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4G TECHNOLOGY AND ITS SERVICES.

One can wonder how fast the technology is changing in the wireless domain.

Before one could just digest the services of 3G , nowadays the buzzword is

already 4G. Now what is this 4G? What led to the invention of this 4G?4G is a

wireless access technology and is the successor of 3G which is expected to

give100 Mbps speed while moving and 1 Gbps speed while stationary. So we can

say that 4G is developed to provide superior data services compared to 3G.So

whats new in 4G?

4G is an entirely packet switched network where all the network elements are

digital.It has higher bandwidths to provide multimedia services at lower

cost.Moreover, it has a tight network security.

4G networks are all IP based heterogeneous networks.So, this will allow users to

select any system at any time anywhere and use multiple systems at the same

time(eg. GPS and WLAN).4G is a spectrally efficient system with high network

capacity i.e more simultaneous users per cell compared to 3G. In 4G, there

should be smooth hand off across the different heterogeneous networks.4G

provides high quality of service for next generation multimedia support like real

time audio, HDTV video content.

IMPLEMENTATION AND CHALLENGES

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4G is implemented in higher frequency bands of 2 8 GHz, to achieve the

specified standards with a bandwidth of 100 MHz or more. The access system to

be used in 4G are OFDM(Orthogonal frequency division multiplexing) and MC

CDMA(Multi Carrier CDMA). Unlike 3G which is based on two parallel

infrastructures consisting of circuit switched and packet switched network

nodes,4G will be based on packet switching only and this requires low latency

data transmission. By the time 4G is deployed , the process of IPv4 address

exhaustion will be in the final stages. So in the context of 4G, IPv6 is essential in

order to support a large number of wireless enabled devices . IPv6 provides

enhanced security and here multi functioning and mobile function are built in.

Just Plug and Play.

Smart antennas are used in the implementation of 4G networks like switched

beam antennas and adaptive array antennas. Switched beam antennas have

fixed beams of transmission and can switch from one predefined beam to

another when the user moves throughout the sector. Adaptive array antennaspossess signal processing algorithms to locate and track the user , minimize

interference and maximize intended signal reception.

To migrate the current systems to 4G with the features mentioned previously, a

number of challenges are being faced. The challenges are Accessing Different

Networks and Terminal Mobility. The solution to Accessing Different Networks

can be through multimode devices or overlay network .In Multi mode

architecture ,a single physical terminal with multiple interfaces to access the

different wireless network. But here the complexity of the hardware of the

device is increased. Secondly a user accesses an overlay network consisting of

several UAPs(Unified Access Platform). Here UAP selects the wireless network for

the user, but more devices are required in overlay network. The two main issues

in terminal mobility are location management and hand off management.

4G network is still in the development stage , and in order to

utilize their new features too many challenges must be overcome. From

commercial point of view growth of 4G in India still remains uncertain as the 3G

services provided by all operators could manage less revenue as compared to

the investment.

by

ABHISHEK RAY

,JTO(MSC

)