The mobile industries transition from 4G to 5G, which could take a decade or longer, will see network operators, infrastructure vendors and device manufacturer’s progressively implement next generation technologies. It is one of the fastest growing and most dynamic sectors in the world.. The development of wireless technologies has greatly improved people’s ability to communicate and live in both business operations and social functions.
From the second generation (2G) mobile communication system debuted in 1991 to the 3G system first launched in 2001, the wireless mobile network has transformed from a pure telephony system to a network that can transport rich multimedia contents. The 4G wireless systems were designed to fulfill the requirements of International Mobile Telecommunications Advanced (IMT-A) using IP for all services. In 4G systems, an advanced radio interface is used with orthogonal frequency-division multiplexing (OFDM), multiple-input multiple-output (MIMO), and link adaptation technologies. 4G wireless networks can support data rates of up to 1 GBps for low mobility, such as nomadic/local wireless access, and up to 100 MBps for high mobility, such as mobile access. More powerful smart phones and laptops are becoming more popular now a days, demanding advanced multimedia capabilities. This has resulted in an explosion of wireless mobile devices and services. The EMO pointed out that there has been a 92 percent growth in mobile broadband per year since 2006. It has been predicted by the Wireless World Research Forum (WWRF) that 7 trillion wireless devices will serve 7 billion people by 2017; that is, the number of network-connected wireless devices will reach 1000 times the world’s population.
One of the most crucial challenges is the physical scarcity of radio frequency (RF) spectra allocated for cellular communications. Cellular frequencies use ultra-high-frequency bands for cellular phones, normally ranging from several hundred megahertz to several gigahertz. These frequency spectra have been used heavily, making it difficult for operators to acquire more. Another challenge is that the deployment of advanced wireless technologies comes at the cost of high energy consumption. The increase of energy consumption in wireless communication systems causes an increase of CO2 emission indirectly, which currently is considered as a major threat for the environment. Moreover, it has been reported by cellular operators that the energy consumption of base stations (BSs) contributes to over 70 percent of their electricity bill. In fact, energy-efficient communication was not one of the initial requirements in 4G wireless systems, but it came up as an issue at a later stage. Other challenges are, for example, average spectral efficiency, high data rate and high mobility, seamless coverage, diverse quality of service (QoS) requirements, and fragmented user experience (incompatibility of different wireless devices/interfaces and heterogeneous networks).
2. Literature Survey
The first generation,1G wireless mobile communication systems, was introduced in the early 1980’s. 1G was analog and supported the first generation of analog cell phones with the speeds up to 2.4kbps. The first commercially automated cellular network( 1G ) was launched in Japan by NTT (Nippon Telegraph and Telephone) in 1979, initially in the metropolitan area of Tokyo. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nationwide 1G network. Analog cellular phones are insecure. Anyone with an all band radio receiver can listen in to the conversation. There were thefts in the airtime.
The second generation, 2G system, fielded in the late 1980s. It was planned mainly for voice transmission with digital signal and the speed up to 64kbps. 2G cellular telecom networks were commercially launched on the GSM standard in Finland by Radiolinja in 1991. The difference between two succeeding mobile telephone systems, 1G and 2G is that the radio signals that 1G networks use are analog, while 2G networks are digital.
The third generation, 3G wireless system, also called UMTS (Universal Mobile Telecommunications Standard), was developed in the late 1990s. 3G is not only provided the transmission speeds from 125kbps to 2Mbps, but also included many services, such as global roaming, superior voice and video quality. The first pre-commercial 3G network was launched by NTT Docomo in Japan on 1998. All the operators provide 3G services on the 2100MHz band. The 3G vision is to create a unified global set of standards requirements that could lead to commercial deployment of advanced multimedia wireless communications.
The fourth generation, 4G is a conceptual framework just raised in 2002. The speeds of 4G can theoretically be promised up to 1Gbps. 4G networks can integrate several radio access networks with fixed internet networks as the backbone. A core interface sits in between core network and radio access networks, and a collection of radio interfaces is used for communication between the radio access networks and mobile users.
The beyond will be 5G with incredible transmission speed with no limitation for access and zone size.
3. Problem Statement
It is widely agreed that compared to the 4G network, the 5G network should achieve 1000 times the system capacity, 10 times the spectral efficiency, energy efficiency and data rate. The aim is to connect the entire world and achieve seamless and ubiquitous communication between anybody (people to people), anything (people to machine, machine to machine), wherever they are(anywhere), whenever they need (anytime), by whatever electronic devices/services/networks they wish (anyhow). This means that 5G networks should be able to support communications for some special scenarios not supported by 4G networks (e.g., for high-speed train users). High-speed trains can easily reach 350 up to 500 kmph, while 4G networks can only support communication scenarios up to 250 kmph. In this article, we propose a potential 5G cellular architecture and discuss some promising technologies that can be deployed to deliver the 5G requirements.