# D2D Assisted Beamforming for Coded Caching

## TL;DR

This paper introduces a novel D2D-assisted beamforming scheme for coded caching that enhances content delivery efficiency by combining local device exchanges with multicast downlink transmission, reducing delivery time and transceiver complexity.

## Contribution

It proposes a new beamforming approach leveraging D2D content exchange, optimizing delivery time, and reducing transceiver complexity in coded caching systems.

## Key findings

- D2D exchange increases multicast rate.
- The scheme reduces overall delivery time.
- Lower transceiver complexity achieved.

## Abstract

Device-to-device (D2D) aided beamforming for coded caching is considered in finite signal-to-noise ratio regime. A novel beamforming scheme is proposed where the local cache content exchange among nearby users is exploited. The transmission is split into two phases: local D2D content exchange and downlink transmission. In the D2D phase, users can autonomously share content with the adjacent users. The downlink phase utilizes multicast beamforming to simultaneously serve all users to fulfill the remaining content requests. We first explain the main procedure via two simple examples and then present the general formulation. Furthermore, D2D transmission scenarios and conditions useful for minimizing the overall delivery time are identified. We also investigate the benefits of using D2D transmission for decreasing the transceiver complexity of multicast beamforming. By exploiting the direct D2D exchange of file fragments, the common multicasting rate for delivering the remaining file fragments in the downlink phase is increased providing greatly enhanced overall content delivery performance.