5g Wireless Architecture V.1

5G WIRELESS ARCHITECTURE By Vadan Mehta About Author Vadan Mehta is having 12 years of experience in wireless telecommunication. He is PMI certified PMP and Cisco certified IPTD. Currently, he is working as telecom consultant for Tata consultancy services (TCS).

ABSTRACT This document represents personal views on 5G network architecture, especially for wireless service providers. Document has 3 segments, Brief history of wireless telecommunication, 4G network architecture, Network Infrastructure sharing and 5G network architecture.

INTRODUCTION “Before you create future, you must envision it “ : UNKNOWN We are living in era of convergence. Convergence is merging of technologies, domain and discrete IT systems. Basic of convergence lies in Digitization. The digitization of everything is creating a more natural communications experience. Boundaries separating various technologies, engineering practices, functions etc. are dissolving. So tomorrow, our car, our mobile phone, our home security system, our office, all the systems that surround us, will communicate with each other automatically to fill our environment with our preferences and our need to feel connected anywhere, anytime and with anyone, across the world. This is called Ubiquitous Computing paradigm. Wireless technologies are going to take taking new dimension in our lives. The wireless broadband will soon become readily available to everybody while, being at home, driving the car, sitting in the park, and even on a pleasure boat in the middle of a lake. And because of this, our need to have information at anytime and to be connected at all places, all the time, will be satisfied. The world of universal, uninterrupted access to information, entertainment and communication will open new dimension to our lives and change our life style significantly. This article is presenting vision of 5G network architecture, explaining concept of Ubiquitous computing, Super Core and Evolution of managed services.

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Brief History of Telecom Moore’s law The way that "Moore's Law" is usually cited is: "the number of transistors that can be fit onto a square inch of silicon doubles every 12 months." Moore's law describes a long-term trend in the history of computing hardware but it also prove true for wireless technologies. From 1G (First Generation) to 4G (4th Generation), wireless bit rate has increased from 2.4 Kbps to 100 Mpbs. Brief description of Wireless Generations: 1G: The first generation, 1G wireless mobile communication systems, was introduced in the early 1980s and completed in the early 1990s. 1G was analog and supported the first generation of analog cell phones with the speeds up to 2.4kbps. The prominent ones among 1G system were advanced mobile phone system (AMPS), Nordic mobile telephone (NMT), and total access communication system (TACS) 2G: The second generation, 2G system, fielded in the late 1980s and finished in the late 1990s, was planned mainly for voice transmission with digital signal and the speeds up to 64kbps. GSM and CDMA IS 95 were prominent technologies. 2.5G 2.5G is used to describe 2G-systems that have implemented a packet switched domain in addition to the circuit switched domain. 2.5 G can provide data rate, up to 144 kbps. GPRS, EDGE and CDMA 2000 were 2.5 technologies. 3G: The third generation, 3G wireless system, was developed in the late 1990s and might be welldone in the late 2000s. 3G is not only provided the transmission speeds from 125kbps to 2Mbps, but also included many services, such as global roaming, superior voice quality and data always add–on. UMTS, CDMA Evdo, HSPA are 3G technologies. 4G: The fourth generation (4G) is a conceptual framework and a discussion point to address future needs of a high speed wireless network that can transmit multimedia and data to and interface with wire-line backbone network perfectly just raised in 2002. The speeds of 4G can theoretically be promised up to 1Gbps. LTE is considered as 4G technology.

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4G Architecture 4G is being developed to accommodate the QoS and rate requirements set by forthcoming applications like wireless broadband access, Multimedia Messaging Service (MMS), video chat, mobile TV, HDTV content, Digital Video Broadcasting (DVB), minimal services like voice and data, and other services that utilize bandwidth. The definition of 4G is to provide adequate RF coverage, more bits/Hz and to interconnect all wireless heterogonous networks to provide seamless, consistent telecom experience to user. Evolved Packet Core (EPC) Evolved Packet Core is the IP-based core network defined by 3GPP (Telecom standard) for use by LTE and other access technologies. The goal of EPC is to provide simplified all-IP core network architecture to efficiently give access to various services such as the ones provided in IMS (IP Multimedia Subsystem). EPC consists essentially of a Mobility Management Entity EPC (MME) and access agnostic Gateways for routing of user datagram. EPC will be a completely new architecture for wireless operators, one that that emulates the IP world of data communications rather than the voicecentric world of wireless. EPC is based on flat IP network theory. FLAT IP ARCHITECURE Premise of 4G, is resting on All IP architecture. Mobile networks have been designed up to this point — for circuitswitched voice. Wireless networks were designed in a hierarchal fashion to aggregate, authenticate, manage and direct calls. A BSC aggregates calls from multiple base stations, allocates radio channels, enables handoffs between base stations and passes on calls to an even more centralized mobile switching center. As packet data networks emerged, they were overlaid on the existing voice-centric architecture, using the BSC for the same mobility management functions and adding the SGSN and GGSN in the case of GSM/UMTS and a PDSN in the case of CDMA to route and manage data sessions, as well as to connect to the Internet or appropriate IP network. As data traffic is increasing rapidly, this voice centric architecture has become cumbersome and harder to manage with too many network entities. Flat network architecture removes that voice-centric hierarchy from the network. Instead of overlaying a packet data core on the voice network, separate and much-simplified data architecture can be implemented that removes the multiple elements from the network chain. BSC functions are divided between Base station and media gateway router. Base station will communicate directly via 3GDT (3G direct tunnel) with media gateway over WAN ( Carrier Ethernet, MW, DWDM etc). Some of the functions of BSC/RNC such as Radio resource management, Radio Bearer Control, and Dynamic allocations of resources will be handled by base stations, while functions such as Distribution of paging messages, Security will be function by mobility manager, located in Gateway router. Page 3

This approach has clearly visible advantages. It will save significant amount of Capex and Opex as, service provider will have fewer hopes and fewer network entities. By reducing the number of hops on the network, data travels faster between end points, greatly reducing the network latency to help support real-time applications such as voice over IP (VoIP), gaming and videoconferencing. The flat IP architectures have emerged with WiMAX, and future LTE networks will be flat by definition.

NETWORK INFRASTUCTURE SHARING Sharing of telecom infrastructure among telecom service providers is becoming the requirement of business in the telecom industry where competitors are becoming partners in sharing their infrastructure (mainly base stations) order to lower their increasing investments.Cell site (base stations) sharing helps in reducing the cost significantly. Some operators were able to bring down the cost of network operations by around 40 percent in the last one year by such sharing arrangements. In addition, the operators save on precious time in terms of locating buildings, negotiating prices and then setting-up their site.

There can be active or passive infra sharing between two network operators. Passive Infra sharing Passive Infra sharing data (India)

The passive elements are defined as the physical network components that do not necessarily have to be owned or managed by each operator. Instead, these components can be shared among several operators. The provider of the infrastructure can either be one of the operators or a separate entity set up to build and operate it, such as a tower company. The passive infrastructure in a mobile network is composed mainly of:  Electrical or fiber optic cables  Masts and Towers  Physical space on the ground, towers, roof tops  Shelter and support cabinets, electrical power supply, air conditioning, alarm systems and other equipment. A collection of passive network equipment in one structure for mobile telecommunications is generally called a “site.” Therefore, when one or more operators agree to put their equipment on (or in) the same site, it is called “site-sharing” or “collocation.” Passive Infra sharing is most popular in recent times. Active Infra sharing In addition to sharing passive infrastructure, operators may also share active elements of their wireless networks. The “active elements” of a wireless network are those that can be managed by operators, such as antennas, antenna systems, transmission systems and channel elements. Operators may share those elements and keep using different parts of the spectrum assigned to them. Although active infrastructure sharing is more complex, it is technically possible. Network operators have to redesign/modify their network elements (Base stations, antennas,) for active sharing. Page 4

Overview of Managed services Managed Services typically include establishing, operating and managing day-to-day operations of a telecom operator’s network, services and business support systems. The term also covers the case where a provider takes responsibility for providing the required network capacity to an operator, when and where needed, as well as hosting of content, applications and enablers. Other business support areas, such as Customer Relationship Management (CRM), provisioning and billing, are generally handled by operators in-house. The Managed Services market within the telecom industry is in a high-growth phase and is characterized by agreements, which vary in scope, between Managed Services providers and a broad range of telecom operators: greenfielders, incumbents and lower-tier operators. Telecom-equipment vendors are showing an increasing interest in Managed Services as a way to benefit from their existing competence and take on new roles in the value chain, covering activities such as network build, including planning and design, field operations, Network Operation Center (NOC) operations, application and service development, and billing. In recent years, operator awareness of Managed Services has increased significantly. Operators that have decided to use Managed Services have mainly been driven by the following opportunities.  Under increasing financial pressure due to increasing competition, operators can improve their financial results by outsourcing functions to a partner that can provide higher efficiency and economies of scale than an individual operator can achieve. 

With an increasing degree of complexity, operators can reduce their need to build network and services-related competence and leave this to Managed Services providers that are experts in managing this complexity (potentially resulting in higher quality).

They can dedicate more of their efforts to revenue-generating activities, such as customer acquisition. The above drivers of the Managed Services market will also apply in coming years. The growing number of Managed Services agreements has, and will over time, create a virtual circle resulting in increasing Managed Services provider competence, leading to even greater efficiency gains and economies of scale. This, in turn, will make Managed Services even more attractive to all types of operators, throughout the world, and most will enter into some kind of Managed Services agreement, in part or in full, to stay competitive in their market. As technologies converge, outsourcing of an operator's business support systems, network and services to the same Managed Services provider can be expected to maximize the end-to-end benefits to the operator in a Managed Services engagement. In the near future, therefore, there is a strong likelihood that the shift in responsibility for roles in the value chain enabled by Managed Services combined with increasing complexity of technology, will result in a win/win scenario for both telecom operators and Managed Services providers. The key to success will be adopting an end-to-end view of managing networks, services and business support systems, with the end-user in mind.

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5G architecture Up to 4G, the wireless evaluation is following path of Moore’s law. The newer generations were identified by increased bit rate. ( 2G ( 9.6 Kpbs) to 4G ( 1Gbps)). There is belief that, 5G will be generation will defy the Moore law and it will be phase of integration of network technologies, rather expansion or evaluation of new wireless standard. As discussed 4G network should fulfill the promise of providing adequate RF coverage and capacity for high volume data applications and acceptable latency for voice applications. Beyond 4G, there will no need for new access technology as 4G technology (as promised) will convert each mobile connection into Broadband connection. Thus telecom operators will invest in developing new Applications rather then developing newer wireless standards. New network applications will be developed to integrate various engineering practices as mechanical, health care, Chemical, Banking etc. to provide seamless, continual and versatile mobile experience to user. Telecom operators will be moving to customer centric approach then technological approach as they are currently using. .

Ubiquitous Computing 5G would be about "ubiquitous computing", that is, having the ability to access the applications we want from any platform, anywhere, any time. To create such an environment, one needs to integrate various applications, emerging from various engineering practices. Human life will be surrounded by intelligent sensors, which will bring radical change to human life’s daily approaches of doing things, as:  Your intelligent car will send SMS to your cell phone, if someone tries to open the door, while you are away from your car.  Your home security camera is attached to secured internet. So that you can view your sitting room on your laptop/mobile phone screen, by accessing secured website.  Your  You will have single bill for all telecom services, regardless of application or network operator.  You are receiving regular MMS from your hospital about your medication need and next doctor appointment.

Key challenges 

Integration of various standards: Each engineering practice has their own standard (F.eks Telecom has 3GPP, 3GPP2, ITU, IETF, etc). To integrate these various standards, requires systematic and time consuming approach.



Common Platform: There is no common architecture for interconnecting various engineering practices. One common governing body is required, which creates a common platform for all engineering practices to regularize the interconnectivity issues as well as knowledge sharing.

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Super Core Concept Existing telecom networks are fashioned in hierarchical way, where subscriber traffic is aggregated at aggregation point(BSC/RNC) and then routed to gateways. (As shown in figure).Flat IP 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 (Flat Network concept, described in previous section) a common ALL IP platform will be emerged. Vision of Super Core is based on IP platform. All network operators ( GSM,CDMA, Wimax, Wireline) can be connected to one Super core with massive capacity. This is realization of single network infrastructure. The concept of super core will eliminate all interconnecting charges and complexities, which is right now network operator is facing. It will also reduce number of network entities in end to end connection, thus reducing latency considerably. E x is tin g s e tu p

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Key challenges 1)

High redundancy requirement: Under Super core concept, all network operators will be moving to single core infrastructure, high redundancy and security among core network entities is required. A failure of single node will impact huge number of subscribers across various network operators. 2) Transparency among network operators, regarding Subscriber data, churn management, etc. 3) Government regulatory framework for Super core.

Flatter IP concept At regular interval, semiconductor manufacturers advance to a new generation with smaller feature sizes. This allows them to incorporate more functions into a given area of silicon and, hence, more features or new capabilities into electronic devices like cell phones. As advancement semi-conductor industry, 22nM CMOS will be reality and this will increase the processing capacity of digital devices significantly. Increased processing capacity will be allow Mobile devices (cellphones, PDAs, etc) to do more tasks (instructions per minute) then before. This will lead to even the Flatter IP network. As Flat IP has shifted some of the BSC/RNC’s radio resource functions to Base station, Flatter IP will shift some of the RR functions, to Mobile devices from Base station. Finally your cell phone will not be just access device but, it will also perform some of the Radio Resource Management functions.

Evolution of Network Infra Sharing As described in previous section, network operators, worldwide are opting for infrastructure sharing. Currently trend is for passive infra sharing as Active infra sharing has certain limitation. But at invention and deployment of Cognitive Radios (Software based radios) and multi-port Base station, will promote active infra sharing at Antenna, Base station and spectrum level at access Ran. So, network operators, offering different access technologies such LTE & Wimax, can have single high capacity base station and antenna. Currently service provider is spending 60% of total expenditure on Capex This arrangement will have significant amount of Capex saving as currently service provider is spending 60% of total expenditure on Capex.

Evolution of Managed Services As previous session has described, network operators are shifting network related activities to managed service vendor. Concept of Super Core complements this trend as all network operators will end up having one massive super core, which will be managed by one or many vendors under managed service contract, bound by SLA (Service level agreements). Thus, during 5G, may be Today's mobile network operators could become service retailers and due to single infrastructure, today's MNO (Mobile network operators) s will effectively be MVNOs (Mobile Virtual network operators).

Summary As data traffic has tremendous growth potential, under 4G existing voice centric telecom hierarchies will be moving flat IP architecture where, base stations will be directly connected to media gateways. 5G will offer even more flatter architecture by using advanced semi conductor technologies as 22mN CMOS. 5G will promote concept of Super Core, where all the network operators will be connected one single core and have one single infrastructure, regardless of their access technologies. 5G will bring evaluation of active infra sharing and managed services and eventually all existing network operators will be MVNOs (Mobile virtual network operators ). This article is written by Vadan Mehta ([email protected]) Page 8