Essay: DEPLOYING IPTV (MOBILE TV) OVER MOBILE WIMAX NETWORKS: A Comparative and Simulation Study

Recently, deployment IPTV or Mobile TV by telecommunication providers worldwide become major issues as well as be the intensive interest topics in research, is expected to be the key income generators in the future and the efficiency of video streaming over 4th generation technology. Several modulation schemes have been specified in IEEE 802.16e standard; namely, BPSK, QPSK, 16 QAM, 64 QAM, and AMC. In this chapter, comparative and simulation study of effecting of Mobile TV in Mobile WiMAX networks is discussed with sort of fixed and adaptive modulation and coding schemes while considering crucial system along with environment criteria such as different real-time video codec like MPEG-4, H.264/AVC, and SVC based on various factors including speed variation of mobile node, random mobility, path-loss, different classes of scheduling services under both adaptive and fixed types of modulations. Outcomes from this analysis study indicate that dynamic adaption modulation schemes along with higher modulation schemes can provide significantly more improved QoS as well as reduce the overall bandwidth of the system.
Introduction
Internet Protocol Television (IPTV) is a way of carrying digital video and audio contents via any IP-based broadband network, deployments IPTV services by telecommunication providers worldwide continuously increase, and also turns into a host of unique effective issues for telecommunications companies, cable TV, as well as satellite television carriers [35]. WiMAX technology is amongst to 4th generation technology which is reliable for providing high QoS at higher data rates for IP-based networks, which commercially introduced for supporting multimedia services like videoconference, gaming, and also Mobile TV transmitting that offers speed of mobility around 30 kmph in an urban and sub-urban environment [4, 5].
The International Telecommunication Union focus group on IPTV (ITU-T FG IPTV) described IPTV as multimedia services like television/ video/ audio/ text/ graphics/ data transferred through IP networks (which also often known as triple play) while providing the demanded degree of QoS along with user experience, safety and security, interactive features as well as reliability. Several kinds of service providers’ has been supported IPTV services that are vary from cable TV and satellite television carriers to the big landline providers as well as private network providers in various environments. IPTV offers a numerous range of abilities which includes [35]:
Interactive TV: The interactive implies two-way functionality of IPTV methods that allowing providers to convey an entire interactive TV portfolio programs, different sort of video streaming services transferred via an IPTV services involve regular live TV, interactive games, High Definition Television (HDTV) as well as high-speed broadband Internet.
Time-shifting: The time shifting is a process for capturing and holding IPTV contents for later on watching, and also digital video recorder has been combined in IPTV components which allows time shifting of programming content.
Personalization: an E2E IPTV system enables customers to customize their Television watching behaviors by permitting them to determine what they really want to observe then when they desire to watch it, and also provide bidirectional communications.
Low bandwidth requirements: Rather than providing each channel to each customer, IPTV systems allows providers to flow the channel that has been requested by the user, so that permits network services to protect networks bandwidth.
Multiple devices accessibility: Watching video streaming content is not restricted to TV displays. Customers usually utilize their personal computers and mobile handsets to reach IPTV services.
There are specific purposes that are sufficient to react to a straightforward matter specifically such as why we turn out planning to utilize 4G technology. Some certain characteristics of 4G which produce it an “above-all” technology [80] are: High performance: Consumers will certainly find it difficult to obtain features of abundant multimedia content across wireless networks with 3G. Instead of this, 4G will probably be recognized by incredibly expensive video quality exactly like HDTV. Interoperability and easy roaming: Several standards of 3G ensure it hard to move around and interoperate through different systems. However, 4G delivers a worldwide standard that delivers universal mobility. Fully converged services: In case a consumer desires to obtain the network from a number of different systems, devices, notebooks, or even PDAs, which is actually no fee to achieve this in 4G which provides smart connectivity and also adaptable for supporting streaming video, VoIP telephony, or even moving images, emailing, Internet browsing, online marketing, as well as location-based services via a varied number of devices which flexible for end user. Low cost: 4G techniques probably turned out to be much cheaper compared to 3G because of they can develop unique best existing networks, demanding neither providers to retool entirely nor service providers to buy expensive extra spectrum. Devices: user-friendly screen, 4G products are predicted to be much more visible and intuitive instead of today\’s text and menu based systems. Enhanced GPS Services: 4G model of GPS technology can allow consumers be practically found in a number of areas, along with finding persons. Scalability: It will be the majority of a challenging issue with the mobile networks. It means the ability to increase the number of consumers together with services. Crisis-Management applications: Natural disasters could possibly be subject to the whole communications commercial infrastructure is at the disarray. Repairing communications immediately are important for wideband wireless mobile communications Networks and also online video media services might be established for several hours rather than days or even weeks’ essential to the repair of wireline communications.
Mobile TV is a method that allows consumers to transfer and obtain TV application via IP-based cable or broadband wireless networks. Consumers may benefit from IPTV services at any place by using mobile handsets. Different types of mobile TV technology methods, particularly: mobile TV over IP which has been outlined during this research study, IPTV over a mobile device, cellular IPTV, internet IPTV. Definitely, with quick adaptation to the user’s demands, Mobile TV might be highly regarded later on. It is suitable for people who can view an IPTV service by numerous wireless networks with mobile handsets.
The performance evaluation of any new emerging technology with various applications is crucial to be able to understand and enhance the system to the preferred level. Emulation is an excellent fidelity type of the physical system that can be a great alternative for simulation. This chapter is going significantly beyond others which provides a comprehensive study of deploying IPTV (Mobile TV) over Mobile WiMAX, including insights into the characteristics and requirements of the new services (IPTV) needed to be supported in our networks. In this chapter, looking out to answer the following issues regarding a large-scale IPTV (Mobile TV) deployment. What exactly are the QoS requirements for the new service we will need to deploy it? Will certainly existing network support this new service and satisfy the standardized QoS requirements? This work is aimed at investigating the efficiency of IPTV (Mobile TV) in Mobile WiMAX networks under various types of adaptive and fixed modulation schemes using simulation software OPNET Modeler. OPNET Modeler presents an extensive progression of system models such as all the required parameters which should be included in the model technique for PHY and/or MAC layers. A set of simulation scenarios under OPNET has been designed for wireless communication. The investigate study together with outcomes provided during this chapter mainly focuses on using real-time audio/video movie which is coded by different video codec like MPEG-4. H.264/AVC, and SVC for modeling and simulation Mobile TV deployment over broadband wireless networks. This chapter is designed to develop a comparative study of efficiency for Mobile TV over Mobile WiMAX while considering mobile speeds, random mobility, and path-loss models under both adaptive and fixed types of modulation schemes as well as identifying factors affecting the efficiency of video streaming.
System Model
To investigate QoS in an IP-based network, it is necessary to analyze real-life cases. It is best and economical to establish a simulation type as close to reality as is possible on which analyzes and numerous model consideration could be carried out before deployment. The simulation set up should represent the actual deployment of IPTV over WiMAX Networks. According to the architecture of IPTV over Mobile WiMAX Networks which represented prior in Section 2.5, Figure 3.1 shows a common network topology of WiMAX architecture including line of sight (LOS) together with non-line of sight (NLOS) communication. This network demonstrated as realistic and employed as a case study only. Though, this work introduced during this chapter might be designed easily for bigger and general networks.
Figure ‎3.1: Case study of WiMAX with fixed and mobile phone [81]
Methodology
Figure 3.2 illustrates a flowchart of a methodology of six steps for an effective new services IPTV deployment. The first two steps are separate which enables them to be achieved in parallel before embarking on service assumption in Step 3. As demonstrated, both Step 4 together with Step 5 can be achieved in sequence. Step 1 and 2 have been explained earlier in Chapter 2 in Section 2.3 and Section 2.5 respectively. On the other hand, steps (3, 4, and 5) will be introduced in subsequent sections during this Chapter. The final step is pilot deployment which is the area for the technical engineers, assist and servicing group to obtain first-hand knowledge about IPTV systems and their behavior. Throughout the pilot deployment, the new IPTV devices and equipment are examined, installed, tuned, checked, handled, supervised, etc. The entire group ought to acquire satisfied with how IPTV operates, how it combines along with other traffic, the way to identify and troubleshoot possible problems.
Figure ‎3.2: Flowchart illustrating methodology steps
Case Study #1: Fixed Node
Simulation Model
This sub-section describes the simulation model which is used for investigating and analyzing effecting of Video on Demand (VoD) over Fixed WiMAX Networks. The simulation was achieved for evaluating the efficiency of VoD in Fixed WiMAX networks while considering various criteria including video codecs, path-loss models, and class’s services under fixed kinds of modulation techniques to evaluate and analyze the performance of the models. Initially, we consider the topology shown in Figure 3.3. In this topology, a video server transmitted the encoded video to the SS. It is supposed that there are n WiMAX cells (BS) connected to the video server via IP-based networks. An SS of each cell connects to the server and request the real-time video stream. It is assumed that each SS at different distances from along BS so that each BS allocates different modulation and coding for SS. For example QPSK ½ assign to SS in BS1, 16 QAM ¾ assign to SS in BS 2, and 64 QAM 2/3 assign to SS in BS n.
Figure ‎3.3. Topology of IPTV (VOD) over WiMAX
Figure 3.4 depicts network topology for our model which is about 7-Hexagonal celled WiMAX BS along with multiple SSs in the range of a BSs. As can be seen from Figure, the BSs are connected to the core network by an IP backbone. However, IP backbone is connected to the video server via server backbone, these represent the service provider network. Our model used only one SS from each BS-cell (mobile x_1). This node in each cell has been assigned to different modulation and coding scheme MCS depending on its distance from BS. For example, mobile 1_1 has QPSK ½ coding and etc. Table 3.1 outlines the common attributes has been used in this investigation.
Figure ‎3.4. OPNET Model of IPTV over Fixed WiMAX
Table ‎3.1: Network Configuration Details
Network Fixed WiMAX Network
Cell Radius 0.2 Km
No. of Base Stations 7
No. of Subscriber Stations 5
IP Backbone Model IP32_cloud
Video Server Model PPP_sever
Link Model (BS-Backbone) PPP_DS3
Link Model (Backbone-server Backbone) PPP_SONET_OC12
Physical Layer Model OFDM 5 MHz
Traffic Type of Services Streaming Video
Application Real Video streaming
Scheduling rtPS
Deploying video streaming in wireless networks faces more challenging task during transmission that is due to the high bandwidth required as well as the delay sensitive of real video compared with others application. Variable bit rate (VBR) video traffic models which precisely represent the characteristics and statistical properties of real-time video, emerged as an attractive alternative to overcome the disadvantages of CBR [82]. Therefore, a VBR video traces of 74 minutes Tokyo Olympics movie encoded by different codecs like MPEG-4 part 2, H.264/AVC, and H.264/SVC have been used in our simulation. This movie traces with different coding have been acquired from Arizona State [12] with [352*288] frame resolution, along with 30 frames per seconds (fps) as an encoding rate. Audio traces have been injected in this investigation work which is about 21.6 fps [43]. Video and audio traces in our simulation have been streamed separately in two independent video conferencing application [83]. The key parameters of this application configuration are the frame inter-arrival time and frame size. The incoming inter-arrival times are configured to the video and audio frame rates of 30 and 21.6.
Results and Discussion
We simulated 66 scenarios and results obtained are collected and summarized in three scenarios based on different video codecs, path loss models as well as various service classes.
Scenario 1: Different video codecs of video application
This sub-section shows the simulation results of three scenarios under this category. Each scenario used different video codec under several modulation scheme in each cell. Free space path-loss model along with rtPS service class have been considered and kept constant. This simulation is used to evaluate the performance parameters, namely: packet jitter, packet E2E delay, data drop, and throughput of the mobile node.
Figure 3.5(a) – (b) depicts average packet jitter along with average E2E delay under several fixed modulation schemes. For different coding, zero jitter indicates that video quality is best. As shown in Figure 3.5(a), average jitter of audio/video streaming is around zero for higher modulation scheme such as (16 QAM, and 64 QAM) whereas QPSK has a worse average jitter under AVC codec. Therefore, subscriber station using higher modulation schemes indicate that better video quality compared with lower modulation scheme (QPSK). It is also observed that video coded by SVC, and MPEG-4 has better average jitter compared with the AVC codec. Therefore, video codec by SVC is the best for deploying IPTV. Figure 3.5(b) depicts average E2E delay for several video codecs under fixed modulation schemes, as it can be seen that the average E2E delay of SVC, and MPEG-4 video codec produced lower packet E2E delay under fixed modulation and coding schemes.
Average Packet Delay Variation (Sec) Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Figure ‎3.5: (a) Average video jitter and (b) Average packet End-to-End delay
As shown in Figure 3.6(a), the average data drop is significantly higher when video coded by AVC codec. The effect of data drops naturally decreases the average WiMAX throughput as shown in Figure 3.6(b). From Figure 3.6(a), it is observed that the data dropped is very low for SVC video codec for all modulation and coding schemes. Whereas, the other different video codecs (AVC, and MPEG-4) have more data dropped. Figure 3.6(b), shows average WiMAX throughput of SS. As we can see, the average throughput for SS obtained video streaming coded by SVC codecs is higher compared with its data dropped as shown in Figure 3.6(a). Whereas, another codec has more throughput but also has more data dropped. According to the results as in Figures 3.6(a) – 3.6(b), it is observed that SVC codec is the best codec used to deploy IPTV over WiMAX, which has better performance (high throughput, low data dropped) under all modulation techniques compared with another video codec. In conclusion, transmitting SVC encoded videos over WiMAX networks is an effective solution for deploying IPTV.
Average Data Dropped (Packets/sec) Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Figure ‎3.6: (a) Average packet data dropped from SS node and (b) Average WiMAX throughput for SS node
Scenario 2: Mobile node with different path loss
Outcomes of more than twenty-eight scenarios have been presented in this sub-section, different performance parameters have been observed in each scenario under several fixed modulation schemes while considering various path-loss models. It is considered in this category keeping the video codec with SVC codec and scheduling service classes as rtPS.
Average Packet Delay Variation (Sec) Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Figure ‎3.7: (a) Average video jitter and (b) Average packet End-to-End delay
Fixed radius BS-cells networks had been considered for each path loss models because of outdoor to indoor and pedestrian path-loss model is designed for small and micro cell network. Fading and multi-path propagation have not been considered in the free space model. Thus, path-loss would be very nominal and the received signal-to-noise ratio (SINR) would be ideal as can be seen in Figure 3.7(a) -(b), which is shown that free space path loss has less packet jitter and also less E2E packet delay under different modulation and coding schemes except for the QPSK. Similarly, higher throughput for free space propagation model under various modulation schemes had been seen in Figure 3.8(b). At the same time, hilly terrain with high tree density have been considered in suburban fixed model which is implies very high path-loss due to scattering and multipath propagation. However, moderately flat terrain has been considered in vehicular model which be less than that of the suburban model. Higher packet drop has been observed from vehicular model when compared with the others as can be seen in Figure 3.8(a), which gives the lowest throughput compared with others except outdoor to indoor and pedestrian which is the lowest one as can be observed in Figure 3.8(b). As a results, free-space model has been the lowest which produced less reduction in SINR that leads to better throughput, lower packet jitter, lower packet E2E delay, and also lower packet data dropped under several MCS as shown in Figures 3.7, and 3.8.
Average Data Dropped (Packets/sec) Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Figure ‎3.8: (a) Average packet data dropped from SS node and (b) Average WiMAX throughput for SS node
Scenario 3: Mobile node with different classes
This sub-section demonstrates outcomes of 35 scenarios under this category where video codec and path loss kept constant, SVC video codec and free-space model respectively. Different performance metrics have been evaluated like packet jitter, E2E delay, packet drop as well as throughput for SS under different fixed modulation schemes while considering several service classes.
Average Packet Delay Variation (Sec) Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Figure ‎3.9: (a) Average video jitter and (b) Average packet End-to-End delay
It is known that UGS and ertPS were designed for supporting VoIP [84]. UGS is designed and used commonly for Constant Bit Rate (CBR) [85]. As observed from Figure 3.9(a) -(b), ertPS and UGS have more packet jitter delay and E2E delay. Similarly, Figure 3.10(a) shows UGS, and ertPS have more packet drop for all modulations and coding schemes that give less throughput as can be observed form Figure 3.10(b). Figures 3.9(a) – (b) depict packet jitter together with E2E delay under various classes’ of service. Thus, mobile users with rtPS, nrtPS, and BE obtain best performance under several modulation schemes which present same packet jitter, and packet E2E delay. Similarly, rtPS class provides greater throughput than other classes’ nrtPS, and BE as can be demonstrated from Figure 3.10(b). Besides, it has a lower packet dropped as can be seen in Figure 3.10(a), which meant that is designed for streaming Audio or Video.
Average Data Dropped (Packets/sec) Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Figure ‎3.10: (a) Average packet data dropped from SS node and (b) Average WiMAX throughput for SS node
Case Study # 2: Mobile Node
Simulation Model
Figure ‎3.11: Model of Mobile TV over WiMAX
The network topology for this case study network is given as in Figure 3.11 that is a snapshot of the OPNET simulation model, which is deployed with 7-Hexagonal celled IEEE 802.16 system using the OFDMA – TDD operating mode with 0.2 Km radius. The MSs were placed in the range of a BSs in circular distribution pattern; total bandwidth has been considered as 5 MHz, divided into 512 subcarriers.
The maximum BS transmission power is considered to be 5W with 15 dBi, which is evenly distributed among all sub-channels; meanwhile, the MS transmitted power is considered as 0.5W with -1 dBi. An ASN-GW gateway has been employed to connect server backbone with IP-backbone that is supported mobility in WiMAX network. Mobile station node (mobile 5_1) has been used with mobility trajectory indicated by white color around cells. The green bidirectional dotted lines represent the generic routing encapsulation (GRE) tunnels. Table 3.2 presents network parameters have been considered.
Table ‎3.2: Network Configuration Details
Network Mobile WiMAX Network
Cell Radius 0.2 Km
No. of Base Stations 7
No. of Subscriber Stations 5
IP Backbone Model IP32_cloud
Video Server Model PPP_server
Link Model (BS-Backbone) PPP_DS3
Link Model (Backbone-server Backbone) PPP_SONET_OC12
Physical Layer Model OFDM 5 MHz
Traffic Type of Services Streaming Video
Application Real Video streaming
Scheduling rtPS
Variable bit rate (VBR) video traces of 74 minutes Tokyo Olympics movie encoded by different codec: MPEG-4 part 2, H.264/AVC, and Scalable Video Coding (SVC) single layer have been employed in our simulation. This movie traces has been obtained from Arizona State [12] with CIF [352*288] frame resolution, and 16 (GoP) Group of Picture have been considered for each codec along with 30 (fps) frames per seconds. In addition 21.6 fps has been considered for audio stream, Video codecs characteristics parameters seen in Table 3.3.
Table ‎3.3: Video codecs traces characteristics
Parameters Tokyo Olympics Movie
Codec MPEG-4 Part 2 H.264 SVC H.264 AVC
Frame Compression Ratio 151.6 18.015 21.709
Minimum Frame Size (Bytes) 8 22 17
Maximum Frame Size (Bytes) 13992 58150 62269
Mean Frame Size (Bytes) 1003.01 8440 7004
Peak Frame Rate (Mbps) 3.36 13.956 14.945
Mean Frame Rates (Mbps) 0.24 2.0258 1.68
Frame Rate (frames/seconds) 30 30 30
Results and Discussion
Series of simulation scenarios were simulated and outcomes obtained are collected and summarized in different scenarios based on several keys parameters including MS with various speed, several path-loss models as well as several kinds of classes under various kinds of adaptive and fixed modulation schemes.
Scenario 1: Different video codecs of video application
This scenario shows the simulation results of series simulation scenarios under this category. Each scenario used different video codec under several modulation and coding schemes. A free-space model along with rtPS class have been considered and kept constant during this scenario. This simulation is used to evaluate the performance metrics including video jitter, E2E delay, and also MS WiMAX packet drop along with MS throughput.
Figure 3.12(a) – (b) depicts average video jitter along with average E2E delay under various adaptive and fixed modulation schemes. As in our knowledge, zero or around jitter indicate that good-quality. So, as shown in Figure 3.12(a), the average audio/video jitter is around zero for adaptive and high modulation schemes compared with QPSK, which has worse variation of jitter for AVC video codec. Hence, it is observed that SVC video codec, and MPEG-4 have a better average jitter compared with the AVC codec. Therefore, video coded by SVC is the best for deploying IPTV. Figure 3.12(b) demonstrates average End-to-End delay for various video codecs under adaptive and fixed modulation schemes, as can be observed that the average E2E delay of several video codecs give lower packet E2E delay when codec by SVC, and MPEG-4 that under several adaptive and fixed modulation and coding schemes.
Average Packet Delay Variation (Sec)
Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Average Data Dropped (Packets/sec)
Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(c) Modulation and Coding Scheme
(d)
Figure ‎3.12: (a) Average video jitter, (b) Average packet End-to-End delay, (c) Average packet data dropped for SS node and (d) Average WiMAX throughput for SS node
As shown in Figure 3.12(c), the average data drop is significantly higher when video coded by AVC codec. The effect of data drops naturally decreases the average WiMAX throughput as shown in Figure 3.12(d). From Figure 3.12(c), it is observed that the data dropped is very low for SVC video codec for all modulation and coding schemes. Whereas, the other different video codec (AVC, and MPEG-4) have more data dropped. Figure 3.12(d) shows the average WiMAX throughput of MS. As we can see, the average throughput for SVC is higher compared with its data dropped as shown in Figure 3.12(c). Whereas, another codecs have more throughput but also have more data dropped. According to the results as in Figures 3.12, it is observed that SVC codec is the best codec used to deploy IPTV over WiMAX, which has better performance (higher throughput, lower data dropped, and lower E2E delay with lower variation jitter delay) under all modulation techniques compared with the other video codecs. In conclusion, transmitting SVC encoded videos over WiMAX networks is an effective solution for deploying IPTV.
Scenario 2: Mobile node with different speeds
This scenario evaluated the effect of different speeds on the performance of Mobile TV under respect several adaptive and fixed modulation schemes obtainable in IEEE 802.16e. Average throughput, data drop, an end to end delay, and jitter for SVC video are evaluated under several modulation and coding schemes and presented effecting of speeds on the efficiency of Mobile TV. Free space model along with rtPS class are considered to be constant during simulation while mobile speed be as kmph.
Figure 3.13(a) depicts average jitter of Mobile TV under several speeds. As in author’s knowledge, video quality is best if the jitter is zero. Mobile users with adaptive modulation (AMC) or even higher modulation schemes obtain better jitter than others QPSK which approximately about 2.5753E-05 seconds under different mobile speeds as can be seen from Figure 3.13(a). Moreover, mobile user with adaptive or higher modulation schemes obtain lower E2E delay than others QPSK under several mobile speeds as can be seen in Figure 3.13(b).
Average Packet Delay Variation (Sec)
Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Average Data Dropped (Packets/sec)
Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(c) Modulation and Coding Scheme
(d)
Figure ‎3.13: (a) Average video jitter, (b) Average packet End-to-End delay, (c) Average packet data dropped for SS node and (d) Average WiMAX throughput for SS node
More mobile speed affects packet drop of MS. It will increase data drop when MS speed increases. Also, hand-off frequency increases when MS speed increases. Figure 3.13(c) presents average data drop which is significantly higher when MS travels with MS speed as much as 150 kmph. Naturally, increasing data drops decrease average throughput for that MS as can be shown in Figure 3.13(d). Mobile station with 16 QAM 3/4, 64 QAM ½, and 64 QAM 2/3 MCS obtain lower data drops under various speeds as can be observed from Figure 3.13(c). However, higher order modulation scheme is more sensible to SNR. On the other hand, MS faces different SINR while travelling through cell that is based on the distance from the BS as well as the propagation environment. While MS moves via cells, SNR decreases when distance increases from BS. So, higher order MCS gives more BLER than the lower order MCS for the same SNR value. Mobile users with adaptive modulation schemes (AMC) and higher order 64 QAM ¾ obtain more data drops than others with various speeds. Mobile users with higher order modulations (16 QAM ¾, 64 QAM ½, and 64 QAM 2/3) have better average throughput as can be observed from Figure 3.13(d). As a results, mobile users use modulations (64 QAM ½ and 16 QAM ¾) present better performance like high throughput with low data drop compared with other modulation techniques.
Scenario 3: Mobile node with random mobility
Average throughput, drop, an E2E delay, and jitter for SVC video are compared under various adaptive and fixed modulation schemes. Figure 3.14(d) depicts average throughput in MAC layer whereas Figure 3.14(c) presents average drop packet in PHY layer while considering different adaptive and fixed modulation schemes. This scenario investigated the effect of random mobility for Mobile TV under several AMC and fixed modulation schemes. However, free-space propagation model along with rtPS class are considered during simulation.
The average video jitter of Mobile TV for random mobility has been shown in Figure 3.14(a), as can be seen average video jitter is around zero under various adaptive and fixed modulation schemes unless QPSK ½ and 64 QAM ½, for that maybe the speed and the path in MS which is changed randomly was high and faraway from BS-cell. Figure 3.14(b) depicts average E2E delay of random mobility, as can be seen lower E2E packet delay has been observed for Mobile TV under adaptive modulation (AMC) and higher modulation schemes (16 QAM, 64 QAM) compared with QPSK unless in 64 QAM ½ and 16 QAM ½.
Average Packet Delay Variation (Sec)
Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Average Data Dropped (Packets/sec)
Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(c) Modulation and Coding Scheme
(d)
Figure ‎3.14: (a) Average video jitter, (b) Average packet End-to-End delay, (c) Average packet data dropped for SS node and (d) Average WiMAX throughput for SS node
As can be shown from Figure 3.14(c), the average data drop is significantly higher when MS moves randomly under different adaptive and fixed modulation schemes. Figure 3.14(c) depicts that data dropped is very low for QPSK modulation schemes and varies with random mobility of MS. For that, adaptive and higher modulation schemes have more data dropped. Thus, the QPSK and 16 QAM ½ have better average throughput when compared with others as can be observed in Figure 3.14(d). As a results obtained from Figures 3.14(c) – (d), it is observed that MS users have QPSK ¾ and 16 QAM ½ modulation schemes present better performance higher throughput together with lower data drops along with lower jitter as well as E2E delay while comparison with others.
Scenario 4: Mobile node with different path loss
This scenario evaluated the effecting of different path-loss model in the performance of Mobile TV under several adaptive and fixed modulation schemes. Average throughput, data drop, an E2E delay as well as video jitter for SVC video are evaluated when considering various adaptive and fixed modulation schemes, and also showed the appropriate path loss model which gives best performance for Mobile TV. Mobile users speed along with scheduling class are considered to be constant as 50 Kmph and rtPS.
Fixed radius (small) has been considered for all path loss models. Because of outdoor to indoor and pedestrian path-loss model has been designed for small and micro cell WiMAX network. In outdoor-2-indoor propagation model MS node faces more data drop when it moves faraway from BS, and also if higher modulation like 64-QAM needs SNR more decreases as well as more data drops obtain as can be observed from Figure 3.15(c). On the other hand, Figures 3.15(a)- (b) depict lower jitter along with lower E2E delay in outdoor-2-indoor model. According from results obtained from Figure 3.15, free space is the best propagation model for deploying Mobile TV, which obtain better performance under adaptive and fixed modulation schemes. MS node change its modulation frequently based on the SINR reduction with decreasing distance from BS which show higher throughput on adaptive modulation (AMC) as can be shown in Figure 3.15(d). Outdoor-2-indoor propagation model has more data drops that gives lowest throughput compared with others modulation schemes as can be observed from Figure 3.15(d).
Average Packet Delay Variation (Sec)
Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Average Data Droped (Packets/sec)
Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(c) Modulation and Coding Scheme
(d)
Figure ‎3.15: (a) Average video jitter, (b) Average packet End-to-End delay, (c) Average packet data dropped for SS node and (d) Average WiMAX throughput for SS node
Scenario 5: Mobile node with different classes
This scenario investigated the performance studies of Mobile TV under several adaptive and fixed modulation schemes when considering different service classes; path-loos model along with mobile speed are considered to be constant as free space and 50 kmph.
Average Packet Delay Variation (Sec)
Average Packet End-to-End Delay (Sec)
Modulation and Coding Scheme
(a) Modulation and Coding Scheme
(b)
Average Data Dropped (Packets/sec)
Average WiMAX Throughput (bits/Sec)
Modulation and Coding Scheme
(c) Modulation and Coding Scheme
(d)
Figure ‎3.16: (a) Average video jitter, (b) Average packet End-to-End delay, (c) Average packet data dropped for SS node and (d) Average WiMAX throughput for SS node
Because of UGS is designed for CBR [85] and our video traces is VBR. So, it is not considered in our simulation. The ertPS was designed to support real-time applications like VoIP service, so it has more video jitter and E2E delay as can be shown in Figure 3.16(a)- (b) when compared with others classes. Therefore from Figure 3.16, rtps classes’ gives higher throughput compared with other classes, nrtPS, and BE.
Summary
This chapter provides a comparative performance study of effecting key issues in Mobile TV while deploying in Mobile WiMAX network. These key issues including mobile speed, video codec, propagation models as well as service classes under different adaptive and fixed modulation schemes. This performance study has been conducted using OPNET simulator, and investigated in terms of jitter, E2E delay, throughput, and also data-dropped. Results obtained from simulation indicate that the SVC video codec is the appropriate codec for deploying IPTV which enhanced video quality. Moreover, adaptive modulation (AMC) and higher modulation schemes provide better performance.
Outcomes obtained from this simulation study present that free space model is the appropriate propagation model for deploying IPTV with respect of several speeds, however outdoor-2-indoor is the worst case which has highest packet drop rate. Furthermore, this investigation studies present that rtPS class is the most appropriate scheduling service for deploying IPTV in Mobile WiMAX networks. The limitations of this investigation study is the certain assumptions like transition power, antenna gain, carrier operating frequency and channel bandwidth.