Digital Optical Fiber Aided Distributed Antennas System

In this thesis, we design an superior architecture of communication network by combing the techniques of distributed antennas (DAS) and fractional frequency reuse (FFR), where the cell-edge area is additionally relies on FFR for the reason of reducing co-channel interference (CCI). Furthermore, the proposed pervasive DAS/FFR scheme has a low complexity by employing a single omni-directional transmit antenna at each remote antenna (RA) and a single receive antenna at each mobile station (MS), but jointly modelling them as a virtual multiple-input and multi-output (MIMO). Hence, the jointly designing the transmit pre-processing (TPP) matrix of all the cooperative RAs in case of downlink (DL) and multiuser detection (MUD) techniques for all the active MSs in the case of uplink (UL) are capable of being invoked for central processing at the base station (BS). We consider a more practical multiuser, multicell scenario with practical cellular parameters, where any particular user's position is mapped to a specific Signal-to-Interference-plus-Noise-Ratio (SINR). This method is capable of demonstrating distribution characters of SINR of the entire cellular area.The dominant interference of our DAS/FFR scheme is caused by the intra-cell interference (ICI) for both cases of DL and UL, especially in the'worst-case direction' when the MS is roaming near the angle halfway between two adjacent RAs. In order to mitigate the ICI, the TPP matrix is designed for all the cooperative RAs is capable of achieving an increased throughput for the entire cell-edge area in DL, regardless of the specific geographic distribution of the users. Our novel combined probabilistic data association (PDA) multiuser detector is invoked by the mobile relays (MR) aided pervasive DAS/FFR architecture, which is capable of substantially reducing the bit-error ratio (BER) for the MS roaming at arbitrary positions, especially in the' worst-case direction'. Practically, the generation of perfect Channel State Information (CSI) is difficult to achieve, whilst having an imperfect CSI obviously leads to a reduced performance. Hence, we introduce power control (PC) for improving the SINR of the MSs roaming in the cell-edge area for both DL and UL scenario.We consider a more realistic optical fibre backhaul, where the BS-RA-MS link will be treated as a composite channel. Hence, the effects of the fibre-induced imperfections on the attainable throughput and the BER performance of the wireless channel can be calculated, especially when applying different wireless transmissioin strategies, such as the modulation scheme, non-cooperative and cooperative processing techniques. This method allows us to portray the geographic of the SINR across the entire cellular area. In the DL of the cooperative DAS aided FFR scheme, a throughput of h=5bits/s/Hz may be maintained for an imperfect optical fibre backhaul, regardless of the specific geographic distribution of the users roaming in the cell edge area. Provided that an idle MR may be activated in the vicinity of the optimum relay position, in the UL of the cooperative DAS aided FFR scheme,80%of the cell-edge area exhibits a BER, which is better than10-4, while the remaining20%has a BER value of [10-410-2]. Naturally, this BER performance improvement is achieved at the cost of potentially halving the throughput, because the MR has to receive and retransmit its information in different time-slots. When applying power control (PC), the BER recorded across the entire cellular area may be reduced, below10-3even without the assistance of MRs.