In this research, the history of wireless networks and communications is reviewed and the major improvements that took place, including the design and architectural improvements in the previous generations of networks up to the next generation of 5G network. The characteristics of the wireless generations kept upgrading from the evolution of these generations as there were different changes that were being made to the wireless network generations in order to achieve improved wireless networks with much better characteristics.
According to Jean DerGurahian, over the last several years, wireless networking has improved significantly as enterprises accommodate increasing numbers of mobile devices accessing their networks. The fifth-generation wireless technology has raised hopes to the telecommunications industry that it will represent a greater leap forward in network performance, enabling enterprises to use a wide range of new applications and services. 5G is expected to carry greater amounts of data over much faster networks with sub-millisecond latency (Jean DerGurahian. 2016), building from the current fourth generation wireless long term services (4G LTE). The speed at which 5G can transfer data is about 10 times that of the current 4G LTE network, up to 10Gbps, equivalent to wireline speeds. A lot more is to be further discussed. This research looked at the two major improvements in the making of the 5G wireless network. These are design improvements and architectural improvements.
The journey of wireless networks began a long time ago. According to Tom Seymour, wireless networks were first developed during the pre-industrial age. The systems that were developed used smoke signals, flashing mirrors, signal flares, or semaphore flags to transmit information over line-of-sight distances. An elaborate set of signal combinations was developed to convey complex messages with these signals and these messages were relayed by observation stations built on hilltops and along roads. These early communication networks were replaced by the telegraph network invented by Samuel Morse in 1838 (Tom Seymour.2011), and later by the telephone. After that, a demonstration of the first radio transmission appeared from Marconi a few decades after the telephone was invented.
Figure 1: the first radio transmission
The radio transmission in figure 1 could transmit information at a distance of approximately 18 miles from one point to another. This gave rise to pocket radio communication. Pocket radio network found commercial application in supporting wide-area wireless data services. These services enabled wireless data access (including email, web browsing and file transfer) at low speed, on the order of 20 Kbps. Although the services did not materialize a strong market due to their low data rates, high cost and insufficient killer applications.
It is clearly visible that mobile data usage is exploding, driven by the increasing dominance of smart devices with better hardware, better user interface design, compelling services and the desire for anywhere and anytime high speed connectivity. According to Mamta Agiwal, the vision of next generation 5G wireless communication lies in providing very high data rates, very low latency, increase of base station capacity and improvement to user’s quality of service(QoS) compared to the current 4G LTE network (Mamta Agiwal.2016). The increasing design of smart devices together with the ascending wireless data demand and usage is creating a load of burden on the current cellular networks. Whereas 5G wireless system with its improved capacity, latency, data rates and quality of service, is expected to be the possible solution to most of the problems of the current networks.
The evolution of wireless networks occurred gradually with their characteristic being slightly different from each other. This is shown in the table below.
1G voice signals only, analogue cellular phones, NMT, AMPS
2G Voice and data signals, Digital fidelity cellular phones, GSM, CDMA, TDMA
3G Voice, data and video signals, video telephony/ internet surfing, 3G w-CDMA, UMTS
4G Enhanced 3G/ interoperability protocol, high speeds and IP based, 4G mobile IP
Table 1: characteristics of wireless network generations
1G: analogue cellular networks
The use of multiple cell sites and the ability to transfer calls from one site to the next was the main technological development that distinguished the first generation mobile phones from previous generations. It was launched in Japan by NTT in 1979 (Tom Seymour. 2016). After five years, another development from Bell Labs was initiated. It was a modern commercial cellular technology which employed centrally controlled base stations (cell sites), each providing service to a small area. In a cellular system, a signal between a cell site and terminal (phone) needs to be strong enough to reach between the two, therefore the same channel could be used for separate conversations in different cells, simultaneously. As the system continued to grow, it gained the ability to reduce transmission power, thus allowing addition of new cells which resulted in smaller cells and increased capacity.
2G: digital networks
The emerging of the second generation occurred in the 1990’s, primarily using the GSM standard. What made the second generation phone system differ from the previous generation was the use of digital transmission instead of analogue transmission. Also, their advanced and fast phone-to-network signalling. As a result of 2G, the rise in mobile phone usage was exponential. Plus, a new variant to communication was introduced by the second generation. SMS text messaging became possible on GSM network and eventually on all digital networks. The digital signal required less battery power, which was one of the benefits of 2G. Another method of digital coding was introduced, which improved the voice clarity and reduced noise in the line. Digital signals are considered environment friendly (Tom Seymour.2016). As improvements continued being done on the systems, secrecy and safety became a concern. Then, digital encryption was introduced to provide secrecy and safety for the data and voice calls. Technology kept improving up to a point where General Packet Radio Services (GPRS) technology was developed, as a successor of 3G. it could provide data rates from 56 Kbit/s up to 115kbit/s. it enabled the use of services like wireless application protocol (WAP) access, multimedia messaging service (MMS) and internet communication services such as world wide web access.
3G: high speeds IP data networks
As people began to use mobile phones in their daily lives, the growth of the demand for data services became clear. It was predicted that if the experience from fixed broadband services was anything to go by, there would be even greater demand for data speeds and 2G could not do the job. Therefore, the industry began working on the next generation known as the 3G technology. For data transmission it used packet switching which is shown in figure 2, instead of circuit switching. This was the technological difference that distinguished 3G from 2G. 3G cellular communications systems had intensions which were to provide a mobile wireless communication capability that would globally provide the ability to support a wide range of services to users. According to Burbank etal, 3G standardization began within the 3GPPwhich was established in 1998 as a collaboration between multiple regional telecommunications standards bodies.
Figure 2: packet switching
4G: mobile broadband growth
Due to the cellular networking landscape aggressive evolution, the era of the fourth generation of cellular networks was brought by. New cellular technologies such as the 3GPP and long term evolution (LTE) advanced. User experience was enhanced with lower latency, higher throughput and always-on-connectivity, enabling a mobile broadband experience comparable to that of the wireless local area network (WLAN) technology (Burbank etal.2013).
The expectations for 4G wireless is basically the high quality of audio/video streaming over end to end internet protocol. The first two commercially available technologies billed as 4G were the WiMax standard and the LTE standard. The introduction of the fourth generation wireless network technology eliminated circuit switching, instead employed an all-IP network.
At the end of 2017, the wireless industry came up with the first official fifth generation standard. 5G brings three new aspects to the table, which are greater speeds, even lower latency (to be more responsive) and the ability to connect a lot more devices at once (for sensors and smart devices). Like other cellular networks,5G networks use a system of cell sites that divide their territory into portions called sectors and send encoded data through radio waves. There is something called a network backbone which cell must be connected to, whether through wired or wireless backhaul connection. 5G will use a type of encoding called OFDM which is similar to the encoding that 4G LTE uses. Their air interface will be designed for much lower latency and greater flexibility than LTE.
There are two types of 5G networks that mobile operators are preparing to roll out. The first is fixed wireless broadband and the second is mobile 5G cellular.
Fixed wireless broadband
Fixed wireless broadband was designed to deliver last-mile internet connectivity to a business or residence using radio signals, rather than a wired connection directly to the premises. To provide broadband, carriers deploy 5G new radios in small cell sites such as on streetlights and telephone poles, to deliver signals to wireless modems installed inside buildings and residences. This replaces the need for fiber, cable or other wireline connections directly to a building.
Figure 3: fixed wireless broadband
Mobile 5G cellular
5G mobile services will be enabled together with the development of Evolved Packet Core LTE advanced wireless connectivity. Cellular 5G mobile cannot be rolled out until 3PP has completed 5G mobile standards, and until 5G- enabled smartphones are commercially available.
With the requirements of sub-millisecond latency and bandwidth limitation in traditional wireless spectrum, cellular networks are now poised to break the Base Station (BS) centric network paradigm. Figure 3 depicts this gradual movement from BS centric to a device centric network. The increase in demand by wireless industry motivated the advancement towards much smaller cell deployment from the initial macro hexagonal coverage. Researchers these days are focused on ways to design user centric networking. User is no longer the final resolution of the wireless network but is expected to participate in storage, relaying, content delivery and computation within the network.
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1. Monika Phogat e tal, “IJETT” avail: http://www.ijettjournal.org (accessed 10 April 2018)
2. Jean DerGurahian, “understanding basics of 5G wireless networks” avail: https://searchnetwork.techtarget.com/feature/understand-the-basics-of-5G-wireless-networks (accessed 10 April 2018)
3. Tom Seymour e tal. “history of wireless communication” the Clute institute online 2011. Avail: www.academia.edu/880496/history_of_wireless_communications