Tradeoffs between storage and latency for cache-aided relay interference channels with No CSIT
| Autor: | Haobo Liang, Roger Shu Kwan Cheng |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Computer science
CPU cache ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS Transmitter 020206 networking & telecommunications Data_CODINGANDINFORMATIONTHEORY 02 engineering and technology Topology Upper and lower bounds law.invention Relay law Channel state information 0202 electrical engineering electronic engineering information engineering Cache Latency (engineering) Communication channel |
| Zdroj: | WCNC |
| DOI: | 10.1109/wcnc.2018.8377046 |
| Popis: | In this paper, we investigate the tradeoffs between storage and latency for a k-user cache-aided relay interference channel with K antennas at the relay when channel state information (CSI) is not available at the transmitters. We propose a cache placement and content delivery scheme, and mainly focus on the case when each transmitter has a cache size capable of storing 1 out of K files in the library. The main contribution of our work is that by applying the relay decode-and-forward (DF) protocol, we can achieve a normalized delivery time (NDT) δ(μ) = (2Κ − 1)/K, which is the upper bound for the Κ-user interference channel with instantaneous CSI at the Transmitter (CSIT) when the normalized cache size at the transmitter is 1/K. We then consider caching at the relay, and based on the sum-Degree of Freedom (DoF) result, we found the achievable NDT to be (Κα + Κ − 1 − β)/(Ka − β), where a is the file splitting parameter and β is related to the relay cache size. We also analyze the case when the transmitter has a normalized cache size of 1. To our knowledge, no one had studied a relay interference channel with no CSIT but with caching. Our results show that caching at the relay side shortens the latency effectively, especially for a network with a large number of users. Furthermore, the presence of a relay in the network renders instantaneous CSIT unnecessary, which is a more practical situation in such systems. |
| Databáze: | OpenAIRE |
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