Objective Function Design For
  Video Stream call management
in 3G Mobile Wireless Networks

Project report submitted to t...
Supervisors Signature Page

                         UNIVERSITY OF ALBERTA

        DEPARTMENT OF ELECTRICAL AND COMPUTER ...
Dedicated to

My father Azmat Ullah Bhatti, mother Shamim, wife
Zarqa, children Asad, Daniyal and my Brothers &
Sisters


...
Abstract

       The commercialization of mobile wireless networks has increased significantly
in recent times. It is prim...
Table of Contents
Abstract       ……………………………..…………………………………… i

Table of Contents         ………………..……………………………….…… ii

List...
3.5.5.     Reservation Scheme……………………………….….…. 31
              3.5.6.     Linear Weighting Scheme………………………....….… 31
    ...
B.2.1   Dedicated Physical Channels   …………. 67
Appendix C:   Project Code …………………………………….………….…… 70




                  ...
List of Abbreviations

3GPP       Third Generation Partnership Project
AMPS       Advanced Mobile Phone Service
BER       ...
PL       Path Loss
RNC      Radio Network Controller
RNS      Radio Network Subsystem
RRM      Radio Resource Management
S...
List of Figures


Figure 2.1: Field created by a charged body.

Figure 2.2: Changing electric field due to moving negative...
List of Tables

Table 2.1: Organizations Submitting Proposals for IMT-2000 System.




                                   ...
List of Symbols

ηAD             Threshold Value of Inter-Packet Delay.

ρ               System Workload

C               ...
Vi              Traffic Volume of Video Clip i.
W               System Bandwidth
Z               Effective Throughput
PAi ...
Acknowledgements

     I take this opportunity to express thanks to my supervisors Dr. Marinal Mandal
and Dr. Ehab Elmalla...
Chapter 1

Introduction

      This chapter presents an overview of our project work. It starts with mentioning
the import...
In this project, we have designed an objective function that will demonstrate the
effectiveness of cost functions. At any ...
along with the currently adopted packet scheduling, power and rate control schemes.
Chapters 4 cover these aspects in prec...
Chapter 2


Introduction to Mobile Wireless
Networks

     The importance of mobile phones has increased phenomenally in r...
(AMPS, 800 MHz) was offered in 1947 in St. Louis, Missouri using a single
transmitter for a large area. However due to F.C...
development of first decoder called Colossus, which was developed to break German
codes. It was a slow machine taking abou...
such as UPS, use single channel system model called ESMR (Enhanced Specialized
Mobile Radio).

2.3. 3G Mobile Wireless Net...
single band for each user, instead of having a unique band for each user as in the past,
made W-CDMA an attractive technol...
The joint efforts of several standard regional organizations towards
standardizing IMT-2000 resulted in two partnership pr...
demands an additional 187 MHz of frequency spectrum. It has been forecasted that
such addition will be enough to fulfil th...
UTRA development is heavily influenced by the GSM and GPRS networks, and
the architecture mainly composed of two parts: UT...
2.5. Importance of Power Control in UTRA

      The base stations in a cell have fixed power budget, The combined transmit...
The CLPC is used both for Uplink (UL) and Downlink (DL) using TPC
commands that are transmitted in the format shown in Fig...
2.7. Summary

     This chapter provides a brief introduction to the wireless networking
technology. It starts by presenti...
Chapter 3
Video            Transmission                       Over           Wireless
Networks
      People’s dependence o...
following shows the bandwidth requirements, if we want to send a full and reduced
colour depth video over wireless link.

...
3.2   Digital Video Coding Standards

      A video is a collection of frames and each frame represents an image. Video
co...
•    MPEG-1: The main focus is to store full motion video in CD-ROMs. It can
     support data rates requirements up to ma...
•     H.261: The standard was developed for video conferencing over ISDN lines,
      supporting data rates, which are mul...
3.3. Video Streaming in Mobile Wireless Networks

     Our work in this report is on facing the challenge and designing an...
The design of IP networks was primarily aimed at providing delay insensitive
services like web browsing and emails, wherea...
1.   Conversational Class

     a.    For highly delay sensitive applications: video, VoIP (Voice Over IP).
     b.    Exa...
The focus of our work is Streaming Class and aimed in particular to video
streaming service in 3G mobile wireless networks...
o     Capacity allocation to large number of mobile users. Low bit rates are
            allocated for each service.

    ...
Round Robin

     o   Classified packets sent to respective queues (0 to N-1), and get served in
         the same order. ...
Weight Fair Queuing (WFQ, WF2Q, WF2Q+)

     o    Delivery packet gets selected from a set of eligible packets using
     ...
Wireless Fair Service Algorithm (WFS)

              It is an enhanced version of WFQ, in which each flow is allocated two...
3.5. Call Admission Control Methods in Mobile Wireless
     Networks
     Call Admission Control (CAC) is defined as a sys...
particular user, thus indicating a bad CAC scheme. Since a call drop will occur
     for such user.

     Here is the list...
Here Kj represents effective bandwidth of users of class j.

    Zhao, Shen, and Mark, [17] used packet delay upper bounds...
3.5.4 Transmitted and Received Power based CAC:

        Knutsson [21] proposed a scheme in which a new call is admitted a...
3.5.7 Distributed Admission Control Scheme (DACS)

        This scheme considers the number of active calls in the origina...
Accepting a new call in a particular cell, also involves neighboring base stations
in the decision making process. After i...
requirements, connection time and a unique Cutoff Threshold value. This scheme
employs finite buffering for handoff and ne...
3.6. Summary

     This chapter focuses on the problem of transmitting video in a mobile wireless
environment. We started ...
Chapter 4

Video             Streaming                    Service                 in         3G
W-CDMA Network
      In pr...
Case #1:       Mobile users with varying mobility are requesting only video
               streaming service of fixed dura...
Operation B: Video stream data files reaching the gateway in packetized form. The
stream file is of known volume and data ...
The gateway receives the incoming data and after performing operation C the
packets get transmitted to their respective de...
If there are no packet delay violations then we can calculate the Total Delivered
Traffic after each completion as,

     ...
where,


     FA = Cost generated by active Service_Level_A users
             NA                 NA                    ...
4.4         Implementation
      Let us expand the insight of the key aspects of our system model, and how we
have impleme...
Step #1:   The first step is to simulate users profile in a 3G mobile wireless cell. This
           will include users mo...
Step #4:   Calculate and Plot Statistics for Z vs. workload (ρ) and Cf, Z and ρ.

           Following are some the remark...
4.4.2 Calculation of Path Loss and SIR.
          We use the log-normal shadow fading model to calculate Path Loss
    (eq...
4.4.3    Packets Scheduling

        Fig. 4.2 shows our scheduling policy, each user requesting a high or low
        prio...
4.6 Summary
     This chapter presents the accomplished project work. It starts by first describing
our project goals. The...
Chapter 5
Conclusions And Future Directions


      Our project work of designing an objective function for 3G UMTS/W-CDMA...
Further research is required to test our approach for several scheduling and call
admission control schemes. So that it ca...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
Objective Function Design For Video Stream call management in ...
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  1. 1. Objective Function Design For Video Stream call management in 3G Mobile Wireless Networks Project report submitted to the department of Electrical and Computer Engineering as partial requirement for M. Eng (Master of Engineering) degree. Submitted By: Raza Ahmad Bhatti On April 23, 2003
  2. 2. Supervisors Signature Page UNIVERSITY OF ALBERTA DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING THE UNDERSIGNED CERTIFY THAT THEY HAVE READ, AND ACCEPT THE DOCUMENT ENTITLED "Objective Function Design for Video Stream Call Management in 3G Mobile Wireless Networks ", SUBMITTED BY: RAZA AHMAD BHATTI IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING. ____________________________ _____________________________ (Dr. Mrinal Mandal) (Dr. Ehab Elmallah) Department of Electrical and Computer Department of Computer Science, Engineering, University of Alberta. University of Alberta. _____________________________ ( ) Department of Electrical and Computer Engineering, University of Alberta. Date:
  3. 3. Dedicated to My father Azmat Ullah Bhatti, mother Shamim, wife Zarqa, children Asad, Daniyal and my Brothers & Sisters for their continuous love, prays and support to encourage me to fulfill my dreams to learn and be creative Also Dedicated to Personalities who have worked and those who are working towards making our globe a better place to live
  4. 4. Abstract The commercialization of mobile wireless networks has increased significantly in recent times. It is primarily due to the ease of access to critical users services in voice and data, and this includes Internet browsing, email, online banking, video streaming and e-fax. Due to the increasing demand of mobile phones, it is becoming critical to keep the users satisfied with the QoS of a mobile network at an affordable cost. Hence an efficient and profitable Scheduling and Call Admission Control (CAC) scheme is crucial for a mobile wireless network. In this research we have considered developing an Objective Function that will output the effectiveness of a Cost Function in comparison to a given QoS for mobile users. Hence at any given time instance it can easily be deduced that if certain QoS, Scheduling and Call Admission Control (CAC) schemes are profitable for the service provider. This information will be of great benefit for the service provider in order not to keep the users happy up to a level where it starts costing service provider. At that point the service provider has to take decision on which user(s) to pick for either degrading the QoS or disconnecting the service based on service contract. The users willing to pay more for guaranteed QoS will remain at the same QoS. On the other hand, the CAC will induce new users wanting guaranteed QoS at the cost of degrading or disconnecting service of users according to the service contract. Which basically indicates that such users can tolerate degraded service or disconnections by having the advantage of paying less in comparison to the users having guaranteed QoS. Considering the design of such an objective function will be an enormous task, if considering real world 3G wireless cells. That is multiple services for multiple cells. Thus we have divided the problem into several subtasks, and we only considered providing video streaming service in a single 3G W-CDMA wireless cell. i
  5. 5. Table of Contents Abstract ……………………………..…………………………………… i Table of Contents ………………..……………………………….…… ii List of Abbreviations ……..………………………..…………..…… v List of Figures ………………..………………………………..……….… vii List of Tables ………………..…………………………..………….…… viii List of Symbols ………………..…………………………..……….……… ix Acknowledgements ………...…………………………….……………… xi 1. Introduction ………………………………………………..….… 1 2. Introduction to Mobile Wireless Networks ……….… 4 2.1. Wireless Telephones, Computers and Networks ………………... 4 2.2. Wireless Networks ……………………………………...………... 6 2.3. 3G Mobile Wireless Networks …………………………………... 7 2.4. Overview on UTRA ….……………………………………….…. 9 2.5. Importance of Power Control in UTRA ……………………… 12 2.6. Summary ……...………………………………………..……... 14 3. Video Transmission Over Wireless Networks ….…….… 15 3.1. Video Service in Mobile Wireless Networks ………...……… 15 3.2. Digital Video Coding Standards ………………………………….... 17 3.3. Video Streaming Service in Mobile Wireless Networks …..………. 20 3.4. Packet Scheduling Methods for Mobile Wireless Networks ….… 21 3.5. Call Admission Control Methods in Mobile Wireless Networks ….. 28 3.5.1. CAC Based on Resource Availability …….……...…… 29 3.5.2. CAC Based on Number of Users ……………………… 30 3.5.3. CAC Based on SIR ……………………...……….….…. 30 3.5.4. Transmit and Received Power Based CAC ……...….…. 31 ii
  6. 6. 3.5.5. Reservation Scheme……………………………….….…. 31 3.5.6. Linear Weighting Scheme………………………....….… 31 3.5.7. Distributed Admission Control Scheme ……………...… 32 3.5.8. Shadow Cluster ……………………………………….... 32 3.5.9. Call Bounding …………………………………..…….… 33 3.5.10. Cutoff Priority ………………………………………...… 33 3.5.11. Call Thinning …………………………………...………. 34 3.5.12. Miscellaneous CAC Schemes …………………………... 34 3.6. Summary ………….…………….……………………………..……35 4. Video Streaming Service in 3G W-CDMA Network …..….… 36 4.1. Problem Definition ……………………………………………...… 36 4.2. System Model ……………………………………….…..…… 37 4.3. Objective Function …….….………………………………....…… 39 4.4. Implementation …….…………………………………….....… 42 4.4.1. Algorithm Architecture …………………………….....… 42 4.4.2. Calculation of Path Loss and SIR …………...………..… 45 4.4.3. Packet Scheduling …………………………………….… 46 4.5. Summary …………………………….……………………….…..… 47 5. Conclusions and Future Directions ……….…………...… 48 References …………………………………..……………….……………… 50 Appendix A: Wireless Technology: History of Development …………….… 54 A.1 Magnetism ………………………………….……... 54 A.2 Electricity ……………………………….………... 56 A.3 Electromagnetism …………………………………... 57 Appendix B: Overview of W-CDMA ………………………….…….………… 59 B.1 Transport Channels …………………………………... 66 B.2 Physical Channels …………………………………... 66 iii
  7. 7. B.2.1 Dedicated Physical Channels …………. 67 Appendix C: Project Code …………………………………….………….…… 70 iv
  8. 8. List of Abbreviations 3GPP Third Generation Partnership Project AMPS Advanced Mobile Phone Service BER Bit Error Rate BS Base Station CAC Call Admission Control CDMA Code Division Multiple Access DL Downlink Eb/No Bit Energy to Noise Density FCC Federal Communication Commission FDD Frequency Division Duplex FDMA Frequency Division Multiple Access GGSN Gateway GPRS Support Node GMSC Gateway MSC GPRS Global Packet Radio Service GSM Global System/Service for Mobile Communication HLR Home Location Register IMT-2000 International Mobile Telecommunication 2000 ME Mobile Equipment MPEG Multimedia Photographic Expert Group MSC Mobile Switching Center MT Mobile Terminal PCS Personnel Communication System PG Performance Gain PSTN Public Switched Telephone Network v
  9. 9. PL Path Loss RNC Radio Network Controller RNS Radio Network Subsystem RRM Radio Resource Management SGSN Serving GPRS Support Node SIR Signal to Interference Ratio SNR Signal to Noise Ratio TDD Time Division Duplex TDMA Time Division Multiple Access UE User Equipment UMTS Universal Mobile Telecommunication System UPS Universal Parcel Service USIM Universal Subscriber Identification Module UTRAN Universal Terrestrial Radio Access Network UL Up Link W-CDMA Wideband CDMA vi
  10. 10. List of Figures Figure 2.1: Field created by a charged body. Figure 2.2: Changing electric field due to moving negative charged particles Figure 2.3: Formation cause of electromagnetic waves. Figure 2.4: UMTS Network Architecture Figure 2.5: UTRA proposed spectrum allocation Figure 2.5: Multiple Access Schemes Figure 2.6: Multiple Access Schemes Figure 2.7: Spread Spectrum Technology Figure 2.8: Jamming Operation in Spread Spectrum Technology Figure 2.9: Spread Spectrum Technology Figure 2.10: Performance Gain using Spread Spectrum Figure 2.11: UTRA Physical Channels Figure 2.12: Structure of UTRA Physical Channels Figure 4.1: System Model Figure 4.2: Packets Scheduling Model vii
  11. 11. List of Tables Table 2.1: Organizations Submitting Proposals for IMT-2000 System. viii
  12. 12. List of Symbols ηAD Threshold Value of Inter-Packet Delay. ρ System Workload C System Capacity Cf Cost Function CapacityResidual Residual Capacity of a System. Da Average Inter-packet Delay Dt1 Inter-packet Delay Threshold Value Eb Energy per bit. FA Cost Effectiveness Generated by Service_Level_A Users. FB Cost Effectiveness Generated by Service_Level_B Users. FC Cost Effectiveness Forecast from Waiting Service_Level_A Users. FD Cost Effectiveness Forecast from Waiting Service_Level_B Users. I Total Received Interference. Pr Power Received by MT. Pt Power Transmitted from Base Station. RA Average Requested Data Rate. RF Reference Rate. Tv Total Volume Td Total Volume Delivered Tf Packets with Earliest Finish Time. Tdif Traffic Volume Delivered for Interrupted Flows. Tsim Simulation Time Tc Current Time ix
  13. 13. Vi Traffic Volume of Video Clip i. W System Bandwidth Z Effective Throughput PAi , PBp Price for a certain date rate of class-A and class-B users respectively, where PAi > PBp NA, NB Total number of service_level_A and service_level_B data rates in service respectively. NWA, NWB Total number of service_level-A and service level-B data rates respectively, waiting to get served. Nusers_i Equivalent No. of Users in Class i. SRAi , SRBp Number of service level-A and B users respectively, served at a common data rate. Q(k) UMTS QoS classes assigned weighting factors: Q(1)=4, Q(2)=3, Q(3)=2, Q(4)=1 TRAj , TRBl Total serving time left for service level-A and B users respectively served at a common data rate. TRWAo , TRWBs Service time requested by waiting users of service level-A and B respectively. WRAi, WRBp Total number of waiting users asking for service level-A and B respectively. x
  14. 14. Acknowledgements I take this opportunity to express thanks to my supervisors Dr. Marinal Mandal and Dr. Ehab Elmallah for their continuous guidance and support throughout the project. Apart from that, I will never be able to forget the support I have received from my department, family members, seniors and friends during one of the worst patches of my life (the car accident); without their love, help and support I would never be able to finish this important task. I would like to individually name some of my friends, seniors and family members as well to show the importance of their contributions towards my rehabilitation to get enough physical and mental strength to finish my project work. Ishtiaq Bhatti and Family, Elder Mamu Jee’s Family, Uncle Sultan Bhatti’s Family, Saeed Bhatti and Family, Elder Khalu Jee and Family, Zia Bhatti and Family, Waheed Bhatti and Family, Majid Bhai and Family, Uncle Majeed and Family, All Bhatti Families, my and Family friends, neighbours (who visited me to show their support), Iffat Tamoor and Family, Tahir Siddique and Family, Imran and Family, Baba Jee and Family, Liaquat Ali, Shamim, and Other Hiking Club Friends, Uncle Abbas and Family, Uncle Barkat Ullah Bhatti and Family, Abbas and Zafar, Bhatti, Dr. Farheen Imran, Dr. Zafar, Dr. Afridi, Qari Idrees, Chacha Saeed, Wasi uz Zaman, Dr. Sohail Zubairi, Dr. Ishtiaq Ahmad, Dr. Tahir Rasul, Uncle Nazeer, Mike, Adil Akbar and Family, Mumtaz Sb. and Family, Tariq Sb. And Family, Dr. Nadeem Khattak and Family, Munawwar and Family, Iqbal Soomro and Family, Amir, Khurrum Shehzad, Shahid, Dr. Tajjamul, Ghulam Farooq and Rizwan. xi
  15. 15. Chapter 1 Introduction This chapter presents an overview of our project work. It starts with mentioning the importance of mobile communication in our daily lives and what are the new challenges the industry is facing. It then mentions our primarily work on designing an objective function for 3G W-CDMA mobile wireless network. The objective function calculates the effectiveness of cost functions by considering factors like QoS and users satisfaction. The service provider can use this figure of merit to determine if at a given time instance the service is generating profit, if not system has to be improved. The use of mobile phones has increased rapidly in recent times. Since consumer dependence on these products has phenomenally increased, the service providers are improving the system further so that consumers will be offered better services on mobile phones for a profit and growth in the industry. This is what has led to the development of 3G UMTS mobile wireless infrastructure. The planning, design and recommendations for 4G and onward systems is well underway. The 3G UMTS infrastructure is designed for providing multimedia services in mobile wireless environment. It primarily divides the offered services into four QoS classes: Conversational, Streaming, Interactive and Background. In a wireless cell, the users mobility is a challenge for the service provider due to the Near Far Effect. The base stations generally have has fixed power budget. In other words, the combined transmitted power from a base station to users mobile equipment cannot exceed a certain maximum (for example 50 W). The users moving away from the base station require more power whereas the users coming closer require less power from the base station. 1
  16. 16. In this project, we have designed an objective function that will demonstrate the effectiveness of cost functions. At any given time instance, it can be determined from the objective function if the offered services are generating profit for the service provider. In addition, this objective function will provide a trade off between the profit margin and user satisfaction. This is very important because if we keep on serving users paying less in comparison to those who are waiting and willing to pay more for a particular service, service inefficiency will result. In worst case, this may lead to events such as corporate downfall, downsizing, cut backs and layoffs. Designing an efficient objective function is a difficult task especially if considered for an ideal 3G UMTS wireless environment, where users are requesting services belonging to one, multiple or all of the UMTS QoS classes in a multiple cellular environment. Therefore we have narrowed down the problem for this project. We have decided to evaluate performance results for Video Streaming service in a single 3G UMTS/W-CDMA mobile wireless cell. In order to achieve our objectives we considered the following core issues: • Packets Scheduling. • Call Admission Control. • Power & Rate Control. • Rate Control. • Predict effectiveness of cost functions. Packet scheduling arranges queues for incoming users streams. Hence the main task is to minimize queuing delays and deliver packets in choice of the objective function. Call admission control deals with the problem to see if/which new service call(s) can be admitted in the system from waiting users in choice of the objective function. This will in turn look for the power and data-rate requirements for that (those) particular user(s) for fixed time duration. Our formula will then take care of predicting the output of cost functions, which if exceeds a certain threshold indicates that the service provider will meet its profit margin target by admitting new user(s) 2
  17. 17. along with the currently adopted packet scheduling, power and rate control schemes. Chapters 4 cover these aspects in precise details, giving out our assumptions and proposed service contract. Significant work has been done by different researchers on the first four issues mentioned above. However, not much work has been done in the fifth issue. Hence, we are addressing this problem in this project. So, it is a new challenging problem we are addressing in our project work. Organization of the report: The report is organized as follows: • Chapter-2: It first provides a historical perspective on mobile wireless industry and then gradually presents the development 3G mobile wireless networks. • Chapter 3: This chapter covers details on the requirements and trade offs of providing video services over mobile wireless infrastructure. • Chapter 4: This chapter provides details on our work on the development of an objective function for video streaming service in a single 3G UMTS/W-CDMA wireless cell. • Chapter 5: It presents concluding remarks and future directions. • Appendix A: It presents an overview of the historical development of wireless technology. • Appendix B: It provides an overview of W-CDMA access scheme for 3G mobile wireless networks. • Appendix C: It presents the MATLAB code for evaluating the performance of the proposed objective function. 3
  18. 18. Chapter 2 Introduction to Mobile Wireless Networks The importance of mobile phones has increased phenomenally in recent times. The Internet growth use of critical applications like email, e-news and web browsing, have made the use of mobile phones more than simple voice communication. First and second generation (1G and 2G) mobile wireless phones were primarily aimed at providing efficient services relating to voice communication. The growth in computers, networks and specially Internet has opened doors to many critical users applications. Peoples dependence on such applications were the cause of developing future mobile wireless networks. The chapter presents a brief overview on the critical development stages leading to mobile wireless networks. 2.1. Wireless Telephones, Computers and Networks Successful wireless transmission was demonstrated by, Morse in 1832. But it was not possible until 1921 to achieve commercial wireless voice communication. In 1921 the mobile radios started operating in the 2 MHz range, and the system was used by the New York law enforcement departments. The system was half duplex and used amplitude modulation. It had some limitations, for example bad weather conditions affecting transmissions, size of radio equipment and operating cost. In 1924, Bell Labs had invented the bi-directional wireless voice band, which was one step closer to make it possible to offer the system for public use. The discovery of frequency modulation by Armstrong in 1935 paved the way for improved voice communication and the reduced equipment size, because with FM modulation can be done at high frequencies. There was rapid development (e.g. development of circuit boards) of wireless technology during Word War-II. The first commercial mobile phone service 4
  19. 19. (AMPS, 800 MHz) was offered in 1947 in St. Louis, Missouri using a single transmitter for a large area. However due to F.C.C. limited frequency use policy, only 23 simultaneous connections were possible in a certain area. The mobile phones were offered only 6-channels with 60 KHz spacing, which resulted in frequent cross talk or poor voice quality. AT&T later developed the concept of using several small transmitters for smaller areas. However this did not solve the voice channel problem. The demand of mobile phone users was huge. In 1976 there were approximately 600 mobile users in NY and 3500 were on the waiting list; 45000 mobile users in entire USA and 20000 on the waiting list. Thus further research and development was essential in order to sustain the market and keep customers happy. PCS mobile phone system with services like messaging, paging and voicemail was offered as an improved system focusing users requirements in the 1850 MHz range using FM. The invention and improvements in digital technology lead the development of system we now see in our daily life, such as GSM, TDMA, and now leading to CDMA and W- CDMA. The development of wireless technology in the current era is heavily dependent on computers and networks. Hence it is very important to have some necessary background knowledge on the development of computer networking. This review will give us an understanding of how technology automatically find its ways for further growth. In 1821, Charles Babbage invented a machine called Difference Engine. The system was developed in an effort to solve numerical problems easily by using method of Finite Difference. While solving Polynomials this system avoids multiplications and divisions, and actually uses simple additions to solve the problem. It was a mechanical system used to calculate series of numerical values and printing results automatically. The inspiration must have come from the earlier Calculator development works of Pascal, Leibnez and Schickard. This was the basis of computer development, computers in our era uses simple addition to solve multiplication and division problems. So, basically its all binary addition inside a computer to calculate arithmetic. Technology development efforts in World War-II resulted in the 5
  20. 20. development of first decoder called Colossus, which was developed to break German codes. It was a slow machine taking about 3-5 seconds for each calculations. John Presper Eckert developed a decoder (ENIAC), thousand times faster than Colossus taking 160KW power using vacuum tubes. When it was run for the first time. The invention of Transistor lead by Shockley, Brattain and Bardeen in 1948 at Bell Labs and is one of the most important inventions in 20th century technology development. This invention made it possible to develop smaller electronic devices (low power consumption). Eventually, the IBM in 1981 introduced a product named PC (Personnel Computer) for public use, the IBM sold 2 millions PCs in 1981, and sold 65 millions more over the next ten year period. Currently as we all know having a computer in house has become essential to keep ourselves well informed, efficient and more productive. As the number of computers increased, first in offices and later at homes, it created a strong need for networking them. This resulted in the development of Ethernet in 1970 for LAN (Local Area Network), WAN (Wide Area Network) and MAN (Metropolitan Area Network). 2.2. Wireless Networks Since wires have a high cost for setting up a large network. There is a need to have wireless LANs and we do see wireless LANs in homes, offices, and now it is reaching to mobile phones in the 3G framework. Wireless phones have started from simple voice communication (1G) service to new services such as video conferencing and video streaming (3G). The wireless technology offers convenience for people in hotels, airports and other travel spots, who need access to services such as email, voice and web browsing. The solution to this problem is Wireless Internet Service Provider (WISP). The demand of wireless networks is ever increasing in the horizontal (public safety, monitoring applications, delivery services, finance and retail) and vertical markets (e.g. WAP, SMS, GPS and web surfing). For example, package delivery services, 6
  21. 21. such as UPS, use single channel system model called ESMR (Enhanced Specialized Mobile Radio). 2.3. 3G Mobile Wireless Networks Work on 3G mobile wireless networks has been started by ITU’s radio communication sector (ITU-R) task group 8/1 in late 80’s. The group defined the requirements for 3G mobile wireless networks. Initially the recommendation were known as Future Public Land Mobile Telecommunication System (FPLMTS). The frequency spectrum for such a network was decided on a worldwide basis in 1992, and these were (1885-2025 MHz and 2110-2200 MHz bands). In year 2000, the FPLMTS got a new name as IMT-2000 (International Mobile Telecommunication System-2000). It provides a framework to support services ranging from few Kbps to 2 Mbps data rate requirements, and have transparent worldwide radio coverage for global roaming. This provides a base infrastructure to connect any two mobile wireless terminals worldwide. The design of IMT-2000 also takes into consideration the different propagation requirements, and has the ability to handle circuit and packet data mode services of variable data rates. All these improvements provide an acceptable quality of service (QoS), which is competitive to wired networks at a reasonable cost to the consumer. Several international telecommunication organizations put their efforts in developing and standardizing the IMT-2000 proposal. The ETSI (European Telecommunication Standards Institute), TIA (Telecommunications Industry Association) of USA, and ARIB (Association of Radio Industries and Businesses) of Japan are prominent members of that group. In June 1998, fifteen IMT-2000 proposals were submitted to ITU-R in which five proposal were for satellite based communication solutions. Table 2.1 lists the organizations that submitted proposals. It can easily be observed in the table that most of the organizations suggested using W- CDMA technology for 3G wireless networks. Features such as improved user capacity, coverage in most propagation environments, ability to solve multi-path fading problem through RAKE receiver, ease in frequency planning due to use of a 7
  22. 22. single band for each user, instead of having a unique band for each user as in the past, made W-CDMA an attractive technology. Table 2.1: Organizations Submitting Proposals for IMT-2000 Proposal Description Multiple Access Source DECT Digital Enhanced Cordless Multi carrier TDMA ETSI Project (EP) DECT Telecommunications (TDD) UWC-136 Universal Wireless TDMA (FDD and USA TIA TR45.3 Communications TDD) TD-CDMA Time Division Hybrid with Chinese Academy of Synchronous CDMA TDMA/CDMA/SDMA Telecommunication (TDD) Technology (CATT) W-CDMA Wideband CDMA Wideband DS-CDMA Japan ARIB (FDD and TDD) CDMA II Asynchronous DS-CDMA DS-CDMA (FDD) South Korean TTA UTRA UMTS Terrestrial Radio Wideband DS-CDMA ETSI SMG2 Access (FDD and TDD) NA: W- North America Wideband Wideband DS-CDMA USA T1P1-ATIS CDMA CDMA (FDD and TDD) Cdma2000 Wideband CDMA (IS-95) DS-CDMA (FDD and USA TIA TR45.5 TDD) CDMA I Multi band synchronous Multi band DS-CDMA South Korean TTA DS-CDMA 8
  23. 23. The joint efforts of several standard regional organizations towards standardizing IMT-2000 resulted in two partnership projects: 3GPP1 and 3GPP2. The 3GPP1 project aim at developing technical specifications for IMT-2000 based on GSM (Global System for Mobile Communication) and UTRA (UMTS Terrestrial Radio Access). The ETSI (European), ARIB (Japan), CWTS (China), T1 (USA), TTA (Korea), TTC (Japan) are the organizations involved in 3GPP1. The first specification for UTRA was released, in December 1999. The objective of 3GPP2 is to develop technical specifications for IMT-2000 based on CDMA2000 RTT and ANSI-41 core networks. The project is headed by TIA and other members include TTC, ARIB, TTA and CWTS. 2.4. Overview on UTRA RACE (Research in Advanced Communication Equipment) and ACTS (Advanced Communication Technologies and Services) were the research initiatives taken by EU (European Union) in 1988 and 1995, respectively, for advancement in the development of UTRA architecture. RACE program had the objectives to research and develop pilot projects for the possible UMTS air interface technologies. ACTS project finally chose two technologies for accessing UTRA air interface, and those were TDMA (Time Division Multiple Access) and W-CDMA (Wideband Code Division Multiple Access). It was ARIB who first made decision on adopting and focusing research on W-CDMA in January 1997. The decision was later followed by ETSI in January 1998. The initial spectrum allocation for UTRA is shown in Fig. 2.5. This frequency spectrum proposal came with the philosophy of voice and low date rates services dominating the IMT-2000 market. The philosophy became invalid soon with increasing demand of high date rate services such as video streaming, video conferencing and digital imaging. It has been forecasted that the proposed frequency bands allocation can sustain until year 2005. High data rate services over UTRA 9
  24. 24. demands an additional 187 MHz of frequency spectrum. It has been forecasted that such addition will be enough to fulfil the services data rate requirements by the year 2010. Uu Iu Circuit Switching Circuit Switching Cell Gateways Domain BS-1 / Node B MSC / PLMN: RNC VLR GMSC PST N, ISDN Cell BS-N / Node B RNS USIM Iub Iur Cu HLR ME Cell BS-1 / Node B RNC SGSN GGSN Internet Cell BS-N / Node B RNS Packet Switching Packet Switching Gateways Domain UE UTRAN CN Ext. Net. Figure 2.4. UMTS Network Architecture W-CDMA W-CDMA W-CDMA W-CDMA DECT (TDD) Uplink (TDD) MS (TDD) Downlink (FDD) MS 1885 1900 1920 1980 2010 2110 2170 2200 ← Frequency (in MHz) → Figure 2.5. Proposed spectrum allocation in UTRA 10
  25. 25. UTRA development is heavily influenced by the GSM and GPRS networks, and the architecture mainly composed of two parts: UTRAN and CN. UTRAN provides air interface for the user mobile terminals where as CN is responsible for routing and switching voice and data connections to external networks. The architecture has open interfaces enabling operation or communication among equipments from different manufacturers. UTRAN contains several Radio Network Subsystem (RNS); each RNS is composed of several Radio Network Controller (RNC), and each RNC controls several Base Stations (BS’s) and User Equipment (UE). RNC is responsible for controlling radio resources and plays a major role in HC (handover control), LC (load control), PC (power control), AC (admission control) and packets scheduling (partially done by RNC). “Iur” interface is used for soft handover among RNC’s, “Iub” to control one BS/Node-B, and “Iu” to interface with CN. In Fig. 2.4, Node B represents base stations (BS). In UTRA architecture the BS’s are similar to BS’s used in GSM networks. Base station is a physical unit for sending and receiving radio signals in cell(s). It’s responsibilities include soft handover, inner closed loop power control, signal spreading, interleaving, coding channels and rate adaptation. Base station accesses user equipment (UE) via the W- CDMA Uu interface. A UE comprises of ME and USIM; and these modules use Cu interface for communication. The ME is user’s mobile equipment whereas USIM is a smart card containing unique subscriber identification number and personnel information. In the core network block of the UMTS network architecture, the home location register (HLR) is responsible for keeping track of subscribers location and charging and routing calls to the respective (where mobile phone is registered at that time) MSC or SGSN. The MSC provides an interface point between the mobile radio network and the fixed network of the outside world, and thus handles all circuit switching requests. The visitor location register (VLR) working along with MSC has the responsibility to keep track the location of roamed mobile terminal. GMSC and GGSN, MSC and SGSN are similar in functionality, with a difference that MSC and SGSN serve as the gateway and switching centre for the packet switched network, respectively. 11
  26. 26. 2.5. Importance of Power Control in UTRA The base stations in a cell have fixed power budget, The combined transmitted power to all the mobile terminals (MT) cannot exceed a certain maximum (for example, 50-watts). Thus an efficient power control is necessary. It is also necessary to solve the near-far problem [3] in a CDMA network. Power control also determines the capacity and coverage of the system. In FDD mode of operation, the power control mechanism employed is called Closed Loop Power Control (CLPC). In TDD mode, it is called Open Loop Power Control (OLPC). We will discuss the two types of control briefly in the respective order. Before discussing power control, it is important to understand the following SIR equation for each MT. The ultimate objective is to get a target Signal to Interference Ratio for each Mobile Terminal. W Prx SIR= (in dB) (2.1) R (γ Iintra_cell + Iinter_cell + ηo W) where, W = Chip Rate in Hz. R = Transmission Data Rate in bits per second. Iinter_cell = Interference received from neighboring cells Iintra_cell = Interference received within cell Prx = Power received from BS ηo = Noise Power Spectral Density γ = Orthogonal Factor In Eq. 2.1, Prx represents the total power received from BS’s and the denominator term (excluding R) represents the total interference received at a MT. 12
  27. 27. The CLPC is used both for Uplink (UL) and Downlink (DL) using TPC commands that are transmitted in the format shown in Fig. A.12(a, b). Hence, discussing UL or DL power control is equivalent. However, when it comes to designing an effective CAC scheme for handling UL and DL, give rise to remarkably different problems. In UL power control, BS measures received power from an MT on its respective DPDCH and DPCCH after RAKE. The BS also estimates the total received interference (information other than from the target MT) in order to estimate the total received SIR, which is compared to the target SIR for that MT. This operation is performed every few milliseconds. Based on these information, BS sends TPC commands to respective MT in order to either increase or decrease transmission power of DPDCH and DPCCH by a step size of ∆TPC dB (typically 1 or 2 dB) to achieve target SIR. The transmissions at unnecessary high power, not only reduces battery life but also results in performance degradation on service quality for other users. In OLPC, an MT has a priori knowledge about the interference level at the BS and DL path loss, sent by BS. Since information is already known, the MT can easily calculate the required transmit power in order to achieve the target SIR. 13
  28. 28. 2.7. Summary This chapter provides a brief introduction to the wireless networking technology. It starts by presenting an overview on the technological developments of wireless networks. A brief overview on the development of computers, wire-line networks and wireless telephones is given in section 2.1, since these are the major contributors in the development of wireless networks. We then gave brief overview on the evolution of 3G mobile wireless networks in section 2.3. A brief review on UTRA has been presented. The importance of power control in mobile wireless environment was described in section 2.5. 14
  29. 29. Chapter 3 Video Transmission Over Wireless Networks People’s dependence on Internet and growth in mobile wireless industry have generated new requirements for the industry in order to provide better services to users and profits for investors. Examples include mobile access to Internet (for example email, browsing, stocks and banking), video conferencing and video streaming etc. Mobile access to Internet has already been offered even in 2G mobile wireless networks. Such a service can tolerate delays while browsing or downloading emails, but for video service the case is not the same, since most users do not want to receive still or distorted video clips. Such a condition may be caused either by a fading channel or network congestion resulting in data rate decrease for the mobile user. Hence, delivering uninterrupted acceptable quality video service is a real challenge to address to have satisfied customers. The traditional concept of treating video as data to achieve certain QoS objectives fails in wireless networks, since the overall network bandwidth cannot be guaranteed at a certain time instance. We note that digital video signal is a collection of frames at a rate of 10-30 frames/sec (FPS). In other words, as long as these 10-30 frames can be delivered every second to the target MT, the QoS objective will be achieved successfully. 3.1 Video Service in Mobile Wireless Networks Digital video is a collection of frames, where a frame refers to a still picture/image. A full depth (8 bits each for red, green and blue, total 24 bits for each pixel) color image of size 358x288 requires 304128 bytes of storage space, whereas for a reduced depth colour image (4 bits each for red, green and blue color components, total 12 bits per pixel) requires 152064 bytes of storage space. The 15
  30. 30. following shows the bandwidth requirements, if we want to send a full and reduced colour depth video over wireless link. Data Rate Requirements for Uncompressed Video: Full Colour Depth Video: 30[fps] x (358x288)[resolution] x 24 [bits per pixel] = 36.5 Mbps Reduced Colour Depth Video: 30[fps] x (358x288)[resolution] x 12 [bits per pixel] = 18.2 Mbps Television Quality Video: 30[fps] x (704x576)[resolution] x 12 [bits per pixel] = 146 Mbps The above bit rate shows that efficient and cost effective transmission of uncompressed video signal is not possible due to very high data rate requirements. Compression is the only solution to the problem. There are several very efficient standards for image (e.g. JPEG) and video compression (e.g. MPEG). The key aspect in guaranteeing video QoS over wireless networks is the use of compression. The level of compression depends on channel quality. It is low for good channels and high for bad channels. Delivering video in 3G wireless networks has become possible due to the development in compression technology. Now let us take a brief look on the existing video coding standards. 16
  31. 31. 3.2 Digital Video Coding Standards A video is a collection of frames and each frame represents an image. Video compression is primarily achieved by transmitting only changes occurring from one frame to another, and by removing information undetected by viewer’s eyes. The number of bits used for coding video signal is proportional to the change between two consecutive frames. There are five widely adopted methods of video compression that are as follows, 1. Discrete Cosine Transform (DCT): It is a lossy compression algorithm, analyzing presence of frequency components in samples taken at regular intervals, and discarding unwanted information as its perceived by viewers eyes. DCT is utilized in several standards such as, JPEG, MPEG, H.261, and H.263. 2. Vector Quantization (VQ): A lossy compression algorithm looking at an array of data and removing redundancy. 3. Fractal Compression (FQ): A similar compression scheme like VQ, where compression is performed by locating redundant sections of an image and are regenerated by using a fractal algorithm. 4. Discrete Wavelet Transform (DWT): This compression scheme mathematically transforms an entire image into frequency components. Its different from other schemes, which works on sections of an image. 5. Motion Compensation: This scheme keeps track of objects motion in successive video frames to accomplish compression. It is an effective scheme to reduce temporal redundancy among consecutive frames. MPEG (Moving Pictures Expert Group) is a known standard in video compression technology. The MPEG group was established in 1988 by ISO/IEC for research and development in digital audio and video compression technology. The following standards have been developed by MPEG. 17
  32. 32. • MPEG-1: The main focus is to store full motion video in CD-ROMs. It can support data rates requirements up to maximum of 1.5 Mbps, in which 1.15 Mbps is for video and 192 Kbps for audio. MPEG-1 supports up to 352 x 240 resolution and frame rate of 24. It is a popular standard for distributing videos over Internet (i.e. .mpg files) and making VideoCD. This is the most popular video distribution format in Asia. • MPEG-2: Applications requiring data rates between 1.5-15 Mbps. It was initially developed for digital television broadcasting. But it is now also used for DVD compression and high definition digital television (HDTV). For HDTV the transmission requirement is 18 Mbps. The significant improvement in MPEG-2 is the ability to compress interlaced video. It supports 720 x 480 resolution and frame rate of 30 or 60 interleaved fields per second. • MPEG-4: The main focus of this standard is to bring television experience on desktops. Its was primarily designed for data rates which dialup modems can support, like 28.8 Kbps, 33.6 Kbps and 56 Kbps. Channels with such capacity can support frame rate of 12 or 15, with a maximum resolution of 172 x 288. Technology advancement in data rates for Internet connectivity made it possible to support higher resolutions and frame rates. MPEG-4 is an object based technology, compressing and keeping track of different objects in an image. • MPEG-7: A standard still under development, the main focus is to provide information about the content, which will include security and integrity, personalization, filtering and content manipulation. In addition to MPEG standards, there are other video compression standards developed by ITU, such as H.261, H.263 and H.264. There are briefly discussed below, 18
  33. 33. • H.261: The standard was developed for video conferencing over ISDN lines, supporting data rates, which are multiples of 64 Kbps. Based on in DCT, the algorithm uses inter-frame and intra-frame compression. It supports QCIF (Quarter Common Intermediate Format, 176 x 144) and CIF (352 x 288) resolutions and can be employed in hardware or software. • H.263: Several enhancements were introduced in this standard over H.261, to improve video quality over modem connections. It supports CIF, 4CIF (704 x 562), 16CIF (1408 x 1152), QCIF and SQCIF (128 x 96) resolutions. The CIF standard is also known as FCIF (Full CIF). • H.264: This standard is a combination of MPEG and H.26L. The ITU-T VCEG (Video Coding Expert Group) initiated work on H.264 in 1997. Later by the end of year 2001, MPEG and VCEG joined together to form JVT (Joint Video Team) and H.264 project was taken over. Here are some of the key advantages offered by H.264. o Bit rates savings up to 50%. o High quality video o Improved error resilience o Adaptable to heterogeneous networks H.264 is a strong candidate for video compression in mobile wireless networks. 19
  34. 34. 3.3. Video Streaming in Mobile Wireless Networks Our work in this report is on facing the challenge and designing an objective function for an efficient and profitable video streaming service on 3G mobile wireless networks. The demand of Internet browsing and its related technologies such as email, video streaming, video conferencing, online banking and IRC, are in high demand. As we all know “Need is the mother of invention”, the development of mobile wireless networks is driven by consumer needs. First generation mobile wireless networks were analog systems used only for voice communications. Later came PCS providing efficient services like voice mail and paging. The rapid development and growth in Internet technologies forced the mobile wireless network investors to seriously think on providing these services to consumers of their industry for ease of access, which will increase mobile phones sale and hence a growth in profit margin. These reasons and previously compiled problems of mobile wireless networks lead to the development of 3G mobile wireless networks, which has its roots in technologies like UMTS and W-CDMA. These technologies provide enough bandwidth requirements to cope services mentioned above. Internet growth has proven the efficiency, flexibility and cost effectiveness offered by IP protocol. Thus implanting IP in wireless networks would be ideal in order to merge two different worlds (wired and wireless). In other words, services such as voice, video steaming and conferencing, web browsing, IRC, email can be exchanged in packet form among mobile wireless and wired network/Internet. We will focus our discussion in particular to video streaming service. There are two main bottlenecks in delivering video streaming service over mobile wireless channel. 1. Delivering information within the maximum allowable delay to meet quality of service objectives and to avoid jitter. 2. The condition of a wireless channel depends significantly on the amount of network load and the weather conditions. 20
  35. 35. The design of IP networks was primarily aimed at providing delay insensitive services like web browsing and emails, whereas the design of mobile wireless networks aimed at providing efficient voice service, which is a delay sensitive service. Thus creating a challenge in providing delay sensitive services over IP networks. This also includes video streaming and video conferencing services, which also requires guaranteed throughput and are delay bound. Providing guaranteed QoS for video streaming over mobile wireless networks is difficult since it is difficult to guarantee the followings: • Packet loss, end to end delay, and delay jitter due to bursty errors caused by several factors including weather conditions. • Service bandwidth due to host mobility, handoffs etc. The base station in a cell has a fixed power budget, varying weather conditions and user mobility etc. Thus an efficient RRM (radio resource management) scheme is required in order to achieve services QoS objectives. There are different approaches to address the problem of efficient multimedia services over wireless channels, and these include studies on MAC protocol, admission control and packets scheduling. Our study focuses on packets scheduling and admission control, since the two are inter-dependent for the design of an efficient and cost effective objective function. 3.4. Packet Scheduling Methods in Mobile Wireless Networks Second generation wireless systems enabled voice traffic for commercial use. Since then the increase in customer’s needs and demands paved the way for the development of third generation wireless systems, aimed at multimedia traffic requiring higher data rates. This also opened door for a wide range of applications to fit in the aimed data rates. That is why it been realized to categories traffic into different classes of varying QoS requirements. In W-CDMA/UMTS the QoS has been divided into following four classes. 21
  36. 36. 1. Conversational Class a. For highly delay sensitive applications: video, VoIP (Voice Over IP). b. Example: Packet or circuit switched core network in UMTS architecture. 2. Streaming Class a. For applications like streaming video and music. b. Example: Packet or circuit switched core network in UMTS architecture. 3. Interactive Class a. For non-real time services like web browsing and IRC. b. Packet switched core network. 4. Background Class a. For delay insensitive application such as email and advertisements. b. In this class, the bit rate is not guaranteed. Efficient Radio Resource Management (RRM) techniques are required to achieve the set QoS requirements, while maximizing systems capacity at the same time. Future evolution of 3G systems are aiming to provide wireless services on an end-to-end IP network. This is a clear indication that technologies dealing with packet switched services will gain momentum. The optimization of systems capacity, a desired target, will depend on the performance of QoS and RRM. Such algorithms should also exploit the bursty nature of packetized traffic for enhancing the overall system capacity. Following are some key characteristics of a 3G wireless channel. • Dynamically varying capacity of wireless channel. • Channel Contention among mobile hosts. • Channel errors are bursty and location dependent. • Scheduling scheme must efficiently tackle uplink and downlink flows. • Mobile hosts have processing power and battery life time as bottlenecks. • Mobile hosts do not compete to occupy channel(s) in order to transmit data. 22
  37. 37. The focus of our work is Streaming Class and aimed in particular to video streaming service in 3G mobile wireless networks. Packet scheduling algorithms aimed at achieving all or a set of the following objectives. • Determination and allocation of available radio resources (power and time). • Monitor radio resource allocation for different services. • Sharing of radio interface resources among services. • Monitoring and controlling system load. Packet scheduler allocates resources for both UL and DL due to asymmetric nature of user traffic. While allocating radio resource for one direction only the algorithm has to reserve resources (low date rate channel) for other direction in order to carry high layer (TCP), data link layer acknowledgements and for power control. There are two main categories of packets scheduling methods. An algorithm is typically a combination of the two categories. 1. Time Division Scheduling o Normally used with shared channels. o Capacity allocation to few mobile users at a given time instance. The allocated bit rates can be very high. o System load determines the scheduling time. o Downlink shared channel is typically a time division scheduling. o Advantages: high bit rates/low delay, low SIR. o Disadvantages: Short transmission time, high setup overhead, high variations in interference levels. 2. Code Division Scheduling o Normally used with dedicated channels. 23
  38. 38. o Capacity allocation to large number of mobile users. Low bit rates are allocated for each service. o System load determines bit rates allocation. o Advantages: long transmission time, low setup overhead, no variations in interference levels. o Disadvantages: low bit rates / higher delay, high SIR Following are some popular packet scheduling methods, and their special features. First Come First Served (FCFS) o In this method, the first packet coming in is the first going out to the destination. o It works well if no congestion. However the method is inefficient in handling poor quality links. Priority Queuing o Classified packets sent to prioritised queues (0 to N-1), thus packets in higher priority queue get served first. Queue i gets service only when queue (i-1) got completely served. o Advantages: High priority queues achieving low delays, high throughput and bandwidth. o Disadvantages: Lower priority queues performance is heavily dependent on the performance of higher priority queue. 24
  39. 39. Round Robin o Classified packets sent to respective queues (0 to N-1), and get served in the same order. This approach is suitable for fixed size packets such as in ATM networks, since algorithm assumes fixed time slot for each packet. o Disadvantages: This method cannot guarantee bandwidth or delay. In addition, it is Insensitive to packet size. Window Priority Queuing o Classified packets sent to prioritised queues (0 to N-1). Only a limited number of packets say N per queue gets served per servicing round. Thus lower priority queues get attention in servicing time. o In this scheme, we can easily observe that a large N corresponds to Priority Queuing, and small N corresponds to Round Robin. Virtual Clock o The main aim of this scheduling scheme is to guarantee bandwidth per flow. o Classified packets are sent to queues having associated bandwidth specifications. o Packets are ordered according to TimeStamp, which is calculated using, Packet Size TimeStamp[n] = TimeStamp[n-1] + (3.1) Queue Rate o This is still not a fair approach, because classes using idle bandwidth will be penalized later. 25
  40. 40. Weight Fair Queuing (WFQ, WF2Q, WF2Q+) o Delivery packet gets selected from a set of eligible packets using following parameters [queue #m, current time (Tc), packet start time (Ts), packet finish time(Tf), Packet on top of queue #m (Pm) ] o The earliest finish time (Tf ) for packet Pm using the following equation, Length(Pm ) Tf (Pm ) = + Tc (3.2) Rate(m) o This scheme ensures fairness based on queue parameters instead of packets properties. Channel State Dependent Packet Scheduling Algorithm (CSDPS) CSDPS algorithm tries to ensure error free scheduling service by employing weighted round robin scheme. An error free channel flow is allocated a slot, and whenever channel errors occur for this particular flow the algorithm skips the flow and allocates the slot to another error free channel. Basically it performs weighted round robin among flows to filter out clean channels. Thus CSDPS does not measure flows lag or lead times, which also sets no compensation as the bottleneck. Its implementation complexity is low. Server Based Fairness Algorithm (SBFA) This scheme reserves some channel bandwidth for compensation to backlogged flows. If a backlogged flow, which has been allocated a slot, cannot transmit due to channel errors then such flow queues a slot request in the compensation flow. The scheme serves the compensation flows along with other flows. SBFA scheme does not have the concept of leading flow. When compensation flow has no slots available, the requested bandwidth is shared by all flows carrying clean channels at that particular time instance. 26
  41. 41. Wireless Fair Service Algorithm (WFS) It is an enhanced version of WFQ, in which each flow is allocated two parameters, the rate weight (ri) and delay weight (Φi.). The start tag is computed same as in WFQ but computation of finish tag is based on Φi. rather than ri. In WFS the lag for a particular flow (caused by erroneous channel condition) increases when some other flow (perceiving good channel) can take its place. The lead and lag times are bounded by per flow parameters. o Wireless Packet Scheduling Algorithm (WPS), Channel-condition Independent Fair Queuing (CIF-Q), Idealized Wireless Fair Queuing (IWFQ) are some other variations of wireless fair queuing algorithms, whereas General Processor Sharing, Self Clock Fair Queuing (SCFQ), Stop and Go and Rate Control Service Discipline (RCSD) are some other methods used for packets scheduling. Following are the approaches we have considered in our project work for packets scheduling: • First Come First Served (FCFS): Here the packet(s) are selected such that intra-cell or inter-cell interference requirements are within the specified limits. • Best Channel First (BCF): Here the channel condition for each user is different and are uncorrelated. Hence the available resources are utilized for users having better channel conditions and requiring less radio resources (e.g. transmit power). The major problem with this approach is the long term fading for users having poor channel condition for extended time. 27
  42. 42. 3.5. Call Admission Control Methods in Mobile Wireless Networks Call Admission Control (CAC) is defined as a system for managing arriving traffic, at the call, connection or session level based on some predefined criteria. A CAC scheme either admits, rejects or delays the incoming calls based on a criteria to achieve some QoS objectives for new and existing users. In a mobile wireless cell, the base station has limited power resources. In other words the combined transmitted power to all mobile terminals cannot exceed a certain maximum level. Each newly admitted call makes this resource further scarce. Hence it is very important to adopt policy that will determine which calls to efficiently admit, block or reject based on available resources. The following outlines some of the basic needs for which CAC is employed. • Maximize revenue. • Fair resource sharing. • Guarantee transmission rate. • Guarantee QoS at packet level. • Some UMTS classes given priority over others. • Guarantee call-dropping probability. • Guarantee signal quality. Let us consider a few cases that will demonstrate the importance of the CAC. 1. The base station has limited power resource, and the combined power transmitted to users cannot exceed the allocated power to the base station. Thus if admitting new users increases the outage probability of existing users, a bad CAC decision results. 2. Mobile equipment is moving from one cell to another in which all of the resources have been fully occupied. A handoff operation is not possible for that 28
  43. 43. particular user, thus indicating a bad CAC scheme. Since a call drop will occur for such user. Here is the list of some the most prominent RRM (Radio Resource Management) schemes used for CAC. • Power Control. • Base station assignment. • Channel allocation. • Bandwidth reservation. • Scheduling or buffer management. Instead of going into the precise details of the CAC schemes mentioned in this section, we are focusing on the main philosophy adopted in the respective CAC scheme and evaluate if it works well in choice of our objective function. A few selected CAC policies are presented in the following, 3.5.1 CAC based on resource availability: Evans and Everitt [16] proposed the following model to measure the available resources.  j Nj  P  ∑∑ X ji > C  ≤ ∝ (3.3)  j=1 i=1    where C is the total available resources, Nj represents total number of users in class j and Xji respresents the resources required by user i. of class j. This particular scheme then defines the admission criteria as, j ∑ Kj Nj ≤ C (3.4) j=1 29
  44. 44. Here Kj represents effective bandwidth of users of class j. Zhao, Shen, and Mark, [17] used packet delay upper bounds for variable bit rate calls, and jitter for all constant bit rate calls as a policy for CAC. 3.5.2 CAC based on number of users: Zu and Hu [18] proposed the following expression to calculate the equivalent number of users in class i. with respect to UMTS class 1 (the voice service), rj SIR j N users_i = N j ρi (3.5) r1 SIR1 where N represents number of users, ρ as activity factor, r as transmission data rate and SIR as signal to interference ratio for class j and 1 respectively. In this particular scheme a Guard band is reserved for handoff calls. Reference [19] also proposes CAC criteria based on the number of users. 3.5.3 CAC based on SIR: Ishikawa [19] makes CAC decision based on measured interference level, whereas Liu [20] uses residual capacity for CAC decision, and it is defined as:  1 1  Capacity residual =  -  (3.6)  SIR TH  SIR   30
  45. 45. 3.5.4 Transmitted and Received Power based CAC: Knutsson [21] proposed a scheme in which a new call is admitted as long as the total transmitted power from base station do not exceed a maximum threshold value. On the other hand Kuri [22] based the CAC decision on the 95% of total power received at the base station. 3.5.5 Reservation Schemes (RS) This scheme makes CAC decision by looking only on the cell from where the call has been originated. It is one of the very simple schemes. Let N and Nh are the total number of channels and number of channels reserved for handoff operations in a cell, respectively. New calls are admitted if following condition is satisfied, N - Nh > No (3.7) where No represent the threshold value. 3.5.6 Linear Weighting Scheme (LWS) This scheme considers average number of calls within D hops from the originating cell, before making a CAC decision. Let S represents the set of all cells within the region of awareness (D-hops), consider N - Nh as the threshold value. The new calls are admitted to the originating cell only if: 1 ∑ Ni < (N - Nh ) |S| i ε S (3.8) For D=0, this scheme reduces to Reservation Scheme. 31
  46. 46. 3.5.7 Distributed Admission Control Scheme (DACS) This scheme considers the number of active calls in the originating and neighboring cells before making CAC decision. This scheme is considered both for one and two dimensional models. Interactive CAC [27] has the philosophy of admitting new users requiring less power resources after evaluating expressions to confirm if the required SIR level can be achieved for each user in the cell. This scheme has a few serious drawbacks. It works well for always active connections, but cannot handle discontinuous transmissions, a very important aspect while dealing with UMTS network. Secondly they demonstrate convergence speed problems. A different approach is to increase power levels to users when interference increases in order to keep SIR at a target value. Thus this scheme admits new call(s) only if estimated power increase keep the SIR within the target value. 3.5.8 Shadow Cluster A mobile terminal exerts influence on the base station in the current cell depending on its current location, data rate requirements and direction of travel. Such influence also moves when mobile terminal switches cells. Thus neighboring base stations that are influenced due to such movements form an area what is called as the Shadow Cluster. This shadow is strongest at the current location of mobile terminal and it fades away based on factors like, such as call duration, data rate requirements, mobile terminal velocity and trajectory. Due to above mentioned factors, the center of this shadow cluster is not the center of a geometric area, but it is the current location of the mobile terminal. In shadow cluster CAC scheme a base station share probabilistic information among neighboring base stations with a future probability of its active mobile terminal(s) moving to the neighboring cells. This allow neighboring base stations to reserve resources for that particular mobile terminal(s) in order to meet a certain call dropping probability threshold in choice of QoS and objective function in our case. 32
  47. 47. Accepting a new call in a particular cell, also involves neighboring base stations in the decision making process. After information exchange about current and future requirements for that particular user in current and neighboring cells, a collective decision takes place whether to accept or reject the admission request. This scheme has a distributed framework and works very well in mini or micro-cellular environment. It does have some processing overheads on the base station and the wire-line network. 3.5.9 Call Bounding The main philosophy behind this CAC scheme is to accept a few users rather than increasing the dropping probability of current users by admitting new users up to a possible maximum. The concept works well because users are more sensitive to call dropping than call blocking. In this scheme, each cell has been assigned a threshold value on the maximum number of active calls/users/mobile terminals. A new call is blocked only if it exceeding the set threshold value. On the other hand the handoff calls are blocked only if all channels are occupied. 3.5.10 Cutoff Priority Instead of putting a limit on the total number of possible calls in a cell, the CAC (in this scheme) decision is based on the total number of active calls at that particular instance in the cell. A new call is accepted if it does not exceed a given threshold value, otherwise it will be blocked. The handoff calls are always accepted as long as there is an available channel. This scheme works under the assumption that average new call channel holding time and average handoff call channel holding time are equal, allowing the use of one-dimensional Markov chain theory. If there assumptions are not true this scheme will not work. Hybrid cutoff priority [28] is an extension of Cutoff Priority scheme from a single traffic stream to multi-class traffic streams. This scheme supports any number of traffic classes each with unique QoS Requirements in terms of channels 33
  48. 48. requirements, connection time and a unique Cutoff Threshold value. This scheme employs finite buffering for handoff and new calls. In addition, the scheme assumes new calls departing due to unwillingness to wait in the queue, and dropping the queued handoff calls due to channels unavailability. 3.5.11 Call Thinning The main idea behind this CAC scheme is to accept new calls with a certain probability and at the time of congestion the newly admitted calls take up the share to reduce currently served data rates or to delay in order to reduce load. Many CAC schemes have been proposed in literature, which are more or less variables of above mentioned schemes. Our system model, initially only work for a single cell, so adopting a download power based CAC scheme in choice of the objective function will be of benefit to us. The performance results of adopted CAC scheme for a single and neighboring cell environment will set the direction of selecting variables of different adequate CAC scheme in choice of objective function. At the very low level its all comes down to power utilization per mobile terminal, thus any steps taken to make an efficient use of this resource will improve the overall system performance. 3.5.12 Miscellaneous CAC schemes: Baldo [23] calculates overload probability (Po) to make CAC decision whereas Baldo [24] proposed the handoff probability (Phf) for CAC decision. Peha [24] and Guo [25] proposed to make CAC decision on bandwidth utility function and degraded service area respectively. 34
  49. 49. 3.6. Summary This chapter focuses on the problem of transmitting video in a mobile wireless environment. We started the chapter by giving the bottlenecks of transmitting a digital video without compression. It showed that no compression of video signal requires very high data rates and hence power allocations for a mobile user. Thus showing the importance of finding ways to reduce data by compression. We reviewed several video encoding schemes and then advantages. We also presented an overview of (in this chapter) packet scheduling and call admission control schemes. We have also reviewed requirements of providing video streaming service in mobile wireless environment. 35
  50. 50. Chapter 4 Video Streaming Service in 3G W-CDMA Network In previous chapters we have given brief overview on relevant technologies, algorithms and architectures, which are of importance in our project work. We have presented (in chapter 2) introduction on the development of personnel computers, wire-line networks and mobile wireless networks. Then we have presented an overview on UTRA (3G) mobile wireless networks architecture, and the importance of power control in 3G networks. We have presented (in chapter 3) an overview on video transmission requirements and the importance of video compression in reducing data rate requirements. Then we have presented an overview on several known video compression technologies. Our study focuses on the design of an Objective Function that provides cost functions as an output for the service provider. These functions will be helpful for the service provider to make critical decisions on CAC, scheduling and power/rate control based on users service contract, in order to keep the system running in a profitable and cost effective manner. The objective function will cater Video Streaming service only in a single cell and later multiple services for UMTS QoS classes for mobile users in 3G W-CDMA multiple cellular environment. 4.1. Problem Definition Ideally we would like our objective function working for a real world 3G mobile wireless networks. Such a task is very wide and can be divided into four possible cases, as mentioned below. 36
  51. 51. Case #1: Mobile users with varying mobility are requesting only video streaming service of fixed duration (1 to 5 minutes) in a single 3G wireless cell. Case #2: Mobile users with varying mobility are requesting services belonging to all or a set of UMTS QoS classes in a single 3G wireless cell environment. Case #3: Case #1 implementation for a multi-cell environment. Case #4: Case #2 implementation for a multi-cell environment. The above case objectives will be taken care of in choice of an Objective Function. The function will try not only to assure a good QoS but also to achieve a good profit margin for the service provider. The above two objectives can only be successfully achieved by achieving efficiency and trade off among the following issues: • Packets Scheduling • Downlink (DL) Power Control. • Data Rate (R) Control. • Call Admission Control (CAC). In this report our main objective is to implement and achieve performance results for Case #1. The design of our project work will be such that it will pave the way for future implementations of other cases. 4.2. System Model The overall system model is shown in Fig. 4.1, where Operations A, B and C are explained as follows: Operation A: Users requesting a streaming video (for example, video streaming request for 3-min soccer world-cup highlights). 37
  52. 52. Operation B: Video stream data files reaching the gateway in packetized form. The stream file is of known volume and data rate requirements. The packets are of varying size and inter-arrival time. Operation C: Gateway performing following tasks: Packet Scheduling, Power Control, Rate Control and CAC. Inte rnet Server Gateway Mobile Users Operation A Operation B 3G Cell Operation C Figure 4.1: System model considered in the design of our objective function. The users who are requesting video streaming service in a “3G cell”.only The following assumptions are made: • The video streaming service is limited within a single cell. • The cell has a diameter of d-meters. • Data rate requirement varies between b1 to b2 bps. • Users mobility in the range [1,5] meters per seconds. • Eight allowable moving directions (N, S, E, W, NE, NW, SE, SW). • IP packets of varying size (s1 to s2) Kbps. 38
  53. 53. The gateway receives the incoming data and after performing operation C the packets get transmitted to their respective destinations. We have identified the mobile users as belonging to one of the following two categories, 1. Service_Level-A: Users requiring guaranteed service, no disconnects or degraded service, and have willingness to pay high for such a service. 2. Service_Level-B: Users having willingness to pay less at the cost of degraded or disconnected service. So, we have to give priority and special consideration to Service_Level_A users while performing Scheduling or Call Admission Control operations. In order to simplify our task further, we can treat all users as starting at same service level, and users can specify one (or more) video resolution(s) that user is willing to pay for. The higher the resolution indicates higher volume. The CAC can make decisions on which resolution to serve based on cost function and available power resources. 4.3. Objective Function The two important factors in the design of objective function is the cost effectiveness at a given time instance from the system and the effective systems throughput. The two cases will provide a trade off among service providers profit margin and user satisfaction. We will be mainly focusing on the later issue in our project work. We define the effective systems throughput as, Td (in bits) Z= (4.1) Tsim (in seconds) where Td is the total volume delivered and Tsim is the simulation or elapsed time. 39
  54. 54. If there are no packet delay violations then we can calculate the Total Delivered Traffic after each completion as, Td = Td + Vi (4.2) Where Vi represents the traffic volume of a video clip. If there are delay violations above a Threshold Value, then we proceed as follows, If Da > ηAD Then abort or degrade service for Service_Level_B users with certain probability. If all users have Service_Level A, then make a decision on degrading or aborting service for those which overall improves the effective system performance, and keep most of the users satisfied. Also penalize the systems Total_ Delivered_Traffic to Reflect Interrupted Flows. where, Da is the average inter-packet delay and ηAD is the threshold value on this delay. For the above mentioned cases, we are also assuming a maximum inter-packet acceptable delay, and service degradation means one of the following cases, i) Switching from a high data rate to a low data rate if possible. ii) If case-1 is not possible then delay the packets. iii) If packets delay exceeds a certain threshold then drop the service for user(s). We propose a cost function (Cf) formula to determine the cost effectiveness to the service provider: Cf = [FA+FB]-[FC + FD] (4.3) 40
  55. 55. where, FA = Cost generated by active Service_Level_A users NA  NA  (4.4) = ∑ PAi SRAi Q(k)  ∑ (TRAj )i   j=1  i=1   FB = Cost generated by active Service_Level_B users NB  NB  = ∑ PBp SRBp Q(k)  ∑ (TRB1 )p    (4.5) p=1  l=1  FC = Estimated cost generation from waiting Service_Level_A users N WA  N WA  (4.6) = ∑ PAm WRAm Q(k)  ∑ (TRWAo )m    m=1  o=1  FD = Estimated cost generation from waiting Service_Level_B users N WB  N WB  (4.7) = ∑ PBn WRBn Q(k)  ∑ (TRWBs )n    n=1  s=1  Here FA is the cost the service providing is getting from Service_Level_A users, which basically are the one’s requiring guaranteed service and are paying higher for such a service. Similarly FC is the expected earnings from the waiting Service_Level_A users, whereas FB and FD are the respective figures from Service_Level_B users. Our aim is to maximize this function with respect to increasing workload and QoS requirements. The given Cost_Function formula is a coarse approach requiring improvements and fine tuning after been put to test for several different scenarios. 41
  56. 56. 4.4 Implementation Let us expand the insight of the key aspects of our system model, and how we have implemented those. 4.4.1 Algorithm Architecture We have implemented a flexible architecture, which let us change the dimension of cell, number of users, packets size and arrival time. Here is the algorithmic approach we have considered for our project. i) All channels in good shape and users are requesting only high priority traffic services (video streaming in our case). ii) Some channels are in bad shape and users are requesting only high priority traffic services (video streaming in our case). iii) All channels are in good shape and users are requesting high and low priority class services. iv) Some channels are in bad shape and users are requesting high and low priority class services. The first two cases are assumed in this work. We will approach the algorithm development as the following steps. Following are the steps taken to accomplish our task. 42
  57. 57. Step #1: The first step is to simulate users profile in a 3G mobile wireless cell. This will include users mobility pattern and video stream download requests. Step #2: Packets with varying data rates and inter-arrival time delivered to the respective serving queues. Step #3: Simulation Run: SimulationStartTime=0; While (Some flow is not completely delivered) { i) Update users location every t1-seconds: ii) Call scheduler to determine which users are going to receive data for the next t2 ms: iii) Wait for t2 ms: iv) Update the queues: (1) Update remaining volume to be delivered for each user and average delay per queue (2) Check if any packets-inter-arrival time delay violations happened: (If true) Give user(s) option to terminate service [with a certain probability]. Also penalize Z to reflect such scenarios. (3) Check complete volume delivery: v) Tsim= Tsim + t2 ms: vi) Compute objective function to see if services are meeting the required profit threshold. If profit margin is below a threshold then call CAC algorithm to decide which user(s) will be dropped or receive degraded service and which new user(s) can be admitted to the system to meet or exceed the profit threshold value. vii) If system has available resources then perform CAC for new requests. } 43
  58. 58. Step #4: Calculate and Plot Statistics for Z vs. workload (ρ) and Cf, Z and ρ. Following are some the remarks taken care of while plotting Effective Throughput vs Workload graph, 1. Every point is an average of “many” simulation runs. 2. Effective Throughput (Z) gets computed only when the workload (ρ) is at a required level. 3. Workload is taken with respect to an estimate of overall systems capacity. We have used the following expression to calculate workload. RA ρ= (4.7) RF where, RA= Average Requested Data Rate. RF = Average Reference Rate. Now in the following bullets we are going to give further details on the insight of our algorithm writing. First we are going to give information on the formulas we have used to calculate path loss, required transmission power and SIR. It is then followed by our approach on packets scheduling. A final decision on a particular scheduling scheme in choice of our objective function can only be reached after getting performance results for different schemes in a multi-cellular environment. 44
  59. 59. 4.4.2 Calculation of Path Loss and SIR. We use the log-normal shadow fading model to calculate Path Loss (equation 4.8). The received power by a mobile terminal at distance d from the base station is calculated using equation 4.9. d PL(d) [dB] = PL (d o ) + 10n log ( ) + Xs [dB] (4.8 ) do Pr (d) [dBm] = Pt [dBm] + PL(d) [dB] ( 4.9) Pt (4π 2) = (4.10) Pr λ2 Where we have considered λ=900 MHz in our project work. Once the received power is known for each mobile terminal in the cell the next equation must be satisfied for each mobile terminal in order to make a successful transmission. The denominator of the equation given below only takes care of intra_cell interference, since we are only considering a single wireless cell. Eb W Pri = ≥ 7 dB (4.11) I R ∑ Prj i≠ j In the above equation the denominator calculates the sum of power transmitted to all the mobiles except the one for which SIR is been computed, and the above equation must be satisfied for each mobile terminal in order to achieve successful transmissions from base station to the mobile terminal. 45
  60. 60. 4.4.3 Packets Scheduling Fig. 4.2 shows our scheduling policy, each user requesting a high or low priority service creates a service queue for that particular user for system to manage. FIFO scheduling policy is applied here, where performance enhancement operations like earliest deadline first or others can also be applied for increasing effective systems throughput. If system permits then each queue gets its 10ms frame duration for data delivery, if not then Service_Level_A users gets priority over others, since they are paying more for the service. Within Service_Level_A users, those with good channel conditions get priority over those with bad channel conditions. This particular issue has also been addressed in objective function formula to calculate the cost effectiveness for the system, in order to keep satisfied users. Others may get degraded service if system permits else service disconnects. High Priority Packets Queue for User i Users With Good Channel Condition Low Priority Packets Queue for User i Users Packets Arrival (Poisson) Performance Enhancing Operations High Priority Packets Queue for User i Users With With GoodChannel Condition Users Bad Bad Channel Condition Low Priority Packets Queue for User i Figure 4.2: Packets Scheduling Model 46
  61. 61. 4.6 Summary This chapter presents the accomplished project work. It starts by first describing our project goals. Then we define the problem followed by presenting our system model. Our approach towards designing an efficient objective function has been described in section 4.1.1. Section 4.1.2 covers in detail our implementation plan. The implementation plan has been described in steps. 47
  62. 62. Chapter 5 Conclusions And Future Directions Our project work of designing an objective function for 3G UMTS/W-CDMA mobile wireless networks is a very important contribution towards achieving a balance and tradeoff in QoS/satisfied users and service provider profit margin. The work needs comprehensive testing in several real world situations in order to fine- tune the work for better results. Further studies are required in order to see the performance of several video codecs in choice of our objective function. An efficient and self-healing video-codec can reduce data rate and power requirements for the respective user(s), and hence increase the probability of keeping satisfied users and admitting new ones. In order to induce efficiency in our objective function it has to get tested for several appropriate CAC and scheduling schemes on the downlink for services belonging to all UMTS QoS classes. So, it is a very competitive task and requires lots of simulations and research. Also in achieving our objective its is imperative to fine tune the Cost_Function formula so that it can be adopted efficiently and effectively in a wide range of UMTS wireless network environments. Our approach is at a very basic level, considering a single UMTS cell for a single wireless service (Video Streaming), the system has to be tested and further developed very carefully in steps. So that it will be easy to adopt it for general purpose use, for all the UMTS QoS classes in a wide range of UMTS wireless networks. 48
  63. 63. Further research is required to test our approach for several scheduling and call admission control schemes. So that it can be deduced that which set of scheduling and call admission control methods can be adopted on permanent basis in choice of our designed objective function. Also further research is required in studying codecs for different services, starting with the video streaming service codecs in our case, this will help reduce data rate requirements for those particular services. 49

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