Different Types of Cellular Communications Technology

Since the first analogue phones, mobile communications technology has gone a long way. Read this article to learn about the journey from 1G to 4G, as well as the technology driving this incredible growth and significant advances along the way.

Mobile communication systems include a radiotelephone that can work while travelling at any speed, is battery powered, and is small enough to be carried by a person. Public land radio, Mobile two-way radio, amateur (HAM) radio, and mobile telephone are all examples of cellular communication technologies.

A cellular phone positioned anywhere on the grid connects to the nearest tower, which is linked to a mobile switching centre to finish the call to the destination device inside that or any other cell, or to a public network fixed phone. Cell sites are also unusual in their capacity to smoothly transfer a call from a moving vehicle to a neighbouring cell.

In 1979, Japan launched the first generation of mobile networks, designated 1G. It provided analogue 2.4Kb/s connectivity with limited coverage and no roaming capabilities. In 1991, 2G used digital signalling to increase the speed to 64Kb/s, and the Global System for Mobile Communications (GSM) standard to improve voice fidelity and dependability. It also enabled the sending of text messages and photographs. 3G was implemented in 2001 and brought worldwide standards into alignment, as well as 256Kb/s speed. Video conferencing, streaming, and Voice over Internet Protocol was among the additional features (VoIP). 4G LTE (Long-Term Evolution), the fourth and most popular version in use today, can give rates of up to 1Gb/s for high-definition video, web access, and gaming applications.

Past and Present of Cellular Network Communications

Before we describe the journey of cellular technology from 1G to 4G, let us explain the key technologies that have contributed to the spectacular expansion of cellular systems in wireless communication. Since the commercial launch of the AMPS (advanced mobile phone system) service in the year 1983, cellular communication systems have grown at an exponential rate.

Concept of Cellular

The advent of cellular services has brought frequency reuse capabilities. Wireless connectivity, digital signal processing, integrated circuits, better battery life, and other advancements fueled the exponential rise of personal communication services.

The following is how the cellular system works: A frequency spectrum is separated into distinct channels, which are assigned to geographic cells spanning a service region in groups. The individual channels can be reused in various cells with sizes ranging from 2 to 50 km. A radio frequency (RF) transmitter is assigned to the service area while neighbouring cells operate on separate frequencies to minimise interference.

Cell phones started off as a clear-cut two-way analogue communication system that used frequency modulation for frequency-shift keying and voice for signalling and controlling information. A digital cellular system, satellite mobile, cordless telephone, and paging are all examples of cellular systems in wireless communication. Analogue cellular systems are classified as 1G (first generation), whereas digital cellular power-efficient wireless is classified as 2G (second generation).

Analogue Cellular Phone

Bell Labs in New Jersey developed the cellular telephone concept as an enhanced mobile communication system in 1970. (AMPS). Illinois Bell launched AMPS, a basic cellular telephone service, on October 13, 1983. For 100% modulation, it employs narrow-band FM with a useable audio frequency range of 300-3 kHz and a maximum frequency variation of 12 kHz. This equates to 30 kHz according to Carson's rule.

AMPS employs frequency-division multiple access (FDMA), which separates signals in the frequency domain. For the length of their call, subscribers are given a pair of voice channels (forward and reverse). Analogue cellular channels provide both audio and digital signalling information through binary FSK (frequency shift keying).

Digital Cellular System

It increases capacity while also improving performance. FDMA employs a frequency canalisation technique for spectrum management, whereas TDMA employs a time-division approach. The cellular RF spectrum that's available is separated into narrow-band radio channels that serve as a communication link (one-way) between base stations and cellular mobile devices.

Types of Cellular Technologies

Cellular technology is the foundation of mobile phone networks, and it is the technology that gives cell phones its name. Cellular technology is defined by the use of numerous tiny linked transmitters rather than a single large one.

The other major notion of cellular technology was "multiple access," which meant that it combined several phones or data connections into a single radio channel.

Multiplexing in wireless communication may be done in three dimensions: code (CDMA), time (TDMA), and frequency (FDMA and variant - OFDMA).

• GSM

The Groupe Special Mobile, an initiative of the CEPT (Conference of European Post and Telecommunications) administration, created the GSM (Global System for Mobile Communications). It was first designed as a cellular system in wireless communication in the 900MHz frequency known as the main band. This major band is divided into two 25-MHz sub-bands: 935-960 MHz and 890-915 MHz.

Furthermore, GSM systems such as Globalstar, ICO, and Iridium utilise LEO (low-earth orbit) or MEO (medium-earth orbit) satellites to function as overlay networks for current PCS and cellular networks. These use dual modes to provide coverage for all regions on the surface of the earth.

IMT-2000 (International Mobile Telecommunication-2000) is basically a 3G standard created by the ITU. It provides worldwide mobility with smooth service delivery and global roaming. An appreciation of the importance of identities and numbering in mobility management, call delivery, international roaming, and charging and billing is critical for understanding how personal communication and cellular networks work.

Well, PCSS (Personal communication satellite service) employs LEO satellite repeaters that use QPSK modulation as well as TDMA and FDMA.

The primary benefits of GSM include worldwide roaming (in accordance with ISDN principles, ensuring interoperability between ISDN and GSM) and features such as privacy and encryption, frequency hopping, short message service, and discontinuous transmission. Call forwarding, waiting, barring, teleconferencing, and holding are also available.

A network subsystem, a base station subsystem, mobile stations, and system interworking and interfaces compose the fundamental architecture.

In order to start and operate a GSM terminal, a SIM (subscriber identity module) is required. The SIM card may be built into the mobile station or it might be a separate item that the user inserts into their mobile device.

• CDMA

Well, CDMA is a type of direct-sequence spread-spectrum technology that allows several users to share the same time and frequency allocations in the same band/space. To assist identify signals from different users in the same spectrum, CDMA provides each user with a unique spreading code to distribute the baseband data before transmission. It is the foundation for 2G and advanced 3G services.

The codec transforms voice to a digital signal after speaking. CDMA distributes the voice stream throughout the whole 1.25MHz bandwidth of the CDMA channel, coding each stream individually. The receiver employs a correlator to disperse the desired signal, which is then processed by a bandpass filter. Also, unwanted signals are not dispersed and are not processed by the filter.

The spreading signal's rate is known as the 'chip rate,' since each bit in the spreading signal is known as a 'chip.' All 2G networks allow only single-user data speeds of around 10 kbps, which is insufficient for fast e-mail and Internet surfing.

CDMA has a capacity that is more than 10 times that of analogue AMPS and five times that of GSM and TDMA systems. It needs fewer cell sites than GSM or TDMA.

• UMTS

Backward compatibility with 2G and 2.5G TDMA technologies is ensured through the UMTS (Universal Mobile Telecommunication System) or W-CDMA. W-CDMA, an air interface standard, was created for packet-based wireless communication, allowing entertainment devices and computers to share the same wireless network and access the Internet at any time and from any location.

UMTS enables data speeds of a maximum of 2.048 Mbps when the user is stationary, permitting them to access high-quality data, streaming audio and video, multimedia, and broadcast-type services. UMTS allows data rates ranging from 8 kilobytes per second to 2 megabytes per second to be carried concurrently on a single UMTS (W-CDMA) radio channel of 5 MHz. 

UMTS time slots are not utilised for user separation but rather to facilitate periodic functions. (This is in contrast to GSM, which uses time slots to divide people.) W-CDMA channels have a bandwidth of 4.4 to 5 MHz.

Due to the difficulty in evolving the worldwide standard, three operational modes have been specified:

A 3G-powered device will be a mobile, personal, multimedia communication device (for example, a TV provider may divert a TV channel to the phone of the subscriber, where it may be seen). Secondly, it'll feature video conferencing, which means subscribers will be able to see and communicate with one another. Thirdly, it'll put forward location-based services, such as sending localised traffic or weather conditions to the phone or allowing the user to identify nearby friends or businesses.

• LTE

Well, LTE, the acronym for Long Term Evolution, is a mobile communication protocol. Mobile data may be exchanged over the air in greater quantities and at faster rates in the cellular network than in previous wireless communication standards. As the term "Long Term Evolution" suggests, this standard will be valid for a long period. This will not alter with the introduction of 5G. The LTE network will remain the basis upon which the cellular network of 5G will be constructed.

LTE is also known as "4G," which stands for the 4th generation of mobile communication technology. It is a collection of improvements to the "UMTS" (Universal Mobile Telecommunications System), the third generation of cellular communications. As a result, 5G is a succession of improvements to LTE. As a result, 5G clearly shows the continued progress of cellular technology.

LTE employs multiple input, multiple output (MIMO) antenna technology, among several other innovations. It enables the transmission of VoLTE and video conferencing through Internet Protocol, along with the usage of time-critical apps like online gaming on your smartphone, due to its low latency. With a 20 MHz bandwidth, LTE may reach downlink rates of a maximum of 300 MBit/s and uplink speeds of a maximum of 75 Mbit/s, with a latency of fewer than 20 milliseconds.

The Bottom Line

Since the implementation of first-generation mobile networks, the telecommunications industry has faced several new issues in terms of technology, effective spectrum usage, and, most crucially, end-user security. Wireless technology of the future will enable ultrafast, feature-packed, and highly secure cellular networks.

If you are someone who is interested in learning the ins and outs of cellular communications, you can do an online short course at Skill-Lync. This course is the starting point for anybody interested in becoming a Protocol Testing Engineer, Network Engineer, or Telecom Engineer.