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Saturday, October 6, 2018

Making Money Online Through Selling Stuff

Do you have a store that sells various stuff like art materials, clothes, memorabilia, toys and other goods? If you have a knack for selling stuff, you can start making money online via e-commerce. This is where most businesses right now start. E-commerce is a term that became very popular in the last few decades. A lot of people are taking advantage of the services offered by these sites. It is a lot more convenient to buy stuff since they are delivered to our homes already. If you have something to sell, you have a lot of channels to utilize. You can do eBay selling, creating a website, selling via social network and others.

  • eBay is one of the most popular options when it comes to selling stuff. From random items to mainstream gadgets and vintage finds, there is something that you will come up at eBay. Set up your account, market your site. Become a certified seller and make your terms and conditions clear to your clients. Like in all platforms of e-commerce online, you need to make sure that the products that you sell are original and high quality. If there are lies and tears, include in the description. Be transparent with your customers.
  • If you prefer to make it a dedicated site that really caters only to your particular services, having a website made is a great option for you. It is much more expensive but it made well, it looks professional. Here you need to set up a payment tool. You can use options like E-wallet services for payments. Credit cards are necessary also. Make sure that the payment methods are secured using a Secure Socket Layer. It is a lot of investment to set up a solid website so if you think this is not for you, you can go to other channels to sell your stuff.
  • You can use social media to sell your stuff. There are some who use Facebook to create accounts dedicated to their products. They upload images, type in the information and the payment methods. This is very informal but works if you sell seasonal items or goods like pastries or other home made products. It is free but it does require a little bit of work to make it more reliable to possible buyers. This is more effective to very limited audiences and these run only in local settings.






Friday, October 5, 2018

The Advantages and Disadvantages of Being Selfless






In my previous article, I looked at some of the advantages and disadvantages of being a selfish person. In this article I will be taking a look at the other side of the coin, the advantages and disadvantages of being a selfless person.

The Advantages Of Being A Selfless Person

The majority of the advantages you gain from being selfless are inner benefits. It feels really good when you can help people out who are in a bad situation. Sometimes the smallest action or caring word can make a big difference in someone's life.

Another thing to consider is that by being selfless and helping others, you are building up good karma. For those that do not like the term karma, you can look at it as simple cause and effect. If you do a lot of good, you can expect it will be returned to you. That goes the same for evil, doing a lot of evil things will catch up to you sooner or later. You reap what you sow.

Perhaps one of the nicest advantages you can enjoy from being selfless is the chance to meet and associate with other selfless people. You generally will not find selfish people volunteering their time and helping people. It is much easier to have mutually beneficial and satisfying friendships, partnerships, and relationships with people that care about you and not just themselves.

The Disadvantages Of Being A Selfless Person

Unfortunately, being altruistic is not all puppies and rainbows. You will have to deal with selfish people that take advantage of your kindness. In some cases, helping a person one time will cause that person to expect you to do anything they want, whenever they want. When you inevitably have to tell them no, they become very angry.

Even people that are not selfish may try to monopoly your time and energy, sometimes unwittingly. They just might really enjoy your company and the good feelings you give them, so they want to be around you as much as possible. Usually a gentle, yet firm reminder that there are other people and obligations in your life that will take care of this issue.

Another possible disadvantage can come from being so selfless that you ONLY think of others and neglect your own needs. You must remember to take care of yourself so that you can continue to help others.

The Bottom Line

In my mind, the advantages of being a selfless person considerly outweigh the disadvantages. As long as you remember to stand up for yourself and take care of yourself, becoming a more selfless person will help to make the world a better place.






What Are Indoor Positioning Systems?






Is the Indoor Positioning System (IPS) something new to you? If so, you should know that it is similar to a GPS that is designed for indoor environments. IPS is used to locate objects or people in a building through a smartphone or tablet. While the technology is new, services that make use of IPS are getting popular in airports, shopping malls, and other venues where LBS and navigation are required.

How does this system work?

This technology uses the internal sensors of a smartphone to locate the indoor position of the device with mathematical algorithms. It's possible to get an accurate location by combining the data from the sensors.

For better user experience, IPS depends upon three elements: the IPS apps, beacons that send signals and the positioning platform.

The technology options

The Indoor Positioning Systems has several approaches. For instance, you can take systems that use RFID, Bluetooth, WiFi or a combo of these technologies. Moreover, when doing the evaluation of the IPS technology, you may want to consider how the extra expensive infrastructure can be minimized and the costs are reduced. As far as the lowest cost and simple option is concerned, you may want to go for a WiFi-based system.

WiFi-based positioning

WiFi-based systems make use of the current infrastructure in order to locate devices without the hardware calibration. For instance, you can read up on the Cupid system of HP that can locate any WiFi-enabled device with an accuracy of 2 meters.

Actually, this type of system sends and receives wireless signals. On the other hand, the WiFi-based system works through the measurement of the distance of the signal from different access points in order to calibrate the position of the device. The access point sends the data back to the relevant "location service". This is the server that runs the analytics and algorithms in order to pinpoint the exact location.

Benefits of the IPS in the office

IPS allows asset tracking, physical security, smart buildings and network management. For instance, if you know the location of a certain device in an office, you may adjust the security settings whenever the device is taken out of the building.

In a big office, you may choose to make it easier for the staff to look for the roaming staff, printers or the conference room. Aside from this, you may also monitor the device location over a certain period and show the staff activity in the office.

As far as practical uses are concerned, IPS has a lot to offer. As a matter of fact, it's become an emerging technology in different industries like hospitality, health and retail, just to name a few. So, if you are looking for a way to improve your customer experience or staff productivity, we suggest that you try out an IPS.

So, this was a brief introduction to the Indoor Positioning System (IPS). If you have an office, we suggest that you use this system to improve the production of your staff and manage other things.






When Money Is The Problem

The use of paper money dates back to the times of the Chinese in 800 AD. Many events happened along the way, where the paper money was used and abandoned and used again. It was during the Civil War that use of paper money to fund the soldiers became paramount. Today, money is the way things happened in the modern world. Without it, no business would exist; without business, no money revolves. In other words, the world would have not been what it looks today.

There are quiet a number of good and bad things when money is the problem. If for example, a country loses its currency and suffers from a greatly devalued currency. Although it is highly for a country's currency to turn zero and worthless, there can be catastrophic consequences that the government and the people will face.

First, the demand for imports would drop to almost zero due to very prices that can no longer be afforded by that country's currency. Also prices for almost everything will skyrocket. This is termed hyperinflation. Second, export demand would hit the ceiling. More countries would buy due to almost ground level prices of export goods. Third, most foreign countries then would look at that country as economically and politically unstable, so their unwillingness to invest.

The upside potential is that the government may have a chance to consider starting again, if there is ever such a thing for countries, but, it seems to be like that for a country that has a way too devalued currency. Much like the computer's reset when it gets stuck somewhere. However, the trail still ends up with one domino collapsing one after another.

There are many factors why this event might be feasible. But the fear of most is when too much politics gets into the arena that instead of the issues at hand are being addressed, most of the energy of policymakers and lawmakers are being diverted into something else. Although rarely does this concept happen, but like I said, it is possible.

In 2008, at the aftermath of the global financial crisis due to the massive housing bubble rupture in the United States, the domino reached to as far as Iceland. The country was in the brink of a nationwide bankruptcy. Prices of goods soared high and stock market prices plummeted.

While its true that the world is being fueled by economies from the different regions through the different countries, governments and financial institutions, the world's downfall can also be instigated by few of the world's leaders and decision makers. Therefore, those that run governments and political machineries should be conscientious enough to put the interest of the major above any personal intention and selfish gain.






Protect Your Android Device From Malware






The adoption rate of mobile devices continues to soar, with Android leading the way. The open-source operating system that is led by Google is now found on more than half of all smartphones. This massive user base has addressed the attention of cybercriminals, who have begun to double down on their efforts to illegally obtain personal information from Android owners. While most mobile malware is found in countries like Russia and China, users from Europe and the United States are not completely immune.

There are a few simple steps you can take to avoid getting your data locked up in an encrypted jail.

  1. App source
Only download apps from trustworthy sources like the Google Play Store. Be wary of any site that allows you to download paid apps for free.

  1. App permissions
Even when downloading from the Google Play Store you need to be careful. Check the permissions the app requests for. Often, apps that include malware will ask for a lot of permissions so that they can quickly gain control of all of your phone's data.

  1. Settings
Google includes numerous settings in the Android operating system that can prevent malicious attacks. Devices running Android 2.2 or higher, which essentially means almost all Android devices, have access to Google's malware scanner. Prior to installing an application, you downloaded outside of the Play store, Google will scan the app and warn you of any potential threats.

  1. Software updates
While this may not be an option for most users, if there is an update for your device make sure you download and install it. Manufacturers, carriers, and Google are constantly pushing out updates with bug fixes, enhancements, and new features that can make your device more secure.

  1. Antivirus apps
The Google Play store is also home to hundreds of antivirus apps that can offer an extra layer of protection. Companies like Avast, AVG, BitDefender, Kaspersky, Sophos, Symantec (Norton), and TrendMicro have long established and histories as some of the most trusted brands in the industry.

  1. Back up your data
Keep your device backed up. You can do this:

  • On your computer.
  • Using a cloud based back up service like Google Drive.
  • On a portable hard disk like a USB pen drive.

Tips on Android ransomware removal

The instructions provided below should help you to remove Android ransomware as well:

Reboot your phone into Safe Mode:

  • Find the power button and then press it for a few seconds until you see a menu. Click Power off.
  • Once you receive a dialog window that suggests you to reboot your Android to Safe Mode, select this option and press OK.
  • If this did not work for you, just turn off your device and then turn it on. Once it becomes active, try pressing and holding Menu, Volume Down, Volume Up or both these buttons together to see Safe Mode.
Uninstall malicious and / or any suspicious and unknown apps:

  • When in Safe Mode, go to Settings. Then, click on Apps or Application manager (this may differ depending on your device).
  • Here, look for the previously-mentioned suspicious app (s) and uninstall them all.

Modern Malware threats are evolving all the time but taking these steps will make it much harder for hackers to gain control of your data. Most of the time cyber criminals are looking to take advantage of silly mistakes that people are making every day. Stay vigilant and 99% of the time you'll stay safe!






The Effects Of Balance Of Trade Surplus And Deficit On A Country's Economy

INTRODUCTION

It is in no doubt that balance of trade which is sometimes symbolized as (NX) is described as the difference between the monetary value of export and import of output in an economy over a certain period. It could also be seen as the relationship between the nation's import and exports. When the balance has a positive indication, it is termed a trade surplus, ie if it consists of exporting more than is imported and a trade deficiency or a trade gap if the reverse is the case. The Balance of trade is sometimes divided into a goods and a service balance. It encompasses the activity of exports and imports. It is expected that a country who does more of exports than imports stands a big chance of enjoying a balance of trade surplus in its economy more than its counterpart who does the opposite.

Economists and Government bureaus attempt to track trade deficits and surpluses by recording as many transactions with foreign entities as possible. Economists and Statisticians collect receipts from custom offices and routinely total imports, exports and financial transactions. The full accounting is called the 'Balance of Payments'- this is used to calculate the balance of trade which almost always result in a trade surplus or deficit.

Pre-Contemporary understanding of the functioning of the balance of trade informed the economic policies of early modern Europe that are grouped under the heading 'mercantilism'.

Mercantilism is the economic doctrine in which government control of foreign trade is of paramount importance for ensuing the prosperity and military security of the state. In particular, it demands a positive balance of trade. Its main purpose was to increase a nation's wealth by imposing government regulation concerning all of the nation's commercial interest. It was believed that national strength could be maximized by limiting imports via tariffs and maximizing export. It encouraged more exports and discouraged imports so as to gain trade balance advantage that would eventually culminate into trade surplus for the nation. In fact, this has been the common practice of the western world in which they were able to gain trade superiority over their colonies and third world countries such as Australia, Nigeria, Ghana, South Africa, and other countries in Africa and some parts of the world. This is still the main reason why they still enjoy a lot of trade surplus benefit with these countries up till date. This has been made consistently predominant due to the lack of technical-know how and capacity to produce sufficient and durable up to standard goods by these countries, a situation where they strictly rely on foreign goods to run their economy and most times, their moribund industries are seen relying on foreign import to survive.

What is Trade Surplus?

Trade Surplus can be defined as an Economic measure of a positive balance of trade where a country's export exceeds its imports. A trade surpluses represents a net inflow of domestic currency from foreign markets and is the opposite of a trade deficit, which would represent a net outflow.

Investopedia further explained the concept of trade surplus as when a nation has a trade surplus; it has control over the majority of its currency. This causes a reduction of risk for another nation selling this currency, which causes a drop in its value, when the currency loses value, it makes it more expensive to purchase imports, causing an even greater imbalance.

A Trade often usually creates a situation where the surplus only grows (due to the rise in the value of the nation's currency making imports cheaper). There are many arguments against Milton Freidman's belief that trade imbalance will correct themselly naturally.

What is Trade Deficit?

Trade Deficit can be seen as an economic measure of negative balance of trade in which a country's imports exceed its export. It is simply the excess of imports over exports. As usual in Economics, there are several different views of trade deficit, depending on who you talk to. They could be perceived as either good or bad or both immaterial depending on the situation. However, few economists argue that trade shortcomings are always good.

Economists who consider trade deficiency to be bad believes that a nation that consistently runs a current account deficit is borrowing from abroad or selling off capital assets-long term assets-to finance current purchases of goods and services. They believe that continual borrowing is not a viable long term strategy, and that selling long term assets to finance current consumption undermins future production.

Economists who consider trade deficiency good associates them with positive economic development, specifically, higher levels of income, consumer confidence, and investment. They appeal that trade deficit enables the United States to import capital to finance investment in productive capacity. Far from hurting employment as may be earlier perceived. They also hold the view that trade deficit funded by foreign investment in the United States to help boost US employment.

Some Economists view the concept of trade deficiency as a mere expression of consumer preferences and as immaterial. These economists typically equate economic well being with rising consumption. If consumers want imported food, clothing and cars, why should not they buy them? That ranging of Choices is seen as them as symptoms of a successful and dynamic economy.

Perhaps the best and most suitable view about Trade deficiency is the balanced view. If a trade deficit represents borrowing to finance current consumption rather than long term investment, or results from inflationary pressure, or erodes US employment, then it's bad. If a trade deficit fosters borrowing to finance long term investment or reflects rising incomes, confidence and investment-and does not hurt employment-then it's good. If trade deficit merely expresses consumer preference rather than these phenomena, then it should be treated as immaterial.

How does a Trade surplus and Deficit Arise?

A trade surplus arises when countries sell more goods than they import. Conversely, trade deficits arrise when countries import more than they export. The value of goods and services imported more exported is recorded on the country's version of a ledger known as the 'current account'. A positive account balance means the nation carries a surplus. According to the Central Intelligence Agency Work fact book, China, Germany, Japan, Russia, And Iran are net Creditors Nations. Examples of countries with a deficit or 'net debtor' nations are United States, Spain, the United Kingdom and India.

Difference between Trade Surplus and Trade Deficit

A country is said to have trade surplus when it exports more than it imports. Conversely, a country has a trade deficit when it imports more than it exports. A country can have an overall trade deficit or surplus. Or simply have with a specific country. Either Situation problems at high levels over long periods of time, but a surplus is generally a positive development, while a deficit is seen as negative. Economists recognize that trade imbalances of either sort are common and necessary in international trade.

Competitive Advantage of Trade Surplus and Trade Deficit

From the 16th and 18th Century, Western European Countries believed that the only way to engage in trade was through the exporting of as many goods and services as possible. Using this method, Countries always carried a surplus and maintained large pile of gold. Under this system called the 'Mercantilism', the concise encyclopedia of Economics explains that nations had a competitive advantage by having enough money in the event a war broke out so as to be able to Self-sustain its citizenry. The interconnected Economies of the 21st century due to the rise of globalization means Countries have new priorities and trade concerns than war. Both Surpluses and shortcomings have their advantages.

Trade Surplus Advantage

Nations with trade surplus have several competitive advantage s by having excess reserves in its Current Account; the nation has the money to buy the assets of other countries. For Instance, China and Japan use their Surpluses to buy US bonds. Purchasing the debt of other nations allows the buyer a degree of political influence. An October 2010 New York Times article explains how President Obama must consistently engage in discussions with China about its $ 28 Billion deficit with the country. Similarly, the United States hinges its ability to consume on China's continuing purchase of US assets and cheap goods. Carrying a surplus also provides a cash flow with which to reinvest in its machinery, labor force and economy. In this regard, carrying a surplus is akin to a business making a profit-the excess reserves create opportunities and choices that nations with debts necessarily have by virtue of debts and obligations to repay considerations.

Trade Deficits Advantage

George Alessandria, Senior Economist for the Philadelphia Federal Reserve explains trade deficits also indicate an efficient allocation of Resources: Shifting the production of goods and services to China allows US businesses to allocate more money towards its core competences, such as research and development. Debt also allows countries to take on more ambitious undertakings and take greater risks. Although the US no longer produces and exports as many goods and services, the nations remain one of the most innovative. For Example, Apple can pay its workers more money to develop the Best Selling, Cutting Edge Products because it outsources the production of goods to countries overseas.

LITERATURE REVIEW

In this chapter, efforts were made to explain some of the issues relating balance of trade and trying to X-ray some of the arguments in favor of trade balances and imbalances with a view to finding answers to some salient questions and making for proper understanding of the concept of trade balances surplus and deficit which is fast becoming a major problem in the world's economy today which philosophies like John Maynard Keynes earlier predicted.

In a bid to find a solution to this, we will be considering the following sub-headings;

(a). Conditions where trade imbalances may be problematic.
(b). Conditions where trade imbalances may not be problematic.

2.1. Conditions where trade imbalances may be problematic

Those who ignore the effects of long run trade deficiencies may be confusing David Ricardo's principle of comparative advantage with Adam Smith's principle of absolute advantage, specifically ignoring the latter. The economist Paul Craig Roberts notes that the comparative advantage principles developed by David Ricardo do not hold where the factors of production are internationally mobile. Global labor arbitrage, a phenomenon described by economist Stephen S. Roach, where one country exploits the cheap labor of another, would be a case of absolute advantage that is not mutually beneficial. Since the stagflation of the 1970s, the US economy has been characterized by slower GDP growth. In 1985, the US began its growing trade deficit with China. Over the long run, nations with trade surpluses tend also to have a savings surplus. The US generally has lower savings rates than its trading partners, which tend to have trade surpluses. Germany, France, Japan, and Canada have maintained higher savings rates than the US over the long run.

Few economists believe that GDP and employment can be dragged down by an over-large deficit over the long run. Others believe that trade shortcomings are good for the economy. The opportunity cost of a forgone tax base may outweigh perceived gains, especially where artificial currency pegs and manipulations are present to distort trade.

Wealth-producing primary sector jobs in the US such as those in manufacturing and computer software have often been replaced by much lower paying wealth-consuming jobs such as those in retail and government in the service sector when the economy recovered from recessions. Some economists contend that the US is borrowing to fund consumption of imports while accumulating unsustainable amounts of debt.

In 2006, the primary economic concerns focused on: high national debt ($ 9 trillion), high non-bank corporate debt ($ 9 trillion), high mortgage debt ($ 9 trillion), high financial institution debt ($ 12 trillion), high unfunded Medicare liability ($ 30 trillion), high unfunded Social Security liability ($ 12 trillion), high external debt (amount owed to foreign lenders) and a serious deterioration in the United States net international investment position (NIIP) (-24% of GDP), high trade deficiencies, and a rise in illegal immigration.

These issues have raised concerns among economic and unfunded liabilities were noted as a serious problem facing the United States in the President's 2006 State of the Union address. On June 26, 2009, Jeff Immelt, the CEO of General Electric, called for the US to increase its manufacturing base employment to 20% of the work, commenting that the US has outsourced too much in some areas and can no longer rely on the financial sector and consumer spending to drive demand.

2.2. Conditions where trade imbalances may not be problematic

Small trade deficiencies are generally not considered to be harmful to either the importing or exporting economy. However, when a national trade imbalance extends beyond prudence (generally thought to be certain [clarification needed] percent of GDP, for several years), adjustments tend to occur. While unsustainable imbalances may persist for long periods (cf, Singapore and New Zealand's surpluses and deficits, respectively), the discrepancies are likely to be caused by large flows of wealth out of one economy and into another tend to become intolerable.
In simple terms, trade deficits are paid for out of foreign exchange reserves, and may continue until such reserves are depleted. At such a point, the importer can no longer continue to purchase more than is sold abroad. This is likely to have exchange rate implications: a sharp loss of value in the deficit economy's exchange rate with the surplus economy's currency will change the relative price of negotiable goods, and facilitate a return to balance or (more likely) an over-shooting into surplus the other direction.

More complexly, an economy may be unable to export enough goods to pay for its imports, but is able to find funds elsewhere. Service exports, for example, are more than sufficient to pay for Hong Kong's domestic goods export shortfall. In poorer countries, foreign aid may fill the gap while in rapidly developing economies a capital account surplus often off-sets a current-account deficit. There are some economies where transfers from nationals working abroad contribute significantly to paying for imports. The Philippines, Bangladesh and Mexico are examples of transfer-rich economies. Finally, a country may partially rebalance by use of quantitative easing at home. This involves a central bank buying back long term government bonds from other domestic financial institutions without reference to the interest rate (which is typically low when QE is called for), seriously increasing the money supply. This debases the local currency but also reduces the debt owed to foreign creditors - effectively "exporting inflation"

FACTORS AFFECTING BALANCE OF TRADE

Factors that can affect the balance of trade include;

1. The cost of production, (land, labor, capital, taxes, incentives, etc.) in the exporting as well as the importing economy.
2. The cost and availability of raw materials, intermediate goods and inputs.
3. Exchange rate movement.
4. Multi lateral, bi-lateral, and unilateral taxes or restrictions on trade.
5. Non-Tariff barriers such as environmental, health and safety standards.
6. The availability of adequate foreign exchange with which to pay for imports and prices of goods manufactured at home.

In addition, the trade balance is likely to differ across the business cycle in export led-growth (such as oil and early industrial goods). The balance of trade will improve during an economic expansion.

However, with domestic demand led growth (as in the United States and Australia), the trade balance will worsen at the same stage of the business cycle.

Since the Mid 1980s, the United States has had a growth deficit in tradable goods, especially with Asian nations such as China and Japan which now hold large sums of US debts. Interestingly, the US has a trade surplus with Australia due to a favorable trade advantage which it has over the latter.

ECONOMIC POLICY WHICH COULD HELP REALISE TRADE SURPLUSES.

(a) Savings

Economies such as Canada, Japan, and Germany which have savings Surplus Typically runs trade surpluses. China, a High Growth economy has tended to run trade surpluses. A higher savings rate generally corresponds to a trade surplus. Correspondingly, the United States with a lower Savings rate has tended to run high trade deficits, especially with Asian Nations.

(b) Reducing import and increasing Export.

Countries such as the US and England are the major proponent of this theory. It is also known as the mercantile theory. A Practice where the government regulates strictly the inflow and flow from the economy in terms of import and export. One major advantage of this theory is that that it makes a nation self sufficient and has a multiplier effect on the overall development of the nation's entire sector.

CRITICISMS AGAINST THE ECONOMIC POLICY OF SAVING AS A MEANS OF REALISING TRADE SURPLUS

Saving as a means of realizing trade surpluses is not advisable. For example, if a country who is not saving is trading and multiplying its monetary status, it will in a long run be more beneficial to them and a disadvantage to a country who is solely adopting and relying on the savings policy as the it can appear to be cosmetic in a short term and the effect would be exposed when the activities of the trading nation is yielding profit on investment. This could lead to an Economic Tsunami.

CRITICISMS AGAINST THE ECONOMIC POLICY OF REDUCING IMPORTS AND INCREASING EXPORTS

A situation where the export is having more value on the economy of the receiving country just as Frederic Bastiat posited in its example, the principle of reducing imports and increasing export would be an exercise in futility. He cited an example of where a Frenchman, exported French wine and imported British coal, turning a profit. He supposedly he was in France, and sent a cask of wine which was worth 50 francs to England. The customhouse would record an export of 50 francs. If, in England, the wine sold for 70 francs (or the pound equivalent), which he then used to buy coal, which he imported into France, and was found to be worth 90 francs in France, he would have made a profit of 40 francs. But the customhouse would say that the value of imports exceeded that of exports and was trade deficit against the ledger of France.

A proper understanding of a topic as this can not be achieved if views from Notable Scholars who have dwelt on it in the past are not examined.

In the light of the foregoing, it will be appropriate to analyze the views of various scholars who have posted on this topic in a bid to draw a deductive conclusion from their argument to serve a template for drawing a conclusion. This would be explained sequentially as follow;

(a) Frédéric Bastiat on the fallacy of trade deficits.
(b) Adam Smith on trade shortcomings.
(c) John Maynard Keynes on balance of trade.
(d) Milton Freidman on trade deficit.
(e) Warren Buffet on trade deficit.

3.1. Frédéric Bastiat on the fallacy of trade deficits

The 19th century economist and philosopher Frédéric Bastiat expressed the idea that trade shortcomings actually were a manifestation of profit, rather than a loss. He suggested as an example to suppose that he, a Frenchman, exported French wine and imported British coal, turning a profit. He supposedly he was in France, and sent a cask of wine which was worth 50 francs to England. The customhouse would record an export of 50 francs. If, in England, the wine sold for 70 francs (or the pound equivalent), which he then used to buy coal, which he imported into France, and was found to be worth 90 francs in France, he would have made a profit of 40 francs. But the customhouse would say that the value of imports exceeded that of exports and was trade deficit against the ledger of France. looking at his arguments properly, one would say that it is most adequate to have a trade deficit over a trade surplus. In this Vain, it is glaringly obvious that domestic trade or internal trade could turn a suggested trade surplus into a trade deficiency if the cited example of Fredric Bastiat is applied. This was later, in the 20th century, affirmed by economist Milton Friedman.

Internal trade could render an Export value of a nation valueless if not properly handled. A situation where a goods that was initially imported from country 1 into a country 2 has more value in country 2 than its initial export value from country 1, could lead to a situation where the purchasing power would be used to buy more goods in quantity from country 2 who ordinarily would have had a trade surplus by virtue of exporting more in the value of the sum of the initially imported goods from country 1 thenby making the latter to suffer more in export by adding more value to the economy of country 1 that exported ab-initio. The customhouse would say that the value of imports exceeded that of exports and was trade deficit against the ledger of Country 1. But in the real sense of it, Country 1 has benefited trade-wise which is a profit to the economy. In the light of this, a fundamental question arises, 'would the concept of Profit now be smeared or undermined on the Alter of the concept of Trade surplus or loss? This leads to Mind why Milton Friedman stated that some of the concerns of trade deficiency are impartial practices in an attempt to push macro- economic policies favorable to exporting industries'. ie to give an undue favor or Advantage to the exporting nations to make it seem that it is more viable than the less exporting country in the international Business books of accounts. This could be seen as a cosmetic disclosure as it does not actually state the proper position of things and this could be misleading in nature.

By reduction and absurdum, Bastiat argued that the national trade deficit was an indicator of a successful economy, rather than a failing one. Bastiat predicted that a successful, growing economy would result in greater trade deficits, and an unsuccessful, shrinking economy would result in lower trade deficits. This was later, in the 20th century, affirmed by economist Milton Friedman.

3.2. Adam Smith on trade shortcomings

Adam Smith who was the sole propounder of the theory of absolute advantage was of the opinion that trade deficiency was nothing to worry about and that nothing is more absurd than the Doctrine of 'Balance of Trade' and this has been demonstrated by several Economists today. It was argued that If For Example, Japan happens to become the 51st state of the US, we would not hear about any trade deficit or imbalance between America and Japan. They further argued that trade imbalance was necessitated by Geographical boundaries amongstst nations which make them see themselves as competitors amongst each other in other to gain trade superiority each other which was not necessary. They further posed that if the boundaries between Detroit, Michigan and Windsor, Ontario, made any difference to the residents of those cities except for those obstacles created by the Government. They posited that if it was necessary to worry about the trade deficit between the United States and Japan, then maybe it was necessary to worry about the shortcomings that exist among states. It further that stated that if the balance of trade does not matter at the personal, neighborhood, or city level, then it does matter at the national level. Then Adams Smith was Right !.

They observed that it was as a result of the economic liability of the US that made their purchasing power higher than that its Asian counterpart who was exporting more and importing less than the US and that it would not be better if the US got poorer and less ability to buy products from abroad, further condemning that it was the economic problem in Asia that made people buy fewer imports.

"In the foregoing, even upon the principles of the commercial system, it was very unnecessary to lay extraordinary restraints upon the importation of goods from those countries with which the balance of trade is supposedly to be disadvantageous. It is obvious a picture that nothing, however, can be more absurd than this whole doctrine of the balance of trade, upon which, not only these restraints, but almost all the other regulations of commerce are founded. When two places trade with one another, this [absurd] doctrine supposes that , if the balance be even, either of them either loses or gains; but if it leans in any degree to one side, that one of them loses and the other gains in proportion to its declination from the exact equivalent. " (Smith, 1776, book IV, ch. Iii, part ii).

3.3. John Maynard Keynes on balance of trade

John Maynard Keynes was the principal author of the 'KEYNES PLAN'. His view, supported by many Economists and Commentators at the time was that Creditor Nations should be treated as liable as debtor Nations for Disequilibrium in Exchanges and that both should be under an obligation to bring trade back into a state of balance. Failure for them to do so could have serious economic consequences. In the words of Geoffrey Crowther, 'if the Economic Relationship that exist between two nations are not harmonized fairly close to balance, then there is no set of financial arrangement that can rescue the world from the impoverishing result of chaos. This view could have been seen by some Economists and scholars as very unfair to Creditors as it does not have respect for their status as Creditors based on the fact that there is no clear cut difference between them and the debtors. This idea was perceived by many as an attempt to unclassify Creditors from debtors.

3.4. Milton Freidman on trade deficit

In the 1980s, Milton Friedman who was a Nobel Prize winner Economist, a Professor and the Father of Monetarism contended that some of the concerns of trade deficiency are unfair criticisms in an attempt to push macro- economic policies favurable to exporting industries.

He further argued that trade deficit are not necessarily as important as high exports raise the value of currency, reducing forward exports, and vice versa in imports, so typically removing trade deficits not due to investment.

This position is a more refined version of the theorem first discovered by David Hume, where he argued that England could not permanently gain from exports, because hoarding gold would make gold more plentiful in England; therefore the price of English goods will soar, making them less attractive exports and making foreign goods more attractive imports. In this way, countries trade balance would balance out.

Friedman believed that deficiencies would have been corrected by free markets as floating currency rates rise or fall with time to discourage imports in favor of the exports. Revising again in the favor of imports as the currency gains strength.

But again there were short comings on the view of Friedman as many economists argued that his arguments were feasible in a short run and not in a long run. The theory says that the trade deficiency, as good as debt, is not a problem at all as the debt has to be paid back. They further argued that In the long run as per this theory, the consistent accumulation of a major debt could pose a problem as it may be quite difficult to pay offset the debt easily.

Economists in support for Friedman suggested that when the money drawn out returns to the trade deficit country

3.5. Warren Buffet on trade deficit

The Successful American Business Mogul and Investor Warren Buffet was quoted in the Associated Press (January 20th 2006) as saying that 'The US trade deficit is a bigger threat to the domestic economy than either the federal budget deficit or consumer debt and could lead to political turmoil ... Right now, the rest of the world owns $ 3 trillion more of us than we own of them '. He was further quoted as saying that 'in effect, our economy has been behaving like an extraordinary rich family that possesses an immense farm. In order to consume 4% more than we produce-that is the trade deficit- we have day by day been both selling pieces of the farm and increasing the mortgage on what we still own.

Buffet proposed a tool called 'IMPORT CERTIFICATES' as a solution to the United States problem and ensure balanced trade. He was further quoted as saying; 'The Rest of the world owns a staggering $ 2.5 trillion more of the US than we own the other countries. Some of this $ 2.5 trillion is invested in claim checks- US bonds, both governmental and private- and some in such assets as property and equity securities.

Import Certificate is a proposed mechanism to implement 'balanced Trade', and eliminate a country's trade deficit. The idea was to create a market for transferable import certificate (ICs) that would represent the right to import a certain dollar amount of goods into the United States. The plan was that the Transferable ICs would be issued to US exporters in an amount equal to the dollar amount of the goods they export and they could only be utilized once. They could be sold or traded to importers who must purchase them in order to legally import goods to the US The price of ICs are set by free market forces, and therefore dependent on the balance between entrepreneurs' willingness to pay the ICs market price for importing goods into the USA and the global volume of goods exported from the US (Supply and Demand).






4G Mobile Broadband - LTE Network Architecture and Protocol Stack






ABSTRCT

The goal of the LTE standard is to create specifications for a new radio-access technology geared to higher data rates, low latency and greater spectrum efficiency. The spectrum efficiency target for the LTE system is three to four times higher than the current HSPA system. These aggressive spectral efficiency targets require using the technology envelope by employing advanced air-interface techniques such as low-PAPR orthogonal uplink multiple access based on SC-FDMA (single-carrier frequency division multiple access) MIMO multiple-input multiple-output multi-antenna technologies, inter-cell interference mitigation techniques, low latency channel structure and single-frequency network (SFN) broadcast. The researchers and engineers working on the standard come up with new innovative technology proposals and ideas for system performance improvement. Due to the highly aggressive standard development schedule, these researchers and engineers are generally unable to publish their proposals in conferences or journals, etc. In the standards development phase, the proposals go through extensive scrutiny with multiple sources evaluating and simulating the proposed technologies from system performance improvement and implementation complexity perspectives. Therefore, only the highest-quality proposals and ideas finally make into the standard.

Keywords: LTE Architecture, UDP, GDP, MIMO, MIME, MCCH, MBMS, QOS

1. INTRODUCTION

The LTE network architecture is designed with the goal of supporting packet-switched traffic with seamless mobility, quality of service (QoS) and minimal latency. A packet-switched approach allows for the support of all services including voice through packet connections. The result in a highly simplified flatter architecture with only two types of node rarely evolved Node-B (eNB) and mobility management entity / gateway (MME / GW). This is in contrast to many more network nodes in the current hierarchical network architecture of the 3G system. One major change is that the radio network controller (RNC) is eliminated from the data path and its functions are now incorporated in eNB. Some of the benefits of a single node in the access network are reduced latency and the distribution of the RNC processing load into multiple eNBs. The elimination of the RNC in the access network was possible partly because the LTE system does not support macro-diversity or soft-handoff.

2. LTE NETWORK ARCHITECTURE

All the network interfaces are based on IP protocols. The eNBs are interconnected by means of an X2 interface and to the MME / GW entity by means of an S1 interface as shown in Figure1. The S1 interface supports a many-to-many relationship between MME / GW and eNBs.

The functional split between eNB and MME / GW is shown in Figure 2 Two logical gateway entities namely the serving gateway (S-GW) and the packet data network gateway (P-GW) is defined. The S-GW acts as a local mobility anchor forwarding and receiving packets to and from the eNB servicing the UE. The P-GW interfaces with external packet data networks (PDNs) such as the Internet and the IMS. The P-GW also performs several IP functions such as address allocation, policy enforcement, packet filtering and routing.

The MME is a signaling only entity and hence user IP packets do not go through the MME. An advantage of a separate network entity for signaling is that the network capacity for signaling and traffic can grow independently. The main functions of MME are idle-mode UE reach ability including the control and implementation of paging retransmission, tracking area list management, roaming, authentication, authorization, P-GW / S-GW selection, bearer management including dedicated bearer establishment, security negotiations and NAS signaling, etc.

Evolved Node-B implements Node-B functions as well as protocols traditionally implemented in RNC. The main functions of eNB are header compression, ciphering and reliable delivery of packets. On the control side, eNB incorporates such functions as admission control and radio resource management. Some of the benefits of a single node in the access network are reduced latency and the distribution of RNC the network side are now terminated in eNB.

Figure 1: Network Architecture

Figure 2: Functional split between eNB and MME / GW.

2.1 PROTOCOL STACK AND CONYTOL PLANE

The user plane protocol stack is given in Figure 3.We note that packet data convergence protocol (PDCP) and radio link control (RLC) layers traditionally terminated in RNC on Figure 4 shows the control plane protocol stack.

Figure 3: User plane protocol.

Figure 4: Control plane protocol stack.

We note that RRC functionality traditionally implemented in RNC is now incorporated into eNB. The RLC and MAC layers perform the same functions as they do for the user plane. The functions performed by the RRC include system information broadcast, paging, radio bearer control, RRC connection management, mobility functions and UE measurement reporting and control. The non-access stratum (NAS) protocol terminated in the MME on the network side and at the UE on the terminal side functions such as EPS (evolved packet system) bearer management, authentication and security control, etc.

The S1 and X2 interface protocol stacks are shown in Figures 2.5 and 2.6 respectively.We note that similar protocols are used on these two interfaces. The S1 user plane interface (S1-U) is defined between the eNB and the S-GW. The S1-U interface uses GTP-U (GPRS tunneling protocol - user data tunneling) on ​​UDP / IP transport and provides non-guaranteed delivery of user plane PDUs between the eNB and the S-GW. The GTP-U is a relatively simple IP based tunneling protocol that permits many tunnels between each set of end points. The S1 control plane interface (S1-MME) is defined as being between the eNB and the MME. Similar to the user plane, the transport network layer is built on IP transport and for the reliable

Figure 5: S1 interface user and control planes.

Figure 6: X2 interface user and control planes.

Transport of signaling messages SCTP (stream control transmission protocol) is used on top of IP The SCTP protocol operates analogously to TCP ensuring reliable, in-sequence transport of messages with congestion control. The application layer signaling protocols are referred to as S1 application protocol (S1-AP) and X2 application protocol (X2-AP) for S1 and X2 interface control planes respectively.

3. QOS AND BEARER SERVICE ARCHITECTURE

Applications such as VoIP, web browsing, video telephony and video streaming have special QoS needs. Therefore, an important feature of any network network is the provision of a QoS mechanism to enable differentiation of packet flows based on QoS requirements. In EPS, QoS flows called EPS bearers are established between the UE and the P-GW as shown in Figure 7. A radio bearer transports the packets of an EPS bearer between a UE and an eNB. Each IP flow (eg VoIP) is associated with a different EPS bearer and the network can prioritize traffic accordingly.

Figure 7: EPS bearer service architecture.

When receiving an IP packet from the Internet, P-GW performances package classification based on certain predefined parameters and sends it an appropriate EPS bearer. Based on the EPS bearer, eNB maps packages to the appropriate radio QoS bearer. There is one-to-one mapping between an EPS bearer and a radio bearer.

4. LAYER 2 STRUCTURE

The layer 2 of LTE consist of three sub layers normally medium access control, radio link control (RLC) and packet data convergence protocol (PDCP). The service access point (SAP) between the physical (PHY) layer and the MAC sub layer provide the transport channels while the SAP between the MAC and RLC sub layers provide the logical channels. The MAC sub layer performances multiplexing of logical channels on to the transport channels.

The downlink and uplink layer 2 structures are given in Figures 8 and 9 respectively. The difference between downlink and uplink structures is that in the downlink, the MAC sub layer also handles the priority among UEs in addition to priority handling among the logical channels of a single UE. The other functions performed by the MAC sub layers in both downlink and uplink include mapping between the logical and the transport channels.
Multiplexing of RLC packet data units (PDU), padding, transport format selection and hybrid ARQ (HARQ).

The main services and functions of the RLC sub layers include segmentation, ARQ in-sequence delivery and duplicate detection, etc. The in-sequence delivery of upper layer PDUs is not guaranteed at handover. The reliability of RLC can be configured to either acknowledge mode (AM) or un-acknowledgment mode (UM) transfers. The UM mode can be used for radio bearers that can tolerate some loss. In AM mode, ARQ functionality of RLC Retransmits transport blocks that failure recovery by HARQ. The recovery at HARQ may fail due to hybrid ARQ NACK to ACK error or because the maximum number of retransmission attempts is reached. In this case, the relevant transmitting ARQ entities are notifiable and potential retransmissions and re-segmentation can be initiated.

Figure 8: Downlink layer 2 structure.

Figure 9: Uplink layer 2 structure.

The PDCP layer functions such as header compression and decompression, ciphering and in-sequence delivery and duplicate detection at handover for RLCAM, etc. The header compression and decompression is performed using the robust header compression (ROHC) protocol. 5.1 Downlink logical, transport and physical channels

4.1 DOWNLINK LOGICAL, TRANSPORT AND PHYSICAL CHANNELS

The relationship between downlink logical, transport and physical channels is shown in Figure 10. A logical channel is defined by the type of information it carriers. The logical channels are further divided into control channels and traffic channels. The control channels carry control-plane information, while traffic channels carry user-plane information.

In the downlink, five control channels and two traffic channels are defined. The downlink control channel used for paging information transfer is referred to as the paging control channel (PCCH). This channel is used when the network has no knowledge about the location cell of the UE. The channel that carries system control information is referred to as the broadcast control channel (BCCH). Two channels typically the common control channel (CCCH) and the restricted control channel (DCCH) can carry information between the network and the UE. The CCCH is used for UEs that have no RRC connection while DCCH is used for UEs that have an RRC connection. The control channel used for the transmission of MBMS control information is referred to as the multicast control channel (MCCH). The MCCH is used by only those UEs receiving MBMS.

The two traffic channels in the downlink are the dedicated traffic channel (DTCH) and the multicast traffic channel (MTCH). A DTCH is a point-to-point channel dedicated to a single UE for the transmission of user information. An MTCH is a point-to-multipoint channel used for the transmission of user traffic to UEs receiving MBMS. The paging control channel is mapped to a transport channel referred to as paging channel (PCH). The PCH supports continuous reception (DRX) to enable UE power saving. A DRX cycle is indicated to the UE by the network. The BCCH is mapped to either a transport channel referred to as a broadcast channel (BCH) or to the downlink shared channel (DLSCH).

Figure 10: Downlink logical, transport and physical channels mapping.

The BCH is characterized by a fixed pre-defined format as this is the first channel UE receives after acquiring synchronization to the cell. The MCCH and MTCH are either mapped to a transport channel called a multicast channel (MCH) or to the downlink shared channel (DL-SCH). The MCH supports MBSFN combining of MBMS transmission from multiple cells. The other logical channels mapped to DL-SCH include CCCH, DCCH and DTCH. The DL-SCH is characterized by support for adaptive modulation / coding, HARQ, power control, semi-static / dynamic resource allocation, DRX, MBM Transmission and multi antenna technologies. All the four-downlink transport channels have the requirement to be broadcast in the entire coverage area of ​​a cell.

The BCH is mapped to a physical channel referred to as physical broadcast channel (PBCH), which is transmitted over four sub frames with 40 ms timing interval. The 40 ms timing is detected blindly without requiring any explicit signaling. Also, each sub frame transmission of BCH is self-decodable and UEs with good channel conditions may not need to wait for reception of all the four sub frames for PBCH decoding. The PCH and DL-SCH are mapped to a physical channel referred to as physical downlink shared channel (PDSCH). The multicast channel (MCH) is mapped to physical multicast channel (PMCH), which is the multi-cell MBSFN transmission channel.

The three stand-alone physical control channels are the physical control format indicator channel (PCFICH), the physical downlink control channel (PDCCH) and the physical hybrid ARQ indicator channel (PHICH). The PCFICH is transmitted every sub frame and carries information on the number of OFDM symbols used for PDCCH. The PDCCH is used to inform the UEs about the resource allocation of PCH and DL-SCH as well as modulation, coding and hybrid ARQ information related to DL-SCH. A maximum of three or four OFDM symbols can be used for PDCCH. With dynamic indication of number of OFDM symbols used for PDCCH via PCFICH, the unused OFDM symbols among the three or four PDCCH OFDM symbols can be used for data transmission. The PHICH is used to carry hybrid ARQ ACK / NACK for uplink transmissions.

4.2 UPLINK LOGICAL, TRANSPORT AND PHYSICAL CHANNELS

The relationship between uplink logical, transport and physical channels is shown in Figure 2.11. In the uplink two control channels and a single traffic channel is defined. As for the downlink, common control channel (CCCH) and dedicated control channel (DCCH) are used to carry information between the network and the UE. The CCCH is used for UEs having no RRC connection while DCCH is used for UEs having an RRC connection. Similar to downlink, dedicated traffic channel (DTCH) is a point-to-point channel dedicated to a single UE for transmission of user information. All the three uplink logical channels are mapped to a transport channel named uplink shared channel (UL-SCH). The UL-SCH supports adaptive modulation / coding, HARQ, power control and semi-static / dynamic resource allocation.

Another transport channel defined for the uplink is referred to as the random access channel (RACH), which can be used for transmission of limited control information from a UE with the possibility of collisions with transmissions from other UEs. The RACH is mapped to physical random access channel (PRACH), which carries the random access preamble.

The UL-SCH transport channel is mapped to physical uplink shared channel (PUSCH). A stand-alone uplink physical channel referred to as physical uplink control channel (PUCCH) is used to carry downlink channel quality indication (CQI) reports, scheduling request (SR) and hybrid ARQ ACK / NACK for downlink transmissions.

5. PROTOCOL STATES AND STATES TRANSITIONS

In the LTE system, two radio resource control (RRC) states previously RRC IDLE and RRC CONNECTED states are defined as described in Figure 2.12. A UE moves from RRC IDLE state to RRC CONNECTED state when an RRC connection is successfully established. A UE can move back from RRC CONNECTED to RRC IDLE state by releasing the RRC connection. In the RRC IDLE state, UE can receive broadcast / multicast data, monitors a paging channel to detect incoming calls, processes neighbor cell measurements and cell selection / reselection and acquires system information. Furthermore, in the RRC IDLE state, a UE specific DRX (discontinuous reception) cycle may be configured by upper layers to enable UE power savings. Also, mobility is controlled by the UE in the RRC IDLE
State.

In the RRC CONNECTED state, the transfer of uncast data to / from UE, and the transfer of broadcast or multicast data to UE can take place. At lower layers, the UE may be configured with a UE specific DRX / DTX (continuous transmission). Furthermore, UE monitors control channels associated with the shared data channel to determine if data is scheduled for it, provides channel quality feedback information, processes neighbor cell measurements and measurement reporting and acquires system information. Unlike the RRC IDLE state, the mobility is controlled by the network in this state.

Figure 11 Uplink logical, transport and physical channels mapping.

Figure 12: UE states and state transitions.

6. SEAMLESS MOBILITY SUPPORT

An important feature of a mobile wireless system such as LTE is support for seamless mobility across eNBs and across MME / GWs. Fast and seamless handovers (HO) is particularly important for delay-sensitive services such as VoIP. The handovers occur more frequently across eNBs than across core networks because the area covered by MME / GW serving a large number of eNBs is generally much larger than the area covered by a single eNB. The
signaling on X2 interface between eNBs is used for handover preparation. The S-GW acts as anchor for inter-eNB handovers.

In the LTE system, the network relies on the UE to detect the neighboring cells for handovers and therefore no neighbor cell information is signified from the network. For the search and measurement of inter-frequency neighboring cells, only the carrier frequencies need to be indicated. An example of active handover in an RRC CONNECTED state is shown in Figure 13 where a UE moves from the coverage area of ​​the source eNB (eNB1) to the coverage area of ​​the target eNB (eNB2). The handovers in the RRC CONNECTED state are network controlled and assisted by the UE. The UE sends a radio measurement report to the source eNB1 indicating that the signal quality on eNB2 is better than the signal quality on eNB1. As preparation for handover, the source eNB1 sends the coupling information and the UE context to the target eNB2 (HO request) [6] on the X2 interface. The target eNB2 may perform admission control dependent on the received EPS bearer QoS information. The target eNB configures the required resources according to the received EPS bearer QoS information and reserves a C-RNTI (cell radio network temporary identifier) ​​and optionally a RACH preamble.

Figure 13: Active handovers.

The C-RNTI provides a unique UE identification at the cell level identifying the RRC connection. When eNB2 signals to eNB1 that it is ready to perform the handover via HO ​​response message, eNB1 commands the UE (HO command) to change the radio bearer to eNB2. The UE receives the HO command with the necessary parameters (ie new C-RNTI, optionally dedicated RACH preamble, possible expiry time of the allocated RACH preamble, etc.) and is directed by the source eNB to perform the HO. The UE does not need to delay the handover execution for delivering the HARQ / ARQ responses to source eNB.

After receiving the HO command, the UE performances synchronization to the target eNB and accesses the target cell via the random access channel (RACH) following a contention-free procedure if a restricted RACH preamble was allocated in the HO command or following a contention-based procedure if no dedicated preamble was allocated. The network responds with uplink resource allocation and timing advance to be applied by the UE. When the UE has successfully accessed the target cell, the UE sends the HO confirm message (C-RNTI) along with an uplink buffer status report indicating that the handover procedure is completed for the UE. After receiving the HO confirm message, the target eNB sends a path switch message to the MME to inform that the UE has changed cell. The MME sends a user plane update message to the S-GW. The S-GW switches the downlink data path to the target eNB and sends one or more "end marker" packages on the old path to the source eNB and then releases any user-plane / TNL resources towards the source eNB. Then S-GW sends a user plane update response message to the MME. Then the MME confirms the path switch message from the target eNB with the path switch response message. After the path switch response message is received from the MME, the target eNB informs success of HO to the source eNB by sending release source message to the source eNB and triggers the release of resources. On receiving the release source message, the source eNB can release radio and C-plane related sources associated with the UE context.

During handover preparation U-plane tunnels can be established between the source ENB and the target eNB. There is one tunnel established for uplink data forwarding and another one for downlink data forwarding for each EPS bearer for which data forwarding is applied. During handover execution, user data can be forwarded from the source eNB to the target eNB. Forwarding of downlink user data from the source to the target eNB should take place in order as long as packets are received at the source eNB or the source eNB buffer is exhausted.

For mobility management in the RRC IDLE state, concept of tracking area (TA) is introduced. A tracking area generally covers multiple eNBs as described in Figure 2.14. The tracking area identity (TAI) information indicating which TA an eNB belongs to is broadcast as part of system information. A UE can detect change of tracking area when it receives a different TAI than in its current cell. The UE updates the MME with its new TA information as it moves across TAs. When P-GW receives data for a UE, it buffers the packages and queries the MME for the UE's location. Then the MME will page the UE in its most current TA. A UE can be registered in multiple TAs simultaneously. This enables power saving at the UE under conditions of high mobility because it does not need to constantly update its location with the MME. This feature also minimizes load on TA boundaries.

8. MULTICAST BROADCAST SYSTEM ARCHITECTURE

In the LTE system, the MBMS either use a single-cell transmission or a multi-cell transmission. In single-cell transmission, MBMS is transmitted only in the coverage of a specific cell and therefore combining MBMS transmission from multiple cells is not supported. The single-cell MBMS transmission is performed on DL-SCH and hence uses the same network architecture as the unicast traffic.

Figure 14: Tracking area update for UE in RRC IDLE state.

The MTCH and MCCH are mapped on DL-SCH for point-to-multipoint transmission and scheduling is done by the eNB. The UEs can be allocated dedicated uplink feedback channels identical to those used in unicast transmission, which enables HARQ ACK / NACK and CQI feedback. The HARQ retransmissions are made using a group (service specific) RNTI (radio network temporary identifier) ​​in a time frame that is co-ordinated with the original MTCH transmission. All UEs receiving MBMS are able to receive the retransmissions and combine with the original transmissions at the HARQ level. The UEs that are associated with dedicated uplink feedback channel are in RRC CONNECTED state. In order to avoid unnecessary MBMS transmission on MTCH in a cell where there is no MBMS user, network can detect presence of users interested in the MBMS service by polling or through UE service request.

The multi-cell transmission for the evolved multimedia broadcast multicast service (MBMS) is realized by transmitting an identical waveform at the same time from multiple cells. In this case, MTCH and MCCH are mapped to MCH for point-to-multipoint transmission. This multi-cell transmission mode is referred to as multicast broadcast single frequency network (eMBSFN) as described in detail in Chapter 17. An MBSFN transmission from multiple cells within an MBSFN area is indicated as a single transmission by the UE. An MBSFN area compresses a group of cells within an MBSFN synchronization area of ​​a network that is co-ordinate to achieve MBSFN transmission. An MBSFN synchronization area is defined as an area of ​​the network in which all eNBs can be synchronized and perform MBSFN transmission. An MBMS service area may consist of multiple MBSFN areas. A cell within an MBSFN synchronization area may form part of multiple SFN areas each characterized by different content and set of participating cells.

Figure 15. The eMBMS service area and MBSFN areas.

An example of MBMS service area consistent of two MBSFN areas, area A and area B, is depicted in Figure 2.15. The MBSFNA area consists of cells A1-A5, cell AB1 and AB2. The MBSFN area consists of cells B1-B5, cell AB1 and AB2. The cells AB1 and AB2 are part of both MBSFN area A and area B. The cell B5 is part of area B but does not contribute to MBSFN transmission. Such a cell is referred to as MBSFN area reserved cell. The MBSFN area reserved cell may be allowed to transmit for other services on the resources allocated for the MBSFN but at a restricted power. The MBSFN synchronization area, the MBSFN area and reserved cells can be semi-static configured by O & M.

The MBMS architecture for multi-cell transmission is described in Figure 2.16. The multicell multicast coordination entity (MCE) is a logical entity, which means it can also be part of another network element such as eNB. The MCE performances functions such as the allocation of the radio resources used by all eNBs in the MBSFN area as well as determining the radio configuration including the modulation and coding scheme. The MBMS GW is also a logical entity which main function is sending / broadcasting MBMS packets with the SYNC protocol to each eNB transmitting the service. The MBMS GW hosts the PDCP layer of the user plane and uses IP multicast for forwarding MBMS user data to eNBs.

The eNBs are connected to eMBMS GW via a pure user plane interface M1. As M1 is a pure user plane interface, no control plane application part is defined for this interface. Two control plane interfaces M2 and M3 are defined. The application part on M2 interface conveys radio configuration data for the multi-cell transmission mode eNBs. The application part on M3 interface between MBMS GW and MCE performances MBMS session control signaling on EPS bearer level that includes procedures such as session start and stop.

An important requirement for multi-cell MBMS service transmission is MBMS content synchronization to enable MBSFN operation. The eMBMS user plane architecture for content synchronization is described in Figure 2.17. A SYNC protocol layer is defined on the transport network layer (TNL) to support the content synchronization mechanism. The SYNC protocol carries additional information that enables eNBs to identify the timing for radio frame transmission as well as detect packet loss.

Figure 16: eMBMS logical architecture.

Figure 17: The eMBMS user plane architecture for content synchronization.

The eNBs participating in multicell MBMS transmission are required to comply with content synchronization mechanism. An eNB transmitting only in single-cell service is not required to comply with the stringent timing requirements indicated by SYNC protocol. In case PDCP is used for header compression, it is located in eMBMS GW. The UEs receiving MTCH transmissions and taking part in at least one MBMS feedback scheme need to be in an RRC CONNECTED state. On the other hand, UEs receiving MTCH transmissions without taking part in an MBMS feedback mechanism can be in either an RRC IDLE or an RRC CONNECTED state. For receiving single-cell transmission of MTCH, a UE may need to be in RRC CONNECTED state. The signaling by which a UE is triggered to move to RRC CONNECTED state solely for single-cell reception purposes is carried on MCCH.

8. SUMMARY
The LTE system is based on highly simplified network architecture with only two types of nodes typically eNode-B and MME / GW. Fundamentally, it is a flattened architecture that enables simplified network design while still supporting seamless mobility and advanced QoS mechanisms. This is a major change relative to traditional wireless networks with many more network nodes using hierarchical network architecture. The simplification of network was
partly possible because LTE system does not support macro-diversity or soft-handoff and since it does not require a RNC in the access network for macro-diversity combining. Many of the other RNC functions are incorporated into the eNB. The QoS logical connections are provided between the UE and the gateway enabling differentiation of IP flows and meeting the requirements for low-latency applications.

A separate architecture optimized for multi-cell multicast and broadcast is provided, which consist of two logical nodes normally the multicast co-ordination entity (MCE) and the MBMS gateway. The MCE allocates radio resources as well as determines the radio configuration to be used by all eNBs in the MBSFN area. The MBMS gateway broadcasts MBMS packets with the SYNC protocol to each eNB transmitting the service. The MBMS gateway uses IP multicast for forwarding MBMS user data to eNBs. The layer 2 and radio resource control protocols are designed to enable reliable delivery of data, ciphering, header compression and UE power savings.

9. REFERENCES

[1] 3GPPTS 36.300 V8.4.0, Evolved Universal Terrestrial Radio Access Network (E-UTRA): Overall Description.

[2] 3GPP TS 29.060 V8.3.0, GPRS Tunneling Protocol (GTP) Across the Gn and Gp Interface.

[3] IETF RFC 4960, Stream Control Transmission Protocol.

[4] IETF RFC 3095, RObust Header Compression (ROHC): Framework and Four Profiles: RTP, UDP, ESP, and uncompressed.

[5] 3GPP TS 36.331 V8.1.0, Radio Resource Control (RRC) Protocol Specification.

[6] 3GPP TR 23.882 V1.15.1, 3GPP System Architecture Evolution (SAE): Report on Technical Options and Conclusions.