When talking about 4G, question comes to our mind is what is 4G Technology. 4G is short for Fourth (4th) Generation Technology. 4G Technology is basically the extension in the 3G technology with more bandwidth and services offers in the 3G. But at this time nobody exactly knows the true 4G definition. Some people say that 4G technology is the future technologies that are mostly in their maturity period. The expectation for the 4G technology is basically the high quality audio/video streaming over end to end Internet Protocol. If the Internet Protocol (IP) multimedia sub-system movement achieves what it going to do, nothing of this possibly will matter. WiMAX or mobile structural design will become progressively more translucent, and therefore the acceptance of several architectures by a particular network operator ever more common.

Many Technologies appear in many different flavours and have many diverse tags attached to them, but that does not really indicate that they are moving in dissimilar tracks. The technologies that fall in the 4G categories are UMTS, OFDM, SDR, TD-SCDMA, MIMO and WiMAX to the some extent.

4G Technology offers high data rates that will generate new trends for the market and prospects for established as well as for new telecommunication businesses. 4G networks, when tied together with mobile phones with in-built higher resolution digital cameras and also High Definition capabilities will facilitate video blogs.

After successful implementation, 4G technology is likely to enable ubiquitous computing, that will simultaneously connects to numerous high date speed networks offers faultless handoffs all over the geographical regions. Many network operators possibly utilize technologies for example; wireless mesh networks and cognitive radio network to guarantee secure connection & competently allocates equally network traffic and bandwidth.

Most 3G subscribers today can expect about 1 megabit per second download speeds on average. 4G networks might deliver as fast as 6 or 7 megabits per second initially. Eventually, a 4G network hopes to be about 10 times faster than 3G.

Ultra mobile broadband refers to the rate of data transmission available on the wireless network. 4G technology may provide data transmission rates between 100Mbps and 1Gbps. For comparison, 3G networks offer data transmission speeds averaging around 200kbps. Network connections on 4G may also be more accurate during travel when user and tower locations are at a constant rate of change—for example, when a user is traveling in a car and signals transfer between towers. This faster, more accurate connection likely can enable the transmission of larger packets of data than 3G networks. Users may be able to access increasingly information-heavy applications, such as HD television signals and real time audio during video chat.

4G wireless service may include modems, netbooks and cell phones. 4G mobile hotspots may offer wireless connections for multiple devices, including computers, netbooks, handheld gaming systems, and mobile phones; with the 4G technology, users may be able to simultaneously download large applications to each device as well. A 4G netbook could operate similarly to a lap top, but with smaller memory and fewer drives; it may offer instant Internet access, downloading, and real-time Web chatting. 
 

• WiMAX and LTE

These are two 4G cellular broadband networks. The WiMAX provides speed up to 128mbps of downloading and for uploading it provides 56mbps, whereas LTE showed in an early implementation speed up to 100mbps downloading and 50 mbps uploading. ITU considers the LTE (Long-Term Evolution) as a standard technology because LTE aims to exceed the specifications of ITU. While WiMAX on the other hand is an IEEE standard, also ITU doesn’t considered WiMAX a true 4G technology because it is not up to the specifications that ITU put forth.

The 4G technology is able to support Interactive services like Video Conferencing (with more than 2 sites simultaneously), Wireless Internet,etc. The bandwidth would be much wider (100 MHz) and data would be transferred at much higher rates. The cost of the data transfer would be comparatively very less and global mobility would be possible. The networks are all IP networks based on IPv6. The antennas are much smarter and improved access technologies like OFDM and MC-CDMA (Multi Carrier CDMA) will be used. Also the security features are much better.
 

Two issues that will be at the forefront of 4G development are the verification of users and the limitation of network access in the heterogeneous architecture. Other vulnerabilities involve providers utilizing different systems and the basis of user-centered design, which allows users to select their preferred connection method. Due to their shared nature, naturally broadcasted states, unclear perimeters, and invisible access; wireless networks are treated as having more vulnerabilities than wired networks. Many different aspects must be taken into account when developing for wireless networks, such as performance on systems with limited capabilities, battery charge issues, and different user states and requirements. Due to the heterogeneous nature of the proposed network, this adds an additional vulnerability requirement for the system. Because the system will allow for multiple available connectionss, a potential attacker will have more systems to evaluate, giving them a better chance of finding vulnerabilities. Finding a systems exploit in one protocol might give access to another, thus complex management systems are necessary that can provide control systems and signaling for devices. Because devices will be connected to different interfaces and through multiple providers, the device will be exposed to attacks from each connection. The device will be exposed at different intervals to attacks based on code related to drivers, communication protocols, transportation and signaling stacks, file-sharing, update features, and other installed applications. Physical security should also be considered with these applications. Device deactivation and erasure are all necessary features for a device that will be utilized on so many fronts. It is difficult to quantify the security risks of 4G when it has yet to be developed, however it is essential that developers find a definable way to find a balance between practical applications and the necessary security levels involved with the network.

Finding the balance between creating practical applications and secure systems will yield the most difficult problems for developers. With the heterogeneous makeup of the 4G system, it will be necessary to ensure that each security measure is universally utilized across each type of network. Thus, the security measure have to be technology-independent, meaning that they will be applied in a top-down nature and be overlaid upon the entire system, not necessarily one of the specific networks, however this often comes at a price. It is considered to be inefficient to secure applications through overlay technologies, which is why previous systems have enforced security through device measures to protect revenues through access controls. This is usually applied through the networks interface hardware. Because of access networks in 4G, such as terminals for local access, it would be best kept as a hardware authentication system so that authentication would be processed on the first network chosen by the user and so that user devices, such as those detailed earlier for access networks, would be authenticated by the device and secure. Each type of network allowed by device will have much different requirements when authenticating user identifies and handling sessions.

 
The answer to this question probably generates more confusion than any other single aspect of WiMAX. In the early days of WiMAX it was common to see statements in the media describing WiMAX multipoint coverage extending 30 miles. In a strict technical sense (in some spectrum ranges) this is correct, with even greater ranges being possible in point to point links. In practice (and especially in the license-free bands) this is wildly overstated especially where non line of sight (NLOS) reception is concerned.

 
 Due to a variety of factors explained in more detail in other FAQ answers, the average cell ranges for most WiMAX networks will likely boast 4-5 mile range (in NLOS capable frequencies) even through tree cover and building walls. Service ranges up to 10 miles (16 Kilometers) are very likely in line of sight (LOS) applications (once again depending upon frequency). Ranges beyond 10 miles are certainly possible, but for scalability purposes may not be desirable for heavily loaded networks. In most cases, additional cells are indicated to sustain high quality of service (QOS) capability. For the carrier class approach, especially in regards to mobility, cells larger than this seem unlikely in the near future. The primary WiMAX focused US carrier Clearwire has stated that its cell sites are planned at about 1.5 miles apart for mobile purposes. This choice is clearly one intended to meet NLOS requirements. In licensed frequencies, expect similar performance or better for WiMAX than in traditional cellular systems.

The technology appears easily extensible to lower frequencies including the valuable 700 MHz spectrum range at which the nation's largest auction (in terms of money spent) concluded in 2008. More likely near term frequencies likely to be supported include the new 4.9 GHz public safety band (sometimes described as a Homeland security band).

The second largest block of frequencies ever auctioned (in terms of money spent) occurred in the summer of 2006 with the AWS auction from the FCC. This spectrum was split with the bulk being at 1.7 GHz and the rest at 2.1 GHz. At this point, the Forum is not expected to develop a product profile for this range as most licensees have announced support for LTE systems or plan to use it for existing GSM/UMTS networks.

The physics of radio signals typically place two primary constrictions on spectrum. To generalize, the higher the spectrum frequency the greater the amount of bandwidth that can be transported---lower frequencies transport less bandwidth. Secondly, the lower the frequency the greater the carry range and penetration of a signal. For example: A 900 MHz license free radio will travel farther and penetrate some tree cover fairly easily at ranges up to one to two miles. But it can carry much less bandwidth than a 2.4 GHz signal which cannot penetrate any tree cover whatsoever, but can deliver a lot more data. The caveat that can somewhat alter this equation is power. Licensed band spectrum such as 2.5 GHz by virtue of being dedicated to one user is allotted significantly higher power levels which aids in tree and building wall penetration.