4G wireless is the short name for the fourth generation of broadband cellular network technology, succeeding 3G and preceding 5G. A 4G system must provide capabilities defined by the International Telecommunication Union (ITU) in IMT Advanced. Potential and current applications of 4G wireless include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, and 3D television.

4G wireless works via an antenna that transmits over radio frequencies, enabling mobile devices to connect to mobile networks. The transmission and receiving capabilities of 4G are powered by MIMO (Multiple Input Multiple Output) and OFDM (Orthogonal Frequency Division Multiplexing) technologies. Both MIMO and OFDM enable more capacity and bandwidth in comparison to 3G. OFDM provides more speed than the primary technologies that powered 3G, such as TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access). With MIMO, 4G reduces network congestion in comparison to 3G, because more users can be supported.

4G wireless is also an all-IP (internet protocol)-based standard for both voice and data, different from 3G, which only uses IP for data, while enabling voice with a circuit-switched network. As an all-IP network, 4G is more efficient for mobile network providers to operate and optimize than managing different network technologies for voice and data.

4G wireless has speeds of up to 100 Mbps, while 3G only promised a peak speed of 14 Mbps. With 4G download speeds, wireless users can stream high-definition video and audio. 4G also enables wireless broadband, which provides a way for users to get internet connectivity without the need for a fixed, wired connection from an internet service provider (ISP).

The difference between 4G and 4G LTE is all about marketing and the history of the 4G specification. LTE (Long Term Evolution) was originally developed to make the transition for carriers easier from 3G to 4G. 4G was first defined by the ITU in 2008, but its speeds and technical specifications were not immediately achievable for mobile networks or mobile devices. As an interim step up from 3G, LTE provides more bandwidth than 3G, without achieving the full bandwidth network speed minimum of 100 Mbps that 4G promises. The term LTE is often used as part of marketing pitches and does not specify or imply a specific speed. Depending on the carrier, speeds range from 20 Mbps to 100 Mbps.

4G LTE-A (LTE-Advanced), however, is a specific term that is defined as enabling 100 Mbps. In effect, it is 4G, with no technical difference from it.

The history of 4G wireless dates back to 2008, when the ITU specified a set of requirements for 4G standards, named the International Mobile Telecommunications Advanced (IMT-Advanced) specification, setting peak speed requirements for 4G service at 100 megabits per second (Mbit/s) for high mobility communication (such as from trains and cars) and 1 gigabit per second (Gbit/s) for low mobility communication (such as pedestrians and stationary users).

However, in December 2010, the ITU expanded its definition of 4G to include Long Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMAX), and Evolved High Speed Packet Access (HSPA+). These technologies, as well as other beyond-3G technologies that do not fulfill the IMT-Advanced requirements, could nevertheless be considered “4G”, provided they represent forerunners to IMT-Advanced compliant versions and “a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed”.

The first-release WiMAX standard was commercially deployed in South Korea in 2006 and has since been deployed in most parts of the world. The first-release LTE standard was commercially deployed in Oslo, Norway, and Stockholm, Sweden in 2009, and has since been deployed throughout most parts of the world. However, it has been debated whether the first-release versions should be considered 4G. According to operators, a generation of the network refers to the deployment of a new non-backward-compatible technology.

As of 2021, 4G technology constitutes 58% of the worldwide mobile telecommunication technologies market. The adoption of 4G wireless has been driven by the increasing demand for mobile data services, such as video streaming, social media, online gaming, and cloud computing. 4G wireless has also enabled new applications and services that were not possible with previous generations of mobile networks, such as mobile health, smart cities, smart grids, and Internet of Things (IoT).

However, 4G wireless also faces some challenges and limitations, such as spectrum scarcity, network congestion, security risks, interoperability issues, and high costs. Moreover, 4G wireless is expected to be replaced by 5G wireless in the near future. 5G wireless is the next generation of mobile communication that promises to deliver faster speeds, lower latency, higher reliability, and more capacity than 4G wireless. The ITU has defined the requirements for 5G standards under the IMT-2020 specification. The first commercial deployments of 5G wireless are expected to take place in 2020.