Overview of Mobile Networking Overview of Mobile Networking Initiatives at WINLABInitiatives at WINLAB

Internet (IP-based)

Infostationcache

WLANAccess Point

WLANHot-Spot

VOIP(multi-mode)

Low-tier clusters(e.g. low power 802.11 sensor)

Ad-hocnetwork

extension

Public Switched Network(PSTN)

BTS

High-speed data & VOIP

Broadband Media cluster(e.g. UWB or MIMO)

BTS

BSC

MSC

CustomMobileInfrastructure(e.g. GSM, 3G)

CDMA, GSMor 3G radio access network

Generic mobile infrastructure

Today Future

GGSN,etc.

Voice(legacy)

High-speed data & VOIP

Relay node

Introduction: The Next GenerationIntroduction: The Next Generation

��������

���� ���������������� � ����������

�� ������������

��

��� !!�"��

#����$��

%&���������

% ��������

��

������������

'()*(

"��

����

�������)�� �

�������

� +()'(�"��

(�%)

(�"�

� +()'(��������

'(�������

�����,

���� ��

�����$����,

������-� . �/������0

(�$����"���������������,

"����1��2������������$��.������������ ��� ���� 1��3�$�����,$. .�������

������� 4� 5��6$��$�

7������

*(��������

"����$��1�$��$��� ������������ ������������2�������.�$����$����,�

�$2��������� �

.�$���$����,����

�$2�� �����������-�$���$��80

9$2������&������ &���$����,$����11��2��� ���� &���:� ����1 � ���:2��;����:����:

������2������� �����

����������$�������$������2���

Introduction: Future Protocol ArchitectureIntroduction: Future Protocol Architecture

Research OverviewResearch Overview

Future Wireless Networks

•••

•••

•••

•••

•••

•••

•••

<>

<>

<>

<>

<>

<>

<>

Research Topics Multimedia Networking

Ad Hoc Networking

Sensor Networking

Security and Privacy

Testbeds and Validation

MultimediaNetworking

Wireless Multimedia MulticastingWireless Multimedia Multicasting

Challenges

• Limited Bandwidth• Time-varying, error-prone

channels• Receiver heterogeneity

Issue: What strategies can we employ to overcome the challenges of the wireless scenario?

FEC

ARQ

Simulcast

���������� �� �����

��������� ������������

�� ������������

Layers

Tools Proposed strategy being examined:1. Employ multiple resolutions of video transmitted to different

multicast groups2. Clients subscribe to multicast groups based on their channel

conditions3. Centralized and distributed strategies for deciding appropriate

group

b1 b2

b1

�����

b2

b2b1

����� �����

�

b1

x*b1+y*b2

b2

Network Coding:�� Incorporate coding at intermediate network nodes• Achieves higher throughput in a multicast network• Challenge: Transmission rate is limited by the minimum capacity of all receivers

Multiple Description Network Coding:• Multimedia MDC can ensure reliable media delivery• MDs are transmitted at a rate of the maximum capacity of all receivers!• Receivers with less capacity receive fewer descriptions• Graceful reduction in media quality

Multiple Description Network CodingMultiple Description Network Coding

Ad HocNetworking

BTS A

AP1

FN1

FN2

FN3

FN4

AP2

AP3Wired Radio Access Network Infrastructure AP beacon(ID, frequency, power, ,bit-rate,service capabilities...)

FN beacon

BTS radiobeacon

BTS serviceadvertisement (into wired net)AP service

advertisement (into wired net)

End-user:seek (FN*, AP*)associate (FN1, AP2)routing update (FN1)routing update (AP2)send data

med-tier radio(e.g. 802.11x)

low-tier radio(e.g. 802.15.x)

Forwarding Node:seek (FN*, AP*)associate (FN3, AP3)routing update (FN3)routing update (AP3)forward data

Protocols needed:Ad-hoc discovery (enhanced beacons, etc.)Ad-hoc MACAd-hoc network routing (extended metrics including energy)handoff, QoS control, multicast (..features)

ad-hocwireless networkinfrastructure

may receiveBTS beaconfor wide-areaservice

laptop

sensor node

Access Point:Seek (AP*, BTS*)Associate (AP2, BTS A)handoff update (AP2)handoff update (BTS A)..forward data & handoff

Discovery and Routing in Ad Hoc NetworksDiscovery and Routing in Ad Hoc Networks

AdAd--Hoc MAC: Hoc MAC: DD--LSMA SchedulingLSMA Scheduling

� Link scheduling to allow parallel transmissions, solves “exposed node”� useful for QoS on ad-hoc FN-FN infrastructure in hierarchical systems

� Distributed scheduling algorithm (upper MAC), using 802.11-based lower MAC

D

E

A

B

C

to C to ERTS retransmit

to C to Cto E to Eto C

t0 t1 t2

T

A

DE

B C RTS

CTSDATA

Upper MACScheduler

D-LSMA

Classified flows

Lower MAC

……

Sensor Networking

AdAd--Hoc Network: Hoc Network: 33--Tier Sensor NetTier Sensor Net� Self-organizing hierarchical ad-hoc wireless network (SOHAN)

under consideration at WINLAB– Tier 1: low-tier mobile nodes, e.g. low-power sensors (MN)– Tier 2: forwarding nodes (FN) with multiple radio interfaces

(UWB, WLAN, cellular…)– Tier 3: wired base stations and access points (BS or AP)– Research on new protocols for: ad-hoc discovery, MAC and

routing

InternetInternet

Forwarding node

low-tier (e.g. sensor) user nodes (MN)

Access Point

FN

AP

Wide-AreaCell

personal-area pico-cell

WLANmicro-cell

BTS

Sensor Energy Conservation via AdaptationSensor Energy Conservation via Adaptation

������

���Active nodes: forwarding packets

Backup nodes: Sleep + Wakeup

Question: How to determine the sleep interval?

�Tradeoff between energy conservation and responsiveness

Current solution: � Use a fixed sleep interval that is small enough� Energy conservation = sleep interval / wakeup time

Proposed Solution:� Adaptive sleep interval

Issue: Network Lifetime

WirelessSecurity andPrivacy

Authentication in Hierarchical Authentication in Hierarchical Ad Hoc Sensor NetworksAd Hoc Sensor Networks

� Public key certificates are not suitable for flat ad hoc networks– To check certificate requires

expensive public key operations

� Three tier architecture:– Varying levels of computational

power within the sensor network– Sensors do not communicate with

each other– Forwarding nodes are radio-relay

� TESLA Certificates– Alternative to PK certificates– Uses symmetric key cryptography– Delayed key disclosure

AP

FN

SN

� Authentication framework:– Access points provide filter to

application– TESLA certificates provide efficient

sensor node handoff– Weak and assured data

authentication provided

3G Multicast Security3G Multicast Security

� Keys must be shared by multicast group participants� As users join and leave, keys must be changed� 3GPP has proposed a new entity, the BMSC for managing broadcast and

multicast services� The BMSC can perform key management

Node B

Node B

Radio Network Subsystem (RNS)

GGSN

SGSNRNC

Node B

UMTS Terrestrial Radio Access Network

BMSC

UMTS Core Network

Internet

TestbedsAndValidation

Emergency Response Infostation� Outdoor Infostations for Rapid

Deployment– For first responders to set up

wireless communications infrastructure at disaster site

– Provides WLAN & sensor net services

– Infostations for caching large files (maps, etc.)

– Wireless backhaul link

� Prototype incorporates:– 802.11 MAC+ for Infostations pass-

through mode– Content caching algorithm & software– Solar panels, antennas and

embedded processor with WLAN card– Can be integrated with 802.11 ad-hoc

sensorsWINLAB’s Emergency Infostation 2002

Medical Sensor with 802.11 WLAN

� First system-level MUSE prototype completed 11/03– New ECG interface board– CerfCube platform with 802.11b

(off-the shelf components)– WINLAB drivers & networking

software

� Next steps– Make this prototype available to

BioMed and UMDNJ collaborators– Integrate with ZnO devices– Continue work towards MUSE

sensor SoP/SoC with low-power 802.11b

ORBIT Testbed� Open-access next-generation wireless network testbed being

developed for NSF network research testbeds (NRT) program

� Large scale “radio grid emulator” for evaluating new concepts for future wireless networks, e.g. ad-hoc sensor nets, pervasive systems...

� Also, outdoor “field trial network” covering RU Busch & NB campuses for real-world application work

Mobile node(robotic control)

Static radio node

Radio link emulation

1. Radio Grid for Lab Emulation

Dual-mode Radio device

2. Field Trial Network

“Open”APIAccess Point(802.11b)

End-user devices

Ad-hoclink

3Gaccess

link

HighSpeed

Net

Firewall

MobilityServer

Wiredrouters

EmulatorMapping

“Open”API

3G BTS

Global InternetGlobal Internetns-2+ scripts

&code

downloads

ResearchUser of Testbed

ORBIT ORBIT TestbedTestbed: : Radio GridRadio Grid