Orthogonal Frequency Division Multiplexing

Published Date: 02 Nov 2017

1G uses analogue signals with up to 2.4Kbps. It was the simplest type to wireless data and voice was the main traffic. 1G is based on FDMA.

Second Generation (2G)

2G uses digital signals with up to 64Kbps

GSM

Based on TDMA

Going all-digital allowed for the introduction of digital data transfer

SMS

Email

2.5G networks, such as GPRS

Third Generation (3G)

Promise faster communication services (includes voice, fax and internet)

Increased spectrum frequency

Support 144 Kbps bandwidth with high speed movement, 384 Kbps and 2 Mbps for stationary.

Based on either circuit switching or packet switching

Fourth Generation (4G)

From 100Mbps to 1Gbps

Also Known as Beyond 3G

MAGIC

M – Mobile Multimedia

A – Anytime anywhere

G – Global mobility support

I – Integrated wireless solution

C – Customised personal service

(Ibrahim, 2006)

4G definition:

"A 4G system will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to users on an ‘Anytime, Anywhere’ basis and at higher data rates than previous generations." (Basudeo, 2012)

A completely new fully IP-based integrated system or systems and networks achieved after convergence of wired and wireless networks.

Technologies Used by 4G

Communications Architectures

Broadcast layer – fix access points connected by fibre, microwave

Ad hoc / hot-spot layer – wireless LAN

Personal layer gateway – devices that connect to upper layers: cell phone, fax, voice, data modem, MP3 players, PDAs.

Info-sensor layer – environmental sensors

Fibre-optic wire layer – high speed subterranean labyrinth of fibre optic cables and repeaters

Ad Hoc Networks

Spontaneous self-organisation of networks of devices

Not necessarily connected to the internet

4G will create hybrid wireless networks using Ad-Hoc networks which forms mesh networking that is very reliable.

Smart antennas

Allow the same radio frequency to be used for other users without worry about interference.

Can’t keep up transmission speeds while device is moving fast

Smart antennas can be employed to find, tune and turn up signal information. Since the antennas can both "listen" and "talk", a smart antenna can send signals back in the same direction that they came from.

Multiple-input and Multiple-output (MIMO)

MIMO uses single multiplexing between multiple transmitting antennas (space multiplex) and time or frequency.

IPv6

Internet Protocol version 6 (IPv6) support is needed that to support a large number of wireless devices, since IPv6 has much larger address space and removing the need for NAT which is the method of sharing a limited number of addresses among a larger group of devices. However NAT will still be required to communicate with devices on IPv4 networks.

Voice over Internet Protocol (VoIP)

VoIP allows only IP packets to be transferred eliminating complexity ……..

Orthogonal Frequency Division Multiplexing (OFDM)

OFDM allows for transfer of more data than other form of multiplexers (time, frequency, code). It simplifies the design of the transmitter and receiver and allows the use of almost the entire frequency band. OFDM is currently used in WiMax and WiFi. Frequencies are spaced so that they do not interface with each other. OFDM also allows for parallel data transmission which permits the sending of multiple signals simultaneously from the same antenna to other device.

Software Defined Radio (SDR) System

A SDR is the use of software to configure to any radio or frequency standard. In the context of 4G, a SDR would be able to work on different broadband networks and would be able to transfer to another seamlessly while traveling outside of the user’s home network. Its advantage is that it can be dynamically update for emerging wireless standard with new software without any changes to hardware.

Applications of 4G

Virtual Presence

It will provide the user services at all times, even if the user if off-site.

Virtual Navigation

It will provide users with virtual navigation through which a user can access a database of street, buildings, etc., of a large city.

Tele-Geo processing application

4G will combine geographical information system (GIS) and global positioning system (GPS) in which a user will get location querying.

Tele-medicine

4G will support the remote health monitoring of patients via video conference assistance for a doctor at anytime and anywhere.

Education

4G will provide a good opportunity to people anywhere in the world to continue their education online in a cost-effective manner.

Features

Support for interactive multimedia, voice, streaming video, internet and other broadband services.

Fully IP based mobile system

High speed, high capacity and low cost-per-bit

Global access, service portability and scalable mobile services

Seamless switching and a variety of quality of services

Better scheduling and call-admission-control techniques

Ad-hoc and multi-hop networks

Better spectral efficiency

Seamless network of multiple protocols and air interfaces since 4G will be all-IP, 4G systems to be compatible with all common network technologies, including 802.11, WCDMA, Bluetooth, and hyper LAN.

Interoperability with existing wireless networks

An all IP, packet switched network.

Evolution towards 5th Generation

The 5G is a completed wireless communication with almost no limitation; somehow people called it real wireless world with additional features such as multimedia newspapers, also to watch T.V programs with the clarity as to that of an HD T.V. 5G will bring almost perfect real world wireless or called "WWW: World Wide Wireless Web". Wearable devices with AI capabilities

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