Introduction
Introduction
With the popularity of services such as online banking, education and healthcare and development of internet, there will be a tremendous increase in mobile and wireless traffic. By 2020, data volume will increase 1000 times compare to the data volume of 2010. Besides, the hybrid communication among people will also demand high speed mobile data communication. Internet of things and the emergence a series of other new applications will generate the demand of millions of network devices, which create unprecedented demand on diversity, and wireless network related application context. The urgent need for efficient, convenient, safety and green 5G network is foreseeable.
With 5G network around the corner, its features, key technologies has been extensively studied by scholars. In this paper, based on my read of the book Fundamentals of 5G Networks and some additional research online, I first introduced the concept and explored the future applications of 5g, then discussed some key technologies of 5G network, including new heterogeneous dense network deployments, device to device(D2D) communications, massive MIMO, and green communications. Brief analysis of challenges regarding these four technologies was also provided.
The Concept of 5G and its Major Features
Concept & Definition of 5G
5G is a new concept, as a term, it has emerged many years, but when it comes to definition, there is no commonly, widely agreed definition. But there are some definitions given by scholars based on the traditional way of define mobile network communications. One of the such popular definition states that 5G is the next generation mobile network which could offer a data rates of tens of megabits per second.1 Based on my read of the book and research on internet, I think 5G is the next generation mobile networks following the 4th generation that serves the information demand of human society of 2020 and afterwards. It is a hybrid network that require a lot of technological progress and creation, that integrate multiple businesses and multi-technologies, and that could satisfy the demand of many future new businesses and services. And its activeness will bring the user experience to a whole new level.
5G major features
In terms of the future of 5G context and applications, there are a lot of descriptions from both the academy and industry. From all these descriptions we can infer the technical needs for the future 5G, which including the following features.
1000x data volume increase. The industry forecasts that the global mobile network data volume will be 1000 times that of 2010. So the data transmission speed of 5G in unit area, especial during peak time, will need to increase 1000 times accordingly, up to at least 100Gb/s/km2.
100x number of mobile devices. With the development of internet of things and intelligence terminals, it is predicted that the total mobile devices will be between 5-10 million. Which means that the devices supported by a 5G network will increase exponentially, up to 100 times compared to 4G network. For some applications and/or special events that may require extremely large data transmission, the number of devices to be supported may reach 1m/km2.
At least 10Gb/s peak speed. The peak speed of 5G data transmission of 2020, when compare to that of 4G, should increase at least 10 times, to 10Gb/s. In some special context, the consumer needs will reach 10 Gb/s.
Significantly reduced latency, increased reliability. The 5G network in 2020 is set to satisfy the high quality needs of consumer experience in any time and places, and some high value context such as emergency communication and industry information system. So it is important to further reduce and control consumer latency, to 5 to 10 times shorter than that of 4G. And for the businesses concerning human life and/or property safety, the reliability of service should higher than 99.999%.
Increased spectral efficiency. Due to the fact that the consumer base, data traffic, and volume will be huge, the need for spectrum will also increase. So new technologies must be utilized in order to improve utility rate of the spectrum. And it is predicted that a 5 to 10 times increase is needed to solve the problem of spectrum shortage.
Low energy consumption. Green communications, energy and cost-per-bit reduction are the trend of future communications. The future 5G network will need to utilize energy saving technology to increase energy efficacy 1000 times in order to meet the 1000x traffic need.
The key technologies of 5G
New heterogeneous dense network deployments
One of the solution to address the challenge of the future ongoing demand for data traffic is the deployments of high dense heterogeneous network. It could solve challenges such as 1000x data transmission speed, increased spectral efficiency and enhanced indoor coverage.
The 5G network architecture will move from traditional cellular network to distributed, heterogeneous network where there may have many different types of network. The deployment of high density heterogeneous network will lead to both the density of base station, macro cells as well as the small/femto cells. All the cells can share the burden of base or macro station effectively, providing a low latency, high reliability user experience. But a series of unwanted consequence will be brought in: inter-cell interference. There are many causes for inter-cell interference, custom deployment and transmit power difference of different devices are possible causes.
Inner and inter layer interferences become more and more complicated, there is a need for effective interferences cancellation and management. 3GPP proposed a ICIC (intercell interference coordination) standard, where they hope to eliminate the interferences through transmit power control, time domain and frequency domain.
Device to device(D2D) communications
The popularity of social networks and all other applications increased the demand for short distance data communication. However, current cellular network has many problems: coverage, volume and power consumptions. In addition to a lack of flexibility, makes it hard to meet the needs of real time and reliability for variety of businesses. Thus, it is very important to study device to device communication. As one of the key technologies for 5g, D2D will serve as an indispensable support and supplement for the cellular network. The chance for largely increased wireless data traffic, low power consumption, real time and reliability can all be greatly increased.
Current industry research on D2D communication mainly focused on aspects like transmit power control and resource allocation. Others focused on mobile network and resource allocation of D2D hybrid communication system. There are also many scholars presented effective algorisms for interference control. Their algorisms really address the problems of resource allocation and interference coordination, but these solutions can not solve problems such as inter base station coordination cost too much and hard to operate. Utilizing multiple antenna to control interference is another possible solution. But although all the above solutions could solve D2D communication problems for current cellular network, there are additional problems in deploying 5G. The first issue is the management of wireless resource, for example, when to launch D2D, how D2D share resource with cellular network. Problems like this make D2D deployment seems complicate and could possibly interference consumer experience. Another issue is concerning real time and reliability, because these two factor are key to communication systems, how to maintain real time and high reliability in service is always important.
Massive Multiple input multiple output (MIMO)
Multiple input multiple output system, is uses the multiple antennas at both the sides like sender side and receiver side to improve communication performance.2 These extra antennas provide more freedom to wireless channels, increase both data throughput and link range without additional bandwidth and transmit power. So it is a promising technology.
Current IMT-Advanced standard applied MIMO transmission technology, greatly increased Spectrum efficiency3. Massive MIMO can increase spectral efficiency as well as energy efficiency. It is the expansion and extension of MIMO. The features of massive MIMO is install large numbers (tens to thousands) of antennas around base station, serve multiple customers simultaneously through space division multiple address (SDMA). Massive MIMO has huge potential in future 5G because it is a technology that is extensible. 4G is inextensible, because there’s limited space for antenna, and angle spread is unavoidable, so it requires antenna number must match device number. However, there is no limit in antenna number in massive MIMO. But challenges are many. One of the main issue is channel estimation.
Green communications
The introduction of Intelligentization provides energy efficient solutions for heterogeneous network deployment while ensure customer experience. Statistics reveal that information and communication technology industry consumes about 10% of global energy. In wireless network, the energy consumes more than half of all energy. So green communication is very vital. To realize green communication, reduce the energy consumption of single base station is the first step. Network scheduling is another way, enabling the network allocate resources and control power dynamically according to the business volume level within service area. To achieve green communication, high energy efficiency transmission mechanism is the key. And a need for all kinds of new network nodes and their components as well as external parts necessary.
Conclusion
In this paper, I briefly discussed the concept, major features of 5G as well as its key technologies. The four technologies: New heterogeneous dense network deployments, Device to device(D2D) communications, Massive Multiple input multiple output (MIMO), and Green communications are commonly believed to be the most important technologies by academy and industry. I also listed challenges to these key technologies. There are several carriers around the globe announced that they are going to provide 5G network service by 2020 by now. As a consumer myself, I really looking forward for the cutting edge 5Gmobile network.