EE194: Wireless NetworksGroup #2: Joseph Cerra and Stuart Peloquin

Dynamic Transmission Power Control in Wireless Ad-Hoc

Networks

Issue from previous presentation

• Received signal strength does not necessarily indicate distance

• What is power in reference to?– dBm

• Can each node run different applications– Yes

• Do they?– Nope

• How do nodes keep track of power levels?– To be discussed

Design

• Built in Classes used/modified:– RouteAodv, Field, FieldInterface,

MacDumb, MacAddress, NetIp, RadioNoise, RadioNoiseAdditive, RadioInfo.

• Designed Classes used:– Heartbeat, AppHeartbeat, MyNode.

• GUI Classes:– MyCanvas, MyMenu, MyButton.

OSI Model

Radio

MAC

Network

Application

mobility

AppHeartbeat.java

NetIp.java

Field.java, FieldInterface.java

RadioInfo.java, RadioNoiseAdditive

Field

Mobility.java

MacDumb.java

Route RouteAodv.java

Implementation

• Main Function: Heartbeat.java – Setup GUI– Setup simulation

• createSim(nodes, length)– Placement, mobility, spacing, fading, pathloss,

field, radioInfo, mapper, packetLoss– CreateNode(node#, field, placement,

radioInfoShared, protMap, pl_in, pl_out)

• createNode– Add: radio noise, mac, network (set protocols and

routing), routing, application– Hookup entities: radio, mobility, field, mac, net– Run application

Implementation

• Application Layer: AppHeartbeat.java– Neighbour entries, beats (TTL)– Message passing– Send / receive packets (ACK)– Stagger initial sleep and wake of nodes– Send random msg to random nodes– Sleep and schedule next random

wakeup

Implementation

• Mac Layer: MacDumb– Neighbour entry table

• Mac address, RSSI, neededPower, power, beats

– Process RSSI information• Store RSSI information for each neighbour• Interpret signal strength change from:

– RSSI– Message passing history

– Compute transmission time at current bandwidth

– Maintain neighbour entry table– Update transmit power

Message Passing

Data DH

Data DH NH

Data DH NH TS MH

Data DH NH TS MH RH

App Layer

Network Layer

Mac Layer

Radio Layer

Data DH NH TS MH rssi

Radio Layer

Data DH NH

Mac Layer

Data DH

Network Layer

Data

App Layer

Implementation

• MAC layer node hash table– Neighbors(MACADDRESS)

» Where MACADDRESS is a particular node

• Power – power sent from node• RSSI – power received from node• neededPower – computed power needed for

reliable communications• Beats – time to live

Implementation

• Computing necessary powerPowerdivided = RSSI / THRESHOLD + 3

if (Powerdivided < 1)

Neededpower = powerSent + powerDivided*2

Elseif (Powerdivided > 1)

Neededpower = powerSent – powerDivided*2

Else // Powerdivided == 1

Neededpower = powerSent + Powerdivided

• Maintaining HashIf TTL == 0

Neededpower = Neededpower + 2

If Neededpower == 15

Remove entry

Simulation Examples

• In the following slides:– Simulation with node:

• Numerical and Graphical Power statistics• Source IP address• Destination IP address

– Destination IP of -1 is a broadcast

– Examples of:• Initialization of nodes• Broadcasts• Power conservation• Clustering

Sim. Example 1 – Initialization / Broadcast

Sim. Example 2 – Power conservation

Sim. Example 3 – Clustering

Simulation Sequence

• In the following slides, two complete simulations are run.

• Simulation timeline:

Initi

aliz

atio

n

~10

beat

s la

ter

~ 20

bea

ts la

ter

~ 30

bea

ts la

ter

Outcome #1

Outcome #2~ 15

0 be

ats

late

r

Initialization

~ 10 beats later

~ 20 beats later

~ 30 beats later

Outcomes

• The outcomes of the simulation differ because of the lifetime of routes in the RouteEntryTable.

• When the entries in the RouteEntryTable are not refreshed often enough, the mobility rate of the nodes may destroy the integrity of the simulation power metrics.

• The following two simulation are examples of high and low lifetime of entries in the RouteEntryTable.

Outcome #1 – High route entry lifetime

Outcome #2 – Low route entry lifetime

Conclusions – JiST SWANS

• Pros– Java based, easy to program– Useful programming tool for simulating WSN– Easy to understand implementation– Easily to implement customized applications

and data structures– Graphical user interface customizable

• Cons– Lacks WSN design capabilities. – No manuals or tutorials– Bytecode rewriter complicates debugging