The 5th Generation Mobile Wireless Networks- Key Concepts, Network Architecture and Challenges

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Now research is going on 5th generation wireless system (5G). It is expected that, it will fulfill the entire requirement that has not been fulfilled by 4G. 5G technology has changed the means to use cell phones within very high bandwidth. User never encountered ever before such a high value technology. All kind of advanced features which makes 5G technology most powerful and in huge demand in near future.5th generation technologies which are on hand held telephone offering more power and features than at least 1000 lunar modules. A user can also attach their 5G technology cell phone with their Laptop to get broadband internet access ^[14].

3. What 5G Technology Offers??

5G is going to be a new mobile revolution in mobile tele-phone market. 5G technologies now we can use worldwide cellular phones and this technology also strike the china mobile market and a user being competent to get access to USA phone as a local phone. Because of 5G technology the customers can be offered approximately priceless handset to its customers. In future also 5G will take over the world market. One of the biggest advantages of 5G is, it has excellent capability to support both software and consultancy. 5G network will provide high connectivity because of switch and router technology.

4. Need of 5G Wireless System

If we will compare 5G with other generation mobile phones, it is obvious that 5G has some extraordinary features and advantages.

1). 5G has better coverage area and high data rate at the edge of the cell.

2). It has low battery consumption.

3). Availability of multiple data transfer path.

4). Around 1 Gbps data rate is easily possible.

5). Security is more.

6). Energy efficiency and spectral efficiency are good.

Due to the above advantages, 5^th generation wireless system is very much essential.

Figure 2. 5G Mobile Phone[6]

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5. 5G Wireless Cellular Architechture

The proposed 5^th generation cellular architecture is shown in Figure 3 below.The architecture shows that it is an IP based model for wireless and mobile networks interoperability. According to the authors ^[6], the 5G wireless system consists of a user terminal and number of independent radio access technologies. User terminal plays a very important role in this system.

Figure 3. Functional Architecture for 5G- Network [6]

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Radio access technology (RAT) means a physical connection method for a radio based communication network. It is shown in the figure that, with in each of the terminals each RATs are the IP link to the outside world and also in mobile terminal there should be different radio interface for each RATs. If someone wants to access four different radio access technologies than four different accesses specific interfaces should be there in the mobile terminal and all of them should be activated at the same time in order to function the architecture.

It is called as the IP based model and the main purpose is to ensure control data for proper routing of IP packets belonging to a certain application connections. Routing of packets is carried out by the users with some specific policies and rules. Application connections are established between clients and servers in the internet i.e. via sockets. These Internet sockets are end points for data communication flows and each socket of the web is an unique combination of local IP address and appropriate local transport communications port, target IP address and target suitable communication port, and type of transport protocol.

In case of interoperability between heterogeneous networks and for the vertical handover between the respective radio technologies, the local Internet Protocol address and destination Internet Protocol address should be fixed and unchanged. Fixing of these two parameters should certain handover transparency to the Internet connection end-to-end, when there is a mobile telephone user at least on one end of such connection. In order to preserve the proper design of the packets and to reduce or prevent packets losses, drive off to the target destination and vice versa should be unique and it should be using the same path.

Figure 4. Deployment Scenario Envisioned For 5G Cellular System [26]

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Each radio access technology that is available to the user in achieving connectivity with the relevant radio access is presented with appropriate Internet Protocol interface or medium. Each Internet Protocol (IP) medium or interface in the terminal is characterized by its IP address and net mask and parameters associated with the routing of IP packets across the network. In uniform inter-system handover the modification of access technology (i.e., vertical handover) would mean changing the local Internet Protocol address. Then, change in some parameters of the socket means change of the socket that is, closing and opening of a new socket. This approach is not adjustable, and it is based on today’s wireless communication. In order to solve this insufficiency we propose a new level that will take care of the abstraction levels of network access technologies to higher layers of the protocol stack. This layer is very critical in the new architecture. From the authors ^[6], to enable the functions of the applied transparency and control or direct routing of packets through the most appropriate radio access technology, in the suggested architecture we introduce a control system in the functional architecture of the networks, which works in complete coordination or works together effectively with the user terminal and provides a network abstraction functions and routing of packets based on defined rules or policies. At the same time this control system is an essential element through which it can determine the quality of service for each transmission technology. Protocol system of the new levels within the occurring protocol stack, which form the suggested design and architecture, is given in Figure (Protocol Layout for the Elements of the Proposed Architecture). The network concept or idea would be provided by creating IP tunnels over IP interfaces obtained by connection to the terminal via the access technologies available to the terminal (i.e., mobile user). In fact, the tunnels would be established between the user terminal and control system named here as Policy Router or blueprint router, which performs routing based on given policies or some strategies. In this way the client side will generate an appropriate number of tunnels connected to the number of radio access technologies, and the client will put a local Internet Protocol address which will be formed with sockets Internet communication of client applications with Internet servers. The way Internet Protocol packets are choosing the right tunnel, would be worked by policies or strategies whose rules will be exchanged via the virtual network layer protocol. This way we achieve the necessary idea of the network to the client applications at the mobile terminal. The process of initiating a tunnel to the Policy Route or strategy router, for routing based on the given strategies, are took out immediately after the initiation of IP connectivity across the radio access technology, and it is started off from the mobile terminal Virtual Network-level Protocol. Initiating tunnel links as well as maintaining them represents basic functionality of the virtual network level ^[6].

In ^[7], the authors have mentioned that, the wireless users stay indoors generally for 80% of the total time and stay outdoors for 20% only. The outdoor base stations are used in the current cellular architecture to communicate with the mobile users. That doesn’t matter, whether they stay indoor or outdoor. When the indoor users communicate with the outdoor base station, the signals penetrate the building walls. Due to this, penetration loss occurs and apart from that data rate, spectral efficiency and energy efficiency are also damaged. In order to avoid these deficiencies, some new technologies are used now days and they are such as- Distributed antenna system (DAS), and MIMO technology ^[8].

Cognitive radio technology is one of the key concepts of 5G. Cognitive radio technology, also known as smart-radio: allowing different radio technologies to share the same spectrum efficiently by adaptively finding unused spectrum and adapting the transmission scheme to the requirements of the technologies currently sharing the spectrum. This powerful radio resource management is achieved in a distributed fashion, and relies on software defined ratio.

6. MIMO Concept for 5G

MIMO stands for Multiple Input and Multiple Output. In wireless communication system this method is used to increase the capacity of channel in radio link b using multiple transmit and receive antennas ^[9]. MIMO has become an important element of wireless communication system standards including IEEE 802.11ac (WI-FI), WI-MAX (4G) etc.

In ^[4], it has been mentioned that MIMO system consist multiple antennas at both the transmitter and receiver. One of the big advantage of this system is more data can be added to the wireless channels. So by using this method the energy efficiency, spectral efficiency and reliability can be improved.in MIMO system the transmitter and receiver part contained large number of antennas or we can say array of antennas. At one time in wireless the term “MIMO” referred to the mainly theoretical use of multiple antennas at both the transmitter and the receiver. In modern technical world, “MIMO” refers to a practical technique for sending and receiving more than one data signal on the same radio channel at the same time via multipath propagation. MIMO is conceptually different from smart antenna techniques developed to enhance the performance of a single data signal.

Figure 5. MIMO System [24]

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In ^{[10, 11]}, the authors mentioned that recently, MIMO is applied to Power line communication for 3-wire installations as part of ITU G.hn standard and Home Plug AV2 specification. In MIMO system the transmit antennas are distributed to in various applications and also the receive antennas are distributed to many devices. In ^[8], it is clearly mentioned that by using this massive MIMO system, the energy efficiency and spectral efficiency can be increased dramatically. One of the biggest advantages of MIMO technology is, here in this method intracell interference and noise can be minimized.

So due to these advantages, MIMO system is one of the key concept of wireless communication system.

7. Cognitive Radio Network

Cognitive Radio (CR) is an adaptive, smart radio and network technology that can automatically detect available channels in a wireless spectrum and also change transmission parameters making more communications to run at the same time and also to improve radio operating behavior. Technologies like adaptive radio and software defined ratio (SDR) are used in cognitive radio network. Adaptive radio is a technology where the communication system operates and changes its own performance and in case of software defined ratio (SDR), various hardware components like modulator, demodulator, amplifier and mixers are replaced by intelligent software system. Generally cognitive radio is used to improve or maximize the utilization of radio frequency spectrum. It is also observed that in some location or at some time, 70 percent of allocated spectrum are sitting ideal. The main feature of cognitive radio is their ability to recognize their communication environment and independently adapt the parameters of their communication scheme to maximize the quality of service for the secondary users ^[13].

Figure 6. Cognitive Radio System [25]

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In cognitive radio cycle a cognitive radio monitor’s spectrum bands.it also catches their information and then detects the spectrum spaces. Apart from that the characteristics of the spectrum spaces that are detected through spectrum sensing. Then, a suitable spectrum band is chosen according to the characteristics and user requirements. Once the band of the operating spectrum is determined, the communication can be executed over this spectrum band.

Figure 7. Cognitive Radio Cycle

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Cognitive radio perceives the radio environment by empowering each user’s receiver to sense the environment on a continuous time basis. Cognitive radio has some research challenges. They are such as spectrum sensing, advance spectrum management, and unlicensed spectrum usage etc. Cognitive radio is already being considered as the candidate for the 5th generation of wireless communications. The study of the cognitive radiowill be one of the most effective scientific ventures in the 21st century.

8. Applications of 5G Technology

From ^[6], we can summarize the applications.

1. One can be able to feel her kid’s stroke when he/she is in her mother’s womb.

2. One can be able to perceive his/her sugar level with his/her mobile.

3. One can be able to charge his/her mobile with his/her own heartbeat.

4. One can be able to view his/her residence in his/her mobile when someone enters.

5. The mobile will ring according to our mood.

6. One can be able to pay all bills in a single payment with his/her mobile.

7. One can get the live share value.

8. One can be able to navigate the train for which he/she might be waiting.

9. One can be able to vote from his/her mobile.

10. One can be able to know the exact time of his/her child birth that too in nanoseconds.

11. One can be able to sense tsunami/earthquake before it occurs.

12. Our mobile can share our work load.

13. One can get an alert in his/her mobile when someone opens his/ her intelligent car.

14. One can be ale to lock his/her car or bike with his/her mobile when he/she forgets to do so.

15. We can be able to expand our coverage using our mobile phone.

16. Our mobile can perform radio resource management.

9. Features of 5^TH Generation Wireless System

In ^{[13, 14]}, the authors have described some features of 5th generation wireless communication system.

Every mobile phone in a 5G wireless system will have an IP address. The technology is expected to support virtual private networks and advanced billing interfaces. The remote diagnostics also a great feature of 5G. The uploading and also downloading speed of 5G technology will be very high. The traffic statistics will be more accurate by using 5G technology. 5G technology provides large broadcasting of data in gigabits which supports almost 65000 connections.

10. 5G Super Core Concept

The 5G will have the following three main technologies:

• Nanotechnology.

• Cloud Computing.

• All Flat IP Platform.

The existing telecom networks are arranged in an ordered way, where subscriber traffic is aggregated at aggregation point (BSC/RNC) and then drives off to gateways. Flat Internet Protocol architecture will lessen burden on aggregation point and traffic will directly move from Base station to Media gateways. When transition from legacy (TDM, ATM) platforms to IP will be concluded, a common ALL IP platform will be appeared. All network operators (GSM, CDMA, Wi-max, Wire line) can be connected to one Super core with enormous capacity. The super core concept will roughly calculate all interconnecting charges, which is now days network operator is facing.

Figure 8. 5G Super Core Architecture [14]

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