Air cards wireless » wimax

The future of mobile network, from LTE to HSPA+

admin — Tue, 03 May 2011 13:06:46 +0000

To meet the strong demand for energy required from smartphones and other mobile devices, telephone companies are engaged in both the construction of new facilities and implementation of existing networks.

The new networks are divided into two main technologies: WiMAX and Long TermEvolution (LTE). The two systems use similar approaches to supply the availability of bandwidth than the current one. A method called OFDM (Orthogonal frequency-division multiplexing) allows a base station to split a portion of spectrum in sub-channels. The signal strength of the subchannels and the number of channels allocated to different devices can be changed. OFDM allows highspeed data transmission, even far away from the base station, and fits well with all types of radio interference present in urban areas, where the signals reflected on the walls produce confusing echoes.

Both LTE and WiMax are based on the MIMO method (multiple input, multiple output). It uses multiple antennas to create a single wireless connection. MIMO can package the data with a higher density in the wireless spectrum available than a system with a single antenna, which consumes the same amount of energy.

WiMax has arrived on the market two years before LTE; it offers a theoretical maximum download speed of 144 megabits per second compared to the 360 of LTE (the United States a standard residential broadband connection is around 10 megabits per second ). LTE seems to have an overwhelming speed advantage, but in reality wireless mobile companies are far from reaching that performance of both technologies. In the U.S., Sprint’s WiMax network reach speeds between 3 and 6 megabits per second, while Verizon’s LTE network is between 5 and 12 megabits per second.

Although Sprint and Verizon have them labeled as 4G, these services do not actually meet the performance criteria that the ITU (International Telecommunication Union) has called officially for 4G services. But the latest version of WiMax and LTE are trying to meet these standards, guaranteeing download speed up to 1,000 megabits per second or even higher.

Although WiMax has been developed more quickly (the first large-scale deployment dates back to 2008) most operators in the U.S., Europe and Japan are using LTE for next-generation wireless networks. The main reason is that they assume that LTE network is technically easier to integrate with their existing structures.

But some suppliers, such as T-Mobile in the United States to upgrade their existing 3G networks, they prefer a system called HSPA+. T-Mobile claims that HSPA+ enables peak download speeds of 21 megabits per second, enough to compete with next-generation networks, at least for now.

At present all the network operators are committed to enhancing the capacity and flexibility of their 3G networks. Over the next four years, when the next generation systems will be developed and 3G chips will become cheap enough to make their appearance in a wide range of consumer products, these systems will attract more subscribers of the LTE network.

The biggest obstacle to the improvement of these systems comes from the wired network, not from the wireless. The cell towers and base stations must be connected to the same network hub. These links from one point to another, which typically use copper telephone wires or special connections or microwave, in recent years have become real bottleneck, forcing operators to adopt the more expensive fiber connections.

About 95 percent of the new Verizon LTE data network will be over fiber. But dig into the streets to lay fiber optic cable in densely populated areas can be expensive. For this reason, AT&T is committed to improving its 3G service in New York, which must withstand the impact of thousands of iPhone users.

3G and 4G wireless networks: diffusion of 30% in 2013

admin — Wed, 25 Nov 2009 17:54:36 +0000

A market analysis conducted by the company In-Stat estimates that within the next four years there will be a considerable expansion of users of connectivity solutions for 3G and 4G: If at the end of 2008, there were a worldwide spread equal to 11 %, by the end of 2013 is expected to spread around 30%, both calculated on total wireless customers.
Daryl School, analyst for In-Stat who has supervised the research, said: “basing our analysis on the awarding of contracts we see that the spread of WiMAX is able to absorb well the hard blows of the economic slowdown, although some operators have slowed down the rate of installation of new networks. WiMAX equipment from Alcatel-Lucent, Alvarion, Motorola and Samsung are showing positive results and others that we have to pay attention are Cisco Huawei and ZTE “.
In a broader perspective WiMAX should be able to resist, in the next two years, the growth of networks, HSPA (High Speed Packet Access) and LTE (Long-Term Evolution). In-Stat claims that mobile WiMAX networks can be an important resource in developing countries and in isolated places, where nets are still unable to reach. The real question that remains is the ability of WiMAX to compete in areas where currently there are already 3G cellular networks and dialup.
According School ,802.16e standard (which describes mobile WiMAX), has been primarily developed for dialup and nomadic services. Clearwire, Korea Telecom and UQ in Japan are some important exceptions, however, who wanted to adopt 802.16e for applications typically more mobile.
Reviewing the allocation of contracts in previous quarters (only in the fourth quarter of 2008 are spread globally 132 new networks: 95 HSPA, 18WCDMA, 12 mobile WiMAX six CDMA EV-DO and TD SCDMA network) In-Stat estimates that the majority of new type of networks will be WiMAX and HSPA, with a significant slowdown in the installation of networks WCDMA and CDMA EV-DO.

Air cards and wimax, these are not the final solution

admin — Sat, 21 Nov 2009 16:08:20 +0000

Nowadays technical terms such as air cards, broadband, wimax, 4G and mobile wireless aircard are very cool but I’d like to be reminded that a wireless technology is only an optimization of radio resources. This should be clear to all, from ordinary citizens to politicians that “push” a technology rather than another.
The famous “Wi-fi” that we all have in our houses, is a fairly “smart” way to use a slice of the space frequencies that the international union for telecommunications (ITU) has set aside for industrial purposes, scientific and medical (ISM band).
It’s neither good nor bad, but only a “reasonable” (according to the engineers of the IEEE) way to use the available frequencies.
The same thing goes for other technologies like the WiMax, ADSL, the UTMS, 3G, Evdo, 4G air cards broadband. These are all technologies that do not solve the connectivity problem of Internet users, but offer a possible solution. For those who do not know, the electromagnetic spectrum is a resource that any nation manages and is divided into slices called “bands”, appropriately allocated for specific purposes. The optical band, which travels THROUGH(?) light bulbs in our home, the band allowed for radio stations, that one for Wi-Fi, WiMax, cellular, cordless, radar, walkie talkies, TV , etc..
All these devices use smartly that part of their responsibility of the electromagnetic spectrum, giving maximum performance in terms of light emitted (when we talk of light bulbs), or transmitted bits per second(digital transmission), for the frequency band in which they have to work.
Not too many people know that,in a certain frequency band, there is a physical limit to the speed of transmission. We will never able to reach speeds of Gigabit / second with the current access point Wi-Fi because of PHYSICS problems. Even ADSL has got the same problems. It doesn’t exist, in many cases, the famous 20, 40, 100 Mb / s because the noise present on our home line phone does not allow – for the Shannon theorem – to arrive at certain speeds. Those who say the contrary is, at best, ignorant.
A single lane road cannot support the traffic of a metropolis at the peak time as well as a wireless technology, although good, has to faced such traffic with the band that has at its disposal.There are no “miraculous” solutions to praise or solutions to pursue. Every technology must not only be seen as such, but declined in the context in which you want to apply. As is clear to us that the optical fiber is not the appropriate technology to connect an aircraft or a boat to the Internet (we should link them to the ground with a cable!), so there should be clear that in many scenarios the WiMax, The air cards Wi-fi, or the HyperLan UMTS, or Evdo may be inappropriate. “Inappropriate” means that ONCE SOMEONE HAS JUDGED requirements of people to connect, speed transmission required, the morphology of the area, availability of existing infrastructure, costs of equipment and possibly licensing, THEN you choose the best solution among the existing ones and later you have to judge if the income (typically given by users subscriptions) outweigh the costs.

Provide connectivity to a country with 10 persons, digging for meters and meters below the ground to get a fiber, it’s not convenient. Probably if exists a place with 10 people, using the optical fiber is not the right technology and we might consider other solutions. It could also happen that none of these solutions is convenient because these 10 people are “few and pay little”. In this case, giving connectivity to these people it’s no longer a duty of an ISP (Internet Service Provider), which is a company that does not do charity but business, but to someone else. Maybe it can be a duty of the country(GOVERN?) giving access to Internet because Internet means democracy. Choosing the wrong solution is tantamount to throwing out taxpayers money and you can explain it only by the ineptitude or corruption of leaders. Otherwise people can reach an agreement among themselves and realize their own infrastructure. This is what happens in certain Community Wireless Network: FreiFunk in Berlin, Guifi in Catalonia, Diirwb in Denmark, Portugal Unimos, Ninux in Rome. People climb on roofs and start to connect their buildings with air cards, antennas, router that cost less than 100 dollars (and sometimes also less then 50!). Anyway, we need competent persons, familiar with the technologies, knowing how to use them. That is why it is wrong to refer to WiMax as the final solution to all problems of “digital divide”. Say that with three antennas we cover the entire Philadelphia is not only misrepresent a technology but it’s also a technical inaccuracy. Not all know, for example, that the Wimax band is shared. Say that with an “antenna” we will cover 1 / 3 of Philadelphia, it means that the capacity of a Wimax station (70 Mbps) should be divided for about 900,000 people (if they are connected at the same time with their air cards). The result of this absurdity? 77 bits/sec per person! It is good neither to send SMS!
In addition, speed on wireless devices, are worse than that one declared. How many of us go about 54Mbps on WiFi networks? Finally, we must consider that the bands in which WiMax operates are subject to licensing costs. And the devices have their own cost.
And nobody knows if wimax actually will cover the gaps left by Wi-Fi or UMTS / HSDPA / 3G and later technologies.
“It depends on…”. And not just by technology but by the investments, by economic crisis and by technology scenario.
It’s hard to predict the future of these things! It is wrong to think that WiMax and air cards will solve all the problems of citizens presenting them as the FINAL solution to the digital divide.

So what should do a state, a municipality?
1)first of all, do not disturb. One of the first things that a legislator should consider is “do not blocking connectivity”, for one reason or another. I am referring to the recent proposal of “Internet safety act” introduced in Usa by Senator John Cornyn and representative Lamar Smith.

2)Investing in coverage of disadvantaged areas, because the state is NOT a company and should NOT do business only.

3)Encourage cooperation and the free spread of news and information. Covering a small town with wireless technology is not difficult and as we said is often just a matter of money. In this case, the technology “off the shelf” (available on the shelf “) such as Wi-fi is a valid weapon, given the low cost of devices and their wide dissemination. But are we sure that only a little village is the problem? How many people in a big town can not afford the Internet connection? It must become an essential public service such as TV or radio.
Through cooperation within blocks, zones or districts, we are able to spread Internet access and lower the cost of connectivity. Simply passing a cable between neighbors, or connecting each other with access points. Often this is what some already do, but it is illegal. Move towards legalization the re-distribution of Internet access can only be a good thing for a civilized society.

4) Knowing the technologies, trying to avoid to give lapidary opinions. The same WiMax could solve some problems even if not used for distribution to individual users, but to create wireless backbones. For example, some mountain areas could be served with a “point to point” WiMax, while the distribution to individual users could be made with the Wi-Fi, because nowadays everyone has a laptop with air cards. Once you know the different technologies you can not only choose the most “right”, but combine them together for the benefit of all.