We study the delivery of 360°-navigable videos to 5G virtual reality (VR) wireless clients in future cooperative multi-cellular systems. A collection of small cell base stations interconnected via backhaul links are sharing their caching and computing resources to maximize the aggregate reward they earn by serving 360° videos requested by the wireless clients. We design an efficient representation method to construct the 360° videos such that they deliver only the remote scene viewpoint content genuinely needed by the VR users, thereby overcoming the present highly inefficient approach of sending a bulky 360° video, whose major part is made up of scene information never navigated by a user. Moreover, we design an optimization framework that allows the base stations to select cooperative caching/rendering/streaming strategies that maximize the aggregate reward they earn when serving the users for the given caching/computational resources at each base station.

Wireless edge caching for mobile social networks (MSNs) has emerged as one of the prospective solutions to provide reliable and low-latency communication services for mobile users on social networking. In this chapter, we first give an overview of MSNs, including their development and challenges. We then discuss mobile edge caching (MEC) paradigms to address emerging issues for MSNs, e.g., service delay, users’ experience, and economic efficiency. In addition to the advantages, the development of MEC networks also places some key challenges’ such as hierarchical architecture of MEC networks, proactive caching, privacy, and security issues. The framework can authenticate MSN users based on public-key cryptography and predict their content demands utilizing a matrix factorization method. Based on the prediction, an optimal content caching policy for an MEC node is presented to minimize the average latency of all MSN users under the MEC nodes’ storage capacity constraints. Furthermore, this framework provides an optimal business model to maximize the revenue for MSN service providers based on the demands of the MSN users and the obtained optimal caching policy.

This chapter presents a content-centric framework for transmission optimization in cloud radio access networks (RANs) by leveraging wireless edge caching and physical-layer multicasting. We consider a cache-enabled cloud RAN, where each base station (BS) is equipped with a local cache and connected to a central processor (CP) via a backhaul link. The BSs acquire the requested contents either from their local caches or from the core network via the backhaul links. We first study the caching effects on multicast-enabled access downlink, where users requesting the same content are grouped together and served by the same BS or BS cluster using multicasting. We study the cache-aware joint design of the content-centric BS clustering and multicast beam-forming to minimize the system total power cost and backhaul cost subject to the quality-of-service (QoS) constraints for each multicast group.

This chapter investigates the impact of caching in the interference networks. First, we briefly review the basics of some classic interference networks and the corresponding interference management techniques. Then we review an interference network with caches equipped at all transmitters and receivers, termed as cache-aided interference network. The information-theoretic metric normalized delivery time (NDT) is introduced to characterize the system performance. The NDT in the cache-aided interference network is discussed for both single-antenna and multiple-antenna cases. It is shown that with different cache sizes, the network topology can be opportunistically changed to different classic interference networks, which leverages local caching gain, coded multicasting gain, and transmitter cooperation gain (via interference alignment and interference neutralization). Finally, the NDT results are extended to the partially connected interference network.

In this chapter, a novel framework is proposed to address critical mobility management challenges, including frequent handovers (HOs), handover failure (HOF), and excessive energy consumption for seamless HO in emerging dense wireless cellular networks. In particular, we develop a model that exploits broadband mmW connectivity whenever available to cache content that MUEs are interested in. Thus it will enable the MUEs to use the cached content and avoid unnecessary HO to small cell base stations (SCBSs) with relatively small cell sizes. First, we develop a geometric model to derive tractable, closed-form expressions for key performance metrics, such as the probability of caching, cumulative distribution function of caching duration, and the average data rate for content caching over an mmW link. In addition, we provide insight on the performance gains that caching in mmW–mW networks can yield in terms of reducing the number of HOs and the average HOF.