Fast DGT Based Receivers for GFDM in Broadband Channels

Generalized frequency division multiplexing (GFDM) is a recent multicarrier 5G waveform candidate with flexibility of pulse shaping filters. However, the flexibility of choosing a pulse shaping filter may result in inter carrier interference (ICI) and inter symbol interference (ISI), which becomes more severe in a broadband channel. In order to eliminate the ISI and ICI, based on discrete Gabor transform (DGT), in this paper, a transmit GFDM signal is first treated as an inverse DGT (IDGT), and then a frequency-domain DGT is formulated to recover (as a receiver) the GFDM signal. Furthermore, to reduce the complexity, a suboptimal frequency-domain DGT called local DGT (LDGT) is developed. Some analyses are also given for the proposed DGT based receivers.Comment: 28 pages, 8 figure

The Research on Strategy of Building Campus Network Security Based on University Management

AbstractCampus network play a crucial role in the study and management of the daily work of schools. With the rapid development and popularization of the campus network, the security issues become increasingly prominent. How to make safe and efficient operation of the campus network, give full play to its teaching, management and service functions, has become an issue cannot be ignored. On the basis of the analysis of the characteristics and common threats to the campus network security management, network security commonly used techniques such as firewalls, VLAN, and so on, made a series of security policy for the campus network characteristics

Advanced sensing techniques for cognitive radio

This SpringerBrief investigates advanced sensing techniques to detect and estimate the primary receiver for cognitive radio systems. Along with a comprehensive overview of existing spectrum sensing techniques, this brief focuses on the design of new signal processing techniques, including the region-based sensing, jamming-based probing, and relay-based probing. The proposed sensing techniques aim to detect the nearby primary receiver and estimate the cross-channel gain between the cognitive transmitter and primary receiver. The performance of the proposed algorithms is evaluated by simulations in terms of several performance parameters, including detection probability, interference probability, and estimation error. The results show that the proposed sensing techniques can effectively sense the primary receiver and improve the cognitive transmission throughput. Researchers and postgraduate students in electrical engineering will find this an exceptional resource

Time-domain N-continuous OFDM: system architecture and performance analysis

N-continuous orthogonal frequency-division multiplexing (NC-OFDM) is a promising technique to achieve significant sidelobe suppression for baseband OFDM signals. However, NC-OFDM usually has high implementation complexity that limits its practical applications. Based on conventional NC-OFDM, this paper proposes a new technique, termed time-domain N-continuous OFDM (TD-NC-OFDM), which shifts the processing burden from the frequency domain to the time domain. This is achieved by adding a smooth signal, which is linearly combined by rectangularly pulsed OFDM basis signals consisting of a novel basis set. We prove that TD-NC-OFDM with the basis set is essentially equivalent to conventional NC-OFDM. Furthermore, using the time-domain structure, an asymptotic spectrum analysis of N-continuous OFDM signals is obtained by developing a closed-form expression related to sidelobe decaying. This paper also examines the impact of TD-NC-OFDMon the received signal-to-interference-plus-noise ratio (SINR) and derives closed-form expressions

Comprehensive Economic Benefits Evaluation Model of Greenhouse Photovoltaic

Abstract: Photovoltaic integrated greenhouse has become an important form of deep coupling between new energy power generation and facility agriculture. Greenhouse photovoltaic power generation will affect the light environment, thermal environment, and water environment of facility agriculture. The precise coupling modeling method of greenhouse photovoltaics and loads is to carry out the basis for the calculation of comprehensive economic benefits of greenhouse photovoltaics. This paper studies the deep coupling modeling method of greenhouse photovoltaic and greenhouse load, and accurately calculates the changes in the light environment, thermal environment, and water environment regulation load of facility agriculture caused by the laying of greenhouse photovoltaics. Firstly, the greenhouse photovoltaic power generation model and the environmental regulation load model of facility agriculture are established; secondly, the coupling relationship between greenhouse photovoltaic power generation and facility agricultural load is described, and on this basis, the comprehensive economic benefits evaluation model of photovoltaic power generation is proposed. The 10kV medium-voltage distribution network and facility agricultural greenhouse that exist in the northern region are used as the research objects. It verifies the validity of the photovoltaic comprehensive economic benefits evaluation model proposed in this paper

Beam Alignment for Millimeter Wave Multiuser MIMO Systems Using Sparse-Graph Codes

In order to achieve millimeter wave (mmWave) beam alignment , a class of beam scanning and searching schemes have been extensively studied [1–3]. Recently, to address the problems of the traditional algorithms have a high sample complexity, some adaptive beam scanning approaches utilize the hierarchical beamforming codebook to reduce the training time at the cost of frequent feedback [2]. Then, to eliminate the feedback link, a random beam alignment algorithm is proposed by utilizing the pseudo-random spreading codes [3]. However, it needs a Pseudo-Noise (PN) sequences with sufficient length to ensure the good correlation properties of different beams. Furthermore, in addition to the above disadvantages, most of the existing algorithms require either a separate pilot sequence per user or long beam scanning time when considering mmWave multiuser uplinking systems. To solve the above problems, a novel class of beam alignment algorithms based on the sparse graph coding theory are proposed in this paper. Firstly, we investigate the uplink mmWave beam training structure. Based on the analysis, the mmWave multiuser beam alignment problem is transformed into the sparse-graph design and detection problem. Secondly, a beam alignment algorithm framework based on sparse-graph coding and decoding is proposed. Furthermore , we derive the theoretical bound to chose the optimal parameters of the designed coding matrix. Finally, two beam alignment algorithms are proposed to detect the beam index in different settings. Simulation results confirm that our beam algorithms outperform the conventional beam training methods. Proposed Uplink Beam Training Scheme. This paper considers a typical uplink mmWave MU-MIMO system, where the BS communicates with K UEs simultaneously. Suppose that the BS is equipped with N R antennas and N RF RF chains, while the k-th UE has M T antennas and M RF RF chains. Then, the channel associated with the k-th UE can be given by [4