WEEK 12

RESEARCH PROGRESS

WEEK 11

Presentation week. On this week we are needed to present about our Final Year Project

By internet research and guideline of the RSP website, I have managed to complete this presentation slide on time. Before the presentation, many things that need to be in focus, example :

1. Introduction
2. Literature Review
3. Problem Statement
4. Research Objective
5. Methodology
6. Block Diagram
7. Project Timeline
8. Project Budget
9. Conclusion
10. Reference

With help from advisor and research from internet, I managed to complete this presentation slide.

WEEK 10

FACTOR EFFECT OF VOICE QUALITY

Delay is caused when packets of data / voice take more time than expected to reach their destination. This causes some disruption in the voice quality. However, if it is dealt with properly, its effects can be minimized . 
Delay mainly comes from three components :

1.  delay caused by voice codec algorithms 
2.  delay caused by queuing algorithms of communications equipment
3.  variable delay caused by various factors(i.e. network conditions, VoIP equipments, weathers etc).

It is very important to minimise the voice traffic delay. Thus, a codec algorithm and queuing algorithm needs to be carefully considered. High QoS should be assured by control delay so that one-way communication delay should be less than 150ms. (ITU states that one-way, end-to-end telephony applications should have less than 150ms delay in echo-free environments to ensure user satisfaction). Although traditionally think the end-to-end delay of 150 ms was considered as acceptable for most applications.
However, in reference [James, 2004], the authors state that a delay of up to 200ms is considered as acceptable. Moreover, a one way end-to-end delay between 150ms to 400ms is considered as acceptable for planning purposes. In this study, 200ms will be considered as the maximum acceptable one way end-to-end delay, high end-to-end delay can cause bad voice quality perceived by the end user.

WEEK 9

TYPE OF WIRELESS NETWORK

• IEEE802.11b

802.11b is a WLAN communication standard. 802.11b has a maximum raw data rate of 11 Mbps and uses CSMA/CD as media access method [Wiki, 2011]. 802.11b is using Direct Sequence Spread Spectrum (DSSS) modulation technique defined in the original standard. Compared to alternatives like 802.11a and 802.11g, 802.11b network equipment costs less. Its relatively low cost naturally resulted in many home and small business networks adopting 802.11b. 802.11b transmits in the 2.4 GHz frequency range. This range is unregulated, which means that radio transmitters built into other products may use the same frequency and interfere with the 802.11b network. These products include some cordless telephones, microwave ovens, garage door openers, and baby monitors [Compnetworking, 2011].

• IEEE802.11n

802.11g is another standard in 802.11 groups. 802.11g supports a maximum           data rate of 54Mbps compared to the 11Mbps of 802.11b. To achieve backward compatibility, 802.11g uses the same communication frequency range 2.4GHz as 802.11b, but uses the Orthogonal Frequency Division Multiplexing (OFDM) based transmission scheme as 802.11a [Compnetworking, 2011]. Similar to 802.11b, 802.11g devices suffer interference from other products operating in the 2.4 GHz band, for example wireless keyboards [Wiki, 2011].

• IEEE802.11n 

802.11n is the newest standard for high-speed Wi-Fi networking. 802.11n is designed to replace the 802.11a/b/g Wi-Fi standards for local area networking. 802.11n operates by utilizing multiple wireless antennas in tandem to transmit and receive data. The associated term MIMO (Multiple Input, Multiple Output) refers to the ability of 802.11n and similar technologies to coordinate multiple simultaneous radio signals. MIMO increases both the range and throughput of a wireless network [Compnetworking, 2011].

802.11n operates on both the 2.4GHz and the 5 GHz frequency bands. An additional technique employed by 802.11n involves increasing the channel bandwidth. As in 802.11a/b/g networking, each device uses a preset Wi-Fi channel on which to transmit. Each 802.11n channel will use a larger frequency range than these earlier standards, which will increase the data throughput. Channels operating at 40 MHz are incorporated into 802.11n which doubles the channel width from 20 MHz in transmitting data. These allow data rates up to 600Mbps and can only be achieved with the maximum of four spatial streams using a 40 MHz-wide channel. Channel operating at 20MHz has a data rates up to 248Mbps [Wiki, 2011]. For this study, only 802.11n operating at 20MHz and 2.4GHz frequency band will be used.

WEEK 8

REVIEW ABOUT VOIP

Voice over Internet protocol (VOIP) is the revolutionary technology relatively new though in the communication industry. VOIP is a method that converts the analog signals into digital signals and then converts back to analog signals upon reaching the destination. This is due to the medium that is used for the transmission i.e. the Internet. The packet switching is the digital mode of transmission. Traditional circuit switched networks are easy to implement but they are very costly.

Voice over Internet protocol requires (VOIP) a relatively high-speed Internet connection. A DSL connection is the right form of broadband connection that can work fine for voice transmission. During the conversion from analog to digital some extra information is added to the voice data so that IP should know what the packet encloses. Most of times a priority tag is added to voice packet which makes IP know that this is a voice packet and needs to be transmitted in priority of the data packets. Other techniques are used to provide Quality of Service (QoS) for the quality of the voice.

In IP the data that has to be transferred is divided into many small packets and reach the destination from different paths. At the destination they have to reorganize themselves in the right order. It happens with the voice packets as they are using the IP. In voice packets 160 bits are added by IP so that it can reach the destination (White, Curtis, 2002)

The Real Time Protocol RTP is also used. "It provides timing information that allows the receiver to reconstruct the original timing of the transmitted material in a way that identifies the content being sent, provides security, and notifies the overriding application of lost data." (Gilmer, 2004)

 

Moreover TCP that is used in the data transmission is no longer used in the voice transmission. UDP, User Datagram Protocol is used instead of TCP. By using UDP, we get the facility that we are no longer waiting for the acknowledgement of the information that is carried to the destination. This reduces much amount of time as the source doesn't has to wait for the confirmation from the receiving end and so continues to transmit voice without any stoppage. "It is useful in cases where one sender wants to send the same information to multiple receivers and is not too worried if some pieces get lost along the way." (Gilmer, 2004)

Since PSTN lines can only achieve around 56kbps, they are not suitable for this kind of communication. For that reason DSL and Cable modem are highly preferred as they can achieve more than 10mbps. Time delay can occur if the connection speed is less. So for real time conversation and removal of delay broadband Internet is required.

Still taking in the view that VOIP is a relatively new technology, it has drawbacks. Since it requires Internet connection so if the power goes off, so does the telephone connection. So for this proper settings must take place. "Sound quality and reliability are still not up to the level of traditional telephone service." (Trope & Royalty, 2004)

WEEK 7

RESEARCH FOCUS

This research is about the study of performance of VoIP over IEEE802.11 WLAN network. The performance of VoIP is associated with delay, jitter and packet loss. The result collected from the research will present the performance of different IEEE802.11 standard. Theoretically, the performance of IEEE802.11 WLAN for each standard have different characteristic from each other. This is due to fact that every IEEE802.11 standard has different transmission technique, different band, and different speed which will affect the performance of VoIP directly. Data from this study will be gathered and analyzed. Lastly, the result obtained from this study will be able to benefit other people for future improvement of VoIP implementation. 

WEEK 6

PROBLEM STATEMENT

This research investigates about the performance of VoIP traffic characteristic over IEEE802.11 WLAN. The increase numbers of user using portable devices have made the WLAN as a preferred medium to transfer all type of data across the internet. Unfortunately, there are certain limitations of the WLAN to transmit data in a distance which have impact on the performance of the traffic especially for real time data traffic. Different version of WLAN has different length of coverage.

WEEK 5

PURPOSE

The purpose of this study is to evaluate the performance of VoIP over :

• IEEE802.11b
• IEEE802.11g
• IEEE802.11n  

WEEK 4

PROJECT DESCRIPTION

VoIP is one of the fastest growing Internet applications today. 

It has 2 fundamental benefits compared with voice over traditional telephone networks

1. by exploiting advanced voice compression techniques and bandwidth sharing in packet-switched networks, VoIP can dramatically improve bandwidth efficiency. 
2. it facilitates the creation of new services that combine voice communication with other media and data applications.

Driven by huge demands for portable access, the Wireless LAN (WLAN) market is taking off quickly. Due to its convenience, mobility and high speed access, WLAN represents an important future trend for the Internet access. 

As a result of the convergence of these two trends, VoIP over WLAN is emerging as an important Internet application and technology.

WEEK 3

Voice Over Internet Protocol

VoIP is a technology that has the ability to transmit voice over data or Internet Protocol (IP) networks. It works in a manner similar to sending email, but instead of only transmitting packets of data.VoIP can send and receive both voice and data packets.VoIP is becoming one of the most widely used technologies today, there are many people and organizations are using VoIP systems worldwide.

VoIP communication software products are already available on the internet. All of them can provide good quality, cheap, and even free phone calls

EXAMPLE:

WEEK 2

INTRODUCTION

Voice over Internet Protocol (VoIP) is a form of communication that allows you to make phone calls over a broadband internet connection instead of typical analog telephone lines .

Public Switched Telephone line (PSTN)

*p/s : This proposal concentrates on the performance VoIP in UniKL BMI network.

WEEK 1

Assalamualaikum.Hye.. I'm Mohammad Syazwan Sahid 51262111324. Data Communications' student,I will present my final year project. 

Title for my project is "PERFORMANCE OF VOIP IN BMI NETWORK".

*p/s : Attend briefing for Fyp Degree students' at Dewan Gemilang University Kuala Lumpur British Malaysian Institute .