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A In term Report

On

AN UNUSED BANDWIDTH UTILIZATION IN WIRELESS BROAD

BAND NETWORKS

Submitted

By

M.Ram Rajesh

Roll no: 11203004

M.Tech (C.S.E)

Under The Guidance

Of

Prof. G.Rama Krishna


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ABSTRACT

Applications that intend to transmit large data are bandwidth demanding. In order to

provide Quality of service, each application reserves the bandwidth from base station(BS).

However, it is difficult for the subscriber station (SS) to predict the amount of incoming data.

To provide Qos SS may reserve more bandwidth than its demand. So, reserved bandwidth

may not be fully utilized every time. Indeed a schema proposed termed as Bandwidth

recycling.The idea of the proposed scheme is to send recycled bandwidth to base station and

allow other SSs to utilize the unused bandwidth.


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CONTENTS Page

Abstract 2

1. Introduction 7

2. Analysis 8-19

3. Conclusion 20

4. Design 21-23

5. References 24


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Equation Index

Equation Number Page Number

1 9

2 9

3 10

4 15

5 16

6 16

7 17

8 17

9 17

10 18


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Figure Index

Figure Number Page Number

1 9

2 10

3 10

4 11

5 11

6 12

7 13

8 15

9 18

10 18


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1.INTRODUCTION

1.1.OVERVIEW:

For variable bit rate applications, QoS services are provided by reserving

the bandwidth. So,the subscriber station (SS) is required to reserve the

necessary bandwidth from the base station (BS) in Dynamic Resource

Reservation passion before any data transmissions.

In order to serve variable bit rate (VBR) applications, the SS tends to

keep the reserved bandwidth to maintain the QoS guaranteed services. Thus, the

amount of reserved bandwidth transmitted data may be more than the amount of

transmitted data and may not be fully utilized all the time. Although the amount

of reserved bandwidth is adjustable via making bandwidth requests (BRs), the

adjusted bandwidth is applied as early as to the next coming frame. The unused

bandwidth in the current frame has no chance to be utilized.

Moreover, it is very challenging to adjust the amount of reserved

bandwidth precisely. For every subscriber station a complementary station is

allocated by base station to caliculate unused bandwidth. So unused bandwidth

is added dynamically to base station and base station will allocate bandwidth

dynamically to other subscriber station on the basis of bandwidth requestTo improve the bandwidth utilization while maintaining the same QoS

guaranteed services, research objective is twofold The existing bandwidth

reservation is not changed to maintain the same QoS guaranteed services and

increasing the bandwidth utilization by utilizing the unused bandwidth. A

scheme proposed, named as Bandwidth Recycling , which recycles the unused


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bandwidth while keeping the same QoS guaranteed services without introducing

extra delay.

2.SYSTEM STUDY

2.1 LITERATURE SURVEY:

2.1.1.WiMAX

Physical and medium access layers are used in the WiMAX networks.

The data can be transferred from one node to another by Physical layer.

Medium access layer is used to exchange the information between two systems.

It lives in the data link layer which handles the breakdown of the packets into

bits. WiMAX is used to provide portable mobile broadband connectivity across

cities and countries through a variety of devices.

The original version of the standard on which WiMAX is specified a

physical layer operating in the 10 to 66 GHz range. The WiMAX MAC uses a

scheduling algorithm for which the subscriber station needs to compete onlyonce for initial entry into the network. After network entry is allowed, the

subscriber station is allocated an access slot by the base station. The time slot

can enlarge and contract, but remains assigned to the subscriber station, which

means that other subscribers cannot use it.

In addition to being stable under overload and over-subscription, the

scheduling algorithm can also be more bandwidth efficient. The scheduling

algorithm also allows the base station to control Quality of service (QoS)

parameters by balancing the time-slot assignments among the application needs

of the subscriber station

2.1.2. Base Station


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A base station refers to the wireless access point for computers with

wireless cards. It is basically a router that communicates with devices. A base

station in a network which allocates bandwidth to subscriber stations .

2.1.3. Subscriber Station

The Subscriber Station (SS) is generalized equipment which is used to

provide the connectivity between the base station and the subscriber. Each and

every subscriber station is connected with the base station; the base station

allows the reservation of bandwidth by the subscriber station. Bandwidth

reservation is an important part of the data transmission. Transmission SS (TS)

is one type of SS which has the ability to transfer the data from one SS to

another. The amount of incoming data will vary for the variable bit rate

applications.

2.1.4. Bandwidth Request

Every subscriber station request the bandwidth to base station by sending

BR s. Here bandwidth request strategies are of two types, namely incremental

requests and aggregate requests. When the BS receives an incremental

bandwidth request, it adds the quantity of bandwidth requested to its current

perception of the bandwidth needs of the connection. When the BS receives an

aggregate bandwidth request, it replaces its perception of the bandwidth needs

of the connection with the quantity of bandwidth requested. The self- correctingnature of the request-grant protocol requires that the SSs should periodically use

aggregate Bandwidth requests. The standard states that this period may be a

function of the QoS of a service and of the link quality, but do not give a precise

value for it. The grant-request may be sent in two possible MAC frame types

that are described in the following subsection. Only the first one (the standalone

bandwidth request) can be aggregate or incremental.


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2.1.5. Traffic Classes in IEEE 802.16 Networks

IEEE 802.16 networks have traffic classes,

1. Unsolicited grant services which is used to support real time data with fixed

size.

2. Real time polling service is to support real time data with variable size.

3. Non real time polling service is to support non real time data with fixed size.

4. Best effort service does not have any specific QoS requirements for example

email and web .

2.1.6. Dynamic Reservation Framework

Dynamic reservation is to limit the cost of signalling and configuration

while adapting to varying levels of offered load for a single CB class of traffic.

WIMAX network is a WAN that collects the traffic from primary (WiMAX)

SS, while each primary SS directly connects one or several Access Points on

which actual subscribers are directly connected through secondary SS. In this

type of architecture, if the configuration of a primary SS has to be modified

every time a new CB flow is activated at a secondary SS, the signalling load

between the primary BS and SS would possibly be overly important. Therefore,

it makes sense to limit the configuration load for primary SS by implementing a

semi-static configuration that is seldom modified, but can still support CB

traffic with good QoS, both in the command plane (by limiting the blocking

probability) and in the transfer plane (by ensuring that enough resources are

available for each non-blocked CB flow).


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If the network operator prefers to use only permanent connections, he has

to choose between reserving a large amount of resources (based on the busy

hour offered load of the target traffic) and then risk blocking other types of CB

traffic, or reserving a significantly smaller amount of resources for the target

traffic and then risk a performance degradation for this traffic. The mechanism

allows operating with a minimum amount of reserved resources when the actual

load is small, while seamlessly reserving the necessary amount of resources

when the actual load significantly increases. The cost in term of signalling can

be optimised together with the gain in reserved resources.

2.1.7. Protocol

The unused bandwidth should be initialized to a known state. Unused

bandwidth is calculated to utilize the unused bandwidth. Fig 1 describes the

format of RM. While the TS have the unused bandwidth, it should transmit

Releasing Message to CS. No agreed modulation occurred between TS and CS.

To maximize the probability of receiving of RM by CS, increase the

transmission coverage of the RM. BPSK has the largest coverage among all

modulations supported in the IEEE 802.16 standard. RM is transmitted via

BPSK without maximize the transmitted power of the TS. Fig 3 describes an

example of corresponding locations of TS, BS and CS. The coverage of

modulation is represented in the solid circle. If the unused bandwidth is used by

the TS then Stuff Byte Value (SBV). Broadcast Connection (B-CID) is attached

with the CL and transmitted first, then SBV is transmitted to distinguish the CL

from other broadcast DL transmission intervals. SBV is transmitted to inform

the BS that TS has no more data. To increase the coverage of the RM without

increasing the transmission power of the TS, the RM is transmitted by the TS

via dished circle that is BPSK .

HT=0 EC TYPE REV CI EKS RSV MSB


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Fig.1 Release Message Format

Frame i-1

ULMAP

Separation ComplementaryStation

TS1 TS2 ... TSk B-CID 0xFF CS1 CS2 ... CSk

Fig.2 Bandwidth Recycling

2.1.8. Scheduling Algorithm

Scheduling algorithm is described to schedule a SS with the highest

priority as the CS. The scheduling factor (SF) is defined as the ratio of the

current requested bandwidth (CR) to the current granted bandwidth (CG). Based

on the SF, the priority of each candidate is decided. Higher priority is given to

the SS when bandwidth demand is increased by the SS with higher SF. The SS

with zero CG has the highest priority. Because of the quality of service

LEN

LSB

CID

MSB

CID

LSB

HCS

ULSubframe

TransmissionInterval of

TS k

PossibleTransmissionperiod of CS k


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requirements, the highest priority is given to the non real time polling services,

then Best effort services.

3.PROBLEM DEFINITION AND FEASIBILITY ANALYSIS

3.1.PROBLEM DEFINITON

Important part in bringing out the network services lies in existingtechnology. Routing and switching are the main methods of delivering the data

through the network. Both have their disadvantages and benefits and there are

many variations of them applying in different ways to different situations.

Another big issue is the resource handling with QoS. In IP world, there are a

few proposals to resource handling problems and besides that there are a few

technologies providing different approaches to QoS problems. These include for

instance ATM and Gigabit Ethernet.

3.2.PROJECT OBJECTIVE

Routing and switching are the main methods of delivering the data

through the network.But, the issue is the resource handling with QoS.The

updated reserved bandwidth is applied as early as to the next coming frame and

there is no way to utilize the unused bandwidth in the current frame.

3.3.PROPOSED SYSTEM

Applications that intend to transmit large data are bandwidth demanding.

In order to provide Quality of service, each application reserves the bandwidth

from base station(BS). However, it is difficult for the subscriber station (SS) to

predict the amount of incoming data. To provide Qos SS may reserve more bandwidth than its demand. So, reserved bandwidth may not be fully utilized


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every time. Indeed a schema proposed termed as Bandwidth recycling.The idea

of the proposed scheme is to send recycled bandwidth to base station and allow

other SSs to utilize the unused bandwidth.

4.SYSTEM REQUIREMENTS

4.1.Hardware Requirements:

PROCESSOR : PENTIUM IV 2.6 GHz

RAM : 512 MB DD RAM

MONITOR : 15 COLOR

HARD DISK : 20 GB

FLOPPY DRIVE : 1.44 MB

CDDRIVE : LG 52X

KEYBOARD : STANDARD 102 KEYS

MOUSE : 3 BUTTONS

4.2.Software Requirements:Front End : Java, JFC (Swing)

Backend : MS-Access (Data Base)

Tools Used : Eclipse 3.3

Operating System: Windows XP/7


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5.SYSTEM DESIGN

5.1.MODULE DESCRIPTION:

5.1.1.Bandwidth reservation:

A Dynamic Resource Reservation scheme is introduced to reserve

bandwidth. Every subscriber station in network should reserves the bandwidth

in order to transfer the application by maintaining the quality of service. So,

each subscriber station should send request to base station as Bandwidth

request, base station allocate the bandwidth on priority bases to the subscriber

station.Dynamic reservation is to limit the cost of signalling and configuration

while adapting to varying levels of offered load for a single CB class of traffic.

WIMAX network is a WAN that collects the traffic from primary (WiMAX)

SS, while each primary SS directly connects one or several Access Points on

which actual subscribers are directly connected through secondary SS. In this

type of architecture, if the configuration of a primary SS has to be modifiedevery time a new CB flow is activated at a secondary SS, the signalling load

between the primary BS and SS would possibly be overly important. Therefore,

it makes sense to limit the configuration load for primary SS by implementing a

semi-static configuration that is seldom modified, but can still support CB

traffic with good QoS, both in the command plane (by limiting the blocking

probability) and in the transfer plane (by ensuring that enough resources

are available for each non-blocked CB flow).


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5.1.2.Bandwidth allocation:

For every subscriber station, base station will allocate the bandwidth on

priority based. So priority based scheduling algorithm introduce. Priority based

Scheduling algorithm is described to schedule a SS with the highest priority as

the CS. The scheduling factor (SF) is defined as the ratio of the current

requested bandwidth (CR) to the current granted bandwidth (CG). Based on the

SF, the priority of each candidate is decided. Higher priority is given to the SS

when bandwidth demand is increased by the SS with higher SF. The SS with

zero CG has the highest priority. Because of the quality of service requirements,the highest priority is given to the non real time polling services, then Best

effort services.

5.1.3. Packet creation and data transfer

Split data into n number of fixed size packets with maximum length of

48 characters. By splitting, data can be easily transmitted to great extent without interruption in network across the different nodes.

NODE 1 NODE 4

NODE 2

NODE 3

RREQ

RREP

RREQ

RREP

RREQ


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5.1.4. Bandwidth recycling module

Subscriber Stations scheduled on the uplink (UL) map should havetransmission opportunities in the current frame. Those SSs are called

transmission SSs (TSs). The main idea is to allow the BS to schedule a backup

SS for each TS. The backup SS is assigned to standby for any opportunities to

recycle the unused bandwidth of its corresponding TS. We call the backup SS as

the complementary station (CS).BRs are made in per-connection basis.

However, the BS allocates bandwidth in per-SS basis. It gives the SS flexibilityto allocate the granted bandwidth to each connection locally. Therefore, the

unused bandwidth is defined as the granted bandwidth which is still available

after serving all connections running on the SS. TS has unused bandwidth, it

should transmit a message, called releasing message (RM), to inform its

corresponding CS to recycle the unused bandwidth and transmit to base station .

Frame i-1

ULMAP

Separation ComplementaryStation

TS1 TS2 ... TSk B-CID 0xFF CS1 CS2 ... CSk

Fig 3 Bandwidth recycling

5.1.4. Qos Guaranteed service Module

ULSubframe

TransmissionInterval of

TS k

PossibleTransmissionperiod of CS k


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Reservation of bandwidth is done due to gain the Quality of service

.Quality of service is the ability to provide different priority to different

applications, users, or data flows, or to guarantee a certain level of performance

to a data flow.

6.SYSTEM DESIGN

6.1.CLASS DIAGRAM:


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6.2.SEQUENCE DIAGRAM


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6.3.USE CASE DIAGRAM:


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7.EXPERIMENTAL SNAP SHOTS

Some snap shorts of nodes to send data

NODE 1


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NODE2


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7.CONCLUSION

Variable bit rate applications generate data in variant rates. It is very

challenging for SSs to predict the amount of arriving data precisely. Although

the existing method allows the SS to adjust the reserved bandwidth via

bandwidth requests in each frame, it cannot avoid the risk of failing to satisfy

the QoS requirements. Moreover, the unused bandwidth occurs in the current

frame cannot be utilized by the existing bandwidth adjustment since the

adjusted amount of bandwidth can be applied as early as in the next coming

frame. We proposed bandwidth recycling to recycle the unused bandwidth once

it occurs. It allows the BS to schedule a complementary station for eachtransmission stations. Each complementary station monitors the entire UL

transmission interval of its corresponding TS and standby for any opportunities

to recycle the unused bandwidth .

8.FUTURE SCOPE

One of the factors causing recycling failures is that the CS does not have

data to transmit while receiving a RM. To alleviate this factor, A schema

propose to schedule SSs which have rejected BRs in the last frame because it

can ensure that the SS scheduled as CS has data to recycle the unused

bandwidth. This scheduling algorithm is called Rejected Bandwidth Requests

First Algorithm


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ragavendra (Repaired) - Copy.docx