performance measurements and analysis of quality of

Performance Measurements and Analysis of Quality of Service in WiMAX

Networks Using Network Simulator NS-2

1Jokhu Lal,

2Dr. Neeraj Tyagi

1Research Scholar CSED, MNNITAllahabad, India

Email: [email protected] 2Professor and Head of Department

CSED, MNNIT Allahabad, India

Email:[email protected]

Abstract

In recent years, there is tremendous growth in the field of wireless communication due to the

availability of portable low cost devices and demand for computation and communication while one is

on move and using number of applications supported by Broadband Wireless Access (BWA)

Networks. Among these networks IEEE802.16, also known by trade name as WiMAX support

different applications like, Voice over IP, Video and Audio streaming, data transport and web access

with Quality of Service (QoS) in mind. Due to slow progress of deployment of Wired Broadband

network (such as ADSL, Cable Modem, Fiber Optical Cable etc.) in rural area, this new technology is

spreading very fast everywhere due to cost effective alternative and ease of deployment.

Our work focuses on performance measurements and analyzing Quality of services for WiMAX

Networks using Network Simulator NS-2. We have used WiMAX module version 2.6 to simulate at

NS-2 to measure the performance for different types of traffic with parameters like throughput, delay,

jitter and packet loss which decide the Quality of Service. From analysis of these parameters for

different type of Services for WiMAX, we find that better results are obtained for those Service flows

which are designed for a particular application groups.

Keywords: WiMAX;QoS; BWA; UGS; OFDMA; NS-2.

1.Introduction In recent past, there has been exponential growth for use of communication network due to

availability of high speed core network and fast progress in access networks. In local loop there is

deployment of fiber optic links, coaxial cables and DSL. Now users have choice to use number of

multimedia applications such as VOIP, video and audio conference, video streaming, online gaming

and data communication on these high speed access networks, which are based on bandwidth and

delay constraints. Complementing and competing with these access network is Broadband wireless

access network which is used today everywhere for reliable, ease and cost effective Internet access.

The latest one such high speed technology is WiMAX network [1][2]. In rural and suburban part of

most of developing countries where DSL or cable based connection are not available, WiMAX may

be boon as it may be installed very rapidly at low cost investment for sparsely scattered residential

user. For small and medium enterprises also, WiMAX will provide a cost effective solution which are

using costly leased line based access. This may also be used as a complement solution like backhaul

to Wi-Fi hotspot, cellular, public safety and private networks. One such use case is shown in Figure 1.

The presence of different types of applications leads to heterogeneous type of traffic load. The main

problem with BWA network is to provide QoS for different applications at changing network

conditions as wireless link characteristic is changing with time and location. When a packet is

traversing from source to destination in WiMAX network, it experiences delay, jitter, packet loss and

out of order delivery.

International Journal of Pure and Applied MathematicsVolume 119 No. 12 2018, 12665-12677ISSN: 1314-3395 (on-line version)url: http://www.ijpam.euSpecial Issue ijpam.eu

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Figure 1: A WiMAX Network Application Scenario.

Considering these issues IEEE802.16 standard includes Quality of Service (QoS) mechanism at MAC

layer. Responsibility of MAC layer among other is to allocate bandwidth as required by different user

applications. It allocates bandwidth based on needs of applications and their QoS preferences. Large

number of applications supported by WiMAX network is grouped in five QoS classes. These services

can be initiated, changed or terminated by Dynamic Service Addition (DSA), Dynamic Service

Change (DSC) and Dynamic Service Deletion (DSD) command message. Both BS and SS can initiate

these message by a two or three- way handshake procedure. To start a service at SS, after detecting a

flow, it calculates whether resources are available or not. If available it sends a DSA message to BS.

On receiving of DSA from SS, BS checks whether request may be supported or not and sends a

response to SS. After getting response from BS, SS sends DSA acknowledgement to BS and new

service is initiated. We included WiMAX Module version 2.6 in Network Simulator NS-2 for

simulation and analyzing of different network scenario and load to measure different QoS parameters.

Throughput, delay, delay variation and packet loss parameters are considered. Simulations scenario is

taken for streaming of multimedia traffic and its effect on different QoS parameters are analyzed.

1.1 WiMAX Functioning Overview

WiMAX standard focused on Physical and MAC layer access due to changing wireless link

conditions and requirements of QoS for different applications. Other higher layer protocols are

generally common for all networks. WiMAX standard works in two modes for sharing medium [1],

[2], [15]. These are Point to Point (PMP) Mode and Mesh Mode. In Point to Point Mode, a Centralize

Base Station (BS) is controller of all communication within its cell and sectors. In communication

from BS to SSs it is broadcast, which is received by all Subscriber Stations (SSs). Transmission from

SSs to BS is directed to and coordinated by BS. In Mesh Mode each node communicates with other

up to BS in the way, thus it works on distributed manner. We are considering here Point to Point

Mode.

1.2 Physical Layer of WiMAX

WiMAX supports wireless MAN-SC, OFDM and OFDMA as physical layers for different

purpose. Wireless MAN-SC was designed for 10 to 60 GHz Spectrum in Line of Sight (LOS)

scenario. Due to very high frequency, these bands are being affected by rain, interference and

multipath effect, thus there are no products available in these frequencies.For Non Line of Sight

(NLOS) communication, WiMAX standardized OFDM PHY below 11GHz frequencies for fixed SSs

also known as IEEE802.16d. Here SSs use Time Division Multiple Access (TDMA) mode to share

media. In OFDM which is a multi-carrier transmission where several sub carriers are used for

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transmission and control of all sub carriers are given to a user at a time. Time slots are allotted to SS

for transmission. In case of mobile subscriber, numbers of users transmit simultaneously using

different sub carrier at same time slot. Thus scheduling is done to allocate sub carriers and time slot to

different users. OFDMA which is norms today for WiMAX PHY is combination of time and

frequency division multiple access.In wireless transmission, state of channel is changing over time, so

Adaptive Modulation and Coding scheme is used based on channel condition. Both MS and BS

estimate about channel condition based on downlink and uplink packets signal strength

respectivelyand finaldecision for most efficient modulation and coding scheme for transmission is

taken by BS.

1.3 MAC Layer of WiMAX

802.16 MAC is connection oriented. A connection which is unidirectionalis made, before

transmission of data.In WiMAX Standard, data transmissions are frame based and partitioned in

uplink and downlink subframe. Downlink transmission from BS to SS is broadcast in downlink sub

frame but only intended SS receives data. In uplink sub frame, SSs transmit data to BS in TDMA slot

assigned to it. Downlink and uplink sub frame are duplex in either FDD where downlink and uplink

sub frames are to be transmitted at same time on different frequencies or TDD where uplink sub frame

follows downlink sub frame at different time on same frequency[3]. At start of each downlink sub

frame, the BS broadcast UL and DL MAP as shown in Figure 2. In these maps there are information

about start and end time of grants of UL and DL sub frame for SSs.

Figure 2: WiMAX Downlink and Uplink Subframe for FDD and TDD.

On beginning of each downlink sub frame, BS sends a sequence of physical preambles to let

synchronize SSs. Also to synchronize with BS uplink scheduler each SS sends a physical preamble

before transmitting data. Service Data Unit (SDU) from upper layers is encapsulated in as Protocol

Data Unit (PDU) by MAC layer and a six byte header is included in MAC Protocol Data Unit

(MPDU). Here bandwidth is requested based on the queue size of a connection on connection basis,

but BS allocates grants on the base of SS. Thus SS scheduler distributed these grants among

connections based on various constraints.

Request for bandwidth may be either incremental basis or aggregate basis. On aggregate

basis, SS requests bandwidth based on whole backlog of the queue, but in case of incremental basis

SS calculate bandwidth request based on difference between current backlog of queue and one carried


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by last bandwidth request. Bandwidth may be requested by any one or mixed of following

mechanism: - unsolicited, unicast polling, broadcast/multicast polls and piggybacking.

There are number of network applications available and increasing continuously day by day.

These are grouped in QoS classes. There are five QoS classes as shown in Table 1:- Unsolicited Grant

Service (UGS), Real Time Polling Service (rtPS), Extended Real Time Polling Service (ertPS), Non

Real Time Polling Service (nrtPS) and Best Effort Service (BE).

Table1: Different QoS Services Classes with use case and QoS specifications in WiMAX system

UGS is used for real time applications with stringent on delay and delay variationswith CBR

type traffic at periodic interval are taken such as TI/EI and VOIP communication. Here grants are

periodic and base period and grants size are given at connection setup phase. SS connection with UGS

service then not request for bandwidth thereafter.

rtPS service class is less stringent on delay, it generates variable size real time application

packets at regular interval like MPEG video. BS provides unicast poll periodically which base period

is decided at connection setup. This period can be set to the interval at which application generate

SDU. When BS polled a SS, SS submit its bandwidth request based on its current queue backlog size

and BS allocate grant in next frame for transmission of data.

ertPS uses efficiency and features of both UGS and rtPS. To overcome delay constraints BS

allocate grants at regular interval in an unsolicited manner like used in UGS and thus save time of

bandwidth requesting. But like rtPS, allocations in ertPS are of variable size. For example, trafficlike

Voice over IP with silence suppression came in this category.

nrtPS and BE services are for application which have no specific delay requirements. The

nrtPS connections are given a minimum bandwidth with Minimum Reserved Traffic Rate (MRTR)

parameters. BS grants unicast polls to nrtPS connections for a large time-scale, which may be upto

one second. nrtPSconnections also use contention based bandwidth requests in response to BS

broadcast or multicast polls which are given in UL-MAP. Main drawback of this mechanism is that

when two or more SSs send bandwidth request in same contention slot, the collision occurred. A

bandwidth request is considered lost if there is not grant from BS in specific time (nearly 50 ms) [3].

BE connection use only contention based slot and piggybacking for bandwidth request as there is no

guaranteed service for this class.

To avoid collision in bandwidth request, SS randomly select a number in its back off window,

which gives the number of contention slots to which defer before sending. Thus this polling is used

for traffics which have no fixed delay constraints, such as bursty web access services. Also, an SS can

send unsolicited bandwidth request for non UGS backlogged connection by using part of grants issued


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for its data transmission. In another technique, incremental unsolicited bandwidth request may be

piggybacked with PDU by 2 bytes MAC sub header.

1.4 Band width Request and Grant Mechanism

In case of down link traffic, BS is the sole controller as it know all about of traffic such as queue

lengths and packet size to make the scheduling decisions. For uplink traffic, SSs send bandwidth

request to BS, which decide how many slots to grant in next uplink sub frame as shown in Figure 3.

Figure 3: Bandwidth Request and Grant Mechanism in WiMAX.

For BE and nrtPS connections, SS sends contention based band width request to BS when

there are backlogged queues on SS side. After receiving grants SS transmits packets to BS. It may be

possible that new packets come to backlogged queue in between. In that case SS can send incremental

bandwidth request by means of specific MAC header or by piggybacking the request with

transmitting connection PDU. A minimum number of contention slots or bandwidth minimum is

reserved in each uplink subframe for broadcast polls [10]. For rtPS connections there are unicast polls

on fixed interval. Polling period of each connection is equal to inter arrival time of SDU, i.e. for video

conferencing 33ms and for VOIP 20ms [3]. For nrtPS connections unicast polls may be set to 500ms

to 1 second [4].

2.Related Works

Different Authors have worked on QoS parameters in WiMAX network for different service

classes. Authors in [4] have investigated in details quality of service parameters for FDD, but

duerequirement of separate transmitter and receiver devices and extra hardware, cost of equipments

for FDD are high. Authors in [6] have simulated and analyzed by taking VOIP type traffic into

account for various QoS parameters, but their focus was for BE service class and its parameters.

Authors in [7] have simulated and analyzed for UGS and ertPS service classes for comparison of

performance of these two service classes. Authors in [8], havealso analyzed performance of only UGS

service class for different QoS parameters. Authors in [5] have simulated and analyzed QoS

parameters for BE, UGS and rtPS service classes only using VOIP and multimedia traffic but they did

not consider nrtPS service class. Authors in [9] have taken VOIP traffic with different codec to

analyze UGS, rtPS and BE service class only for different QoS parameters. Continuing our work [11]

we have measured and analyzed various QoS parameters such as throughput, packet loss, average


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delay and average jitter of different service classes for video traffic based on WiMAX module 2.6

integrated with NS-2.

3.Proposed work

With the help of QoS, Systems reliability and accuracy are measured. To measure QoS

quantitatively parameters like throughput, packet loss, delay and jitter or variation in delay of arrival

of consecutive packet are used. By taking a real time video streaming traffic simulation was done and

these parameters were measured and analyzed for different service classes.These parameters are

defined as follows:

3.1 Parametersfor Quality of Service Throughput: Numbers of Packets send per second or per time slot is known as throughput. It is rate

of data or packets transferred in unit time through a network. For calculation of throughput TP, in

Equation 1, PacketSizei is the packet size of ith packet which reached the destination node, PacketSt0

is the start time of first packet from the source node and Packetarrn is the last packet arrival time at

destination node.

TP=∑𝑖 PacketSize 𝑖

Packetarr 𝑛−PacketSt 0

Equation1: Calculation of Throughput

In above equation every transferred packet size is added to total transfer of data. Difference

between time of first packet starting time from source node and last packet arrival time at destination

node is calculated as total time.

Delay: Time taken by a packet to traverse from source node to destination node is known as delay or

latency. Delays in packets are due to: processing delay, transmission delay, propagation or traversal

delay, network or queuing delay. In equation 2 average delay is calculated as packetarri is time when

packet reaches destination node and PacketSti, is the time when packet “i” leaves the source node and

“n” is total number of packets.

Average Delay=∑𝑖 Packetarr 𝑖−PacketSt 𝑖

n

Equation2: Calculation of Average Delay or Latency

Jitter: Delay variation of two consecutive packets between source node and destination node is

known as jitter between packets. Jitter reveals the variation in latency in network due to congested

network, different route followed packets, queuing time at nodes followed by packets etc. Jitter

reveals stability and effectiveness of a network.In equation 3 show the steps to calculate average jitter.

It is the average of absolute difference in time it takes for consecutive packets to reach the destination

node.

AverageJitter =∑𝑖⃒ Packet arr𝑖𝑒 − Packet St𝑖𝑒𝑡 − (Packet arr𝑖 − Packet St𝑖)⃒

n − 1

Equation3: Calculation of Average Jitter


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Packet Loss: It revealed the perceived quality of applications. Packets losses are due to several

reasons such as error in bits, overflowing of buffers, congested networks etc.Packet loss is the ratioof

sum of all packets which are not reaching to destination node over the sum of packets which leaves

the source node and can be calculated as shown in equation 4.

𝑃𝑎𝑐𝑘𝑒𝑡𝐿𝑜𝑠𝑠 =∑ Lost Packet Size𝑖

∑Packet Size𝑗× 100

Equation4: Calculation of Packet Loss

3.2Details of Simulation WiMAX network was simulated with help of network simulator (NS-2) [13]. WiMAX

module patch release version 2.6 [14] was integrated with NS-2. In dynamic nature of networks

network simulator NS-2 have proved useful as it is simple event driven network simulator. It have

good support for simulation of TCP, routing protocols and multicasting protocols for wired and

wireless networks. Core of simulator is written in C++ and it uses OTcl script as interpreter.

Configuration of network and traffic agents etc is specified in TCL file. Different Simulation steps of

WiMAX on NS-2 are shown in Figure 4.

Figure 4: Simulation Steps of WiMAX Module on Network Simulator NS-2

For different network scenariosTCL Scripts were written and that was run on NS-2 which

produces trace files. To calculate throughput, packet losses, delay and jitter from these trace filesperl

scripts were used. Graphs are plotted using GNU Plot. The traffic is started after some time to allow

mobile node to complete registration as after simulation starts each node goes through basic

registration procedure to get associated with base station.

3.3 Results andAnalysis A real time scenario is considered to analyze QoS for WiMAX. As due to availability of wide

bandwidth, today streaming videos on Internet is a common phenomenon. We used video streaming

for analysis of different service classes.

Video traffic generated from different subscriber stations are set up. Video streaming falls in

Variable Bit Rate (VBR) type traffic, where packet size changed on the basis of frame type. For

example in case of MPEG traffic, „I‟ and „B‟ frames are smaller in size than a „P‟ frame, At the same

time for H.263 traffic there are „I‟ frames, „P‟ frames and „PB‟ frames. Due to simplicity in MPEG-4

video coding with enhanced compression performance and to provide a network friendly video


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representation, we have taken MPEG-4 data stream of high quality for simulation purpose. Over

Networks, video streams packets are transported.Transport protocol used for this purpose is Real-time

Transport Protocol (RTP).

To obtain VBR frame stream Mr. Bean movie with high quality MPEG-4 encoded was used

from the website in [12]. A trace file is generatedusing this file.This trace file is attached to the UDP

agent as a traffic source. The trace file which is in binary format contains information of time, frame

number, frame type and packet size etc. Analysis is done using BE, nrtPS, rtPS and UGS services

flows for the video traffic. The parameters for analysis are throughput, packet loss, delay and jitter.

These parameters are observed for each service flow by increasingnumber of nodes for video traffic.

Figure 5Show the variation of throughput for video traffic in case of increasing number of

nodes. In comparison of with BE and nrtPS service flows, rtPS and UGS service flows have higher

throughput.There is lowest throughput for BE service flow. If we compare UGS service flow with

other service flows, UGS have much higher throughput than BE and nrtPS service flow, and rtPS

service flow throughput was nearly equal to that of UGS for same number of nodes.

Figure 5: Throughput of video traffic for different service flows with increasing Number of Nodes.

As UGS grants are fixed on periodic basis in each round of scheduling and there is no packet

loss due to this it has high throughput. For rtPS, as BS polls each SS for grant of bandwidths in each

frame, and due to this number of control packets are being used, for this reason some packets get

loosed. In case of nrtPS polling interval are large and there is contention based request so there is no

guarantees of bandwidth allocation in each frame. For BE as there is no guaranteed service,

bandwidths are allotted only when there is remaining resource after serving three types of services.

Due to that there is lowest throughput for this service class.


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Figure 6: Packet loss of video traffic for different service flows with increasing Number of Nodes.

Figure6above showspacket loss for four service flows. In case of UGS service flow,there is constant

packet loss.The reason behind this is due to UGS bandwidth grant is fixed in each round on regular

interval, so packets are being sent in every round. For BE and nrtPS service flows packet loss increase

as the number of nodes increase. Value of packet loss is less if number of nodes is less for BE and

nrtPS service flow but it increases rapidly for increasing number of nodes.When numbers of nodes are

less, then adequate resources are available for nrtPS and BE service flows but on increasingnumber of

nodes there are chances for collisions of packets due to contention for requests of grant for resources

and thus more packet loss. For rtPS service flow there is slight variation in packet loss as number of

nodes increases and it is lowest amongall flows. This is due to the factthat each SS is polled by BS to

take request on regular interval and thus packets are sent on regular basis without collisions.

Figure 7: Average Delay of video traffic for different service flows with increasing Number of Nodes.

Figure 7 shows the average delay for four service flows on increasing number of nodes. UGS

service flow has higher delay but variation in delay is lessin comparisons to BE, nrtPS and rtPS flows.

Due to the fact thatgrants for UGS service flows are fixed on regular interval, but video traffic is of

VBR nature all packets are not sent on time for these flows. BE service flow got bandwidth allotted

only when there is any remaining resource available after serving all service flows. For BE service

flow average delay increases rapidly in comparison with rtPS service flowas number of nodes


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increases due to collision of packets as there is no guaranteed allocation of resources for these flows .

Although value of average delay is higherfor rtPS service flow than nrtPS service flow but variation

in delay is less than nrtPS service flow. The reason is that for rtPS bandwidths are allotted on regular

basis and for nrtPS, it is allotted on large polled interval as well as contention basis in which there is

collision of bandwidth request packets. As in case of BE service flow the value of delay increases in

nrtPS service flow also as number of nodes increases.

InFigure 8 below, it shows changes in average jitter for BE, nrtPS, rtPS and UGS service

flows with increasing number of nodes. From figure,it seems that there is no any relation with jitter

valueand number of nodes for UGS service flow. This is due to the fact that there is fixed allocation

for UGSservice flow and video traffic is a variable bit rate service and all packets are not being served

in fixed intervals thus delay variation in packets are not fixed. In case of rtPS service flowbandwidth

request is sent by each SS based on packets in queue requirement on fixed interval, so it has lowest

jitter among all service flows for maximum number of nodes and it is nearly constant.BE and nrtPS

service flows have lower jitter for small number of nodes, but it increases rapidly as number nodes

increases. This is due to the fact that at the time when bandwidth is available, video traffic for BE and

nrtPS service flows introduced least jitter, but on increasing the number of nodes, the network

resources are being distributed between all nodes, and thus results in increasing jitter for

these service flows. For rtPS service flows there is small changes in average jitter with the increasing

nodes due to guaranteed allocation of resources and it remains nearly constant for increasing numbers

of nodes.

Figure 8: Changes in average Jitter for all four service flows with increasing numbers of node for

video traffic.

4. Conclusion

The performance was analyzed for BE, nrtPS, rtPS, and UGS service flows with different

QoS parameters such as throughput, packet loss, delay and jitter and was compared for video traffic

which passed through WiMAX network with increasing number of nodes. When we consider packet

loss and average jitter, rtPS service flow is better than all three service flows. There is slight change in

variation in delay or jitter for rtPS service flow and it has least value when numbers of nodes are

being increased due to the fact that there are regular interval polling for rtPS service flow. For average

delay, value is high for rtPS than BE and nrtPS service flows, but there is slight variation in value as

number of nodes increases and in case of BE and nrtPS it increases rapidly due to non availability of

resources to these service classes and also due to collisions of packets. The delay is maximumfor UGS

service flow as it is of VBR type of traffic and allocations for UGS service flow are fixed in each

frame thus all packets are not being sent on regular interval. rtPS service flows show least packet loss

as number of nodes increases and throughput is much higher than BE and nrtPS service flows and is

equivalent to UGS flow for video traffic due to the fact of regular resource allocation at fixed

interval. From above it shows that rtPS service flow is best choice for streaming video traffic as in


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case of rtPS service flow bandwidth are periodically requested based on queue size which are not

fixed as in case of UGS service flow, where bandwidth are fixed on regular interval irrespective of

traffic which may be utilized or not .

References

[1].IEEE standard 802.16, “IEEE standard for Local andMetropolitan Area Networks, Part 16: Air interface forfixed Broadband Wireless Access Systems”, 2004. [2]. IEEE standard 802.16e, “IEEE Standard for Local and Metropolitan Area Networks, Part 16: Air interface for fixed and Mobile Broadband Wireless Access Systems”, 2005. *3+.C.Ciconetti, L.Lenzini and C.Ekluud, “ Quality of Service Support in IEEE 802.16 Network”, IEEE Networks, Volume 20, NO.2, 2006. *4+. C.Ciconetti, A.Erta, L.Lenzini and E.Mingozzi, “Performance Evaluation of the IEEE 802.16 MAC for QoS Support”, IEEE Transactions on Mobile Computing,Vol.6, No.1, January 2007. [5]. R.A. Talwalkar and M.Ilas, “Analysis of Quality of service (QoS) in WiMAX networks”, IEEE International Conference on Networking, 2008. [6]. D.Joshi and S.Jangale, “Analysis of VOIP traffic on WiMAX using NS2 Simulator”, International Journal of Advanced Research in Computer Science and Electronics Engineering, Vol.1, Issue2, April2012. *7+. I. Adhicandra, ‘Measuring data and VOIP traffic inWiMAX networks”, Journal of Telecommunications, Volume 2, Issue 1, p1-6, April 2010. [8]. M.Vikram and N. Gupta, “Performance Analysis of QoS Parameters for WiMAX Networks”, International Journal of Engineering and Innovative Technology, Vol.1 Issue 5,May 2012. *9+. Tarik Anouri and A. Haqiq, “Performance Analysis of VOIP Traffic in WiMAX using various service Classes”, International Journal of Computer Application (0975-8887), Volume 52, No.20, August2012. [10]. Jokhu Lal and Neeraj Tyagi, “Proposal of a CombinedDownlink and Uplink Scheduling Architecture for Mobile WiMAX”, International Conference on Recent Trends in Computer Scienceand Engineering Central UniversityBihar, Patna, February,2014. [11] Jokhu Lal and Neeraj Tyagi, “Performance Analysis ofQuality of Service for Different Service Classes inWiMAX Network”,International Conference on Recent Advances in Mathematics, Statistics and Coputer Science,Bihar, India, 29-31 May 2015. [12]. “MPEG-4 and H.263 Video Traces for Network Performance Evaluation”, (Master’s Thesis) Athamnoh K.http://trace.eas.asu.edu/TRACE/pics/FrameTrace/mp4/Verbose_bean.dat. [13]. The Network Simulator ns-2 http://www.isi.edu/nsnam/ns/ . [14].NIST, Seamless and Secure mobility, NS-2 NISTWiMAX Module, http://www.antd.nist.gov/seamlessandsecure,December,2009. [15]. C.So-In, Raj Jain and A.K. Tamini, “Scheduling in IEEE 802.16e Mobile WiMAX Networks: Key Issues and a Survey”, IEEE Journal on Selected areas incommunications, Vol.27,No.2, February 2009.

Authors Biography

Jokhu Lalobtained B.Tech degree from Institute of Engineering & Technology, Lucknow,

Lucknow University, India in 1994 and M.Tech from Motilal Nehru National Institute of

Technology (MNNIT) , Allahabad, India in 2004. Presently he is pursuing Ph.D from

MNNIT, Allahabad, India. In 2004 he joined as Lecturer Computer and promoted to Head

of Department Computer in 2013 in Department of Technical Education Government of

Uttar Pradesh (India). He is currently posted at Government Girls Polytechnic, Allahabad

(India).

His research interests include Broadband Wireless Networks, Quality of Service and

Scheduling in Wireless Networks.


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Dr. Neeraj Tyagi is Professor and Head of Department, Computer Science and

Engineering, Motilal Nehru National Institute of Technology (MNNIT, formerly known as

MNREC), Allahabad, India. Dr. Tyagi has completed his B.E., M.E. and PhD from

MNNIT Allahabad in Computer Science and Engineering. Dr. Tyagi has more than 25

years of teaching and research experience and also Industrial experience of working with

renowned companies like:-G.E (Capital) - U.S.A,Electronic Data Systems (now HP

Enterprise Services) - U.S.A,Warman International- Australia. His research interests

include Mobile Computing, Vehicular Ad Hoc Network, Wireless and Sensor Network,

Routing Protocol, Unix and Linux Network Administration.He is also a member of IEEE

Communication Society.


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performance measurements and analysis of quality of

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