Coded caching under various heterogeneous settings has been intensively studied. Specifically, in a shared-link model, a coded caching scheme based on a popularity-first caching strategy has been proved to be order-optimal under arbitrary popularity distributions. It is of great interest to investigate whether a similar conclusion holds in a device-to-device (D2D) network. Unlike shared-link models, since the server does not participate in the delivery phase in D2D networks, the caching scheme must ensure that all files can be recovered from the union of users’ caches. In this paper, we consider a D2D network constrained to uncoded prefetching and propose a new achievable scheme that caches popular files preferentially while allocating the minimal but necessary cache space to unpopular files. Then we derive new lower bounds on the average transmission rate under arbitrary popularity distributions. The proposed lower bounds are established via a novel decoupling method that isolates the rate analysis of popular files from the cache space allocated to unpopular ones, which could be of independent interest for future work. Finally, we prove that our proposed scheme achieves order-optimality among uncoded schemes under arbitrary popularity distributions. Numerical results validate the effectiveness of the proposed scheme and the tightness of the new lower bounds.
Jinbei Zhang, Wenjie Guan, Kai Huang et al.· IEEE Transactions on Communi...· 0 citations
Integrated sensing, communication, and computing (ISCC) technology significantly improves spectrum efficiency and reduces hardware costs by unifying the functionalities of sensing, communication, and computation. However, the degradation of wireless link quality caused by obstacles may lead to severe offloading latency. This paper investigates the application of reconfigurable intelligent surface (RIS) technology in ISCC network to enhance the reliability of wireless links and improve the efficiency of computation offloading. In the proposed network, integrated sensing and communication (ISAC) devices employ the same hardware and signaling mechanisms to perform both sensing and communication tasks, while mobile edge computing (MEC) technology is leveraged to process sensing data. To address the cross-layer resource management problem, we formulate a total latency minimization problem for both communication and computation under sensing accuracy constraints, by jointly optimizing the waveform precoding design matrix of ISAC devices, the beam pattern scaling factor, the RIS’s reflective beamforming, and the computing frequency of edge server (ES). Since this problem is highly non-convex, we propose an iterative algorithm based on block coordinate descent (BCD) framework, which leverages semi-definite relaxation (SDR) method, the Charnes-Cooper transform (CCT) method, and closed-form solution to alternately optimize three variable blocks until convergence is achieved for the final solution. Extensive simulations validate the effectiveness of the proposed scheme, demonstrating that the RIS-assisted joint optimization scheme significantly reduces the total system latency. Moreover, we reveal the trade-off between sensing accuracy and system latency.
Yingsheng Peng, Jinbei Zhang, Jingpu Duan et al.· IEEE Transactions on Green C...· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
