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موضوع: WiMax

  
  1. #1
    نام حقيقي: 1234

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    WiMax

    کد:
    http://www.windowsnetworking.com/articles_tutorials/WiMax-Part1.html

    Russell Hitchcock


    A three part series on 3G wireless broadband by discussing WiMax.

    PART-1

    Introduction

    WiMax is a technology which has been touted as the future of long-range wireless networking. Many people consider WiMax synonymous with the term 3G. Lately though this association has proven tenuous, largely due to the emergence of a technology called Long Term Evolution (LTE). This series of articles will discuss the rivalry of these two third generation long-range wireless networking technologies.
    What is WiMax?

    WiMax is a standard of the Institute of Electrical and Electronics Engineers (IEEE) with the 802.16 designation. From my previous article on WiFi (802.11), we now know that the 802 part of 802.16 means that the standard was implemented by the LAN/MAN subcommittee which has the 802 designation. The 16 of 802.16 means that this standard was created/approved by the Broadband Wireless Access Working Group within the LAN/MAN subcommittee.
    History of WiMax

    The idea for what is now known as WiMax began in the mid 1990's. At that time, the technology industry was seeing tremendous growth and new, exciting ideas were being found everywhere. It was clear to telecommunications service providers that there was a huge desire for broadband Internet access. This desire was coming from both home users and corporate users. Many telecommunications companies began planning and designing distribution networks that would be capable of handling the high traffic volumes expected. In most cases, their answer was fibre optic cables.
    The need to use fibre optic cables to provide widespread broadband Internet access came at a huge cost. Some estimates put this cost at about $300 per foot of fibre. As you can imagine this type of network would get very expensive very quickly. As this was being done, some industry players were busy looking for an alternative which could provide the widespread broadband Internet access without costing an arm and a leg. Their solution was to use a wireless technology.
    In the early days of this wireless broadband access, and still today actually, its biggest cheerleader was Intel. Intel was in the midst of a prolonged slump in sales and saw an opportunity in this type of wireless access, and for good reason. Up until this point Intel had been a key player, a very successful player I might add, in the emerging WiFi market. Intel had been involved with WiFi since the beginning and even integrated WiFi capability into their popular Centrino line of processors. Since Intel had the expertise and the experience in WiFi wireless access they were hoping that they could leverage that into success in another type of wireless access.
    Of course, Intel had some challenges. Firstly, in North America many service providers were already implementing fibre optic networks for the delivery of broadband Internet access so many business leaders felt that the market for wireless broadband Internet access may be limited to developing markets. Secondly, some service providers had already begun experimenting with their own wireless broadband solutions.
    In these early days there was a real patchwork of technologies which didn't adhere to any agreed upon standard. Without an agreed upon industry standard many users were hesitant to purchase the required hardware for fear of being "locked-in" to a particular service provider. Or worse, that the technology would prove unpopular and would quickly become obsolete. This fear by consumers is perfectly rational and has been previously shown to be justified (just look at the VHS / Beta fiasco). So, with consumers hesitant to purchase the required hardware it is understandable that hardware manufacturers would be hesitant to even make the devices and risk low sale volumes. Intel recognized the problems of not having an agreed upon standard and set about to convince others. It didn't take a lot of convincing.
    What's in a name?

    In 2001, the IEEE released their 802.16 standard for broadband wireless access. Shortly thereafter the WiMax Forum was set up to promote the standard, and the term WiMax was born.
    You might not think that a name is all that important for such a standard. In many cases I would agree; as long as the name is not stupid (that is; it needs to be easy to pronounce, easy to remember, and be reflective of the standards capabilities). In the case of WiMax though I think the name is an important part of its story.
    When most people hear WiMax they think "Oh. Like WiFi, only to the max." I think this is very important, and I also think that the name WiMax was purposefully chosen to evoke such thoughts from consumers. What I am not sure about is whether this was a smart thing to do or not. On the plus side everyone who is even somewhat familiar with WiFi can immediately grasp the concept of WiMax; that it can provide wireless access to the Internet but has a longer range and larger throughput that WiFi. On the negative side of things is that all of the negative thoughts towards WiFi (justified or not) also get transferred over to WiMax.
    For instance, WiFi is primarily viewed as a home networking solution (or perhaps a small office, or a coffee shop). There may be some network security issues, there could also be interference issues, and there is also some significant performance degradation when there are multiple users (except of course for 802.11n, see my article on that for the reason why). Many people can accept these issues because of the convenience provided by WiFi. However all of these issues (in most cases incorrectly) get transposed upon WiMax. As a result, the WiMax Forum has opened up the opportunity for a competitor to become the "professional" standard for "serious" networks; in other words the "big-boy" standard.
    The Technology

    Why are these criticisms incorrectly transposed onto WiMax? Well, let us start with security. For starters a great deal has been learned from WiFi and there is no logical reason to think that these lessons would not be applied to WiMax. Also, most security concerns of WiFi stem from the fact that the user, or consumer, is the network administrator and typically is not a networking security expert. WiMax is not in the hands of the user; it is a telecommunications service provider's solution. This means that the service provider is administering the network and will (or should be) employing network security professionals to secure the network properly.
    In regards to performance degradation resulting from many users, this is not an issue with WiMax. First of all, this problem has been largely solved in WiFi with the inclusion of MIMO. Likewise MIMO has been included in the WiMax standard. If you would like to know more about WiMax's implementation of MIMO I would recommend you read this article which I found quite interesting.
    Another aspect of the WiMax technology that can help with performance degradation (speed degradation as well as noise caused by interference) is that WiMax uses leased spectrum. This means that WiMax uses frequencies which costs a lot of money to use. So your microwave, or cordless phone would not be causing any interference problems with your WiMax connection and the service provider can better allocate sufficient bandwidth per user to avoid the speed degradation (to a point at least).





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  2. #2
    نام حقيقي: 1234

    مدیر بازنشسته
    تاریخ عضویت
    Jul 2009
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    کد:
    http://www.windowsnetworking.com/articles_tutorials/WiMax-Part2.html

    WiMax vs LTE: Part 2 LTE


    Introduction

    In my previous article in this series, I discussed the popular and well known 3G wireless technology called WiMax. In this article I will discuss its competitor, LTE. LTE stands for Long Term Evolution and is also known as 3GPP LTE, with 3GPP short for 3rd Generation Partnership Project, a standards partnership responsible for the evolution and maintenance of the GSM standards. LTE is also commonly, though incorrectly, thought to be a 4G, or 4th Generation, technology; it is not.
    3G or 4G?

    The confusion people have over whether LTE is 3G or 4G is understandable and stems from how the technology was introduced. In my previous article I discussed the history of WiMax which started in the mid 1990s and quickly gained widespread recognition. In fact many people have considered WiMax synonymous with the term 3G for many years now. So why do people incorrectly think that LTE is a 4th Generation technology? Well, LTE was introduced considerably later than WiMax (about 2004) and there are some distinct advantages LTE has over WiMax (more on this later and in my next article which will more directly compare the two standards and their technologies), these factors cause most people to assume that since LTE is newer, with some additional advantages so it must be the next generation of technology. In fact, LTE is not 4G because it does not meet the 4G specifications set out by the International Telecommunication Union (ITU). It does however meet the ITU's 3G specifications, which is why I am referring to it as a 3G technology.
    History

    The 3GPP was formed in the late 1990s with the goal of evolving the specifications for technologies around GSM. Since that time all of the standards associated with GSM technology are developed and maintained by the 3GPP. The 3GPP, as its name implies, is made up of a number of partners. These partners are themselves standards organizations located around the world which are responsible for; approval and maintenance of the 3GPP scope, allocation of resources, and acting as a body of appeal on procedural matters.
    Originally, GSM was developed as a circuit-switched network which was excellent for voice transmissions but very bad for data transmissions. This all changed with the introduction of the General Packet Radio Service (GPRS) standard, now maintained by the 3GPP like all GSM standards. The GPRS standard provided a method of routing packets over a GSM network and is often described as a 2.5G standard.
    The data transmission capabilities of GSM networks further evolved with the introduction of Enhanced Data Rates for GSM Evolution, also known as EDGE. Introduced in 2003, EDGE provides three times the performance of GPRS and is itself a 3G technology, based on the ITU's 3G specification.
    Data transmission capabilities improved further still with the introduction of another 3G standard from the 3GPP called High Speed Packet Access (HSPA). While EDGE networks can provide a theoretical down link data rate of up to 1 MB/s, HSPA networks can provide a theoretical down link data rate of up to 14 MB/s. So there should be a significant throughput advantage of HSPA networks; however, in practise this has not been the case. For instance, in early 2009 Vodafone completed a test of an HSPA+ network which promised a down link data rate of up to 16 MB/s but admitted that most users would only experience a download data rate of up to about 4 MB/s.
    HSPA+, also known as Evolved HSPA, is an extension of the base HSPA standard and provides for a theoretical down link data rate of 56 MB/s. An additional aspect of HSPA+ is the introduction of an optional all-IP architecture. An all-IP architecture is a major innovation in the wireless telecommunications industry and is something that is necessary for LTE. HSPA+ also utilizes an antennae technology called Multiple Input Multiple Output (MIMO). Like the all-IP architecture, MIMO is a technology used in LTE.
    So if you look at where GSM started as a circuit switched network designed for efficient, high mobility voice applications, and where it is today with EDGE, HSPA, and HSPA+ you can see that the 3GPP has progressively evolved the GSM standard to be efficient for high mobility data applications (which does include voice data). Along with consistent and significant increases in data rates, the 3GPP has also slowly introduced significant architectural changes which are required to meet their objectives of maximizing GSM's capabilities in the third generation as well as moving towards the fourth generation.
    Technology

    As I mentioned early there are two major evolutions in LTE. The first of these evolutions is the move to an all-IP architecture. That means that the technology has left behind for good the circuit switched network of GSM's roots. This is a significant move the telecommunications companies which will adopt LTE as their 3G technology of choice. To date the advantages that the 3GPP's standards had was that they were simply upgrades to the existing GSM networks which provided more throughput and allowed for more data intensive applications to communicate over the network. Now that the standards have moved away from the circuit switched architecture it's hard to make that argument that this is merely an upgrade. No, this is a significant change. In fact I feel that it's analogous to the software Operating System (OS) industry. Where the EDGE and HSPA were like service pack upgrades to Windows XP, while LTE is similar to a full OS version release like Windows 7. I guess that would make HSPA+ kind of like Vista; technically there, but nobody really cares .
    The second major evolution in LTE is with the use of MIMO. This is a technology which is also used in WiMax and I suspect that every wireless technology will soon use it both for its promise of speed improvements as well as the promise of reduced interference (or at least the reduced effects of the interference). Basically what MIMO is, is a system of transmitting data wirelessly where the sending side uses multiple antennae to transfer either the same data or different parts of the same data, while the receiving end used multiple antennae to receive the different signals. This setup can either be used to increase the throughput data rates or it can be used to reduce the effects of interference; this can be done when the sending side transmits the same data over each antennae, and when the receiving side receives multiple copies of the same data it can compare them and is more easily able to determine what the original signal was meant to be (that is without the effects of the interference).
    So that, in a nutshell, is LTE. I hope I have done an adequate job explaining the roots of the LTE as well as the basis for it's capabilities. This article, along with my previous article on WiMax form the basis for my next article which will compare and contrast the two competing technologies. Also in my next article I will discuss the successes of each technology as well as give my opinion on which one will come out on top. Until then, and as always, feel free to send me an email if you have any questions.




  3. #3
    نام حقيقي: 1234

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    Jul 2009
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    کد:
    http://www.windowsnetworking.com/articles_tutorials/WiMax-Part3.html
    WiMax vs. LTE: Part 3


    Introduction

    In my previous two articles I presented WiMax and LTE, the two giants competing for market share in the 3G telecommunications space. In this article I will compare and contrast the two from a technological and a business perspective. First, let's review the two standards.
    WiMax review

    WiMax, which is also known as IEEE standard 802.16, is a 3G wireless broadband access standard developed and maintained by the IEEE. As its name suggests, WiMax can be thought of as an extension of WiFi to the fully mobile telecommunications markets. Like WiFi version 802.11n, WiMax also contains support for Multiple Input/Multiple Output (MIMO) antennae, which is critical for supporting multiple simultaneous users. Also like WiFi, a major supporter and promoter of WiMax is Intel. Unlike WiFi; WiMax is designed for hundreds of users per base station, the users are highly mobile often switching from base station to base station throughout a single communication cycle, and the base station ranges are measured in kilometres not metres.
    LTE review

    Long Term Evolution (LTE) is also a 3G wireless broadband access standard though it is developed and maintained by the 3rd Generation Partnership Project (3GPP). The 3GPP is an organization responsible for the development, maintenance, and promotion of the GSM family of standards. LTE is the latest in the family of GSM standards which have been evolving from GSM's roots as a circuit switched architecture to an all-IP based architecture. Starting with the General Packet Radio Service (GPRS) standard and including the Enhanced Data Rates for GSM Evolution (EDGE) and High Speed Packet Access (HSPA) standards the GSM standards have been marching slowing but confidently towards an all-IP architecture.
    Convergence

    As the LTE standard has moved the GSM standards towards what is more traditionally thought of as a computer networking standards, WiMax has moved traditional computer networking towards what has traditionally been thought of as mobile telephony standards. So you can see that the two standards are coming from different backgrounds (with different strengths and weaknesses) and converging on common ground.
    As you might have guessed, the industry players backing each technology reflect the history of each standard. WiMax's most significant backer, as I mentioned before is Intel. Intel has a very strong history in the computer industry and was also a major supporter of WiFi. Likewise the major supporters of LTE are, in general, the telecommunication service companies and the traditional mobile handset makers (like Ericsson). Largely, this is due to the fact that people like to work with what they are comfortable with. Intel, as a result of its history, is comfortable with traditional computer networking and so has naturally drifted towards WiMax. Ericsson, among others, is comfortable with GSM technologies and so it is quite natural and understandable that they would be drawn towards the LTE standard.
    The consumer

    It Is not only tech companies who like to work with what they are comfortable with. This sort of thinking also infects consumers decisions. Due to the name WiMax consumers quite naturally think of WiFi which has for many years been a part of the home networking world. Consumers will immediately think that WiMax is something used to network a computer. LTE, though not having a strong name association with GSM, is closely associated with GSM (from a consumer's point of view) through its supporters and the telecommunications services companies like AT&T. So consumers will immediately think that LTE is something used to network their mobile phones; though this link is likely not as strong as the link WiMax has to WiFi.
    So there exists two consumer preconceptions for the two 3G standards. I am of the opinion that the standard which ultimately gains more widespread acceptance (and therefore wins) will be the standard with the most advantageous consumer image. Now, a preconception does not make an image. However, as the saying goes you only get one chance to make a good first impression. While a good advertising campaign for a good standard with a good roll-out strategy can make a difference, competing against a strong competitor having a strong first impression is always difficult.
    That's the exact situation we have here. Both of these standards are excellent, both have an impressive list of industry heavy weights supporting the standard, and both have excellent roll-out plans. There should be no doubt that both standards will soon be in the hands of very capable advertising professionals. So to me, this whole competition (barring a massive mistake, or genius maneuvering) comes down to who has the favourable first impression.
    Who wins?

    So which technology has the advantageous position? This is where the debate lies. While LTE invokes the impression of mobility, WiMax invokes the impression of computing. I think that the question we are really trying to answer is whether consumers want a phone which is networked to the Internet, or do they want a computer they can carry with them like a phone? The lines are obviously very blurred here. As the iPhone has shown, there is a very large and significant portion of the market which want a computer they can carry with them like a phone. This view has been strengthened by the fact that many handset manufacturers have responded to the iPhone's success by introducing handsets themselves that are much more computer like (and yes, some handset manufacturers even did this prior to the iPhone). Is this portion of the market the majority? It's difficult to say, though I think it is. Another advantage which WiMax has is that children use, and are comfortable with, computers long before they are of the age to purchase or use a mobile phone. So young people soon to enter the mobile phone (or should we say mobile communication device) market will already be familiar with computers, but not as much with traditional mobile phones. This differs from the market today as the majority of adults are comfortable with both mobile phones and computers.
    Who wins? If I was a betting man my money would be on WiMax. I know many people think differently but as I have laid out I believe WiMax is starting out with a huge advantage which will be quite difficult for LTE to overcome. Separate from my "positive preconception" argument, I also believe that WiMax has an advantage in its history. That is that coming from the computer and computer networking side of things WiMax has supporters from those industries. In my opinion this is an advantage because it seems that the computer industry has a very strong history of tough competition and strict, never-ending development cycles, while the traditional handset makers do not seem to be as hardened to this type of competition. As always, if you have any questions or comments on this article or any previous article don't hesitate to email me and I will do my best to respond promptly




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