UPCOMING WIRELESS TECHNOLOGY

NAVEED RAFIQ
Apr 02 - 08, 2007

OVERVIEW OF WIRELESS GENERATION

Few years back the notion of transmitting information's without the use of wires must have seen like magic. In the late 70's 1 G was introduced featuring the first mobile phone system "cellular mobile radio telephone" which used analog voice signaling, and were little more sophisticated than the repeater networks used by amateur radio operators. Then in early 90's introduced another system called 2 G, which used digital signaling, and then more enhancements brought in wireless communications by introducing 3G system. Recently 3G (WCDMA/UMTS) technology is been widely used. The maximum theoretical data transfer with this 3G technology is 2Mbps (practically it could be a max of 384Kbps or even less). To bring true multimedia capabilities such as high-speed data access and video conferencing to the handset a Japanese company announced another technology, which will be launched properly within 2 years most probably.

INTRODUCTION TO 4 G:

One of the biggest mobile company in Japan NTT DoCoMo which have the distinction of bringing the first 3G network in world market has announced in March, 2002 the proving trial on the next generation of mobile communication technology, which has been called '4 G' (fourth generation). This new technology has already been in the development process since 1998. Currently 3 G is been used worldwide which supports multimedia, packet-based transmission of voice text, broadband and video data at rates from 384 kilo bytes per second (Kbps) to more than 2 mega bytes per second (Mbps). 4 G will increase data transmission rates upto 100 Mbps (uplink) and 20 Mbps (downlink), allowing more bandwidth for new applications such as video phones, video / audio download and interactive games.

4G will represent another quantum leap in mobile Internet speeds and picture quality as its speed could be as high as 100Mbps. It is proved that 4G could bring connection speeds of up to 50 times faster than 3G networks and could offer three-dimensional visual experiences for the first time. The following graph represents what has been the typical progression of wireless communications:

The 4G technology will be able to support Interactive services like Video Conferencing (with more than 2 sites simultaneously), Wireless Internet etc due to its high data transmitting speed. Global mobility would be possible and the cost of the data transfer would also be comparatively very less. 4G would build on the second phase of 3G, when all networks are expected to embrace Internet protocol (IP) technology. Its network based on Ipv6. The antennas will be much smarter and improved access technologies like OFDM and MC-CDMA (Multi Carrier CDMA) will be used. Also the security features will be much better.

OFDM

Orthogonal Frequency division multiplexing (OFDM) spread spectrum technique distributes the data over a large number of carriers that are spaced apart at precise frequencies.

This spacing provides the "orthogonality" in this technique which prevents the demodulators from seeing frequencies other than their own. This is useful because in a typical terrestrial broadcasting scenario there are multipath-channels and due to this it becomes very hard to extract the original information.

MC-CDMA

Multicarrier CDMA is a combination of OFDM and CDMA techniques. MC-CDMA ensures good performance in severe multipath conditions as this technique considered a very likely candidate for future wireless systems because it marries the best of OFDM and CDMA.

Due to a capability of transmitting high data rates upto 100 Mbps 4G is expected to provide high resolution images (better quality than TV images) and video-links as these requires a bandwidth of 100MHz hence allows 3D virtual reality and interactive video/ hologram images. The 4 G technology also increase the interaction b/w the compatible technologies, so that the smart card in the handset could automatically pay for goods in passing a linked payment kiosk. The new communications model has already prompted the development of new versions of HTML, Java, GIF, HTTP and many more useful protocols. However, it is expected that new standard protocols will be required for use with 4G.

Location based services is another notable advance application for 4 G system based on visualized and virtual navigation scheme. It supports a remote database containing graphical presentation of streets, buildings and other physical characteristics of a large metropolitan area. If a subscriber is moving in a vehicle equipped with the appropriate wireless device, he could access the database which would provide the platform on which would appear a virtual representation of the environment ahead. This type of application is reffered to as "Telegeoprocessing", which is a combination of Geographical Information Systems (GIS) and Global Positioning Systems (GPS) working in concert over a high-capacity wireless mobile system.

LIMITATIONS OF 4G

Despite of promising 4 G communications there are certain limitations such as cost. The equipment required to implement a nextgeneration network is still very expensive. In Asian networks implemented technique is Pay-Per-Use model of services but this will be difficult to implement in USA, where the public is used to a service-for-free model (e.g., the Internet), that's why the expenses should be kept realistic.

Another limitation is operating area. Rural areas and many buildings in metropolitan areas are not being served well by existing wireless networks. This limitation of today's networks will carry over into future generations of wireless systems. The hype that is being created by 3G networks is giving the general public unrealistic expectations of always on, always available, anywhere, anytime communications. The public must realize that although high-speed data communications will be delivered, it will not be equivalent to the wired Internet at least not at first. If measures are not taken now to correct perception issues, when 3G and later 4G services are deployed, there may be a great deal of disappointment associated with the deployment of the technology, and perceptions could become negative. If this were to happen, neither 3G nor 4G may realize its full potential.

Fourth generation networks are likely to use a combination of WiMAX and WiFi.

WiMAX

WiMAX (Worldwide Interoperability for Microwave Access) is a wireless industry coalition whose members organized to advance standards for broadband wireless access (BWA) networks. WiMAX 802.16 technology is expected to enable multimedia applications with wireless connections. WiMax also has a range of up to 30 miles, presenting provider networks with a viable wireless last mile solution.

Wi-Fi

Wi-Fi (short for "wireless fidelity") is a term for certain types of wireless local area network (WLAN) that use specifications in the 802.11 family. The term Wi-Fi was created by an organization called the Wi-Fi Alliance, which oversees tests that certify product interoperability. Wi-Fi has gained acceptance in many businesses, agencies, schools, and homes as an alternative to a wired LAN. Many airports, hotels, and fast-food facilities offer public access to Wi-Fi networks.

CONCLUSIONS

The entire network would be packet switched (IP based). All switches would be digital. Higher bandwidths would be available which would make cheap data transfer possible. The network security would be much tighter. Also QoS will imrpove. More effecient algorithms at the Physical layer will reduce the Inter-channel Interference and Co-channel Interference. 4G networks may eventually deliver on all the promises. At times, it seems that technological advances are being made on a daily basis. These advances will make highspeed data/voice-over-Internet-protocol (VoIP) networks a reality.