN™ Air Interface for Fixed Broadband Wireless Access IEEE 802.20 Mobile Broadband Wireless Access

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Aerial Backbone
Two different solutions can be distinguished
High Altitude Platforms (HAPs)
HAPs are relatively easy to deploy and due to their intrinsic ad hoc nature they are particularly suited to be employed in emergency/disaster situations

Satellite
Satellite has the high advantage to be highly reliable and ensure a wide coverage the main drawbacks are
– the low SNR affecting the direct communication to specific small devices – the considerable delay that could be critical for particular Real-Time applications

Their use depends on the different applications’ requirements (QoS) and on the scenarios They can act as reliable redundancy links
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Backbone Network Elements

MESA Router
MESA Gateway

MESA DBs (User profile, devices identification,
authentication…)

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MESA Router (1)
MESA Router is used if the peer-to-peer connection between source and destination MESA node is not feasible or convenient the routing through MESA APs is not feasible or convenient the connection requires the MESA gateway to interconnect with external backbones MESA Routers can be fixed or portable (integrated in MESA APs) MESA Router can implement gateway functions A MESA Router is connected with MESA gateway other MESA Routers using
the MESA backbone any other backbone

MESA APs MESA nodes
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MESA Router (2)

Connection can be either wired or wireless
AP-to-Router connections could be wireless more likely while router-to-router and router-to-gateway connections can be wired, wireless, aerial depending on the scenarios

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MESA Gateway

MESA Gateway is a particular router that manages
MESA network communications to and from external

networks

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MESA DBs

MESA User Profiles Database tracks all users accesses to the MESA network The MESA Device Identification Database has to check all the devices (not users) authorized to access the MESA network The MESA Authentication Server manages and provides the parameters to perform authentication, authorization and data encryption

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Interoperability
Interoperability with existing infrastructures and systems is a critical but fundamental task for the MESA system The MESA system should be able to inter-work with the existing
Wireless networks
TETRA, TETRAPOL, TETRA II (?), Project 25, 2G/2.5G/3G (?), Fixed and Mobile BWA (?), DVB-T (?), WLANs (?), UWB and/or satellite… depending on the implemented interfaces

wired networks
xDSL (?), PSTN (?), ISDN (?), GiBE (?), SDH and/or Ethernet (?)… depending on the implemented interfaces
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