Proc. SPIE. 10559, Broadband Access Communication Technologies XII
KEYWORDS: Radio optics, Modulation, Radio over Fiber, Spatial light modulators, Signal processing, Antennas, Analog electronics, Data communications, Broadband telecommunications, Mobile communications
One of important applications in 5G mobile communications is the enhanced mobile broadband (eMBB). A promising approach for achieving 5G eMBB under the limited radio bandwidth and energy is an introduction of a small-cell structured network. An advanced utilization of multi-input multi-output (MIMO) transmission is also another possible approach. First, the conceptual structure of distributed MIMO network is introduced. A number of distributed antennas (DAs) are deployed over a macro-cell area and they are connected to a macro-cell base station (MBS) via optical mobile fronthaul. Then, we present the recent advances in distributed MIMO cooperative transmission, i.e., space-time block coded transmit diversity (STBC-TD) for improving the link capacity of a macro-cell edge area, minimum mean square error multiuser multiplexing combined with singular value decomposition (MMSE-SVD) for increasing the sum capacity, and blind selective mapping (SLM) for reducing the transmit signal peak-to-average power ratio (PAPR).
If a large scale disaster similar to the Great East Japan Earthquake 2011 happens, some areas may be isolated from the communications network. Recently, unmanned aircraft system (UAS) based wireless relay communication has been attracting much attention since it is able to quickly re-establish the connection between isolated areas and the network. However, the channel between ground station (GS) and unmanned aircraft (UA) is unreliable due to UA’s swing motion and as consequence, the relay communication quality degrades. In this paper, we introduce space-time block coded (STBC) amplify-and-forward (AF) relay for UAS based wireless relay communication to improve relay communication quality. A group of UAs forms single frequency network (SFN) to perform STBC-AF cooperative relay. In STBC-AF relay, only conjugate operation, block exchange and amplifying are required at UAs. Therefore, STBC-AF relay improves the relay communication quality while alleviating the complexity problem at UAs. It is shown by computer simulation that STBC-AF relay can achieve better throughput performance than conventional AF relay.