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Dear students,

A Graded Discussion Board for 'Data Communications (CS601)' will be opened on Tuesday 12 August, 2014 and it will be closed on Wednesday 13 August, 2014.

Discussion Topic

A well reputed organization wants to implement a communication network among its head office and three branches in a city. The communication technology should be able to serve with good quality of service (QoS) and reliability. The organization has to choose either Wi-Fi or WiMAX. In your opinion, which of the given technique is more suitable for such scenario? Give two proper reasons to support your answer in either case.

Read the following instructions carefully before sending your comments:

  1. GDB will have weight-age of 5% of your total subject marks.
  2. Your discussion must be based on logical facts.
  3. You should post your comments on the Graded Discussion Board & not on the Regular MDB. Both will run parallel to each other during the time specified above.
  4. Your comments should be relevant to the topic i.e. clear and concise (Maximum 5-7 lines answer).
  5. Books, websites and other reading material may be consulted before posting your comments. (Do not copy the material as it is.)
  6. No extra time will be given for discussion.
  7. You cannot participate in the discussion after the due date or through e-mail.

Views: 3582

Replies to This Discussion

thanks for sharing sis

in of my view wimax is best because of

1-An ideal Wi-Fi based network reaches around 100metres as it maximum range.Wi-Fi is needed to serve for household and corporate needs of interconnectivity. Wi-Fi technology connects printers to pc etc. 
 whereas an ideal WiMAX network can reach about 80-90kilometers. WiMAX serves a larger network. WiMAX can be used to provide internet services to a larger area.



2-Wi-Fi does not guarantee any QoS but WiMax provide your several level of QoS. Wi-Fi does not provide ubiquitous broadband while WiMAX does.

Please Discuss here about this GDB.Thanks

Our main purpose here discussion not just Solution

We are here with you hands in hands to facilitate your learning and do not appreciate the idea of copying or replicating solutions.

i think the wimax is better then wifi  because

WiMAX is similar to the wireless standard known as Wi-Fi, but on a much larger scale and at faster speeds. A nomadic version would keep WiMAX-enabled devices connected over large areas, much like today.s cell phones. We can compare it with Wi-Fi based on the following factors.

The bandwidth and range of WiMAX make it suitable for the following potential applications:

  • Providing portable mobile broadband connectivity across cities and countries through a variety of devices.
  • Providing a wireless alternative to cable and digital subscriber line (DSL) for "last mile" broadband access.
  • Providing data, telecommunications (VoIP) and IPTV services (triple play).
  • Providing a source of Internet connectivity as part of a business continuity plan.
  • Smart grids and metering

nice 

A few key differences..... 

1. WiFi allows wireless internet surfing at broadband speed at 100m. WiMax allows wireless internet surfing at 1-5km from the radio base station. (Note: That however mean WiMax is more costly than WiFi) 

2. WiFi is cheap or free at some locations. WiMax is expensive and will definitely require a paid subscription. 

3. WiFi is a fixed wireless technology; WiMax is a portable wireless technology (Note GSM/CDMA/3G are 'mobile' wireless technologies. That means you can still be connected while driving a car / riding a train in excess of 100km/h) 

4. WiFi operate at 2.4Ghz, while WiMax operate at 2.3/2.5Ghz. In other words, different frequency bands. 

5. WiFi is commercially available; WiMax is only available from 2008. ( One wonders whether WiMax is reinventing the wheel, when 3.5G (HSDPA/HSUPA/EVDO) will be available by then )

WiMAX is similar to the wireless standard known as Wi-Fi, but on a much larger scale and at faster speeds. A nomadic version would keep WiMAX-enabled devices connected over large areas, much like today’s cell phones. We can compare it with Wi-Fi based on the following factors.

IEEE Standards:

Wi-Fi is based on IEEE 802.11 standard where as WiMAX is based on IEEE 802.16. However, both are IEEE standards.

Range:

Wi-Fi typically provides local network access for around a few hundred feet with speeds of up to 54 Mbps, a single WiMAX antenna is expected to have a range of up to 40 miles with speeds of 70 Mbps or more. As such, WiMAX can bring the underlying Internet connection needed to service local Wi-Fi networks.

Scalability:

Wi-Fi is intended for LAN applications, users scale from one to tens with one subscriber for each CPE device. Fixed channel sizes (20MHz).

WiMAX is designed to efficiently support from one to hundreds of Consumer premises equipments (CPE)s, with unlimited subscribers behind each CPE. Flexible channel sizes from 1.5MHz to 20MHz.

Bit rate:

Wi-Fi works at 2.7 bps/Hz and can peak up to 54 Mbps in 20 MHz channel.

WiMAX works at 5 bps/Hz and can peak up to 100 Mbps in a 20 MHz channel.

Quality of Service:

Wi-Fi does not guarantee any QoS but WiMax will provide your several level of QoS.

As such, WiMAX can bring the underlying Internet connection needed to service local Wi-Fi networks. Wi-Fi does not provide ubiquitous broadband while WiMAX does.

Comparison Table:

Freature

WiMax
(802.16a)

Wi-Fi
(802.11b)

Wi-Fi
(802.11a/g)

Primary
Application

Broadband Wireless
Access

Wireless LAN

Wireless LAN

Frequency Band

Licensed/Unlicensed
2 G to 11 GHz

2.4 GHz ISM

2.4 GHz ISM (g)
5 GHz U-NII (a)

Channel
Bandwidth

Adjustable
1.25 M to 20 MHz

25 MHz

20 MHz

Half/Full Duplex

Full

Half

Half

Radio Technology

OFDM
(256-channels)

Direct Sequence
Spread Spectrum

OFDM
(64-channels)

Bandwidth
Efficiency

<=5 bps/Hz

<=0.44 bps/Hz

<=2.7 bps/Hz

Modulation

BPSK, QPSK,
16-, 64-, 256-QAM

QPSK

BPSK, QPSK,
16-, 64-QAM

FEC

Convolutional Code
Reed-Solomon

None

Convolutional Code

Encryption

Mandatory- 3DES
Optional- AES

Optional- RC4
(AES in 802.11i)

Optional- RC4
(AES in 802.11i)

Mobility

Mobile WiMax
(802.16e)

In development

In development

Mesh

Yes

Vendor
Proprietary

Vendor Proprietary

Access Protocol

Request/Grant

CSMA/CA

CSMA/CA

As wireless networking tends to spread itself outside offices and houses, it becomes utterly needed to invent protocols and systems which could support large scale networking with high data speeds. Several technologies for such wide accesses have been in the communications market such as 2G, 3G and the recent, 4G.  There are, however, many tradeoffs in using these technologies on a larger basis such as providing internet or stream multimedia wirelessly. This is why a new protocol, named WiMAX was incepted. Linguistically, it seems like an extended technological term to Wi-Fi, but there are several differences between these two protocols. This article will explore about various differences between WiFi and WiMax - the two wireless connectivity technologies share.

 

1. Abbreviated Term: Wi-Fi stands for Wireless Fidelity, a term that was more of a marketing stint as it rhymed with Hi-Fi. WiMAX, on the other hand, stands for Worldwide Interoperability for Microwave Access, a term fulfilling technological as well as commercial requirements.

 

2. Official Release: Wi-Fi was officially launched in the year 1997 where as WiMAX came to the picture in the year 2004.

 

3. IEEE Standards: Wi-Fi has been defined under IEEE 802.11x standards where x is various Wi-Fi versions. WiMAX is standardized under 802.16y family of wireless networking where y refers to various WiMAX versions.

 

4. Versions of the Standard: Depending on several factors such as frequency, range, encryption, application etc., Wi-Fi has several versions of it such as 802.11b, 802.11g, 802.11n. On the similar factors, WiMAX has a number of different versions too:802.16a, 802.16d and 802.16e are some popular WiMAX versions.

 

5. Frequency Band: Wi-Fi has been defined under ISM bands where user has to pay no extra charging for utilizing those bands. On the contrast, there is no bar on frequency usage in the WiMAX. This means that WiMAX protocols might work in the ISM bands or they might use a licensed frequency version for which the user probably would be charged.

 

6. Range: An ideal Wi-Fi based network reaches around 100metres as it maximum range whereas an ideal WiMAX network can reach about 80-90kilometers in terms of range.

 

7. Data Transfer Rates: Wi-Fi based networking can transfer data at speeds up to 54mbps. On the other hand, WiMAX networks exchange data at speeds upto 40mbps. In WiMAX, data transfer rates have more variation as distances to be covered are quite larger.

 

8. Channel Bandwidth: Wi-Fi networks have a channel bandwidth of 20MHz, whereas WiMAX networks have a flexible bandwidth option which ranges from 1.25MHz to 20MHz.

 

9. Bandwidth Efficiency: This term refers to bits of information sent per second per unit frequency. This is a measure of how qualitatively the channel is managed by the network. Bandwidth efficiency of a WiMAX channel (upto 5bps/s/Hz) is theoretically twice as efficient as Wi-Fi based networks (upto 0.44bps/s/Hz for 802.11a and 2.7bps/s/Hz for b/g/n standards).

 

10. Difference in MAC Layer: MAC layer is an essential part of an OSI model. It defines communication procedures that a protocol uses.  Wi-Fi’s MAC layer uses CSMA/CA protocol which is not connection oriented while that in WiMAX is connection oriented.

 

11. Encryption Techniques: Encryption techniques in WiMAX include Triple Data Encryption Algorithm and Advanced Encryption Standards. On the other hand, in Wi-Fi, encryption techniques are Advanced Encryption Standard (AES) and RC4.

 

12. Authentication: Authentication is process under Network Security where connection is checked for its identity before being established.  Both these wireless networking technologies apply different set of protocols for authentication purposes. Wi-Fi uses Extensible Authentication Protocol (EAP) Wired Equivalent Privacy (WEP) security algorithms depending on the Wi-Fi version. On the other hand, WiMAX uses X.509 or PKMv2 as authentication algorithms.

 

13. Applications: Wi-Fi and WiMAX, though being used for same purpose of data exchange, are designed to cater two completely different needs. Wi-Fi is needed to serve for household and corporate needs of interconnectivity. Wi-Fi technology connects printers to computer, gaming consoles to router etc.

WiMAX serves a larger inter-operable network. WiMAX can be used to provide internet services to a larger area where it can serve households, mobile phones and even Wi-Fi spots. WiMAX has a different hardware specification and currently WiMAX serving towers tend to be as tall as Wi-Fi towers. On the other hand, Wi-Fi antennas are small enough to be placed on 5 inch by 3 inch routers.

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