Evolution of LTE 4G Network & Its Techniques

WHAT IS 4G ?

4G Network Architecture

4G is the fourth generation of mobile phone mobile communication technology standards.

It is a successor to the third generation (3G) standards.A 4G system provides mobile “ Ultra Broadband speed” – to be counted in gigabytes per second.
In March 2008, the International Telecommunications Union-Radio communications sector (ITU-R) specified a set of requirements for 4G standards, named the IMT-Advanced.
Set peak speed requirements for 4G service at 100 Mbit/s for high mobility communication and 1 Gbit/s for low mobility communication.
The peak bit rate is further improved by smart antenna arrays for multiple-input multiple-output (MIMO) communications.
A 4G system does not support traditional circuit switched telephony service, but all-Internet Protocol (IP) based communication such as IP telephony.

Evolution of 4G Network

EVOLUTION OF 4G

In April 2006, KT started the world's first commercial mobile WiMAX service in Seoul, South Korea.

In February 2007, the Japanese company NTT DoCoMo tested a 4G communication system prototype with 4×4 MIMO at 100 Mbit/s while moving, and 1 Gbit/s while stationary.

In Dec 2009, The first commercial LTE deployment was by TeliaSonera & NetCom. The modem devices on offer were manufactured by Samsung, and the network infrastructure created by Huawei & Ericsson.

3G Vs 4G

SYSTEM KEY COMPONENTS OF 4G

a) System standards

· LTE Advanced

· WiMAX 2

b) Multiplexing and access schemes

· OFDM+ MIMO, W–OFDM, MC-CDMA

· IPv6 SUPPORT

d) Advanced antenna systems

· Multiple antenna technologies are used to achieve high rate, high reliability and long communication range.

e) Software-defined radio (SDR)

· Standards constituted by a 4G device can be realized using SDR.

A) System standards

LTE

1) Long Term Evolution (LTE) is a radio platform technology that will allow operators to achieve even higher peak throughputs than HSPA+ in higher spectrum bandwidth.

2) LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) on the downlink, which is well suited to achieve high peak data rates in high spectrum bandwidth.

LTE capabilities include:

1) Downlink peak data rates up to 326 Mbps with 20 MHz bandwidth

2) Uplink peak data rates up to 86.4 Mbps with 20 MHz bandwidth

3) Operation in both TDD and FDD modes

4) Scalable bandwidth up to 20 MHz, covering 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz in the study phase

5) Reduced latency, up to 10 milliseconds (ms) round-trip times between user equipment and the base station, and to less than 100 ms transition times from inactive to active

WiMAX 2

· WiMAX stands for Worldwide Interoperability for Microwave Access. WiMAX 2 also called Wireless MAN-Advanced has become the first true 4G technology to be approved by the IEEE and ITU.

· This technology supports MIMO, femto cells, self-organizing networks & relays, and multicarrier operation. It supports both 120Mbps downlink and 60Mbps uplink speeds.

· The unique and excellent infrastructure of WiMAX is offering Ultra-Wideband and providing range from 2 to 10 GHz and outstanding time response.

Shows Mobility & Coverage v/s Data Rates of different Technologies

b) Multiplexing and access schemes in 4G

OFDM

· Orthogonal frequency-division multiplexing (OFDM) is a frequency division multiplexing (FDM) scheme that uses a digital multi-carrier modulation method.

· OFDM uses the spectrum more efficiently by making all the sub-carriers orthogonal to one another, using fast Fourier transform (FFT) to prevent interference between the closely spaced sub-carriers.

· In OFDM, the guard band is reduced by the orthogonal packing of the subcarriers, improving the spectral efficiency .

· Since each carrier in an OFDM signal has a very narrow bandwidth (i.e. few kHz), the resulting symbol rate is low.

· Due to the orthogonal nature of the modulation, these multiple sub-carriers overlap in the frequency domain, but do not cause Inter-Carrier Interference (ICI).

· In OFDM, the guard band is reduced by the orthogonal packing of the subcarriers, improving the spectral efficiency.

FFT- FAST FOURIER TRANSFORM

OFDM MODEL

SYSTEM KEY COMPONENTS OF 4G

IPv6 SUPPORT

The IP address is based on IPv6

Ø IPv4 X.X.X.X (32 bits)

Example: 216.37.129.9

Ø IPv6 X.X.X.X.X.X (128 bits)

IPV6 SUPPORT EXAMPLE

· Needs for security and manageability

· 4G system uses the Internet Protocol version 6 (IPv6) to locate devices.

· There is room for approximately 3.40 * 10³⁸ unique addresses.

· There are enough addresses for every phone to have a unique address.

· Voice over Internet Protocol (VoIP) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks

IP BASED CORE NETWORK

c) Advanced antenna systems

Smart antennas (MIMO) are antenna arrays with smart signal processing algorithms used to identify spatial signal signature such as the direction of arrival (DOA) of the signal, and use it to calculate beam forming vectors, to track and locate the antenna beam on the mobile/target.

Transmitter with multiple antennas

Smart antennas Types

· It offers significant increases in data throughput and link range without additional bandwidth or increased transmit power.

· It achieves this goal by spreading the same total transmit power over the antennas to achieve an array gain that improves the spectral efficiency and to achieve a diversity gain that improves the link reliability.

Example of advanced antenna:

· Switched Beam Antenna

· Adaptive Array Antennas

d) Software-defined radio (SDR)

· Due to the constant evolution of mobile communication systems (2G, 3G, and 4G), the wireless industry is facing problems in global roaming to provide different services to the mobile subscribers. SDR technology promises to solve these problems by implementing the radio functionality as software modules running on a generic hardware platform.

· The main purpose of SDR is to make a user terminal operate in different kinds of wireless networks, overcoming power, cost, size, and compatibility limitations.

· Flexibility and reconfigurability

· Interoperability

· Connectivity

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