Power Line Communication

Powerline Communications, is a breakthrough communications technology for high-speed data, voice and media transfer over existing power lines. PLC provides home networking and broadband internet access using existing electric infrastructures without the need to install new networks. PLC is a cost effective wide broad band telecommunication system offering high speed, opening a wide range of new business opportunities and improving the operations of the electric system.

Power lines, unlike fiber-optic lines, are already installed in U.S. homes. Current power line speeds are 3-4 megabits per second, but a new generation of modem chips has opened the door to in-home access at about 10Mbps. The average U.S. broadband connection speed obtained through cable or DSL now stands at about 2Mbps.

36 million U.S. homes are connected to the Web through broadband. By next year, the number of broadband subscribers in the U.S. will surpass the number of Dial-up users and comprise more than half of the nation’s 83 million Internet households. Fees for broadband access, meanwhile, are dropping by double-digit percentage points annually.

South Korea, with a population about one-sixth that of U.S., has 17 million broadband users, an 80% percent penetration rate. More importantly, those users pay no more than American broadband subscribers and get access speeds at least four times those of the U.S. broadband; and often as fast as 20Mbps. Japan has 25 million subscribers who receive such super-fast services. In both markets, access fees average about $20 a month, significantly less than what Americans pay.

There are about 140 million broadband subscribers worldwide and this number is expected to become more than double by the year 2008.

For utilities, existing power lines are capable of delivering the radio frequencies that carry broadband data. What they need to install are fiber lines that carry bits of data from a central distribution office and “inject” them onto localized power grids. From there the data can be distributed to individual homes. A bonus for consumers is that once a home is subscribed, any power outlet can be used to link all components capable of networking, eliminating the need to invest in Ethernet cabling or a wireless system.

PLC promises high-speed data transmission with higher data rate than ADSL without adding new wiring, and it enables broadband services like internet and VoIP easily through existing power lines.

As there remain technical problems on distance and quality of telephone lines, broadband Internet service has not been expanded in Russia. The 200Mbps PLC modems shipped to Russia promise high speed communication services over access networks. They consist of a head end, which receives high-speed communication signals, a repeater, which amplifies the signals, and customer premises equipment (CPE). That is installed at the subscriber house. The modems employ the orthogonal frequency division multiplexing (OFDM) modulation scheme, and achieve low-noise communications by superimposing many sub-carriers. PLC chips by DS2, a Spanish chip vendor, are adopted in the modems.

Communication deployment of PLC has been accelerated in Europe and USA. In Korea, regulations on PLC will be eased in this month to promote PLC deployment. Only experiments are allowed in Japan due to concerns that the PLC radiation could cause interference to other radio receivers. Deregulation of PLC services in Japan is expected after the influence of PLC on radio receivers is evaluated.

Broadband over Power Lines (BPL), is also known as power-line internet or Powerband is the use of PLC technology to provide broadband Internet access through ordinary power lines. A computer (or any other device) would need only to plug a BPL “modem” into any outlet in an equipped building to have high-speed Internet access.

BPL offers obvious benefits over regular cable or DSL connections: the extensive infrastructure already available would appear to allow more people in more locations to have access to the internet. Also such ubiquitous availability would make it much easier for other electronics, such as televisions or sound systems to hook up. However, variations in the physical characteristics of the electricity network and the current lack of IEEE standards mean that provisioning of the service is far from being a standard, repeatable process and the amount of bandwidth a BPL system can provide compared to cable and wireless is in question. High-speed data transmission or broadband over the Power Line uses the electric circuit between the electric substations and home networks. A standard used for this is ETSI PLT.

PLC modems transmit in medium and high frequency (1.6 to 30 MHz electric carrier). The asymmetric speed in the modem is generally from 256kbit/s to 2.7 Mbit/s. In the repeater suited in the meter room the speed is up to 45 Mbit/s and can be connected to 256 PLC modems. In the medium voltage stations, the speed from the head ends to the internet is up to 135Mbit/s. To connect to the internet, utilities can use optical fiber backbone or wireless link.

The functionality of the system is very simple. An MV Node injects data coming from the Network Operator into the medium voltage power line. Data flows over the electric grid from the substations to the final users’ socket. This data is sent using different frequency bands through the low voltage lines, where repeaters are installed. A repeater regenerates the PLC signal on the low voltage lines between home units, including an MV Node, an LV Head End, another Repeater and CPEs. Finally, the end user connects the CPE, design for quick and easy installation, to one standard electric socket to receive the data signals.

PLC allows access to new territories in developing countries, remote rural areas, and residence buildings. This technology is generally applicable to all types of network specifications, topologies, frequencies, and voltages. Large- scale projects can be implemented and economically attractive. It provides new sources of revenue for companies. It uses existing power lines so there is no need for additional cable connections. It offers point-point multipoint access via distribution lines for multiple users with only one master modem. It provides fast data access rate in the high frequency band. Helps in improving the use of existing fixed assets, and enables energy efficiencies, cost savings and operational improvements.

Submarine Cable

Fiber optic technology experienced a phenomenal rate of progress in the second half of the twentieth century. Early all-glass fibers experienced excessive optical loss, the loss of the light signal as it traveled the fiber, limiting transmission distances.

This motivated scientists to develop glass fibers that included a separate glass coating. The innermost region of the fiber, or core, was used to Transmit the light, while the glass coating, or cladding, prevented the light from leaking out of the core by reflecting the light within the boundaries of the core.

In 1990, Bell Labs transmitted a 2.5 GB/s signal over 7,500 km without regeneration. In their experiment in 1998, Dense Wavelength-Division Multiplexing (DWDM technology, which allows multiple wavelengths to be combined into one optical signal), increased the total data rate on one fiber to one terabit per second (10¹² bits per second). Today, DWDM technology continues to develop. Because of fiber optic technology’s immense potential bandwidth, 50 THz or greater, there are extraordinary possibilities for future fiber optic applications. Broadband service available to a mass market opens up a wide variety of interactive communications for both consumers and businesses, bringing to reality interactive video networks, interactive banking and shopping from the home, and interactive distance learning.

With the installation of the submarine cable at its landing station at Cox’s Bazar coast, BangladeshMay 20^th 2006. Thus a door to new opportunities has opened. Now our country will have a 10-gigabyte data-transfer capacity per second that is, 68 times higher than the current speed. The capacity is considered adequate for the next 10 years and the submarine cable has a life of 15 years. The commissioning of the new systems is supposed to set a landmark in the country’s telecommunications and information communication technology sector as it should tremendously enhance the performance and capacity in this field. IT-enabled value-added services like call centre, tele-medicine, and distance education at overseas universities are among the sectors of the high-tech productive activities. The state-owned Bangladesh Telegraph and Telephone Board (BTTB) and over 100 Internet service providers (ISP) now have a 155-megabyte data-transfer capacity per second. embarked onto the global information superhighway on

The South East Asia-Middle East-West Europe-4 project connects the country with undersea optical fibre passing from Singapore through Malaysia, Thailand, Bangladesh, India, Sri Lanka, Pakistan and a number of Middle-Eastern countries to finally land in France. Bangladesh earlier signed an agreement with 12 countries under a consortium in 2004 to implement a mega-project at a cost of Tk 628 crore for installing the submarine cable down the seabed. But earlier unfortunately, Bangladesh had missed the opportunity to get onto the information superhighway by not joining the group when the submarine cable passed through the Bay of Bengal.

Under the Submarine Cable Project, the government claims to be implementing a number of schemes. Those include construction of cable-landing station, a 22,000-kilometre trunk route and 1,200-1,400-km branch route of submarine cable, installation of optical fibre link between Chittagong and Cox'sbazar along the highway, upgrading the existing Chittagong-Dhaka optical fibre link, installation of optical link between Chittagong and Cox'sbazar over electrical grid line and other installations.

So, the submarine cable is expected to enhance the capacity of telecommunications and data transfer significantly from the present level, giving a high-speed, low-priced Internet and telecommunications gateway to the users to catch up with the fast-moving world. Our country will earn millions of foreign currency using this cable. And through our covered eyes this is only a superficial hope regarding the future of submarine cable. But the actual situation is not so!

It is true that the country has linked itself to the super highway but no policy has been made whatsoever in order to distribute or to make proper use of the connection. The present owner of this submarine cable is ‘Bangladesh Telegraph and Telecommunication board’ (BTTB).

Hostilities arose between the BTTB and the Internet service providers (ISPs). Most of the ISPs can not accept the authority of BTTB over the submarine cable. It is because internet, mobile and fixed telephones service are the prime uses of the submarine cable. BTTB itself has all three services. Therefore question is arising that how will BTTB justly distribute the band width among others.

[The Internet service providers, including the ISPAB and such other trade bodies, are willing to create a committee for monitoring all related matters regarding the submarine cable. They lawfully can not accept the monopoly of BTTB’s control as there is a competition between the service they provide and that of BTTB.] They believe that BTTB neither has any mission nor any vision to make any kind of policy regarding the distribution of the bandwidth.

As we know that the submarine cable that our country is connected to has a capability of carrying 10 gigabytes per second. But the interesting news is that, at present only 155 MB/s data is being transmitted using this cable. It is found that due to the scarcity of necessary equipment and infrastructure the complete capability of the submarine cable can not be used at the moment. And for that reason BTTB has to be satisfied by only 155MB/sec transfer rate. A part of this rate is being used by BTTB and the rest is distributed to the ISPs. At present the STM1 is active for which only 155MB/sec is available from the submarine cable. The BTTB should implement STM 16 as soon as possible. But BTTB does not have the required equipments or infrastructure. In order to do so, altogether BTTB will probably take a few years or so.

[Moreover, complains are arising that BTTB has scarcity of technical personnel with the proper knowledge in this field and it is evident from the present situation that even after the submarine cable has been connected, the relevant works are proceeding very slowly. Therefore it is a matter of great suspicion that whether BTTB will be able to provide the submarine cable service properly or not. ]

The submarine cable connection has been disconnected about 9 times from the time the submarine cable has been connected till today. So the concerned people are suspecting that this kind of ill event may occur many times in future. Therefore, if the internet connection is made solely dependent on submarine cable, then in future the ISPs will be in trouble as BTTB does not have any backup line at the moment. Almost in every country they have backup lines for the submarine cable because at any time the cable can be disconnected in some other country or for some other unavoidable reasons. BTTB claims that they shall provide backup through (Very Small Adapter Satellite) VSAT and microwave. But this backup is very weak and therefore the internet service providers will have to use their own VSAT to implement backup.

Recently, BTTB has announced a new tariff plan for using internet. The rate for getting less than 2MB/sec using CMEU4 submarine cable is as follows: Registration fee=20,000 Taka, Testing fee= 75,000 Taka, for 128 KB/sec, modem charge=84,000 Taka, Yearly fee=21,000 Taka, For 192kB/sec – 1MB/sec, life time charge=1,26,000 Taka and yearly fee= 31,500 Taka. For more than 1 MB/sec, Life time charge= 2, 31,000 Taka and yearly fee= 57,750 Taka.

Through the tariff plan announced by BTTB, the public will not be benefited because there is no chance of any change in the current rate. Since the ISPs will keep their own VSAT as backup along with the submarine cable, the cost of the ISPs will not be any less and therefore they will not be able to provide the internet service to the public at any lower price than that existing at present. But taken as a whole it can be expected that the speed of the present connection will be enhanced. The work that required 1hour previously can now be done in about 40 minutes.

Many media has transmitted the news that Bangladesh will be able to earn millions of foreign currencies by giving voice related services when Bangladesh will be connected to the submarine cable. However, it is also true that VOIP is still illegal in our country. VOIP should be made legal if the business of call centers is to flourish. While distributing bandwidth to the ISPs BTTB has set prohibition regarding the voice related services. As a result businesspersons can not do any business regarding call center at the moment.

Now the fact is that some of the own personnel of the government is doing the VOIP business illegally and for that reason the government is suffering from indecision. But if the government grants special permission then call center can thrive and in that case the law will no longer interfere. If VOIP is made legal, each year the country will earn about 1500 crore taka. Simultaneously, the profit of the government will increase. The country will get increasingly more work related to call center. The amount of work will increase to such an extent that in the first two years there will be job opportunity for about 1 million people.

Therefore the difficulties of taking the full advantage of the submarine cable can be summarized as follows:

1. Only 155 megabytes per second data is being transferred using this submarine cable that has a capacity of 10 gigabytes per second.
2. Since there is no strong backup, the ISPs can not rely completely on the submarine cable.
3. Instead of the price being lowered, the price of the internet service would remain the same.
4. To provide the full advantage of the submarine cable it would take BTTB few more years.

It is not a fallacy that the submarine cable should open doors to thousands of possibilities. But to prove it real, the proper distribution of bandwidth of the submarine cable is vital. Moreover it has to be distributed throughout our country. At the same time, the confinement imposed by the law of our country should be eliminated. To get the complete advantage of this submarine cable, the government, the non-government organizations, the enlightened society and the general public must step forward and work together in unison. Then only we can expect to see our country accelerate in the field of information technology.

P.S. This Article of mine was published in August 24, 2006 in Daily News Today