Wireless Communications and Mobile Technology

4.0 “last mile” broadband access solution

Metropolitan-Area networks (MAN) connections to home and business office, especially in those areas that were not served by cable or DSL or in areas where the local telephone company may need along time to deploy broadband service WIMAX is useful. The WIMAX –based wireless solution makes it possible for the service  provider  to scale-up or scale-down service levels in short times with the client request.

4.1  cellular back haul

The networks for cellular base  stations bypassing  the public switched  telephone network (PSTN); the cellular service providers can look to wireless back haul as a more cost effective alternative. The robust WIMAX technology  makes it  a nice choice fir back haul for  enterprises such as hot spots as  well as  point-point back haul solutions.

WIMAX helps back haul enterprise connections to the internet for WIFI hot spots.  It will allow users  to  connect to  the wireless internet service provider even  when they roam  outside  their  home  or  business  office. A variety of new business services by wireless internet service provider are possible.

5.0 WIMAX Usage Scenarios

5.1 Extending the Reach of Communication and Government Services

In Indian cities, house holds with internet access use it to keep  in  touch with their families and friends or in other parts of the country or  abroad. But dial-up connection, currently the most prevalent method of internet access does not provide the service quality or reliability for applications like video chat. Low bandwidth results in video frames being dropped and in poor  audio quality, and makes  the telephone unavailable for the duration of the internet connection

Broadband facilities solve these problems and extend the reach and variety of personal communication to include the efficient VOIP, video conferencing,  instant messaging and quick access to e-mail.

Broadband access can increase the effectiveness of e-governance initiatives E-governance can reduce wait times for service and increase productivity in government offices.

India is already testing the e-governance idea in pilot programs aimed at bringing local government services to people through internet  access. E-seva is  one  such initiative, created by the  Andhra Pradesh  government  to  provide  its  citizens  with online services such as obtaining birth certificates and various licenses, payment of utility bills and taxes, tickets reservations for transportation services and listings of government pay orders and policies.

Gramdoot is a similar initiative by Rajasthan government. The states of Karnataka,  Madhya Pradeshand  kerala  also  have several internet-based  services andliteracy programs. Broader internet adoption driven by cost-effective  technologies like WIMAX can speed-up and extend the reach of government services at a reduced cost toboth the people and government.

5.2 Improved Education, Health Care and Entertainment

With higher bandwidth and faster speeds broadband internet can make education more accessible by delivering interactive distance education at low cost.

In India, schools and libraries in rural or remote areas without wired infrastructure or broadband services can  be  cost  effectively  connected  to  broadband  using WIMAX. Video conferencing tools can help  students to study a  variety of subjects with educators who may  not  be  able to  commute to  remote  areas.  Lecture classes from urban schools and top universities can be broadcast to rural students, and  the students could use the broadband facilities of WIMAX for communicating with  teachers and with their remote classmates.

The Indira Gandhi  National Open University(IGNOU)  is  already encouraging state governments andconventional universities to establish distance learning programs, providing financial support and grants for programs and facilitating development of multimedia materials for delivery through distance learning programs.

Other premier institutions such as the Birla institute of technology and science (BITS), pilani, are already offering distance learning programs through relation- ships  with  industry and  development agencies.  BITS  conducts off-campus  degree programs as  a means of continuing education for the employed professionals as part of the human restores.  Development programs  of  specific organizations  at various  off-campus centers. BITS  offering include  degree  programs  in  math’s,  science  and engineering, computer sciences, medical and health care and other fields. Extensive and reliable broadband internet can help this internet-based quality distance education reach more people across the nation.

Agriculture and health care can also benefit from  broadband  services.  High resolution pictures or real time images of crop diseases can be transmitted to Agricultural experts in a different geographic location  for  immediate expert advice, thuscontaining the  crop  diseases  faster.  Similarly,  doctors  can  use  real-time  video  conferencing to discuss patient symptoms with far away experts, thus providing faster and  better  care to the patients. Videos of this and similar scenarios are available at the Intel web site.

The many social advantages of broadband internet also include telecasting of entertainment programs,  as “on-demand”  movie  and  infotainment  servicebusiness models evolve. Entertainment delivered  via  broadband  could  be  an  event  for  social gatherings in isolated villages.

5.3 Back haul for Meshed Wi-Fi Local Area Network

India has one of the fastest-growing IT industries in the world, and this growth is expected to continue. Broadband internet connectivity is critical for many business, so IT- dependent industry concentrates in areas where broadband service is available. Wireless last-mile broadband could accelerate the development of meshed office wireless LANs (like wi-fi), and business could than backhaul the LAN traffic to the WIMAX network. Service providers will be able to quickly provide on-demand high-speed connectivity to businesses anywhere within their base station range.

6.0 Wi-Fi Mesh Networks, The path to mobile Ad Hoc

6.1 – Makings of a Wi-Fi Mesh Network: Wireless Roaming Cells

(WC) by combining at least two P-to-P or P-to-Mp wireless cells create a roaming effect and thus is the start of a Wi-Fi™ Mesh Network. Roaming is the ability to maintain network connectivity while moving from one access point to another. The basic service set (BSS) is the area of  RF coverage provided by an access point, also referred to as a wireless cell. The AP is the master for the wireless cell and controls traffic flow to and from the network for its given RF circle. The RF coverage of a wireless cell is limited and each county has its own set of rules of cell coverage.

To extend the BSS or to simply add wireless devices and increase the range of an existing wired system, an Access Point can be added, hints this unit is the point at which wireless end users can access the network. Because the wireless end users ranges from PDAs, Laptops, tabletops, PCs, these wireless accessible devices are called Wireless Clients most manufactures.

Normally, Wireless Local Area Networks (Wireless LANs) are configured using a peer-to-multipoint network, which has one access point (AP) that controls communications with other wireless devices accessing the network. Signals in peer-to-multipoint networks converge at a single access point. The reliability of these networks is set by the quality of the RF linkage between the central AP and the end points.
In a real-world application, it can be problematical to find an ideal location for an access point that provides dependable communication
with each end point, especially if two or more floors exist or due to a home’s physical structure. Moving an access point to improve communications with one node will often degrade communications with other end points. The status of a communication link between wireless devices, at any given time, is a function of their positions, transmission power levels, antenna patterns, interference levels, and many other minor phenomena.

7.0 WIMAX Benefits

7.1 cost and investment risks

• Interoperable equipment lets operators purchase WIMAX-Certified equipment from more than one vendor[4].
• A stable,  standards-based  platform  improves  Op  ex by  sparkinginnovation at the network management  layer,antenna layersand elsewhere in the protocol stack.
• Better bits per second per Hz at longer ranges.

7.2 Scalable System Capacity

• Easy addition of channels maximizes cell capacity.
• Flexible channel bandwidths accommodate allocations for both licensed and unlicensed spectrums.

8.0  Today’s wireless applications

Wireless access at LAN speeds:

Workers today need secure access to an organizations network, whether they are at the office, at a branch location, at home, or at the airport. with wireless connection, they can enjoy full access to their applications and data, enabling them to work from a wide variety of locations within range of an access point. Therefore, workers can stay connected and be fully productive from almost anywhere.

Internet/intranet access:

Today, workers require continual access to the internet and to the company intranet. wireless technology lets employees take advantage of these capabilities constantly, conducting research and communicating with co workers and business partners through email and instant messaging. Without the physical restriction of wired connection.

Highly mobile computing:

Currently, most wireless computing is conducted with laptop computers. However, that scenario is rapidly changing and broadening. More and more, wireless vendors are offering silicon solutions that dramatically power consumption and cost of wireless solutions. As a result wireless capabilities increasingly will be featured in smaller devices, such as very small laptops, PDAs and phones .these devices when connected wirelessly to the company network, will become critical productivity tools for workers who do not spend their entire day at a desk

Conclusion:

The IEEE 802.16 wireless MANTM air interface standard provides the wireless alternative to cable and DSL. The WIMAX can offer a solution to what is normally called the “last-mile” problem by connecting individual homes and business offices communications. It’s high throughout, scalability, and QOS features, are combined with techniques for coverage extension. IMAX provides world-wide broadband connectively. The standard is intended to allow for multiple venders to produce interoperable equipment.

References:

1. IEEE 802.16-2001,”IEEE standard for local and metropolitan Area networks-part 16: Air later face for fixed broadband wireless access system”, apr.8, 2002.
2. www.ieee.org
3. www.wimaxforum.org
4. http://computer.howstufffworks.com
5. www.intel.com
6. www.wi-fitechnology.com

Submitted by Anand.Govuri and G.Guru charan