Powerline Communication (PLC)
It is a fact that there are some places in the world where there is not constant supply of power. Elsewhere in the western part of the world, not only do they have continuous supply of power but they can also transport Internet and many more through the powerlines. Unbelievable is it? Read through.
Powerline Communication or just PLC, is a method of transporting telephony and high data rate services such as the Internet over the electricity supply network. That means you would be supplied Internet, from the transformer station right through to every main socket in a building. Get the picture?
Network industry projections say that powerline communication (plc) technology is going to be a multi-billion dollar industry and of course would be very popular. The impact might be as strong as the television had in the 1950's. So can it be. Because powerlines are ubiquitous. There is at least one power outlet in every room in a home. In comparison, the phoneline solution offers far fewer installed connection points. While wireless solutions can reach most locations within the home, they are probably more expensive than a powerline solution.
Without doubt the powerline represents the most challenging medium over which to transmit signals. The electricity supply network is a noisy environment because of the switching actions of household appliances. In addition, it suffers problems because it is part of an unterminated network with many outlets. Therefore, it has not merited a great deal of serious attention in comparison with RF and phoneline solutions. Security of information is also an issue, especially in multi-unit housing.
Every powerline company has a proprietary approach to networking. None of these methods are interoperable, nor can they coexist. Each company believes that it can effectively create a de facto technology based upon its own approach.
The many different approaches differ from the type of technique used to transmit the information (spread spectrum vs. orthogonal frequency division multiplexing, or OFDM), to the implementation of Quality of Service (QoS), to the frequency bands are used in operation. These unique approaches are a direct result of the need to solve the specific challenges that the powerline poses.
Generally speaking, some of those firms with powerline control backgrounds have been using spread spectrum technology, which is the basis of the CEBus home automation protocol. However, other players believe in OFDM since it offers scalability to higher data rates significantly beyond 10Mbps. However, OFDM is generally perceived as a more expensive solution.
The basic question as to whether the electricity supply network could be used for communication applications has been the subject for research for many years. Narrowband technologies in the kbit/s range have already been available for some time.
Suman Benedicta,
Content Team – BSNL Portal, Intelligroup Asia Pvt Ltd,
content@bsnl.in
http://portal.bsnl.in/Knowledgebase.asp?intNewsId=19635&strNewsMore=more
International Cell-Phone Service
Different wireless service providers, in different countries, use different technologies for their customers. GSM (Global System for Mobile communications) has been picked up as an international standard in most European, African and Asian countries. In this part of the world, GSM operates in the 900-MHz and 1800-MHz frequency ranges. In the United States, there are CDMA, TDMA and iDEN, among others & GSM operates at the 1900 frequency.The standard U.S phones aren't compatible with the international GSM standard.
Varied technology around the world creates problem with international roaming. Different countries use different systems, so there's a chance that the user's phone won't function at all in some parts of the world.
In countries that use GSM 900 MHz and 1800 MHZ, cell phone users can use the same cell phone to connect to the specific service providers in these different countries, GSM-users simply needs to switch subscriber identification module (SIM) cards.
SIM cards are small removable disks that slip in and out of GSM cell phones. They store all the connection data and identification numbers you need to access a particular wireless service provider.
In addition to international compatibility, the GSM standard supports a number of useful features, including
Encryption technology that makes phone calls more secure
Data networking
Group III facsimile services
Short Message Service (SMS) for text messages and paging
Call forwarding
Caller ID
Call waiting
Multi-party conferencing
If the user uses the local service provider’s services, the advantage of using that he gets a local phone number and can pay all the bills at home, just as he would with the domestic cell phone service. But, these service plans are more expensive and will have to pay for incoming calls as well as outgoing calls. In most cases, it's probably easier to get prepaid international SIM cards instead. These prepaid cards incoming calls are free and are charged the local service rate, even though the cards connect you to local wireless providers.
Madhavi Chalamalasetti
Content Team - BSNL Portal, Intelligroup Asia Pvt Ltd,
content@bsnl.in
Charge mobiles while on the move
Mobiles are being used for many purposes. Though they are primarily meant for communication, with many essential features being incorporated in them, it has become necessary to carry these gadgets everywhere. It is also necessary to charge the phones regularly so that communication remains uninterrupted. But, it is also possible for a person to be in a place such as a proverbial Timbuktu, where it may not be possible to find an electrical connection to charge the phone. A new battery-enabled charger from Energizer may help the user charge his mobile anywhere.
Energizer Holdings, Inc., US, is a leading manufacturer of batteries, battery-powered gadgets and flashlights. The company released a portable battery charger called ‘Energi To Go’ that can be used to charge cell phones, iPods and gaming devices, with disposable e2 lithium AA batteries. There are two such battery models - a two-battery charger for mobile phones and a four-battery charger for gadgets such as iPods, PlayStstion Portable and Nintendo DS. According to market research firm Roper ASW, almost 20 per cent of cell phones lose charge at least once a week. This charger lets the users make a call in about 30 seconds of activating ‘Energi To Go’.
With a view to offering greater mobility to its subscribers, Sprint, US, announced that it is bringing ‘Energi To Go’ charger into the market for the first time. The charger has a single-barrel design made from durable aluminium and a patented intelligent control chip that ensures maximum power transfer from the charger to the phone. The charger is also useful for 80 per cent of Sprint Nextel phones. This provides greater flexibility to the customers to charge their mobile phones while on the move.
The power requirements of mobile gadgets have gone up. The ‘Energi To Go’, which is available from Sprint Stores, can be used to access the Internet, send emails, capture photos, play music and listen to radio on a number of models of mobiles. These chargers come with ‘smart tip’ technology that optimises power transfer from the battery to the charger. The ‘smart tip’ assesses the power levels in the AA batteries and the battery in the mobile gadget, adjusting the rate of transfer to appropriate level for each of the gadgets. Many organisations are bringing out cells that are functioning as a link between the present day batteries and the future fuel cells. The Energizer batteries are part of the transition. As of now, Energizer has a strong presence in the alkaline and lithium cylindrical cell market. The company is optimistic that it would be able to experience substantial growth in the years to come with new models of batteries.
Content Team -- BSNL Portal -- Intelligroup Asia Pvt. Ltd.
content@bsnl.co.in
To power mobiles without chargers...
The mobile phone industry has been making efforts to introduce user-friendly features. One such attempt is to power cell phones wirelessly. Splashpower, UK, specialises in wireless power for portable devices. The company has introduced two devices - the Multi SplashPad and the Single SplashPad. These products are based on Paraflux, the patented technology from the company. With this product range, the possibility of provisioning wireless power to a wider range of gadgets has gone up. This technology can be harnessed to offer interoperable and universal wireless charging capacity. The company is making intensive efforts to provide solutions to the power crunch faced by the latest mobile devices that have greater power requirements.
Splashpower's Multi SplashPad allows the users to power many gadgets at the same time just by placing them on the surface of the pad. This device can be used to power mobile phones, PDAs, MP3 players and digital cameras. There is no need to plug in the charger and the process of charging does not consume more time than other plugged charging devices. The Single SplashPad charges one gadget at a time and is capable of working with a wide range of devices. It is thin, light and easy to carry. It is a worthy innovation that can be offered by OEMs to the consumers. Electromagnetic induction is used by the pads to charge mobile devices. The process is similar to that used in charging electric toothbrushes.
The company has also developed receiver modules in order to enable manufacturers to incorporate wireless capacity straight into their mobile products. Splashpower also introduced some accessories that can be used to charge the existing mobile devices. These accessories enable the user to power NTT DoCoMo's FOMA 3G phones and Apple iPod. 'Resonance' is the phenomenon used in these devices by the research team at Massachusetts Institute of Technology. Resonance makes an object vibrate when energy of a particular frequency is applied. When two resonant objects of the same frequency are close, they tend to bond strongly. In this instance, instead of using acoustic vibrations, they exploited the resonance of electromagnetic waves. Electromagnetic radiation includes radio waves, infrared and X-rays.
Systems such as radio antennae that use electromagnetic radiation are not appropriate for the effective transfer of energy because they disperse energy in all directions, wasting it. Hence, the team came up with 'non-radiative' objects that have what is referred to as 'long-lived resonances'. When energy is applied to them, it does not escape and remains bound to them. 'Tails' of energy blink over the surface. When another resonant object with the same frequency comes nearer to the tails, the energy gets transferred from that gadget to the other. A copper antenna designed to possess long-lived resonance is capable of transmitting power to a laptop, which has an antenna resonating at similar frequency. The energy not passed onto the gadget will be reabsorbed. These systems would be capable of transferring energy over a distance of three to five metres.
Reference:
BSNL, India.
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