Edge-Caching Wireless Networks: Performance Analysis and Optimization

Abstract

Edge-caching has received much attention as an efficient technique to reduce delivery latency and network congestion during peak-traffic times by bringing data closer to end users. Existing works usually design caching algorithms separately from physical layer design. In this paper, we analyse edge-caching wireless networks by taking into account the caching capability when designing the signal transmission.Particularly, we investigate multi-layer caching where both base station (BS) and users are capable of storing content data in their local cache and analyse the performance of edge-caching wireless networks under two notable uncoded and coded caching strategies. Firstly, we calculate backhaul and access throughputs of the two caching strategies for arbitrary values of cache size. The required backhaul and access throughputs are derived as a function of the BS and user cache sizes. Secondly, closedform expressions for the system energy efficiency (EE) corresponding to the two caching methods are derived. Based on the derived formulas, the system EE is maximized via precoding vectors design and optimization while satisfying a predefined user request rate. Thirdly, two optimization problems are proposed to minimize the content delivery time for the two caching strategies. Finally, numerical results are presented to verify the effectiveness of the two caching methods.

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“…Therefore, the total delivery time in the HD mode is the summation of the delivery time on the backhaul link and on the access link. The delivery time of the HD mode is computed by the standard max-min design [3]. Fig.…”

Energy‐Aware Smart Connectivity for IoT Networks: Enabling Smart Ports

“…A holistic view of communication, computation, and caching is presented in [18] using graphbased representations as learning methods for innovative resource allocation techniques. The performance of the edgecaching as well as the energy efficiency and delivery time is investigated in [19] with quality of service (QoS) constraints.…”

Energy-efficient design for edge-caching wireless networks: When is coded-caching beneficial?

“…Proposition 2, where its proof can be found in [14] due to space limitation, derives the access links' throughput under the coded-caching strategy for arbitrary value of M u . In the special case δ = 0 and MuK N ∈ Z + , Q cod,AC is shorten as…”

“…2) Signal transmission for coded caching strategy: One can use the beamforming design derived in the previous subsection to delivery the requested files in the coded-caching method. However, since the coded caching strategy transmits a common (coded) message X S (see [3], [14] for details) to all users during the delivery phase, using the orthogonal beams might result in resources redundancy. Instead, the BS applies physical-layer multicasting to precode the coded data [12].…”