This post covers Mobile and Wireless Networks by Khaldoun Al Agh, Guy Pujolle, and Tara Ali-Yahiya.

Basic Ideas

• The 5G - Fundamental System Design

  • Along with the efforts of 3GPP to deliver evolved specifications for LTE Advanced (LTA-A), that include many revolutionary characteristics described Chapter 4, there is an initiative within 3GPP itself to define the specifications of 5G in its latest release so this technology will be used in 2020 and beyond. Release 14 is being developed and buzzwords are:

  • Internet of Things, C-RAN (Cloud RAN), full virtualization, low bit-cost, high spectral and energy efficiency

  • These specifications cover new techniques that enable the high data rate to satisfy the high demand of different types of traffic, lower cost bits to be delivered by 5G, and less energy to be consumed to transmit a bit.

  • Besides these important characteristics, there are many scenarios expected where billions of wireless devices will be deployed and should communicate wirelessly.

  • This will bring a new challenge of a large number of devices with different signaling protocols, diverse types of traffic, different methods of resource allocation, quality of service (QoS), mobility and interference management

  • From LTE Advanced to 5G: the big transition

    • As shown in Figure 5.1, 5G will be ready in 2020. However, it is difficult to understand what the specification for 5G will be from the figure, and whether there is a gap between the evolution of LTE-A and the first 5G specifications. Work is still in progress on recent releases, especially release 14 and beyond, as LTE-A witnessed the addition of new features that make it the perfect technology of the future.
    • However, it is important to understand the soft transition from LTE-A to 5G as once the releases finish, the next step will be introducing new services on top of features introduced in LTE-A.
    • Thus, one can understand 5G as the enhancement of the radio capabilities used in LTE-A for different types of networks and communication technologies.
    • In this topic, we will show how LTE-A paved the way for 5G. Then, we will introduce the radio capabilities that should be added to evolved elements in LTE-A in order to form what we call 5G.

  • D2D communication In the LTE Release 12 and beyond, focus will be on network controlled device-to-device-communication or D2D, where the macrocell base station performs control signaling in terms of synchronization, beacon signal configuration and providing identity and security management.

  • As D2D allows devices in close proximity to communicate directly with each other, they enable authorities to communicate out-of-network-coverage or during network outages (e.g. in the case of a natural disaster).

  • There are also commercial benefits of D2D, with new applications building on the physical proximity of users.

  • The enhanced D2D in LTE-A concerns the introduction of group communications that allow authorities to create and dissolve groups on demand with resource-efficient communications (e.g. multicast) within the group.

    

  • LTE–WiFi integration for traffic offloading With the increasing and rapid growth of traffic through the use of billions of smartphones, we need to know how to deal with the huge amount of traffic that an LTE operator has to process. LTE uses small cells, which can be represented by femtocells, metrocells, etc., to offload traffic from macrocells by positioning the small cells either inside the macrocell or at the edge.

  • The best choice is the deployment of WiFi as an integrated part of the cellular network because the operator can cope with high traffic.

  • The 3GPP proposes using WiFi to offload the macrocell, especially for the bulk traffic that does not require any special handling for service delivery or charging.

  • The 3GPP-standard mechanism for this is built around a new functional element, the Access Network Discovery and Selection Function (ANDSF).

  • The ANDSF conveys policies to devices facilitating selection of either cellular or WiFi access for different kinds of traffic

    

  • Vehicular communication Vehicular communication (V2X) has many uses, including navigation and driver assistance, travel information, congestion avoidance, fleet management, payment transactions and traffic control and safety. V2X can include many scenarios, just like vehicular-tovehicular or vehicular-to-pedestrian communication.

  • The use of LTEA in such a context is advantageous since it provides many capabilities over which many services can be built once it is integrated technically in V2X. For example, V2X moving in all directions is not a big obstacle for LTE-A as it already has extensive coverage in rural and urban area, besides the low latency and high capacity make the deployment of V2X easier.

  • One more important issue is the enabling of D2D communication in LTE that would facilitate the communication of these mobile vehicles by the use of such communications.

  • Massive capacity support In dense areas, where there is heavy traffic, many users and a huge number of base stations, there is a need for technologies beyond LTE-A. Different scenarios can be perceived. Small cells can be used as proposed in LTE offload big cells to a large number of small cells according to procedures and algorithms.

  • However, there is still a problem of license and interference issues that should be addressed. Therefore, 5G attempts to use LTE, which should be suitable for unlicensed spectrum bands where higher frequency bands should be used (up to 10 GHz).

  • As per dense deployment, high frequency bands will be used to create spectrum flexibility by dividing and sharing them among operators in order to optimize the use of the spectrum according to the scenario detected through studying the radio map of the area of deployment.

  • Ubiquitous communication support: One of the most important issues to be covered in 5G is interworking within different types of networks within the same technology, for example making LTE radio more adaptable to various technologies

  • Improvement in radio characteristics Regardless the improvement done in LTE-A, there is still more need to improve the capabilities of the radio, especially when we are

    5G talking about interworking scenarios for different kinds of networks; i.e. macrocell, femtocell, picocell, D2D, MTC, relay, etc.

  • The coordination of conference in such context is considered to be very hard and new algorithms should be used in 5G to ensure minimum interference.

  • Furthermore, the use of 3D beamforming will be important since it combines horizontal beam pattern adaptation, as applied for beamforming and multiple input multiple output (MIMO) schemes, with vertical antenna pattern adaptation.

  • The recent availability of flexible antenna techniques enables fully dynamic antenna pattern adaptation which can be specified per resource block and piece of user equipment (UE), and makes 3D beam forming practically feasible shown in Below figure