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Abstract
Nowadays, the explosive data traffic demand has been craving innovative technologies for future wireless networks. Classic theory has revealed that the capacity of a multiple-input and multiple-output (MIMO) channel can increase
linearly with the number of antennas. However, besides deploying multiple antennas at base stations, there are many challenges to develop MIMO to further boost the wireless network capacity.
In this thesis, advanced MIMO technologies are studied to exploit the degree of freedom gain under a variety of proposals for future wireless networks.
First, a new linear vector physical-layer network coding scheme is proposed for a MIMO two-way relay channel where the channel state information is unavailable at transmitters. We present an explicit network coding method
that minimizes the error probability at high signal-to-noise ratios (SNRs). We propose a novel typical error event analysis and show that the proposed scheme achieves the optimal error rate performance at high SNRs. Numerical results show that the proposed scheme significantly outperforms existing schemes.
Second, a new caching scheme is proposed for a random wireless device to-device (D2D) network, where each node is equipped with a local cache and intends to download files from a prefixed library via D2D links. The distributed MIMO technology is employed between source nodes and neighbours of the destination node for cache deliveries. The induced multiplexing gain and diversity gain increase the number of simultaneous transmissions, improving the network throughput. The average aggregate throughput scales almost linearly with the number of nodes, with a vanishing outage probability, and outperforms existing ones when the cache size is limited.
Third, a hybrid D2D-cellular scheme is proposed to make use of the standby users who possess D2D communication capabilities in close proximity to each other, and to improve the rate performance for cellular users. Through D2D
links, a virtual antenna array is formed by sharing antennas across different terminals to realize the diversity gain of MIMO channels. We then design an orthogonal D2D multiple access protocol and formulate the optimization
problem of joint cellular and D2D resource allocation. Extensive system-level simulations demonstrate that the cellular rate performance is significantly improved.