SPRING 2013

ENSC 427: COMMUNICATION

NETWORKS PERFORMANCE ANALYSIS OF LTE VS. WiMAX

FINAL REPORT

http://www.sfu.ca/~srajara1/Index.html

Team #08

Ng Jackie 301056206 jna10@sfu.ca Zhu Wangyi 301159678 wangyiz@sfu.ca

Rajaratanam Sutharsan 200081017 srajara1@sfu.ca

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Contents ABSTRACT ...................................................................................................................................................................... 3

INTRODUCTION ............................................................................................................................................................. 3

BACKGROUND ............................................................................................................................................................... 4

WiMAX ...................................................................................................................................................................... 4

LTE ............................................................................................................................................................................. 5

3. NETWORK TOPOLOGY ............................................................................................................................................... 5

Server Subnet in Edmonton ...................................................................................................................................... 6

WiMAX Configuration for Client Subnet in Vancouver ............................................................................................. 7

LTE Configuration for Client Subnet in Vancouver .................................................................................................... 7

4. SCENARIOS ................................................................................................................................................................. 8

Set #1 – Video Streaming from Edmonton Server .................................................................................................... 8

Scenario #1 – Single Cell WiMAX HQ video streaming ............................................................................. 8

Scenario #2 – Single Cell LTE HQ Video Streaming ................................................................................... 9

Scenario #3 – Single Cell LTE HQ Video Streaming (same direction SS) ................................................... 9

Scenario #4 – Multi Cell WiMAX HQ Video streaming ........................................................................... 10

Scenario #5 – Multi Cell LTE HQ Video streaming .................................................................................. 11

Set #2 – Video Conferencing within Vancouver ...................................................................................................... 11

Scenario #6 –WiMAX Video Conferencing within 1 km ......................................................................... 12

Scenario #7 – WiMAX Video Conferencing beyond 1 km ...................................................................... 12

Scenario #8 – LTE Video Conferencing within 1 km ............................................................................... 13

Scenario #9 – LTE signal strength beyond 1 km ..................................................................................... 14

5. SIMULATION RESULTS ............................................................................................................................................. 15

Scenario #1 - Single Cell WiMAX HQ Video Streaming Results ............................................................................... 15

Scenario #2 Single Cell LTE HQ Video Streaming Results ........................................................................................ 16

Scenario #3 Single Cell LTE HQ Video Streaming Results (one direction) ............................................................... 17

Scenario #4 Multi Cell WiMAX HQ Video Streaming Results .................................................................................. 18

Scenario #5 Multi Cell LTE HQ Video Streaming Results ......................................................................................... 19

Scenario #6 and #7 WiMAX Video Conferencing Results ........................................................................................ 20

Scenario #8 and #9 LTE Video Conferencing Results............................................................................................... 21

6. DISCUSSION ............................................................................................................................................................. 22

Single Cell LTE Analysis - Scenario #2 vs. Scenario #3 ............................................................................................. 22

Single Cell WiMAX vs. Single Cell LTE ...................................................................................................................... 23

Multi Cell WiMAX vs. Multi Cell LTE ........................................................................................................................ 23

Video Conferencing Scenarios – Scenario #6 to Scenario #9 .................................................................................. 24

LTE Error in OPNET 16.0 .......................................................................................................................................... 25

WiMAX and LTE Comparisons ................................................................................................................................. 24

Difficulties ............................................................................................................................................................... 24

Future Work ............................................................................................................................................................ 26

CONCLUSION ............................................................................................................................................................... 26

REFERENCES ................................................................................................................................................................. 27

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ABSTRACT

The wide spread use of wireless devices and in particular smartphones has resulted

in the rapid rise for greater capacity and speed of existing network technologies. To

this end, LTE (Long Term Evolution) and WiMAX (Worldwide Interoperability for

Microwave Access) became the two leading technologies considered for adoption to

address this need. In the last two years, LTE has gained far greater support and

adoption in the industry thus leaving WiMAX future prospects limited. In our project

we intend to investigate the performance characteristics of both LTE and WiMAX.

We will utilize OPNET 16 to simulate various cases (mainly single/multiple mobile

stations and single/multiple base stations) and compare and contrast the latency,

throughput and other performance characteristics of each of the respective wireless

broadband technologies with the hope that the results we obtain clearly illustrate

one technologies’ superiority over the other.

INTRODUCTION

As technologies continue to advance at a dramatic rate, more functions that require

high speed internet are being used on mobile phones. In order to keep up with this

demand, new 4G wireless technologies are being implemented, with LTE and WiMAX

being the most popular ones. In our project, we will simulate a scenario in OPNET

16.0 where we have clients in Vancouver that stream high quality video from a

server in Edmonton. With this simulation, we will tabulate the results for mobile

clients using LTE and WiMAX and compare their results for Quality of Service (QoS).

We will compare their results based on the following QoS parameters:

Video packet loss

Delay

Throughput

Packet loss (dropped)

Signal to Noise Ratio (SNR)

With these results, we will compare the strengths and weakness of each technology.

We will then summarize if LTE or WiMAX will be more suitable at streaming online

movies.

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BACKGROUND

In this section, we will go over the background information of WiMAX and LTE and

how they are relevant technologies for us to investigate.

WiMAX

Due to the rapid growth of media consumption on mobile devices a new fast and

stable wireless technology was needed. WiMAX (Worldwide Interoperability for

Microwave Access) is a wireless communication technology emerging in the

competitive wireless communication market. First proposed in 2001, WiMAX is

approved as a wireless communication standard with its IEEE 802.16e-2005 standard

in December 2005. WiMAX is capable of achieving theoretical speeds of up to 75

Mbps and can cover distances of up to 50km. Due to its high data rate and large

coverage, WiMAX is capable of solving many cities “Last Mile Problem”. In addition,

WiMAX equipments are relatively low cost and energy efficient. Because of these

benefits, WiMAX is currently deployed in many countries around the world.

WiMAX utilizes Orthogonal Frequency Division Multiplexing (OFDM) air interfaces for

both downlink and uplink. By implementing OFDM, WiMAX is able to space the

orthogonal subcarriers tightly together and increase the efficiency of the data

transfer and maintain a high bandwidth. WiMAX occupies the 2-11 GHz range for

non line of sight and 10-66 GHz for line of sight with up to 20 MHz of bandwidth.

With the IEEE 802.16e-2005, WiMAX now supports mobile products, which further

increases its functionality in the wireless market. With this update, Mobile WiMAX is

considered as a technology capable of replacing gradually outdated cellular wireless

networks. Due to its large distance and low equipment costs, North American

telecommunication companies are implementing WiMAX as a backhaul to the rural

urban communities. Currently, WiMAX is used by 178 countries with over 10 million

subscribers around the world.

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LTE

LTE (Long Term Evolution) is a new wireless communication standard documented

and standardized by 3GPP in December 2008. First proposed by NTT DocoMo, LTE is

officially known as “document 3GPP Release 8.” LTE is capable of achieving

download speeds of 326.4 Mbps and uploading speeds of 86.4 Mbps.

Similar to WiMAX, LTE employs OFDM for downlink. However, LTE employs Single

Carrier Frequency Division Multiple Access (SC-FDMA) for uplink. SC-FDMA is a new

transmission scheme proposed by 3GPP that reduces the peak-to-average-power

ratio. By employing SC-FDMA, LTE users will be able to maintain highly efficient

signal transmission while reducing power usage on their mobile device thus

extending battery life.

Due to development by 3GPP, LTE implementation rapidly grew in the mobile

communication market. Even though it is standardized in Dec 2008, Swedish telecom

operator TeliaSonera deployed LTE in Stockholm, Sweden and Oslo, Norway in Dec

2009. However, LTE is not compatible with 2G and 3G network. Therefore, it requires

its own separate bandwidth.

In our project, because of licensing issues, we will be using LTE Advanced in place of

LTE. LTE Advanced is the next generation of LTE wireless technology. Officially

standardized in March 2011, LTE Advanced fully meets the original requirements for

4G.

3. NETWORK TOPOLOGY

In our project, we simulate clients in Vancouver trying to use WiMAX and LTE to

watch a High Quality (HQ) movie from a server located in Edmonton through the

cloud. In order to simulate the scenario, we create a server subnet in Edmonton and

a client subnet in Vancouver. The overview topology is shown in Figure 1.

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Figure 1: WiMAX and LTE Overview Topology

In order to be able to compare the two technologies fairly, the server subnet, the

wires, and the cloud will remain the same for all of our scenarios. The client subnet

will be adjusted to WiMAX and LTE configurations depending on the scenario.

Server Subnet in Edmonton

For the server subnet located in Edmonton, we have an Ethernet server connected to

a cloud through a DS3 router. As stated earlier, the server subnet in Edmonton will

remain the same for both the WiMAX and LTE client configurations in Vancouver.

The Ethernet server topology in OPNET is shown in Figure 2.

Figure 2: Server Subnet in Edmonton

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WiMAX Configuration for Client Subnet in Vancouver

For both the WiMAX and LTE Configuration, we have 3 clients in Vancouver that are

simulating the same HQ movie from Edmonton using the same tower. For WiMAX,

the Base Station (BS) is connected to 3 Subscriber Stations (SS) wirelessly within a

radius of 6 km. The WiMAX configuration in Vancouver is shown in Figure 3.

Figure 3: WiMAX Client Subnet in Vancouver

LTE Configuration for Client Subnet in Vancouver

Similar to the WiMAX configuration, the LTE configuration also have 3 clients that are

simulating the same HQ movie from a single tower. The ENodeB, is connected to 3

UE wirelessly within a radius of 6km. An EPC is connected in between the ENodeB

and the cloud. The LTE configuration in Vancouver is shown in Figure 4.

Figure 4: LTE Clirent Subnet in Vancouver

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4. SCENARIOS

In order to find out the strengths and weakness of WiMAX and LTE, we created 2 sets

of scenarios where we test the properties of the two technologies. Overall, we have

created 9 different scenarios to test the different aspects of the two technologies.

The scenario parameters are listed in the following subsections.

Set #1 – Video Streaming from Edmonton Server

In this set of Scenarios, we will use the topology stated in the Network Simulation

Section as the basis for testing. For each of the different scenarios, we will introduce

certain changes to the parameters that will be listed in detail in the following

Scenarios.

Scenario #1 – Single Cell WiMAX HQ video streaming

In order to find how range affects the delay and throughput for WiMAX, we create a

topology where 3 subscriber stations are wirelessly connected to a base tower from

different distances. The components arrangement is shown in Figure 5.

Figure 5: Scenario #1 - Single cell WiMAX Topology

The three Subscriber Stations are 2km, 4km and 6km away from the base tower.

With this arrangement, we will observe the impact that an incremental increase of

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2km will have on the performance of WiMAX. For this scenario, we expect the

Subscriber Station 6km away from the base station to have the highest delay and

lowest throughput.

Scenario #2 – Single Cell LTE HQ Video Streaming

Similar to Scenario #1, we create a topology where 3 UEs are wirelessly connected to

a ENodeB from different distances. The components arrangement is shown in Figure

#6.

Figure 6: Scenario #2 - Single cell LTE Topology

The 3 UE are 2km, 4km and 6km away from the ENodeB tower. For this scenario, we

also predict the UE 6km away from the base station to have the highest delay and

lowest throughput.

Scenario #3 – Single Cell LTE HQ Video Streaming (same direction SS)

Due to getting some unexpected results with our LTE model (we will go over the

details of the results in the Discussion section), we decided to run another Single Cell

LTE HQ Video Streaming scenario. The components are shown in Figure #7.

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Figure 7: Scenario #3 - Single cell LTE Topology (same direction SS)

Instead of having 1 SS in 1 direction away from the ENodeB tower, we decided to

have them all to the east of the tower. We again expect the furthest SS (6km away)

to have the greatest delay and lowest throughput.

Scenario #4 – Multi Cell WiMAX HQ Video streaming

After the single cell (single transmitting tower) experiments, we want to increase the

traffic in our simulations to test how the wireless transmission technology reacts to

more load. We decide to add 2 more BS with identical amount of users into the

Vancouver client subnet. All the BS are then directly connected to the cloud and the

HQ Movie server in Edmonton. The WiMAX multi cell topology is shown in Figure #8.

Figure 8: Scenario #4 - Multi cell WiMAX Topology

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Each BS will have a SS that are (from left to right) 2km, 4km and 6km away. For this

scenario, we expect each SS in this simulation to have higher delay and lower

throughput in the system due to the increased traffic in the scenario.

Scenario #5 – Multi Cell LTE HQ Video streaming

Similar to Scenario #5, we added 2 more EnodeB with a single UE. The new LTE

topology is shown in Figure #9.

Figure 9: Scenario #5 - Multi cell LTE Topology

The 3 UE have different distance from each EnodeB tower. Starting from the left, the

UE are 2km, 4km, 6km from their respective tower. The 3 EnodeB towers are all

directly connected to a single EPC. For this scenario, we predict a lower throughput

and a higher delay for all 3 UEs.

Set #2 – Video Conferencing within Vancouver

Due to getting unexpected results, we wanted to conduct further simulations with

the technologies in order to be able to get more concrete data on the two wireless

technologies. Instead of HQ video streaming, for Scenario #6 to Scenario #9 we will

focus on doing video conferencing within a small campus with the hope that the data

we obtain will give us a more accurate outlook of how the technology will perform

and ideas on how to improve our video streaming simulations.

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Scenario #6 –WiMAX Video Conferencing within 1 km

In order to test the effective range of the WiMAX base station, we created 2

scenarios in order to test the difference when two users are video conferencing

within the close proximity of a Base Station. Figure #10 illustrates the scenario where

the 2 video conferencing users are both within 1km of the cell tower.

Figure 10: Scenario #6 WiMAX Video Conferencing Topology

The red octagon in the topology outlines a 1km cell surrounding the base station. In

this scenario, we have 3 Subscriber Stations within the 1 km range of the base tower.

The SS (mobile_1_1) closest to the tower will be video conferencing with mobile_1_3.

Mobile_1_2 is just a control we inputted into this scenario and it should not receive

any signal or affect the two other SS. For this scenario, we expected a very high

throughput with very low delay.

Scenario #7 – WiMAX Video Conferencing beyond 1 km

For Scenario #7, instead of having SS3 within the 1 km range of the base tower, we

moved subscriber station (shown as mobile_1_3 in Figure 11) to approximately 2km

away from the BS (each square represents 0.5km in the figure). With this setup, we

should see a significant increase in the delay time and perhaps no throughput for

mobile_1_3. Mobile_1_1 AND Mobile_1_2 was not moved in order to provide a

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control that we can compare with Scenario #1 in case of errors. Figure #11 illustrates

our topology for Scenario #2. We expect significantly lower throughput and higher

delay for UE3 in this scenario.

Figure 11: Scenario #2 Topology

Scenario #8 – LTE Video Conferencing within 1 km

Similar to Scenario #6, we used a similar approach to test LTE. For Scenario #8, we

put 3 User Equipments within close distance of the EnodeB. In this arrangement, UE1

will be video conferencing with UE3. UE2 will be idle and should not interfere with

UE1 and UE3. In this scenario, we expect UE3 to receive a lot of throughput with

minimum delay. Figure 7 illustrates our topology for Scenario #3.

Figure 12: Scenario #3 Topology

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Scenario #9 – LTE signal strength beyond 1 km

Using an identical scenario topology as Scenario #8, we wanted to test the range of

LTE beyond 1 km. In order to test the LTE’s range beyond 1 km, we moved the UE3 to

2km away from the EnodeB tower (each square is 0.5km wide). In this setup, we

expect UE3 to have increased delay and decrease in its throughput. The topology is

shown in Figure #13.

Figure 13: Scenario #4 Topology

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5. SIMULATION RESULTS

In this section, we will show the simulation results from each scenario. We will also compare the results for similar scenarios to observe the similarities and differences between the technologies and how certain parameter affects the results.

Scenario #1 - Single Cell WiMAX HQ Video Streaming Results

For this scenario, we simulated for 5 minutes and we got results for the throughput and delay. Figure #14 (a-b) will show the results for the 2 parameters.

Figure 14(a) and 14(b): Scenario #1 throughput (left) and delay (right) for Single Cell WiMAX

From Figure 14(a) and Figure 14(b), we notice that the results all resemble the same shape. This shows that all 3 SS are all functioning similarly. However, the throughput for the SS2, 4km away from the BS, is lower than the 2km and 6km SS. To further surprise us, SS3 (6km away from the BS) has the lowest delay of all 3 SS. In our theory, we expect SS1 to have the lowest delay out of the 3 SS because of the distance the signal is required to travel. In order to further investigate this situation, we re-run this scenario and picked up the packet loss data as shown in Figure #15.

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Figure 15: Scenario #1 Packet Loss for Single Cell WiMAX

From Figure #15, we notice SS1, the closest SS, has the highest packet dropped rate

out of the 3 SS. We do not understand why SS1 will have more than double the

amount of packet loss compared to the further station, as the parameters for all 3 SS

are identical. Logically, the lesser amount distance the data packets need to travel,

the less likely there will be loss packets. Therefore, this data is not we expected as

well. However, considering there are nearly 1.4 million bits / second being

transferred, losing around 200 more packets / sec then the other SS is not too

significant.

Overall, Scenario #1 results are very different from what we expected. Since all 3

parameters are different from what we expected, we conclude that there might be

some parameter errors in our topology that might have caused this result.

Scenario #2 Single Cell LTE HQ Video Streaming Results

We also simulated this scenario for 5 minutes such that we can compare the results

with Scenario #1. For this scenario, we have simulated throughput (bits/sec) and

delay. The results are shown in Figure #16 (a) and Figure #16 (b).

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Figure 16 (a) and 16 (b): throughput (left) and delay (right) for Single Cell LTE

From Figure #16(a), we notice the closest UE, UE_1, has a different curve compared

to UE_2 and UE_3. UE_1 has a major drop in throughtput around the 3 min mark.

However, at the 3 min mark for Figure #16(b), we notice UE_1 has a significant drop

in delay. We feel that this substantial drop in delay might be caused by the sudden

drop in the amount of bits are going to UE_1 at around that time frame. However,

we are unsure of why such results are displayed as all 3 UEs used identical

parameters. However, for this scenario, we did not put the 3 UE in the same

direction. Thinking the position of the UE in regards to the direction of the EnodeB

might have an effect on the results, we proceed to Scenario #3 where the UEs are all

in the same direction of the EnodeB tower.

Again, the data is not what we expected. Especially the delay of all 3 UEs are in the

second ranges.

Scenario #3 Single Cell LTE HQ Video Streaming Results (one direction)

Simulating this scenario, we got the following results as shown in Figure #17.

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Figure 17 (a) and (b): throughput (left) and delay (right) for Single Cell LTE (one direction)

After putting the 3 UE in one direction of EnodeB tower, we noticed that the 3 UE

have very similar results. However, we are still noticing the trend where the closest

UE has the lowest throughput and the highest delay. Furthermore, the delay still

remains in the 16 – 18 second range which is substantially higher than we expected.

Scenario #4 Multi Cell WiMAX HQ Video Streaming Results

For this scenario, we encountered a bug (to be discussed in the discussion section)

and had to reduce the simulation time down to 3 minutes. Figure #18 (a) and (b)

shows the results we got from this scenario.

Figure 18(a) and (b): Throughput (left) and delay (right) for Mulit Cell WiMAX scenario

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Again, we notice that the WiMAX results don’t seem to be affected by distance. From

Figure 18(a), we notice that the furthest SS (ss9) has the highest throughput despite

it is the furthest away from its tower. We also notice that the throughput for ss1

(closest SS) is identical to the throughput for ss5 (4km away from BS). As for the

delay, ss1 and ss5 both have a slight drop in delay before the delay increased

substantially. However, ss9 appears to be unaffected. We again do not understand

what went wrong with the simulation as all the SS have the same parameter.

Scenario #5 Multi Cell LTE HQ Video Streaming Results

We also simulated this scenario for 3 minutes and we got the results shown in Figure

19(a) and (b).

Figure 19(a) and (b): Throughput (left) and delay (right) for Multi Cell LTE scenario

Surprisingly, our expectation matches the results we have generated. The

throughput of the UE closest to the EnodeB (UE_1) has the highest throughput, while

the UE furthest away from the EnodeB (UE_5) has the lowest throughput. Also, the

delay for UE_5 is also the highest of the 3 UEs. However, the delay for the LTE is still

higher than what we expected. With UE_5 requiring a astonishing 1min waiting time,

the LTE performance is still no where close to what we should expected.

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Scenario #6 and #7 WiMAX Video Conferencing Results

After running the simulation in Scenario #2, the results for delay and throughput

(bits/sec) are displayed in Figure 20 (a) and (b).

Figure 20(a) and 8(b): WiMAX delay (left) and throughput (right) beyond 1km

After moving mobile_1_3 4 times the distance away from the BS, we noticed that

there is a substantial increase in the delay in comparison to mobile_1_1 (0.5 km

away from the BS) and mobile_1_2 (1km away from the BS). From Figure 8(a), we

observe the delay is approximately 3.6 ms. This is nearly 2 times higher than the

second highest delay that is within 1 km of the base tower.

From Figure 8(b), we notice that the throughput of mobile_1_3 is nearly 0. In

contrast, both mobile_1_1 and mobile_1_2 have a very high bits/sec rate higher than

This is the first substantial evidence we have that distance does have an effect on the

throughput and delay of WiMAX.

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Scenario #8 and #9 LTE Video Conferencing Results

Figure 21(a) and 9(b): LTE delay (left) and throughput (right) beyond 1km

For both Figure 9(a) and Figure 9(b), we notice that all the User equipments have

identical delay and throughput (bits/sec). This result is not what we expected and it

shows that our topology or perhaps the LTE_adv module in OPNET 16.0 has some

issues that remain to be resolved. Since the 3 UEs are at different distance from

each other, there should be differences in the reception as distance should affect the

time it takes for the data to travel from one location to another. We will look into

this error further in later scenarios and the discussion section.

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6. DISCUSSION

In this section, we will go over the results and see the advantage and disadvantage of

each technology and find the overall superior wireless technology is -- if the results

are conclusive. We will also talk about the errors and interesting results that we have

noticed from our work with OPNET 16.0.

For easy viewing, we summarized the results of Set #1 into Table #1.

Scenario #1 Scenario #2 Scenario #3 Scenario #4 Scenario #5

Technology WiMAX LTE LTE WiMAX LTE

Cell Single Single Single Multi Multi

Number of BS / EnodeB

1 1 1 3 3

Number of SS / UE

3 3 3 3 3

Highest Throughput

(bits/sec) 1,300,000 800,000 675,000 1,400,000 32,000

Lowest Delay (sec)

0.17 11 16 0.17 21

Table 1: Summarized Data for Scenario #1 - Scenario #5

Single Cell LTE Analysis - Scenario #2 vs. Scenario #3

From Table 1, there is a big difference between the throughput and delay. Based on

our calculations, we notice that the throughput dropped by approximately 16% while

the delay increased by 45%. However, we have not changed the distances between

the 3 UEs to the EnodeB. We have only changed the UE’s direction in reference to

the EnodeB. Although the 2 parameters are lower, all 3 UEs are working similarly to

each other. Therefore, we will use Scenario #3 as our example to compare to other

technologies. We also can conclude that the direction of the UE in reference to the

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EnodeB does have an impact on the performance of LTE; however, we are unsure of

the exact amount of changes it has towards the UEs performance.

Single Cell WiMAX vs. Single Cell LTE

Assuming the LTE module is working fine, by comparing the results from Scenario #1

and Scenario #3, we can see that WiMAX is the superior technology. By some quick

calculations, we notice that WiMAX has 190% more throughput in the same amount

of time. Considering that we are using LTE_adv in place of LTE to compare with

WiMAX, this amount is very substantial and shows that WiMAX is by far the faster of

the 2 technologies. The delay data also supports WiMAX is the superior technology.

By comparing Scenario #1 and Scenario #3 data, LTE has 94 times higher delay than

WiMAX. In conclusion, based on our simulations, we are led to conclude that WiMAX

is the superior technology versus LTE.

Multi Cell WiMAX vs. Multi Cell LTE

Out of all the LTE scenarios we ran in this project, only the Multi Cell LTE gave us

results that are similar to what we have expected. However, LTE still had a very low

throughput and a very high delay that we were unable to explain.

Despite adding more towers to reduce the amount of traffic through 1 tower, we

didn’t see any specific improvements for both WiMAX and LTE. Instead, we see a

decrease in throughput and increase in delay when comparing Multi Cell LTE to

Single Cell LTE.

Similar to the Single Cell, WiMAX’s data again provided better simulations results.

WiMAX’s throughput is higher than LTE by 43.75 times and LTE’s delay is 123.53

times higher than the WiMAX’s delay. Again, we are unsure of why LTE’s delay and

throughput are so low. One theory that we discussed was because the LTE signals

have to transfer through an extra component, the EPC, thus slowing down the signal

process.

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Video Conferencing Scenarios – Scenario #6 to Scenario #9

Due to the unsatisfactory results we get for our LTE scenarios in set #1, we decided

to create Video Conferencing Scenarios. From these scenarios, we can prove that

when the SS is further away from the BS, the throughput drops while the delay

increases. However, since we ran into more LTE problems with these Scenarios, we

are unable to fully compare the results between the WiMAX and LTE technologies.

We tabulated the data from Scenario #6 – Scenario #9 in Table 2.

Scenario #6 Scenario #7 Scenario #8 Scenario #9

Technology WiMAX WiMAX LTE LTE

Throughput (bits/sec)

200,000 0 650,000 650,000

Delay (sec) 0.0014 0.0036 16.5 16.5

Table 2: Summarized Data for Scenario #6 - Scenario #9

The data from Table 2 shows some interesting results. From our video streaming

scenarios, all the delay results for WiMAX are better than LTE. However, the LTE has

a much higher throughput (3.25 time higher) than the throughput of WiMAX. This is

what we expected based on our research. However, WiMAX performed much better

in the delay results we obtained from our simulations.

WiMAX and LTE Comparisons

Due to the underperforming LTE results, our simulations show that WiMAX is a

superior technology to LTE. However, through our research, the difference between

the two technologies should not be that significant.

Difficulties

We faced 3 major difficulties when working on our project. The 3 problems are: LTE

module problems, inconsistent results and student account running out of memory.

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LTE Error in OPNET 16.0

Unfortunately, based on the results we obtained we are led to suspect that the LTE

module in OPNET 16.0 seemed to be not functioning properly. Through a series of

scenarios and tests, we noticed that distance between the UE and ENodeB didn't

affect the delay and throughput. This is a problem we have discussed numerous

times with our TA and other groups and were unable to find any solution to resolve

the issue. In order to further test this problem, we did create a scenario where we

moved a UE 40 km away from the EnodeB. In the end, the results were the same as

Scenario #8 and #9, where the UE are only 0.5km and 2km away from the tower.

Inconsistent Results

During our simulations, we notice that when we re-simulate the same topology. The

data we receive can be different from the last simulation. Even though we did not

change any of the parameters in the scenarios, we noticed the results are different.

A good example would be Scenario #2. The 3 UEs can have a different simulation

result each time when we simulate. We are unsure of the problem but we assume it

is a parameter issue. Later on when we standardized more parameters, the

occurrences of these inconsistent results dropped and were able to successfully

complete our project.

Account out of Memory

We also ran into memory issues when simulating our project. Before we begin

Scenario #4 and Scenario #5, we tried simulating scenarios where there are 3

BS/EnodeB with 3 SS/UE each. These simulations created large files (in excess of

300MB - 700MB each) in our student directory and filled up the memory. This led to

instability in the computers we used and resulted in OPNET crashing. When we

attempted to re-login we were unable to login to our account. Later on, we asked Mr.

Chow to increase the memory of our account and delete a few files and we are able

to login normally again. From then on, we limited the size of our topology to avoid

having the same issues again.

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Future Work

Since LTE and WiMAX are still relatively new and developing technologies, there are

many opportunities to test these technologies. We hope to better understand the

causes of the unexpected results and find ways to resolve them.

Furthermore, we can increase the scope of our project by increasing the number of

users utilised per simulation to see how the two technologies react to more stress

and traffic in the network. We also wish to work on more simulations that are more

mobile related as that is the trend of recent technology development.

CONCLUSION

Overall, we set out 2 goals for this project: to observe how distance affect WiMAX

and LTE and how LTE and WiMAX compare to each other. We completed our first

goal and have noticed that at further distances, both technologies tend to perform at

degraded performance levels. However, due to the unexpected results obtained

leading us to suspect faults in the LTE module, we are unable to find a conclusive

answer to which technology performs better.

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REFERENCES

[1] M. Torad, A.E. Qassas and H.A. Henawi, "Comparison between LTE and WiMAX based on System Level

Simulation Using OPNET modeler", 28th National Radio Science Conference, Apr. 2011, pp 1-9. [Online] Available:

IEEE Xplore, http://ieeexplore.ieee.org/Xplore/guesthome.jsp [Accessed: 16 Feb. 2013].

[2] A. Checko, L. Ellegaard, and M. Berger, Capacity planning for Carrier Ethernet LTE backhaul networks, Wireless

Communications and Networking Conference (WCNC), University of Denmark, April 2012, pp 2741-2745. [Online]

Available: IEEE Xplore, http://ieeexplore.ieee.org/Xplore/guesthome.jsp [Accessed: 15 Feb. 2013].

[3] L. Chen, W. Chen, B. Wang, X. Zhang, H. Chen and D. Yang, "System-Level Simulation Methodology and Platform

for Mobile Cellular Systems", IEEE Communications Magazine, 2011, pp148-155, Vol 49 Issue 7. [Online] Available:

IEEE Xplore, http://ieeexplore.ieee.org/Xplore/guesthome.jsp [Accessed: 16 Feb. 2013].

[4] A. Zakrzewska, M. S. Berger, and S. Ruepp, Modeling Multistandard Wireless Networks in

OPNETÓ ,OPNETWORK, Technical University of Denmark, 2011, pp 1-5. [Online] Available: Technical University of

Denmark, http://www.dtu.dk/English/Service/ [Accessed: 15 Feb. 2013].

[5] Z.Abichar, J. M. Chang, and C. Y. Hsu, WiMAX vs. LTE: Who Will Lead the Broadband Mobile Internet?Ó , IT

Professional, 2010, pp 26-32,Vol 12 Issue 3. [Online] Available: IEEE Xplore,

http://ieeexplore.ieee.org/Xplore/guesthome.jsp [Accessed: 16 Feb. 2013].

[6] K.Alutaibi, Lj. Trajkovic, “Performance Analysis of VoIP Codecs over Wi-Fi and WiMAX Networks”, OPNETWORK

2012, Washington, DC, Aug. 2012. [Online] Available:

http://www2.ensc.sfu.ca/~ljilja/papers/OPNETWORK2012_final_final.pdf [Accessed: 5 Mar. 2013]

[7] R.Gill, T.Farah, and Lj. Trajkovic, “Comparison of WiMAX and ADSL performances when steraming audio and

video content”, OPNETWORK 2011, Washignton, DC, Aug 2011. [Online] Available:

http://www2.ensc.sfu.ca/~ljilja/papers/Opnetwork2011_farah_gill_final.pdf [Accessed: 5 Mar 2013]