802.15.5 mesh topology

802.15.5 MESH

TOPOLOGY

Y SUNIL RAJ KUMAR

MTECH ECE,

REG NO 14043029

DEPT OF ELECTRONICS ENGINEERING,

PONDICHERRY UNIVERSITY

Goal of mesh topology

• The purpose of developing IEEE 802.15.5 is

to “provide the architectural framework

enabling WPAN devices to promote

interoperable, stable, and scalable

wireless mesh topologies and, if needed,

to provide the amendment text to the

current WPAN standards that is required

to implement this recommended

practice.”

11/04/15Dept of electronics engineering,

Pondicherry University2

FEATURES

• Easier network configuration,

• Node discovery,

• Multicast,

• Reliable broadcast,

• Synchronized and unsynchronized operations,

• Power saving (ON/OFF scheduling strategy)

route tracing.





TERMS DESCRIPTIONS

• Mesh coordinator: An entity that

manages the mesh network. It refers to

the root of the logical tree of a mesh

network whose tree level equals zero.

• Coordinator: A device that is capable of

relaying data frames for other devices.

• End device: A device that is not capable

of relaying data frames for other devices.



Mesh frame format

OCTAETS 12

MESH FRAME PAYLOAD MESH HEADER



1 2 1 1 2 2 2 1

TTL MESH

SEQUUEN

CE

NUMBER

DESTI

NATIO

N ID

SOURCE

ID

DESTIN

ATION

TREEID

SOURCE

TREEID

MESH

ID

MESH

FRAME

CONTROL

MESH HEADER

OPERATIONAL OVERVIEW



802.15.5

Low-rate WPAN mesh

High-rate WPAN mesh

HIGH RATE MESH OVER

802.15.3B MAC

LOW RATE MESH OVER

802.15.4 MAC



Challenges of LR WPAN Mesh

• Reliable

• Large Scale

• Low Duty Cycle

• Resource Limited

• Mostly Battery-Powered

• Simplicity yet Robustness

• Self-Configuration and Self-Healing





The reference model for low-rate WPAN mesh

Tree Formation and Addressing

In a LR-WPAN mesh network, a tree

is formed for both addressing and

routing purposes.

• Adaptive Tree (AT)

a. Initialization Phase

b. Operation Phase

• Meshed Adaptive Tree (MAT)



Adaptive Tree Formation

Initialization Phase

• Stage 1: Association

• Stage 2: Reporting number of

children

• Stage 3: Address assignment

a. An AT is formed.

b. Additional addresses can be

reserved



Adaptive Tree Formation

Operation Phase

• Normal data transmissions

i.Look at the address blocks for the

destination address and route the

packet accordingly.

ii.If not found, route through

parent

• Nodes are still allowed to join the

network



Meshed AT Formation

• Neighbors treat each other as a

child.

• Advantages

I. Shorter paths

II.Elimination of SPOFs



Unicast Routing• Meshed Adaptive Tree

I.Provides the basic functions of routing.

II.Immediately available after MAT is

formed.

• Distributed Link State

I.More efficient routing can be achieved.

II.Requires exchange of neighbor

information.

III.Note global link state information is

NOT needed11/04/15

Dept of electronics engineering,


Unicast Routing –Summary

• Simplicity

I.No route discovery.

II.No route repair.

• Adaptive Address Assignment (AAA)

I.avoiding “running out of addresses”

problem.



• Meshed AT (MAT)

i.shorter path.

ii.Robustness.

• Distributed Link State

i.Scalability

ii.multiple paths

iii. robustness

iv.shorter path



Multicast Routing

• This multicast routing proposal is based on the

Adaptive Tree protocol for the unicast routing.

• The Adaptive Tree (AT) algorithm constructs a

shared tree which spans all the nodes in a WPAN

mesh network.

• Our goal is to find a minimum sub-tree of the

Adaptive Tree which covers all multicast

members within each multicast group.



IEEE 802.15.5-HR

• Layer architecture.

• Network architecture.

• Super frame architecture Single.





The reference model for high-rate WPAN

mesh



High Rate Mesh Service Support WPS

• Network Setup

• Tree Topology Discovery

• ID Assignment

• Neighborhood-based Wireless Path

Selection

• Tree-based Wireless Path Selection

• Centralized Wireless Path Selection



Network Setup

• Mesh Coordinator (MC)

initializes the mesh

network

• Regularly announces mesh

capability in its beacon

• New MPN Cs scan for

beacons

• MPNCs choose free time to

send beacons



Tree Topology Discovery

11/04/15 Dept of electronics engineering,


• Each Mesh Pico net Controller

(MPNC)belonging to the tree

i.Waits for descendant report(s) from

its children.

ii.Estimates the number of own

descendants.

iii.Reports number of descendants to

parent.

• Process is repeated upon

i.Topology discovery request from MC

ID Assignment

• After receiving topology update

frames from all children

i.MC reserves a block of IDs.

ii.Assigns intervals of IDs to children.

iii.Size of interval is proportional to

reported number of children.

• MPNC receives an ID block.

• MPNC assigns ID to himself and its

DEVs



APPLICATIONSMultimedia home network



Interconnection among PC and

peripherals



• Interconnection among handheld devices

• Automation and Control

• Etc….





Technology

802.15.5 mesh topology