Experimental Study of SDN-Based Evolved Packet Core Architecture for Efficient User Mobility Support

The mobility management architecture in current generation LTE networks results in high signaling traffic. In this chapter, we present an Evolved Packet Core (EPC) architecture based on Software Defined Networking (SDN) concepts. The proposed EPC architecture centralizes the control plane functionality of the EPC thereby eliminating the use of mobility management protocols and reducing mobility related signaling overheads. The architecture utilizes the global network knowledge with SDN for mobility management. The proposed architecture has been implemented in the ns-3 simulator. A prototype testbed has also been implemented using the Floodlight SDN controller, a Software Defined Radio platform and relevant software.

Design and Measurement Results for Cooperative Device to Device Communication

In this chapter, the authors present the simulation and measurement results for direct and single hop device-to-device (D2D) communication protocols. The measurement results will further argument the development of D2D communication and will also help in understanding some of the intricate design issues which were overlooked during theoretical or computer simulations. The measurements were taken on a proof-of-concept experimental testbed by emulating a cellular scenario in which a Base station (BS) and many D2D enabled devices coordinate and communicate with each other to select an optimum communication range, transmit parameters, etc. A testbed (Multi-carrier) was developed using Software Defined radio which incorporates the concept of Spectrum Sharing through static sub-carrier allocation to D2D user by cellular system which will eventually enhance the performance of cellular as well as D2D communication system. Our purposed and deployed protocol have shown significant improvement in received Signal to Noise Ratio (SNR) as compared to conventional direct transmission schemes.

Adaptive Multimedia Services in Next-Generation Broadband Wireless Access Network

There is a massive upsurge in data traffic over the Internet due to multimedia services. The upcoming heterogeneous broadband wireless access networks (BWANs) provide higher data rates, increased capacity, and enhanced network coverage. Since the smart phone usage and multimedia service demand is increasing at a much faster pace as compared to the capacity and resources of the underlying network technology, adaptive multimedia services are essential to provide satisfactory quality of experience (QoE). The focus of this chapter is to discuss the adaptive techniques to provide better multimedia services to heterogeneous users in next-generation networks. These techniques consist of video streaming optimization using MPEG-DASH, video caching schemes, quality aware video transcoding, web optimization of multimedia services, and user-centric cross-layer optimization.

Fault Tracking Framework for Software-Defined Networking (SDN)

The emergence of software-defined networking (SDN) raises a set of fundamental questions, including architectural issues like whether control should be centralized or distributed, and whether control and data planes should be separated. Several open problems exist in SDN space, ranging from architectural questions that are fundamental to how networks scale and evolve to implementation issues such as how we build distributed “logically centralized” control planes. Moreover, since SDN is still in its early stage, there is an opportunity to make fault tracking framework a more integral part of the overall design process. Although SDN's goal is to simplify the management of networks, the challenge is that the SDN software stack itself is a complex distributed system, operating in asynchronous, heterogeneous, and failure-prone environments. In this chapter we will focus on three key areas: 1) SDN architecture, 2) scalable SDN systems to understand which pieces of control plane can be run logically centralized fashions, and 3) fault tracking framework to track down the failures in SDN.

Link Level Resource Allocation Strategies for Green Communications in LTE-Advanced

Mobile operators are showing a growing concern for energy efficiency in cellular networks in the recent past not only to maintain profitability, but also to tackle the overall environment effects. Such a trend is motivating the standardization bodies, network operators and researchers to aggressively explore techniques to reduce the energy consumption in the network. This trend has stimulated the interest of researchers in an innovative new research area called green cellular networks which is a vast research discipline that needs to cover all the layers of the protocol stack and various system architectures. Since Long Term Evolution-Advanced (LTE-A), which promises better support to richer applications, is fast emerging as the next generation cellular network standard and expected to aggravate the energy consumption problem, various techniques have been proposed and researched to improve its energy efficiency. This chapter discusses three link level techniques that attempt to reduce the energy consumption of a LTE-A cell with intelligent MAC layer algorithms.

D2D- and DTN-Based Efficient Data Offloading Techniques for 5G Networks

With the advancement of smart phone technologies cellular communication has come to a stage where user bandwidth has surpassed the available bandwidth. In addition, the well-organized but stubborn architecture of cellular networks sometimes creates hindrance to the optimal usage of the network resources. Due to this, a User Equipment (UE) experiencing a poor channel to the Base Station (BTS) or evolved NodeB (eNB) or any other Access Point (AP) retransmits the data. In such scenarios, Device-to-Device (D2D) communication and offload/relay underlying the cellular networks or the access networks provides a unique solution where the affected UE can find a close proximity offloader UE to relay its data to eNB. Delay Tolerant Networks (DTN) is another framework which has potential usage in low-connectivity zones like cell edge and/or remote locations in cellular networks. This chapter investigates various possibilities where D2D and DTN can be jointly used to improve teledensity as well delayed but guaranteed services to poor or no connectivity areas.

Radio Environment Maps and Its Utility in Resource Management for Dynamic Spectrum Access Networks

Recent measurements on radio spectrum usage have revealed the abundance of under-utilized bands of spectrum that belong to licensed users. This necessitated the paradigm shift from static to dynamic spectrum access (DSA). Researchers argue that prior knowledge about occupancy of such bands, such as, Radio Environment Maps (REM) can potentially help secondary networks to devise effective strategies to improve utilization. In the chapter, we discuss how different interpolation and statistical techniques are applied to create REMs of a region, i.e., an estimate of primary spectrum usage at any arbitrary location in a secondary DSA network. We demonstrate how such REMs can help in predicting channel performance metrics like channel capacity, spectral efficiency, and secondary network throughput. We show how REMs can help to attain near perfect channel allocation in a centralized secondary network. Finally, we show how the REM can be used to perform multi-channel multi-hop routing in a distributed DSA network.

Resource Allocation in Multi-Tier Femtocell and Visible-Light Heterogeneous Wireless Networks

The increasing demand in mobile data traffic, data hungry services and high QoS prerequisites have led to the design of advanced multi-tier heterogeneous cellular networks. In this chapter, a multi-tier heterogeneous wireless network is examined consisting of the macrocell, multiple femtocells and multiple Visible Light Communication (VLC) cells. Distributed resource allocation approaches in two-tier femtocells are presented focusing on (a) power allocation and interference management, (b) joint power and rate allocation, and (c) resource allocation and pricing policies. Similarly, the most prominent resource allocation approaches in two-tier VLC cells are examined, including (a) user association and adaptive bandwidth allocation, (b) joint bandwidth and power allocation, and (c) interference bounded resource blocks allocation and power control. The resource allocation problem in the two-tier heterogeneous environment where both femtocells and VLC-LANs are simultaneously present is also discussed. Finally, detailed future directions and comprehensive conclusions are provided.

Energy Efficient Resource Allocation Scheme via Auction-Based Offloading in Next-Generation Heterogeneous Networks

The focus of this chapter is centered on the network underutilization during low traffic periods (e.g., night zone), which enables the Mobile Network Operators (MNOs) to save energy by having their traffic served by third-party Small Cells (SCs), thus being able to switch off their Base Stations(BSs). In this chapter, a novel market approach is proposed to foster the opportunistic utilization of unexploited SCs capacity, where the MNOs lease the resources of third-party SCs and deactivate their BSs. Motivated by the conflicting interests of the MNOs and the restricted capacity of the SCs, we introduce a combinatorial auction framework. A multiobjective framework is formulated and a greedy auction algorithm is given to provide an energy efficient solution for the resource allocation problem within polynomial time. In addition, an extensive mathematical analysis is given for the calculation of the SCs cost, which is useful in the market framework. Finally, extended experimental results to estimate the potential energy and cost savings are provided.

User-Oriented Intercell Interference Coordination in Heterogeneous Networks (HetNets)

HetNet is a hot research topic in the next generation broadband wireless access network and mitigating the intercell interference could improve the system throughput. Users care whether their requested data rates can be satisfied or not the most. Hence a user-centric intercell interference coordination scheme (i.e. resource allocation scheme considering user request) is necessary. In this paper, at each specific subframe, when users have data requests, the corresponding base station first selects which user to serve based on each user's ‘instant data rate', data rate request and capacity gained. Then given the users selected, a method is proposed to help choose which intercell interference coordination scheme to use in order to maximize the users' data rate satisfaction ratios. Intensive simulations are conducted and the results demonstrate that the proposed scheme achieves considerable gains over competing schemes in terms of the data rate satisfaction ratio and system capacity in Config.4b scenarios defined by 3GPP.