4-G wireless systems

Presented by: Rashmi Deoli

ECE 4th year

Contents:

• Introduction

• History

• Technology used

• Applications

• Limitations

4G wireless in one view:

4g is the short name for 4th generation wireless, the stage ofmobile communication that will enable things like ip-basedvoice, data, gaming services and high quality streamedmultimedia on portable devices with cable modem-liketransmission speed.

technology 1G 2G 2.5G 3G 4G

Design began

1970 1980 1985 1990 2000

implementation

1984 1991 1999 2002 2010

service Analog voice, synchronous data to9.6kbps

Digital voice, short messages

Higher capacity, packetized data

Higher capacity broadband data up to 2mbps

Higher capacity,completely ip oriented

standards AMPS,TACS,NMT etc…

TDMA,CDMA,GSM,PDC

GPRS,EDGE,1*RTT

WCD,CDMA MA2000

Single standard

Data bandwidth

1.9 kbps 14.4 kbps 384 kbps 2 Mbps 200 Mbps

multiplexing FDMA TDMA,CDMA

TDMA, CDMA CDMA CDMA

Core network

PSTN PSTN PSTN packet network

Packet network

Internet

About 4G wireless systems

• 4g is the fourth generation wireless network communications technology standard.

• This new generation of wireless is intended to complement and replace the 3g systems.

• 4g infrastructures is consisting of a set of various networks using IP(internet protocol) as a common protocol.

• Application adaptability and being highly dynamic are the main features of 4g services .

• 4g systems are fully ip-based wireless internet

1.Technologies that comprise 4g:4g is based entirely on packet switched networks.

Standards such as 3g and Bluetooth are incorporated in to 4g standards.

2.Need for 4g:firstly 3g’s maximum data transfer rate 384kbps to 2mbps is much slower than 20 to 100mbps of 4g.

With its use of existing technologies and communicationstandards, 4g present a comparably inexpensive standard.

3.Specifications of 4g:4g can provide 10 times increase in data transfer over 3g.

This speed can be achieved through orthogonal frequencydivision multiplexing(OFDM).

OFDM can not only transfer data at a speed of more than100mbps, but it can also eliminate interference that impairshigh speed signals.

4.Potential applications of 4g:

4g provides a seamless network for users who travel and require uninterrupted voice/data connections.

Navigation menus is also present in 4g technology.

It provides a vast number of applications for mobile devices.

Transmission system

4g network example:

Technology used in 4g

• OFDM

• UWB

• Smart antennas

• IPv6

OFDM:

• It transmits a large amount of digital data in a radio wave

• OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver .

• By inserting a cyclic prefix between adjacent OFDM signal inter signal interference is virtually eliminated if the max. channel delay spread is less than the time interval of cyclic prefix.

• In OFDM the subcarrier pulse used for transmission is rectangular.

• Here modulation can performed by an IDFT ,which can be generated very efficiently as an IFFT . so, receiver only needs a FFT to reverse this process.

UWB:

An advanced technology that can be used in 4G technology

It is typically detected as noise.

It can use any part of the frequency spectrum, which means thatit can use frequencies that are currently in use by other radiofrequency devices .

It uses a frequency of 3.1 to 10.6 Hz.

It uses less power , since it transmits pulse instead of continuoussignal.

Special antennas are needed to tune and aim the signal

IPv6

IPv6 means Internet Protocol Version 6 .

The Internet Protocol (IP) is the method or protocol which data is sent from one

computer to another on the internet.

Each computer (known as a host) on the Internet has at least one IP that uniquely identifies it from all other computers on the Internet.

It includes128 bits, which is 4 times more than 32bits IP address in IPv4.

Quality of serviceIn wireless networks, Quality of Service (QOS) refers to the

measure of the performance for a system reflecting its transmission quality and service availability.

4G is expected to have at least a reliability of 99.99%).

In 4G QOS may be divided in following ways-

Transaction-level QOS describes both the time it takes to complete a transaction and the packet loss rate.

Circuit-level QOS includes call blocking for new as well as existing calls .

User-level QoS depends on user mobility and application type .

Software defined ratio

A software defined radio is one that can be configured to any radio or frequency standard

through the use of software.

The phone should automatically switch from operating on a CDMA frequency to a TDMA frequency whenever it is required.

Roaming can be an issue with different standards, but with a software defined radio, users can just download the interface upon entering new territory, or the software could just download automatically.

Application

In traffic control.

Multimedia – video services

Telemedicine.

Crisis Management

Virtual Navigation

Limitations

Cost is another factor that could hamper the progress of 4G technology. The equipment required to implement the next generation network are still very expensive.

A Key challenge facing deployment of 4G technologies is how to make the network architectures compatible with each other. This was one of the unmet goals of 3G.

As regards the operating area, rural areas and many buildings in metropolitan areas are not being served well by existing wireless networks.

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