1,721,051 research outputs found
Dataset for: Self-Interference Cancellation and Channel Estimation in Multicarrier-Division Duplex Systems with Hybrid Beamforming
No full textThis dataset contains: Figure 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 of the paper "Self-Interference Cancellation and Channel Estimation in Multicarrier-Division Duplex Systems with Hybrid Beamforming. IEEE Access. Each folder is named according to its content, where the curves of each figure are stored in mat files. To regenerate the results, please use the Matlab.</span
Dataset for: Multicarrier-Division Duplex: A Duplexing Technique for Shift to 6G Wireless Communications
No full textThis dataset contains the matlab files for Figures 3, 6, and 8 from the paper Bohan et al (2021), 'Multicarrier-Division Duplex: A Duplexing Technique for Shift to 6G Wireless Communications' published in IEEE Vehicular Technology Magazine. Each folder is named according to its content, where the curves of each figure are stored in mat files. To regenerate the results, please use the Matlab.</span
Dataset in support of the Southampton doctoral thesis 'Optimization of multicarrier-division duplex wireless systems'
No full textThis dataset contains: Figure 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 2.10, 2.11, 2.12, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10, 4.3, 4.4, 4.5, 4.7, 4.8, 4.9, 4.11, 5.6, 5.7, 5.8, 5.9, 5.10, 5.11, 5.12, 5.13, 5.14, 6.4, 6.5, 6.7 and 6.8 of the aforementioned thesis. Each folder is named according to its content, where the curves of each figure are stored in mat files. To regenerate the results, please use the Matlab.</span
Dataset for: Resource Allocation in Millimeter-Wave Multicarrier-Division Duplex Systems with Hybrid Beamforming
No full textThis dataset contains: Figure 3, 4, 5, 6, 7, 8, 9, and 10 of the aforementioned paper. Each folder is named according to its content, where the curves of each figure are stored in mat files. To regenerate the results, please use the Matlab.
Article in IEEE Transactions on Vehicular Technology. 10.1109/TVT.2021.3095226</span
Dataset in support of the publication 'Multicarrier-division duplex for solving the channel aging problem in massive MIMO systems
No full textThis dataset contains: Figure 3, 4, 5, 7, 8, 9, and 11 of the aforementioned paper. Each folder is named according to its content, where the curves of each figure are stored in mat files. To regenerate the results, please use the Matlab.
Article in IEEE Transactions on Vehicular Technology. 10.1109/TVT.2022.3209799</span
Optimization of multicarrier-division duplex wireless systems
No full textOwing to the potentials of enabling to double spectral efficiency (SE) and reduce network latency, inband full duplex (IBFD) has drawn a lot of research so as to substitute the conventional half duplex (HD) of time-division duplex (TDD) and frequency-division duplex (FDD). However, the selfinterference (SI) problem has hindered IBFD from practical deployment. Inspired by the principles of full duplex (FD), in this thesis, a multicarrier-division duplex (MDD) scheme is introduced, which is capable of combining the advantages of IBFD and HD, while simultaneously circumventing their drawbacks. Firstly, in order to make MDD feasible for the operation in large-scale multiple-input multiple-output (MIMO) systems, the thesis commences with addressing the SI problem in propagation-domain with considering the SI cancellation (SIC) requirement of practical analog-to-digital converter (ADC) at receiver. Then, the channel estimation (CE) in MDD MIMO systems is proposed by exploiting the reciprocity and correlation existing between the uplink (UL) and downlink (DL) subchannels. Secondly, the potential of MDD with resource allocation (RA) is first demonstrated, when an unfair greedy algorithm is applied for RA in the multiuser single-input single-output (MU-SISO) systems. Then, a suboptimal algorithm is proposed for MDD millimeter-wave (mmWave) MIMO systems to jointly maximize the sum-rate and achieve the proportional fairness among DL and UL mobile stations (MSs). Two mainstream hybrid precoding strategies are evaluated in the proposed RA scheme and the impact of insufficient SIC on RA is also studied. Thirdly, upon taking the advantages of the flexible time-frequency resource scheduling provided by MDD, two types of frame structures are designed to relieve the channel aging problem in high-mobility communication scenarios. Correspondingly, two Wiener-filtering based predictors (WPs) are introduced under the proposed frame structures for comparing the performance between MDD and TDD, when both CE and residual SI errors are invoked. Moreover, the closed-form expressions for approximating the lower bounded average sum rates of both MDD and TDD systems are derived, when the zero-forcing (ZF) precoding and maximal ratio combining (MRC) are respectively assumed for DL transmission and UL detection. Following the above studies in the context of cellular systems, the synergies between MDD and cellfree massive MIMO (CF-mMIMO) networks are focused. Firstly, a distributed MDD-CF scheme is introduced to enable the FD-style operation but with reduced inter-AP (access point) interference (IAI) and inter-MS interference (IMI). Then, two optimization cases of MDD-CF systems are analyzed by considering simultaneously AP-selection, power- and subcarrier-allocation, under the constraints of individual MSs’ quality of services (QoSs). Specifically, in the first optimization case considering one coherence time (CT) interval, a quadratic transform with successive convex approximation (QTSCA) algorithm is proposed to achieve the SE maximization. By contrast, in the second optimization case on the basis of one radio frame, a two-phase CT (TPCT) interval is designed for MDD-CF systems to guarantee the robust performance over time-varying channels. Correspondingly, a twostep iterative optimization algorithm aided by bisection method is proposed for SE maximization. Our studies show that the proposed QT-SCA algorithm is capable of converging and achieving reliable performance within a few of iterations. However, its complexity increases exponentially with the sizes of CF networks, determined by the numbers of APs, UL/DL users, subcarriers, etc. With this regard and to attain the dynamic power allocation at reduced overhead, a heterogeneous graph neural network (HGNN) is specifically designed for CF networks, which is named as CF-HGNN. The CF-HGNN consists of the adaptive node embedding layer, message passing layer, attention layer and the downstream power allocation layer. Our studies show that CF-HGNN is scalable to the MDDCF networks with various numbers of nodes and subcarriers. Furthermore, when assisted by the proposed user clustering, the CF-HGNN trained based on a small CF network can be applied to the large-scale MDD-CF networks, which may cover large area, have a big number of subcarriers and/or simultaneously support a big number of nodes
Resource allocation in millimeter-wave multicarrier-division duplex systems with hybrid beamforming
No full textIn-band full-duplex (IBFD) systems require promising resource allocation (RA) strategies to fully exploit the available time-frequency resources. Furthermore, the acquisition of channel state information and signal reception in IBFD systems are significantly impacted by insufficient self-interference cancellation (SIC), impeding the applications of IBFD in practical wireless systems. Multicarrier-division duplex (MDD), which benefits low-budget SI mitigation in digital domain and flexible subcarrier assignment, is expected to be a promising transitional technique from half-duplex (HD) to IBFD. To demonstrate the advantages of MDD over HD, this paper first compares the upper-bound performance of MDD and HD by applying unfair greedy RA. Then, considering the millimeter-wave (mmWave) with hybrid beamforming, we propose the RA optimization with the quality-of-service constraints on both downlink (DL) and uplink (UL) mobile-stations (MSs). To solve this non-convex RA problem, we divide it into a suboptimal subcarrier allocation problem solved by the proposed improved fair greedy (IFG) algorithm, and a convex power allocation problem. Furthermore, we design two general hybrid precoder based on matrix factorization and direct approach, and a combiner having high SIC capability. Our results show that the proposed RA algorithm can achieve the performance near the upper-bound achieved by the unfair greedy algorithm, while guaranteeing the proportional fairness among all DL/UL MSs. The performance of the two precoding schemes is depended on the number of radio frequency chains supported. Finally, the proposed SIC algorithm is able to provide sufficient SI mitigation, which can be implemented without impacting the RA operation.</p
UAV-enabled integrated sensing and communication in maritime emergency networks
No full textWith line-of-sight mode deployment and fast response, unmanned aerial vehicle (UAV), equipped with the cutting-edge integrated sensing and communication (ISAC) technique, is poised to deliver high-quality communication and sensing services in maritime emergency scenarios. In practice, however, the real-time transmission of ISAC signals at the UAV side cannot be realized unless the reliable wireless fronthaul link between the terrestrial base station and UAV are available. This paper proposes a multicarrier-division duplex based joint fronthaulaccess scheme, where mutually orthogonal subcarrier sets are leveraged to simultaneously support four types of fronthaul/access transmissions. In order to maximize the end-to-end communication rate while maintaining an adequate sensing quality-of-service (QoS) in such a complex scheme, the UAV trajectory, subcarrier assignment and power allocation are jointly optimized. The overall optimization process is designed in two stages. As the emergency area is usually far away from the coast, the optimal initial operating position for the UAV is first found. Once the UAV passes the initial operating position, the UAV’s trajectory and resource allocation are optimized during the mission period to maximize the end-to-end communication rate under the constraint of minimum sensing QoS. Simulation results demonstrate the effectiveness of the proposed scheme in dealing with the joint fronthaul-access optimization problem in maritime ISAC networks, offering the advantages over benchmark schemes
Self-interference cancellation and channel estimation in multicarrier-division duplex systems with hybrid beamforming
No full textDesign of full-duplex (FD) wireless systems faces many challenges, including self-interference cancellation (SIC), capability to provide high capacity, high flexibility for operation, best usage of resources, etc. In this paper, we propose and investigate a multicarrier-division duplex (MDD) based hybrid beamforming system operated in FD mode, which is endowed with the advantages of both time-division duplex and frequency-division duplex. It also shares some merits of FD and allows to be free of self-interference (SI) in digital domain, but faces the same challenge of SI as the FD in analog domain. Hence in this paper, we first propose an adaptive beamforming assisted SI cancellation scheme with taking into account the practical requirement of analog-to-digital conversion (ADC). It can be shown that the proposed approach is capable of jointly coping with the desired signals’ transmission and SI suppression. Then, channel estimation (CEst) in MDD/MU-MIMO system is proposed by exploiting the reciprocity between the uplink and downlink subcarrier channels that is provided by MDD. Correspondingly, the orthogonality-achieving pilot symbols are designed, and the least-square (LS) CEst as well as linear minimum mean-square error (LMMSE) CEst are derived. Finally, the performance of MDD/MU-MIMO systems employing the proposed SIC method is investigated, with respect to the SI cancellation capability, sum-rate potential, CEst performance, and the effect of CEst on the achievable performance. Our studies show that MDD/MU-MIMO provides an effective option for design of future wireless transceivers
Generation Effect in Words and Logos
No full textMentor: Prof. Stephen EngelGeneration effect refers to the phenomenon that people memorize information better when they are self-generated rather than simply shown. This effect has been widely applied into fields of education and advertizing. This experiment examines people's memorization of three kinds of visual input of words: negative space, interest (negative space with thin lines that marks of boundary of the letter in negative space), control. We asked the participants to judge the sound components of the words shown, then administered a series of Sudoku which prevents them from rehearsing the words. Finally, a memory task will be given, which presented the participants with the words shown in the first task and check their memorization. We hypothesize that there is a generation effect present in the negative space group. Hence, people would show a higher level of memorization of the words that were presented with negative space. The current data suggests that people memorize the interest group better than the negative space group, better than control group. We explain this in terms of the cueing effect of the lines in the interest group. This experiment is still in progress and we are gathering more data. Current results are subject to change.This research was supported by the Undergraduate Research Opportunities Program (UROP).Li, Bohan. (2012). Generation Effect in Words and Logos. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/122934
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