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Wireless Deployable Network System (WIDENS)An Ad Hoc Network for Public Safety Application

Navid Nikaein and Raymond Knopp

Institut Eurecom

www.widens.org

@July 1st, 2005 ©Navid Nikaein2

WIDENS

European 6th Framework Information Society Technologies (IST) Collaborative Industry/Academia Research Project

Description: Rapidly-deployable reconfigurable Wireless Ad Hoc

communication system for future public safety, emergency and disaster applications

Time frame : February 2004 – January 2006 Total Research Funding: 2,9 Meuro Project Cost : 5,9 Meuro

@July 1st, 2005 ©Navid Nikaein3

Motivation

Interest among PMR players in US and Europe in broadband rapidly deployable systems e.g. 4.9 GHz

Interest of military manufactures First ad hoc deployable system, e.g. SURAN,

GloMo, JTRC MESA Project

ETSI/TIA standardization effort

@July 1st, 2005 ©Navid Nikaein4

Introduction to Widens

Objectives Propose and prototype a new generation of interoperable public safety

system Design a self-organised communication infrastructure anticipating and

responding to future emergency applications and services Participation on Joint TIA/ETSI MESA activities (standardization issue)

Challenges Public Safety users

Identify core functionalities of such system Collaborate with specialists and professional organisations Increase their efficiency during emergency operations

Technological aspects Design a scalable communication system, rapidly deployable Validate its feasibility through a prototype and the definition of scenarios

Market interests Propose ad-hoc hotspots as access networks to existing PMR

@July 1st, 2005 ©Navid Nikaein5

Broadband Target

1996 1998 2000 2002 2004 2006 0.01

0.1

1

10

100

1000

2.4Ghz

5 Ghz

60 Ghz

HIPERLAN/1 802.11b

HIPERLAN/1 802.11a

Piconets, scartternets

WLAN

Ultrawideband

PAN

Cellular HSDC

GPRS

EDGE

UMTS

Space/time coding Bluetooth

Home RF

WIDENS

@July 1st, 2005 ©Navid Nikaein6

Project Structure:Focus WP4

- Mobile ad Hoc system architecture

- Integration of the system in a single terminode prototype plat-form - Validation in open air field trial- Contribution to MESA standards

WP2:

SystemArchitecture

WP5:

Integration andevalutaion

WP6 : Dissemination

WP3:Scalable auto-

configurable network

WP4:

Ad Hoc Mac and Phyadaptations

WP1 : Project Management

Results of the project

@July 1st, 2005 ©Navid Nikaein7

RF Issues:4.9 Regulation in USA

Feb.14 2002, Confirmed May 2, 2003 : FCC transfers 4.9 GHz band (4940-4990 MHz) from Federal Government use to systems in support of public safety

To be used for a variety of broadband applications both temporary and permanent operations both fixed and non-aeronautical mobile applications permits “hot spot” operations permits operation of temporary fixed links (< 1 year)

Largest single FCC offering for public safety spectrum in history – direct result of 911 and lobbying by Motorola/APCO

@July 1st, 2005 ©Navid Nikaein8

4.9 GHz:Frequency Utilization

Licensees authorized to use 50 MHz of spectrum in 4.9GHz band. Ten 1 MHz channels and eight 5 MHz channels Aggregation to 20 MHz permitted Time-Division Duplexing in spirit (although FDD not

explicitly ruled out)

1 MHz Channels 5 MHz Channels

UWB (unlicensed)

@July 1st, 2005 ©Navid Nikaein9

First Link Budget (5.85GHz)

Tx/Rx Separation

(m)

5.85 GHz Outdoor

Path Loss wrt 1m FS(dB)

Receive Power

(dBm)

Maximum Bitrate (Mbps)BER=10e-5,Gemtek 802.11a receiver

Normalized to 7.68 msps

10 30 -41 20.8

20 38 -50 20.8

30 45 -57 20.8

40 47 -59 20.8

50 50 -62 20.8

60 52 -64 20.8

70 54 -66 20.8

80 56 -68 20.8

90 58 -70 20.8

100 60 -72 18.5

200 67 -79 13.8

250 70 -82 9.2

300 72 -84 6.9

400 75 -87 4.6

500 79 -91 2.3

600 81 -93 <2.3 (undefined for 802.11a), timing synch still possible

700 84 -96 <2.3 (undefined for 802.11a), timing synch still possible

800 85 -97 <2.3 (undefined for 802.11a), timing synch still possible

900 86 -98 <2.3 (undefined for 802.11a), timing synch still possible

1000 87 -99 <2.3 (undefined for 802.11a), timing synch still possible

•Measurements performed at

Virginia Tech (MPRG 1998)

•NLOS flat suburban area, foliage, houses, 5.5m TX antenna

•Results for 25 dBm/11.5dBi TX, 0dBi RX

@July 1st, 2005 ©Navid Nikaein10

User Studies

Collaboration with professionals (fire services, police, ambulance) Characteristics identification (structure, deployment and applications)

Preliminary results Detailed organisational structure varies between different public

safety forces Common characteristics

Deployed in small groups of several units interacting among each other Mainly following a hierarchical structure But, direct communication should also be provided to increase the

autonomy of each players Deployment topology depends on the type and on the size of the

emergency scene Public Safety deployment scenarios fall into four groups

Concentration around a point (e.g. a bus crash) Front line (e.g. forest fires, floods) Ring: working around a place (e.g. urban fires, bomb deactivation) Random Distribution (e.g. an earthquake)

@July 1st, 2005 ©Navid Nikaein11

Typical Scenarios:Concentration, Front, Ring, Random

@July 1st, 2005 ©Navid Nikaein12

Requirements of Public Safety Applications

Broadband, reliable, and secure links Reconfigurable and rapidly deployable system Adaptive and optimized layer interaction: cross-layer Support for organizational structure of public safety

users User interactions Network topology Users’ priority

Support for user requirements Hard QoS for multimedia applications

Note: Firefighters, peacekeeping forces, emergency doctors, rescue teams are typical public safety users

@July 1st, 2005 ©Navid Nikaein13

WIDENS MAC/PHY Layer

Tightly coupled MAC/PHY layer Opportunistic scheduling based on wideband channel

quality and traffic volume (temporal) Carrier and antenna multiplexing Cross-layer optimization

MAC defines a cluster-based topology MAC frame is time-slotted, like TDMA

Network time synchronization is done by cluster-heads Hard QoS Support

MAC is Connection-less Channel access is quasi random but contention-free due

to feedback based scheduling Fully reconfigurable MAC/PHY: SDR Concept OFDM(A) & multi-antenna capable: Spectral Efficiency

@July 1st, 2005 ©Navid Nikaein14

Reconfigurability: Cluster Topology Nodes are capable of multi-hop routing Nodes can dynamically assume three roles

Cluster-head: regulate/coordinate traffic within a cluster Relay: interconnect to clusters Gateway: interconnect to other networks

Cluster topology is built dynamically Geographic/Propagation characteristics of terminodes Processing capabilities of nodes

DSP (e.g. MIMO) Multiple-frequency capacity (tune on several channels

at once) Power-levels

Connectivity of nodes with other networks Connectivity with fixed and wireless networks

@July 1st, 2005 ©Navid Nikaein15

Illustrative Deployment: Example

ClusterheadsRelays

Cluster-head synchronization signal is designed to allow adjacent cluster, which are out of communication range, to synchronize to each other

Cluster-head is not an AP or BS: no concept of UL & DL Possibility of nodes being connected to several cluster-heads

multi-hop Routing

@July 1st, 2005 ©Navid Nikaein16

Reconfigurability:RF Agility Nodes need to tune over wide bandwidths

Regional differences in allocations Same equipment for different nations

Exploit temporary openings in spectrum for covering special events (Olympics, political event, etc.)

Spectrum efficiency via dynamic channel allocation (network determines best frequency planning)

Interoperability with cellular systems Reuse of existing 2G/3G terminals in emergency

scenarios by playing role of BTS/Node-B Dual-band radios addressed in WIDENS

2 GHz legacy radios (3G, narrowband tuning) 4-6 GHz for new Ad Hoc MAC/PHY (wideband tuning)

@July 1st, 2005 ©Navid Nikaein17

Reconfigurability:Software Radio

No one air-interface/network topology is optimal for every emergency scenarios

Radio parameters should be adjustable (at least offline prior to deployment) Framing as a function of delay requirements (typical

services), short (a few ms) or long (tens/hundreds of ms)

Modulation/coding as a function of propagation environment (rich or no multipath, time-variation)

Example: Number of OFDM carriers, pilots, prefix length, subband-allocation possibilities

@July 1st, 2005 ©Navid Nikaein18

Reconfigurability: Algorithm Adaptation

Goal: Maximizing spectral efficiency (better services) Adapt as a function of a specific propagation

environment E.g.1: nodes adapt (or download from a peer in

the network) DSP algorithm (e.g. MIMO) to suit multi-path richness (e.g. outdoor/indoor)

E.g.2: nodes adapt different scheduling algorithms depending on the application senarios either at deployment or over-the-air

@July 1st, 2005 ©Navid Nikaein19

Channelization

@July 1st, 2005 ©Navid Nikaein20

MAC/PHY Channels

CHSCH – Synchronization Channel Time (slot/frame) synch delivered by CH Allows for time/freq synchronization of cluster, detectable across clusters for

multi-cluster synchronization CHBCH – Beacon channel

Temporal resource allocation (TxOps) MCH – Measurement Channel

Contention-free broadcast by each node (except CH) Relays wideband channel measurements (via pilots) to connectivity region Relays QoS queueing information to CH for fair TxOps scheduling respecting L3

negotiated QoS 1-hop link information (in support of L3 routing algorithms) 2-hop Neighborhood information (in support of L3 routing algorithms)

SACH/SACCH – Scheduled Access Channel Node data channel granted by CH on slot-by-slot basis every frame

(<20ms) Dynamic Allocation (Scheduling) on frequencies/antennas

Exploit both Multiuser Diversity and spatial multiplexing Scheduling algorithms with both hard QoS (fixed rate/delay-limited multiuser diversity) Soft QoS guarantees (proportional fair, maximum throughput, maximum goodput, etc.)

@July 1st, 2005 ©Navid Nikaein21

Hierarchical Opportunistic Scheduling

Scheduling (polling) is a hierarchical process involving both the cluster-head that provides transmission opportunities (TxOps) and nodes themselves acting as routers that finely control physical resources CH schedules TxOps based on QoS, traffic volume

and wideband channel quality measurements Nodes maps their traffic queues over physical

resources using reconfigurable scheduling policies satisfying different QoS based on wideband channel measurements w.r.t. their destinations

Indeed, the MAC sees the PHY as a resource over which several data flows can be finely scheduled

@July 1st, 2005 ©Navid Nikaein22

Hierarchical Opp Scheduling

MCH feedback (Traffic Volume)

CH

Relay Relay

CHBCH allocations (TxOps)

SACH allocations (spatial OFDMA)

Relay

CH

CH

1 2

2 Legend

@July 1st, 2005 ©Navid Nikaein23

Demonstration Equipment

For the WIDENS demonstrator, new reduced form-factor PCMCIA SDR modules have been developed MIMO capable (two-antennas) multi-frequency capable

2 GHz today 4-6 GHz at end of project

An important part of signal processing can be performed on the onboard FPGA in order to reduce the burden on the host PC.

FPGA AD/DA

RF

WIDENS-specific equipment (2GHz,5GHz at end)

@July 1st, 2005 ©Navid Nikaein24

SDR Design Flow (L1/L2/L3)

L1/L2 Specs L1/L2C

Implementation

PC Cluster RF EmulatorL1/L2 SpecsL1/L2

C Implement.

L3 SpecsL1/L2/L3

C ImplemntIn Linux

Based RTOS

Real-timePC-based Terminalswith real RF.

Port to SoPC (reconfigurable hardware)

Embedded system

@July 1st, 2005 ©Navid Nikaein25

Conclusion

WIDENS is the first European IST project in the area of future public safety communication and information systems

The project will contribute to the development of future integrated European public safety system development by providing system concept and technology platform for ad hoc broad band rapidly deployable network.

Reconfigurability and cross-layer optimization are a built in feature in the design of the system and not only in its implementation