On the Spectral Efficiency and Energy Efficiency Analysis of Cache-Enabled Heterogeneous Networks with Device-to-Device Communication and Cooperative Transmission
Date
2021-01-07
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Abstract
The Heterogeneous network (HetNet) is a viable candidate for achieving high spectral efficiency (SE) and energy efficiency (EE) in fifth-generation (5G) networks. Cache-enabled HetNets with device-to-device (D2D) communication can exploit the availability of cheap memory to improve file delivery and reduce file download latency. In HetNets with simultaneous requests for different file types, the design problems centered on what file to store and how to utilize limited caching capacity impact the SE and EE. In this thesis, an association scheme that computes the D2D communication range based on out-of-cell interference is proposed for establishing cellular and D2D links in a HetNet. The proposed interference-aware, D2D distance threshold-based association scheme achieves up to 67% gain in the SE and EE compared to the state-of-the-art minimum path loss-based association scheme. Further, a popularity and size-aware (PSA) caching scheme is proposed in a hybrid microwave/millimetre wave HetNet. The PSA caching scheme allocates memory blocks for caching according to Pareto, lognormal, and Gamma file size distributions based on empirical measurements and is different than the state-of-the-art probabilistic, size-weighted-popularity (SWP)-based, and most-popular-content (MPC) caching schemes that assume equal file size. Numerical results show that the proposed PSA caching scheme provides up to 33% increase in the cache hit probability compared to the probabilistic and MPC caching schemes. Besides, the PSA scheme achieves up to 17% gain in the file transmission success probability compared to the state of the art. Also, cooperative transmission among transmitters under the PSA caching scheme realizes up to 70% gain in the file transmission success probability compared to a non-cooperative transmission scheme. Lastly, the integration of large scale antenna arrays is proposed to enhance the transmission capacity of a cache-enabled HetNet with D2D communication. The results reveal that the transmission capacity of the HetNet scales linearly with the number of antenna elements per transmitter, provided that the number of antenna elements is not so large. The results in this thesis prove the usefulness of adopting content-aware caching and multiple transmission schemes to improve the performance of a HetNet with unlimited file requests and limited caching capacity.
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Keywords
Caching, Heterogeneous Networks, Device-to-device, Cooperative transmission, Spectral efficiency, Energy efficiency
Citation
Ochia, O. E. (2021). On the Spectral Efficiency and Energy Efficiency Analysis of Cache-Enabled Heterogeneous Networks with Device-to-Device Communication and Cooperative Transmission (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.