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We investigate error performance and an optimum power allocation scheme for multiple-input multiple-output (MIMO) channel physical layer network coding (PNC) based two-way relay system. Zero forcing precoding technique is used at source nodes to facilitate PNC operations at the relay node. First, system error performance is investigated by introducing upper and lower bounds for BPSK modulation system...
This paper presents an analytical investigation on the outage performance of dual-hop multiple antenna fixed-gain amplify-and-forward relay systems in the presence of co-channel interference. Exact closed-form analytical expressions for the outage probability of the systems are derived. Moreover, simple outage probability approximations at the high signal to noise ratio regime are provided, and the...
In this paper, three novel efficient power control algorithms are proposed for V-BLAST system with both total power constraint (TPC) and per-antenna power constraints (PAPC). Through analysis of the Karush-Kuhn-Tucker (KKT) conditions of the optimization problem, we find out that the antennas with the optimal power control can be divided into two sets. The optimal allocated power (OAP) of each antenna...
Optimizing energy efficiency (EE) for the MIMO broadcasting channels (BC) is considered in this paper, where a practical power model is taken into account. Although the EE of the MIMO BC is non-concave, we reformulate it as a quasiconcave function based on the uplink-downlink duality. After that, an energy efficient iterative waterfilling scheme is proposed based on the block-coordinate ascent algorithm...
A multi-pair two-way relaying scenario with multi-antenna mobile stations is considered. The bidirectional communications between the mobile stations are supported by an intermediate non-regenerative multi-antenna relay station. It is assumed that the mobile stations can subtract the back-propagated self-interference. Different relay transceive filter design approaches which utilize the fact that...
For the design and performance evaluation of advanced wireless communication systems employing multiple-input multiple-output (MIMO) technologies, realistic MIMO channel models with a good tradeoff between accuracy and complexity are indispensable. This paper compares the statistical properties of the two latest standardized MIMO channel models: Long Term Evolution-Advanced (LTE-A) and IMT-Advanced...
Interference alignment is proposed for achieving the maximum degrees of freedom in interference channels. In the present paper, a scenario consisting of several pairs of multiple antenna nodes and a single MIMO relay helping the interference alignment is considered. The interference alignment is performed in two subsequent transmission phases assuming a time-invariant channel during the two transmission...
In this work, we investigate the impact of placing a half-duplex relay in the X channel in the presence of limited channel state information (CSI). Specifically, we consider the scenarios when the sources have no CSI, while the relay either has perfect CSI or delayed CSI. We develop transmission strategies for each scenario to facilitate interference alignment with the help of the relay. We show that...
The degrees of freedom (DoF) has been recognized as a powerful metric to characterize the capacity of interference channels in the high signal-to-noise (SNR) region. In this paper, by utilizing linear interference alignment, we investigate the DoF of multiple-input and multiple-output (MIMO) interference relay channels without symbol extensions. An innovative algorithm is presented to align the interference,...
In this paper, we develop linear interference alignment (IA) approach for multi-input-multi-output interference broadcast channel (MIMO-IBC). Since multiple data streams from each base station (BS) to multiple mobile stations (MSs) experience identical channel, it is hard to ensure the rank constraint to the intended MSs in the desired cell meanwhile ensure the interference aligned at the unintended...
This paper studies robust transmission strategies for downlink time division duplex coordinated multi-point (CoMP) systems with non-ideal uplink-downlink channel reciprocity due to imperfect antenna calibration. By exploiting the statistics of antenna calibration errors, we first characterize the optimal parametric precoder structure that maximizes the weighted sum rate, based on which a closed-form...
The multi-input multi-output (MIMO) system with a subcarrier intensity modulation (SIM) scheme in free-space optics (FSO) has a huge merit for ultra wide band communications mainly due to its diversity gain to be able to mitigate the signal scintillation caused by the atmospheric turbulence. In this study, we have analyzed the performance of the orthogonal space-time block codes (OSTBCs) in FSO links...
While Half-Duplex cooperative systems provide an alternative means to achieve diversity gain, they suffer from multiplexing gain loss due to the necessary two-phase transmission protocols that are employed. In this paper two new transmission techniques are presented for systems with multi-antenna relay nodes employing the Decode-and-Forward (DF) protocol which achieve improved multiplexing and diversity...
Cooperated multi-point technique in HSPA+ system has not been paid attention until the Single Frequency Dual Cell (SF-DC) mode, where one user equipment (UE) may be served by dual NodeBs simultaneously in the single carrier frequency network, is proposed recently. In the previous research, the system-level performance with SF-DC operation had not been studied comprehensively. The main contribution...
In this work, we revisit the issue of fair resource allocation in relay-enhanced wireless networks. Our focus this time is on Type-1a relays as proposed for LTE-Advanced. The latter operate as out-band relays, i.e., the backhaul and relay access link use separate carrier frequencies. If carrier aggregation is applied at the macro base station, the backhaul carrier may also contain part of the macro...
We propose a spectrum-sensing and data-transmission scheme that utilizes multiple-input and multiple-output (MIMO) technology to enable the spectrum to be sensed and data to be transmitted simultaneously. By using our proposed scheme, the degradation of quality of service (QoS) that is caused by spectrum sensing can be reduced and the system throughput of a cognitive radio (CR) system can be increased,...
Wireless mesh networks (WMNs) are emerging as a cost effective solution for last-mile broadband access. Multiple antennas or multiple input multiple output (MIMO)-based systems have the potential for improving the capacity of these networks manifolds. However, unique physical layer characteristics associated with MIMO-based systems require joint design among physical layer and upper layers. In this...
Interference mitigation approaches in the presence of multiple receive antennas in the uplink of a multi-cell wireless communications system are studied in this paper. A formulation based on interference pricing is proposed, where it is shown that a single price per base-station can be computed and exchanged, in order to set the mobile transmit powers per cell. The work is premised on a decentralized...
Wireless mesh networks (WMNs) are increasingly being deployed as backbone wireless networks for broadband Internet access. Use of multiple radios and multiple channels (MRMC) can bring substantial throughput improvement to these networks. In addition, multi-antennas or Multiple Input Multiple Output (MIMO) technology has great potential for improving the throughput of WMNs via spatial reuse and/or...
In heterogeneous cellular networks (HCN) which consists of macrocells and numerous picocells, efficient interference management schemes between macrocells and picocells are so crucial to the overall system performance. We propose a dynamic cooperative silencing control (DCS) scheme for intercell interference control (ICIC). It is a low-complex, low-feedback and distributed algorithm using only strongly...
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