TY - JOUR
T1 - D2D-assisted caching on truncated Zipf distribution
AU - Li, Qiang
AU - Zhang, Yuanmei
AU - Pandharipande, Ashish
AU - Ge, Xiaohu
AU - Zhang, Jiliang
PY - 2019/1/1
Y1 - 2019/1/1
N2 - In this paper, device-to-device (D2D)-assisted caching is considered to offload traffic from the capacity-stringent backhaul networks to the proximity of users. First, a three-layer hierarchical content provision model is established, where a requested content can be fetched from the local cache directly, from the cache of a proximal device through D2D communications, or from the serving base station through backhaul transmissions. Then, for a general multi-unit-cache equipped at each device, we propose independent content placement in each cache unit and correlated content placement in each cache unit without repetition, based on which the problem of maximizing the edge cache hit ratio is formulated. Instead of optimizing the caching probability for all contents in the library, we propose a parameter-based caching framework based on a truncated Zipf distribution, where only the position of truncation and the Zipf exponent are involved. For jointly determining the optimal values of the two parameters, a genetic algorithm and a two-step search algorithm are designed. The simulation results demonstrate that the correlated content placement outperforms its independent counterpart, and significant performance gains can be achieved by the proposed parameter-based caching framework in comparison with most existing approaches.
AB - In this paper, device-to-device (D2D)-assisted caching is considered to offload traffic from the capacity-stringent backhaul networks to the proximity of users. First, a three-layer hierarchical content provision model is established, where a requested content can be fetched from the local cache directly, from the cache of a proximal device through D2D communications, or from the serving base station through backhaul transmissions. Then, for a general multi-unit-cache equipped at each device, we propose independent content placement in each cache unit and correlated content placement in each cache unit without repetition, based on which the problem of maximizing the edge cache hit ratio is formulated. Instead of optimizing the caching probability for all contents in the library, we propose a parameter-based caching framework based on a truncated Zipf distribution, where only the position of truncation and the Zipf exponent are involved. For jointly determining the optimal values of the two parameters, a genetic algorithm and a two-step search algorithm are designed. The simulation results demonstrate that the correlated content placement outperforms its independent counterpart, and significant performance gains can be achieved by the proposed parameter-based caching framework in comparison with most existing approaches.
KW - cache-hit-ratio
KW - content placement
KW - D2D-assisted caching
KW - multi-unit-cache
KW - Zipf distribution
UR - http://www.scopus.com/inward/record.url?scp=85061746620&partnerID=8YFLogxK
U2 - 10.1109/ACCESS.2019.2894837
DO - 10.1109/ACCESS.2019.2894837
M3 - Article
AN - SCOPUS:85061746620
SN - 2169-3536
VL - 7
SP - 13411
EP - 13421
JO - IEEE Access
JF - IEEE Access
M1 - 8625415
ER -