Wireless & Unbounded Media

Know what, morning class is truly challenging people's will and faith XD
Struggle almost every morning to wake up and go to class on time, and today is not any exception too. 

I'm quite convinced that even thing as difficult as waking up from sweet slumber has failed to beat me up, what more can defeat me today, right?

Fighting～

Back to the main topic ! Today we learnt about wireless and unbounded media aka unguided media.

What is wireless?

Wireless network : A telecommunication network which its interconnection between nodes is implemented without the use of wires.

Wireless communication : Involves radio frequency, microwave and infrared (IR) short range communication.

Devices commonly use wireless technology are portable computers, desktop computers, hand-held computers, PDA, cellular phones, pen-based computers and pagers.

As for pratical purposes,

1.  Mobile users can use their cellular phone to access e-mail
2. Travelers can access to internet in places like airport using portable computer
3.  Users at home can connect devices to computer to synchronize data and transfer files

Types of Wireless Network

1. Wireless Wide Area Network (WWAN)

 

2. Wireless Metropolitan Area Network (WMAN)

3. Wireless Local Area Network (WLAN)

4. Wireless Personal Area Network (WPAN) 

What is Wi-Fi?

- Wireless-fidelity

- Transmits computer data over distances using radio waves 

- Based on IEEE 802.11 specifications

-describe the underlying technology of WLAN

What is Bluetooth? 

- Industrial specification for WPAN

- A way to connect and exchange information between devices

- Licenced by Bluetooth Special Interest Group

What is Broadband ?

- Provides high speed wireless access over a wide area from devices such as personal computers and data networks.

- Having instantaneous bandwidth greater than around 1 MHz 

- Supporting data rates greater than about 1.5 Mbit/s

Cellular Systems : 0G, 1G, 2G, 3G, 4G

* 4G is 10 times faster than 3G but more expensive.

* 3G- WDMA.EVDO,HSP

* 4g- LTE, Wi Max

Unbounded Media

- Transport electromagnetic waves without physical conductor
- Signals are broadcasting through air
- Available to anyone who has a capable device

Terrestrial Microwave
- Requires line-of-sight transmission and reception requirement
- The taller the antenna, the longer the sight distance
- Signals transmit one-way
- To increase distance, a system (repeater) can be installed with antenna.

2 types of antenna:

 1. Parabolic Dish

 

 2. Horn

Satellite

- Super tall antenna & repeater

- Single bounce

- High quality communication 

- Capable of monitorning any location on earth

- Geosynchronous satellite : orbit speed is based on distance from the planet

- Mininimum 3 satellites to provide full global transmission

Transmission from earth to satellite ---> uplink

Transmission from satellite to earth ---> downlink

Radio frequency 

-a rate of electrical oscillation ranging from 3KHz to 300GHz

-corresponds to the frequency of radio waves

Cellular Phone

 - a device that can make and receive telephone calls over a radio link whilst moving around a wide geographic area

 - It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network.

My little reflection of the day:

Today,my classmates shared us the steps to create a webpage using Microsoft Office 2003.

I learnt quite a lot from the tutorial given by them, for instance, how to hiperlink on a webpage.

I feel that this course has opened a very special window for my life. I view more :)