4G is the fourth generation of mobile telecommunications technology, succeeding 3G. A 4G system must provide ITU-defined capabilities in IMT Advanced. Potential and current applications include modified mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing and 3D television.
Recent activity in the 4G mobile communication systems (fourth generation) has impregnated the career in its implementation as soon as possible. 4G Wireless is an upcoming standard witnesses growing interest among researchers and providers. It is designed to enable seamless integration and communication between wireless devices across diverse wireless standards as well as wireless broadband networks. Access to different radio technologies is facilitated by the IP-based 4G mobile communication system that connects the user.
In March 2008, the International Telecommunication Union-Radiocommunication Sector (ITU-R) specified a set of requirements for the 4G standards, called the International Mobile Telecommunications Advanced Specification (IMT-Advanced), establishing the maximum speed requirements for the 4G service at 100 megabits per (Mbit / s) for high mobility communications (such as trains and cars) and 1 gigabits per second (Gbit / s) for low mobility communication (such as pedestrians and stationary users).
Since the early versions of Mobile WiMAX and LTE support much less than 1 Gbit / s peak bit rate, they are not fully compatible with IMT-Advanced, but are often branded 4G by service providers. According to operators, one generation of the network refers to the deployment of a new non-retro-compatible technology. On 6 December 2010, ITU-R recognized that these two technologies, as well as other technologies that do not meet the IMT-Advanced requirements, could be considered "4G", provided they represent IMT-Advanced precursors according to versions and " a substantial level of improvement in performance and capabilities over the initial third generation systems now deployed. "
Mobile WiMAX Release 2 (also known as Wireless-MAN-Advanced or IEEE 802.16m) and LTE Advanced (LTE-A) are versions compatible with previous IMT-Advanced compatible versions of the two previous systems, standardized during spring 2011 promising speeds in the order of 1 Gbit / s. Services were expected in 2013.
Unlike previous generations, a 4G system does not support traditional circuit-switched telephony service, but all Internet Protocol (IP) -based communication such as IP telephony. As noted below, the spread spectrum radio technology used in 3G systems is abandoned in all 4G candidate systems and is replaced by OFDMA multi-carrier transmission systems and other frequency domain equalization schemes that allow transfer rates very high bits despite wide propagation of multiple radio paths (echoes). The peak bit rate is further enhanced by intelligent antenna matrices for multiple-input multiple-output (MIMO) communications.