Caching Eliminates the Wireless Bottleneck in Video Aware Wireless Networks

Abstract

Cellular data traffic almost doubles every year, greatly straining network capacity. The main driver for this development is wireless video. Traditional methods for capacity increase (like using more spectrum and increasing base station density) are very costly, and do not exploit the unique features of video, in particular a high degree of asynchronous content reuse. In this paper we give an overview of our work that proposed and detailed a new transmission paradigm exploiting content reuse, and the fact that storage is the fastest-increasing quantity in modern hardware. Our network structure uses caching in helper stations (femto-caching) and/or devices, combined with highly spectrally efficient short-range communications to deliver video files. For femto-caching, we develop optimum storage schemes and dynamic streaming policies that optimize video quality. For caching on devices, combined with device-to-device communications, we show that communications within clusters of mobile stations should be used; the cluster size can be adjusted to optimize the tradeoff between frequency reuse and the probability that a device finds a desired file cached by another device in the same cluster. We show that in many situations the network throughput increases linearly with the number of users, and that D2D communications also is superior in providing a better tradeoff between throughput and outage than traditional base-station centric systems. Simulation results with realistic numbers of users and channel conditions show that network throughput (possibly with outage constraints) can be increased by two orders of magnitude compared to conventional schemes.

Individual Preference Aware Caching Policy Design for Energy-Efficient Wireless D2D Communications

“…We thus focus on a single cluster. 4 We denote the number of active users in a cluster as K A ; the number of inactive users as K I . The total number of users is then K = K A + K I .…”

“…The potential of D2D-based video caching renders it widely discussed in recent years [4]- [11], and existing papers have demonstrated that, using either theoretical or empirical approaches, the wireless video caching can improve the throughput by orders of magnitude [8]- [11].…”

Stochastic Content-Centric Multicast Scheduling for Cache-Enabled Heterogeneous Cellular Networks

“…[11], [12], [15]) and consider multicast scheduling for a given caching design. Notice that caching in general is in a much larger time-scale (e.g., on a weekly or monthly basis) while multicast scheduling is in a shorter time-scale [4], [8], [10]. Consider time slots of unit length (without loss of generality) indexed by t = 1, 2, · · · .…”

“…Recently, caching at BSs has been proposed as an effective way to alleviate the backhaul capacity requirement and improve the user-perceived quality of experience in wireless networks [4]- [7]. Caching has received significant attention in the literature [8]- [12].…”

Finite length analysis of caching-aided coded multicasting

“…Recently, to tackle this problem, caching at the wireless edge has been proposed [3], [4]. Caching could take place at small cell/WiFi access points or at end user devices [5], [6], by prefetching popular content at off-peak periods to alleviate peak traffic later.…”