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Dynamic spectrum auction is an effective way to stimulate primary users to lease their idle spectrum and meanwhile solve the competitions among secondary users through bidding. Due to the spatial reusability of spectrum, multiple users which are separate enough can have access to the same spectrum simultaneously without interfering each other. In this paper, we propose a spectrum auction framework...
Relying on physical layer security is an attractive alternative of utilizing cryptographic algorithms at upper layers of protocol stack for secure communications. In this paper, we consider a two-hop wireless relay network in the presence of an eavesdropper. Our scenario of interest spans over a four-node network model including a source, a destination, a trusted relay, and an untrusted eavesdropper...
Most channel access schemes for cognitive radio only consider using the idle periods of the primary users. Such schemes are not using the spectrum efficiently, since transmission opportunities also arise when a primary transmitter is active but its corresponding primary receiver is far away from the cognitive user. By detecting the signal power of the acknowledgments, a cognitive user is able to estimate...
Opportunistic beamforming is a promising technique for downlink channels in cellular systems. When opportunistic beamforming is to support multiple users at a time, beams should be formed to avoid interference and this requires the feedback of channel state information (CSI) from users to a base station (BS). With limited feedback, to minimize the impact of interference, the best beamforming matrix...
This paper presents a multiple-symbol differential spatial division multiple access (MS-DSDMA) system conceived for low-complexity and high-bandwidth-efficiency applications operating in time-varying fading channels, where no channel estimation is required. A low-complexity adaptive multiple-symbol differential interference suppression (MS-DIS) scheme is proposed, which is based on the maximum signal-to-interference-plus-noise...
An ultra-high data rate Time Reversal (TR) Multiple-Input Multiple-Output (MIMO) Ultra-Wideband (UWB) communication system with space-time pre-equalizer is proposed. When the symbol duration is set to approach the duration of UWB monocycles, the data rate is close to the limit due to the extremely large bandwidth, resulting in the severe intersymbol interference (ISI). The zero-forcing (ZF)criterion...
New low-complexity adaptive receivers are proposed for time-hopping binary phase shift keying ultra-wide bandwidth systems with multiple users. Both additive white Gaussian noise and multipath fading channels are considered. Numerical results show that the new adaptive receivers outperform the conventional matched-filter receivers in both additive white Gaussian noise and multipath fading channels,...
Among the techniques proposed to reduce interference in cellular ODFMA networks, base station cooperation (BSC) is currently the technique known to achieve the highest network throughputs. Its deployment however is vastly expensive and cheaper alternatives are expected to play an important role in future wireless access standards. This contribution introduces relay-augmented networks based on the...
Consider the max-min fairness linear transceiver design for a multi-user MIMO interference channel. Assuming perfect channel knowledge, this problem can be formulated as the maximization of minimum SINR utility, subject to individual power constraints at each transmitter. In this paper, it is shown that when the number of antennas at each transmitter (receiver) is at least two and at each receiver...
Inter-cell co-channel interference (CCI) mitigation is investigated in the context of cellular systems relying on dense frequency reuse. A distributed Base Station (BS) cooperation aided soft reception scheme using the Probabilistic Data Association (PDA) algorithm and Soft Combining (SC) is proposed for the uplink of multi-user multi-cell MIMO systems. The realistic hexagonal cellular model relying...
This paper studies the cooperative interference control in a two-cell downlink OFDMA system, which can be modeled as an interfering broadcast channel. It is assumed that each cell can simultaneously access the same frequency band, which corresponds to a universal frequency-reuse in cellular systems. We study the joint power and subcarrier allocation over the two cells to maximize their sum throughput...
In this paper, we analyze the influence of a blanking nonlinearity onto OFDM systems in detail. We will derive closed-form expressions for the signal degradation and the interference, which is introduced by the blanking nonlinearity. The theoretical results will be validated by simulations, which illustrate the detrimental blanking influence in a descriptive way. In addition it will be shown how the...
In this paper, we investigate the distributed power allocation strategies for a spectrum-sharing femtocell network, where a central macrocell underlaid with several femtocells. Assuming that the macrocell protects itself by pricing the interference from the femtocells, a Stackelberg game is formulated to jointly consider the utility maximization of the macrocell and the femtocells. Then, the Stackelberg...
In this paper, recent results in game theory and stochastic approximation are brought together to mitigate the problem of femto-to-macrocell cross-tier interference. The main result of this paper is an algorithm which reduces the impact of interference of femtocells over the existing macrocells. Such algorithm relies on the observations of the signal to interference plus noise ratio (SINR) of all...
Mesh Wireless Local Area Network (WLAN) is a promising access network to enhance channels utilization, extend access coverage with simple and cheap network components. Power management affects mesh WLAN network coverage, topology, throughput, traffic routing and end to end delay. In this paper, power management problem is formulated to show its impact on mesh WLAN network throughput. Then this formulation...
Transmit diversity schemes with multiple streams obtain reliable transmission but suffer from interference when decoding multiple streams simultaneously. In this paper, we present closed-loop space-time block codes for multiple streams with limited channel information in order to ease suppressing interference at a receiving station. The proposed scheme includes constellation rotation in Alamouti coding...
In this paper, an efficient closed-loop link adaption scheme consisting of adaptive modulation and coding as well as adaptive precoding is proposed for the 3GPP LTE-A uplink. The uplink envisaged in the LTE-A cellular network will support precoded multi-rank transmission from the users and have base stations with advanced non-linear receivers. Our proposed scheme considers one such advanced receiver,...
This paper proposes an inter-cell co-channel interference (CCI) mitigation method with the mixed deployment of evolved NodeBs (eNBs) and relay nodes (RNs) for Long Term Evolution (LTE)-Advanced systems studied in the 3rd Generation Partnership Project (3GPP). Supporting RNs for LTE-Advanced can increase coverage in areas without service, and also improve system capacity. Although RNs can improve system...
The inlay approach for the Broadband Aeronautical Multicarrier Communications (B-AMC) system is exposed to severe interference from the adjacent channels of the distance measuring equipment (DME) system. Here, we propose a simple technique to mitigate DME interference and subsequently enable transmission in the spectral gaps of the DME channels. The proposed technique uses a precoding at the transmitter...
In this paper, we propose a reduced-complexity beamforming coordination method for the emerging two-tier MIMO-femtocell systems. With a small overhead signaling, the proposed scheme implements the cross-tier interference control between the macrocell and the femtocell. Furthermore, we develop the exact analytical expressions of the ergodic capacity of selected users in both tiers. We show through...
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