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The Shunbei oil-and-gas field in the Tarim Basin features a typical strike-slip fault-controlled fractured-vuggy reservoir. The formation of these reservoirs is primarily influenced by fracturing related to structural stress during periods of fault activity. This contrasts with reservoir types such as matrix vugs controlled by original sedimentary facies and caves modified by karst. To study the development mechanism and distribution patterns of strike-slip fault-controlled reservoirs under the influence of multi-stage structural stress, comprehensive analysis of field observations, core samples, well logging data, seismic surveys, and drilling dynamic data was conducted to characterize the development characteristics of fault-controlled reservoirs. This included different strike-slip faults, different parts along a single strike-slip fault, and different stratigraphic levels vertically. Combined with stress field numerical modeling, multi-stage structural stress recovery was carried out to predict the main development periods and distribution patterns of fault-controlled reservoirs. Significant variations in internal stress states were observed across different segments during periods of strike-slip fault activity. Tensile stress predominated in pull-apart segments, resulting in predominantly tensile fractures, whereas compressional stress state in push-up segments led to a variety of fracture types. The fault-controlled fractures in the top of the Yijianfang Formation in the Shunbei area were mainly developed during episode Ⅲ of the Middle Caledonian period and the Late Caledonian-Early Hercynian period. Few fractures were developed during the Middle to Late Hercynian period and thereafter. Compared to the Shunbei No.1 fault, the Shunbei No.18 fault exhibited higher fracture opening degree and density with a large displacement. Strike-slip fault-controlled reservoirs exhibit a cluster-like structure. Structural differences of the reservoirs are influenced by internal stress states in different segments during fault activity. Pull-apart segments typically feature a large fault core-damage zone with more cavities and 'double-cluster' structures, whereas push-up segments display more diverse fault core-damage zones with greater separability and 'multi-cluster' structures. The stress intensity during the strike-slip fault activity controls the types and scale of reservoir spaces, with smaller fault zones dominated by fractures and larger fault zones developing extensive fault core-damage zone architectures. The scale of fault-controlled reservoirs is positively correlated with fault activity intensity. Early fault activity promotes significant fracture development, while later stages, characterized by increased burial depths, result in few newly derived fractures due to reduced rock susceptibility to fracturing.

Abstract In order to investigate the acoustic oscillation characteristics of gas–liquid pintle rocket engines and elucidate the path by which spray combustion process provides energy to the combustor pressure oscillation, a LOX/GCH4 pintle engine with rectangular combustor was designed. By adding transverse velocity disturbance for the first time, the acoustic response of spray combustion process was simulated, and the effect of excitation amplitude on acoustic response was researched. Numerical results show that the adopted transverse velocity disturbance can excite the first-order transverse acoustic oscillation with same excitation frequency in the engine combustor. The acoustic response maintenance mechanism under extrinsic excitation is summarized for pintle engines. Besides, the temperature distribution inside the engine combustor tends to be uniform, and the low-frequency oscillation caused by the flame transverse swing gradually disappears. The amplitude of combustor pressure oscillation is dominated by excitement amplitude and phase difference between the pressure and heat release in combustion reaction region. In addition, the time-averaged combustor pressure can be amplified mainly by transverse velocity disturbance. The research work can provide a reference for related fire tests on the acoustic response of a subscale gas–liquid pintle engine.

In recent years, the Ordos Basin has undergone a reevaluation, transitioning from a perception of a single block to a focus on understanding the influence of multiple stages and fault systems on hydrocarbon accumulation. This study utilizes the latest 3D seismic and drilling data alongside a theoretical model of strike-slip fault to analyze fault geometry and kinematics in the Xunyi-Yijun area of the basin's southern region. The mechanisms of fault formation are predicted and the related impacts on the formation and accumulation of deep carbonate rocks are also discussed. The results indicate the presence of three fault systems in the Xunyi-Yijun area, with decoupling between deep and shallow layers. The Lower Paleozoic strike-slip faults exhibit distinct characteristics, including high vertical structure, dip swing, and a "flower-shaped" structure in the section. The faults display "compression shear in the northwest, tension shear in the center, and segmental deformation on trunk fractures" on their planes.Moreover, the Lower Paleozoic strike-slip faults experienced two stages of tectonic activities with greater intensity observed from the Late Ordovician to the Silurian, marking the primary period of fault development. The activity intensity during the Middle to Late Permian was relatively weaker, with faults exhibiting inherited strike-slip characteristics. These faults formed two groups, one with a NE strike and the other with a NW strike. Additionally, during the second stage of the Caledonian period, ocean subduction and closure lead to stress being transferred to the basin interior. It is believed that the NE and NW strike basement weak zones existed in the southern Ordos Basin. As a result, the Lower Paleozoic strike-slip fault system likely formed due to the activation of oblique compression. This fault system has the potential to enhance the physical properties of deep carbonate reservoirs and create high-quality karst or tectonic fracture reservoirs in the Xunyi-Yijun area. Moreover, The formation of the "upper source and lower reservoir-lateral source and lateral reservoir" combination along the strike-slip fault belt is an area of interest for deep oil and gas exploration in the Xunyi-Yijun region.

A communication network integrating multiple modes can effectively support the sustainable development of next-generation wireless communications. Integrated sensing, communication, and power transfer (ISCPT) represents an emerging technological paradigm that not only facilitates information transmission but also enables environmental sensing and wireless power transfer. To achieve optimal beamforming in transmission, it is crucial to satisfy multiple constraints, including quality of service (QoS), radar sensing accuracy, and power transfer efficiency, while ensuring fundamental system performance. The presence of multiple parametric constraints makes the problem a non-convex optimization challenge, underscoring the need for a solution that balances low computational complexity with high precision. Additionally, the accuracy of channel state information (CSI) is pivotal in determining the achievable rate, as imperfect or incomplete CSI can significantly degrade system performance and beamforming efficiency. Deep reinforcement learning (DRL), a machine learning technique where an agent learns by interacting with its environment, offers a promising approach that can dynamically optimize system performance through adaptive decision-making strategies. In this paper, we propose a DRL-based ISCPT framework, which effectively manages complex environmental states and continuously adjusts variables related to sensing, communication, and energy harvesting to enhance overall system efficiency and reliability. The achievable rate upper bound can be inferred through robust, learnable beamforming in the ISCPT system. Our results demonstrate that DRL-based algorithms significantly improve resource allocation, power management, and information transmission, particularly in dynamic and uncertain environments with imperfect CSI.

Many Ordovician reservoirs discovered in the eastern section of Bachu-Maigaiti area ("Bamai area" for short) in the Tarim Basin are closely related to multi-stage active faults, making it the key to find oil and gas reservoirs in this area by identifying the source faults that cut through Cambrian gypsum-salt layers. Combined with the analysis of fault structure based on a large number of new seismic data and previous studies, the fault system in the eastern section of the Bamai area, especially the distribution and activity characteristics of strike slip faults are reunderstood. The results show that along with the migration and evolution of palaeo-uplift and the activities of large thrust fault zones in Bamai area, a series of high-angle and small-distance NE strike-slip faults that play a role of deformation and regulation are also developed, which together constitute the deformation tectonic system in the area. Two types of strike slip faults are developed in this area. One is superimposed and developed simultaneously or later with the NE and nearly EW Cambrian post-salt decollement zone of bruchfalten, with its strike consistent with that of the thrust fault belt, which is mainly distributed in the boundary and interior of the Hetian paleo-uplift. The other is developed in the compression-shortening zone confined by the large thrust fault belt, intersected with the nearly EW thrust fault belt at a large angle, and mainly distributed in the Hetian palaeo-uplift and Bachu faulted uplift. The former mainly formed in the late Hercynian period with weak local activities in the late Himalayan period, and the latter mainly formed in the late Himalayan period. The strike-slip faults superimposed with the Ordovician carbonate rocks that has experienced karst transformation in the middle and late Caledonian and early Hercynian are more conducive to the formation of effective fracture-karst vug reservoirs. They connect the upper and lower strata of the gypsum-salt layers, and their active period is consistent with the main hydrocarbon generation period of the deep subsalt source rocks, which is more conducive to transporting hydrocarbon source upward to the Ordovician system for accumulation. The large-scale reservoir located above the source and connected with two types of high-angle strike-slip faults is the favorable exploration direction of Ordovician.

Unmanned aerial vehicles (UAVs) are extensively employed in pursuit, rescue missions, and agricultural applications. These operations necessitate substantial data and video transmission, requiring significant spectral resources. The unlicensed millimeter wave (mmWave) spectrum, especially in the 60 GHz frequency band, offers promising potential for UAV communications. However, WiGig users are the incumbent users of the 60 GHz unlicensed spectrum. Therefore, to ensure fair coexistence between UAV-based new radio-unlicensed (NR-U) users and WiGig users, unlicensed spectrum-sharing strategies need to be meticulously designed. Due to the beam directionality of the NR-U system, traditional listen-before-talk (LBT) spectrum sensing strategies are no longer effective in NR-U/WiGig systems. To address this, we propose a new cooperative unlicensed spectrum sensing strategy based on mmWave beamforming direction. In this strategy, UAV and WiGig users cooperatively sense the unlicensed spectrum and jointly decide on the access strategy. Our analysis shows that the proposed strategy effectively resolves the hidden and exposed node problems associated with traditional LBT strategies. Furthermore, we consider the sensitivity of mmWave to obstacles and analyze the effects of these obstacles on the spectrum-sharing sensing scheme. We examine the unlicensed spectrum access probability and network throughput under blockage scenarios. Simulation results indicate that although obstacles can attenuate the signal, they positively impact unlicensed spectrum sensing. The presence of obstacles can increase spectrum access probability by about 60% and improve system capacity by about 70%.

Unmanned aerial vehicles (UAVs) are extensively employed in pursuit, rescue missions, and agricultural applications. These operations require substantial data and video transmission, demanding significant spectral resources. The ultra-broad bandwidth of 0.1–10 THz in the Terahertz (THz) frequency range is essential for future UAV-based wireless communications. However, the available bandwidth in the THz frequency spectrum varies with transmission distance. To enhance spectral efficiency over this variable bandwidth, we propose using hierarchical modulation (HM) in the overlapped spectrum and traditional quadrature amplitude modulation (QAM) in the non-overlapped spectrum for closer users. Furthermore, we analyze the single-user case and utilize the block-coordinated descent (BCD) method to jointly optimize the modulation order, subcarrier bandwidth, and sub-band power to improve the system sum rate. Finally, considering the mobility and randomness of UAV users, we design a modulation switching rule to dynamically adjust to changes in distance as users move, thereby enhancing data rates. Simulation results demonstrate superior performance in data rate and design complexity compared to existing methods such as hierarchical bandwidth modulation (HBM) and HM schemes.

In recent years, significant oil and gas discoveries have been achieved in the Permian Upper Wuerhe Formation and the Triassic Baikouquan Formation on the marginal slope of oil generation sag, Junggar Basin. However, in the central sag of the basin, no oil or gas show has been discovered in target formations, and low production has been made only by two wells. As a result, it is necessary to deepen the understanding of the mechanisms of oil and gas accumulation and clarify the main controlling factors. The analyses of the accumulation conditions in the central sag and some wells show that the direct reason for the failure to find oil and gas in the sag is the lack of local source-connecting faults and poor reservoir properties. An accumulation model with source in the lower section and reservoir in the upper section controlled by both source-connecting faults and favorable sand bodies was established for the Permian and Triassic strata in the sag. The sandbody lithologic reservoirs of fan-delta front subfacies in the Upper Wuerhe and Baikouquan formations under the background of stratigraphic overlap are the primary direction of exploration, covering an area about 3 600 km2. The comprehensive exploration of unconventional oil and gas in the Middle-Lower Permian source rocks and conventional oil and gas in multiple layers outside the source area should be targeted.

Strike-slip faults, proven to be closely linked to hydrocarbon migration and accumulation, are widespread in the Tarim Basin Craton. Deformation patterns in the eastern part of the Central Uplift Belt of the Tarim Basin are analyzed in detail to understand the deformation model and genetic mechanism of strike-slip faults, how their patterns impact reservoir formation and influence oil and gas potential. Regional tectonic events are taken into consideration to identify the primary factors that controlled the development of strike-slip faults in the region. The Tazhong Uplift in the eastern part of Central Uplift Belt is believed to be a complex anticlinal uplift formed by compression-and-torsion acting on the Cambrian – Middle Ordovician platform during the middle–late Caledonian period. Multi-stage development of this north-trending fault–fold belt and the NE-trending strike-slip faults make it structurally complex. The NE-trending Paleozoic strike-slip faults were formed jointly by the differential thrusting of the Tazhong Uplift along Fault No. I and the NE-trending shear sliding of the basal fault blocks during the middle–late Caledonian – early Hercynian. Based on the distribution of effective source rocks, the tectonic setting during the period critical to hydrocarbon accumulation, and the distribution of conductive faults, the northern slope of the Tazhong Uplift— especially its west-central part where the NE-trending faults are developed is not only located close to the northern hydrocarbon source rock area but also possesses conditions suitable for the development of carbonate reservoirs. In addition, the NE-trending faults provide passage for initial development of the reservoir and the subsequent migration of oil and gas from the Aman area to the uplifted zone, making the Tazhong Uplift an extremely favorable area for oil and gas accumulation with substantial potential for exploration.

It is difficult to distinguish reservoirs and non-reservoirs based on the rock's physical properties. The quality of post-stack seismic data in the loess plateau is poor, which makes it a technical bottleneck for the prediction of reservoir of the Upper Paleozoic, and the exploration in the southern Ordos Basin was then constrained. Block evaluations have indicated that the northeastern part of Zhenjing district has a good potential for exploration, with the second member of Permian Shanxi Formation and the first member of Xiashihezi Formation as the main target beds. The results of 3D seismic facies analysis in Zhenjing area are consistent with the regional sedimentary facies studies on provenance and the distribution of sand bodies, indicating that seismic data can be used for the prediction of reservoir. The distribution of sedimentary facies of a series of seismic forward modeling showed that the sand bodies distributed with a certain distance and thickness in the second member of Shanxi Formation and the first member of Xiashihezi Formation formed recognizable seismic reflections. This vertical spatial combination of stratigraphic lithology is consistent with the depositional model of regional superimposed and thick single-type sand bodies, which is the typical form of reservoir-caprock combination that has been discovered in the surrounding gas reservoirs. The reservoir prediction based on the optimal number of wave crests from the forward simulation results confirmed that the superimposed and the thick single-type sand bodies of the second member of Shanxi Member were distributed in SW-NE directions. Furthermore, the picking and interpretation of co-phase axis and the structural mapping of seismic profile were carried out, which directly delineated the distribution range and burial depth of lithologic traps in the sand bodies of the second member of Shanxi Formation, and provided drilling targets for exploration and deployment in this area.

The Neoproterozoic Binggounan Formation mud shale in the Hongliugou Ⅰ section on the northwestern margin of the Altyn Tagh fault was deposited in a passive continental margin. They are shelf sediments about 60 m thick, interbedded with siliceous rocks, undergone a low temperature thermodynamic metamorphism, and had hydrocarbon generation potential. The tectonic background, provenance, weathering and sedimentary environment of the mud shale were discussed with regard to stratigraphic sections, mineralogy and geochemical analyses. The mud shale was mainly composed of silica-rich clay rock and mud-rich siliceous shale, followed by mud-silica mixed shale. They have simila-rities in Si, Mg, K, P, Sc, Y, Hf, Th Sc contents compared with the Post Archaean Australian shale (PAAS). The Ti, Mn, Fe, Ta contents and δEun, δCen, ΣREE values are higher, while the Al, Ca, Na, Nb and Zr contents are lower. The primitive sediment sources of the Binggounan mud shale were recycled sedimentary clasts, intermediate mafic and acid intrusive rocks, similar to a normal shale and arenites argillites and ensialic of continental upper crust in composition. The shale has undergone moderate chemical weathering in warm and humid conditions. The formation was divided into three sedimentary cycles from bottom to top, mainly anaerobic and anoxic, and occasionally oxidized. Hydrothermal alteration also occured in the lower section. The mud shale with a clay content of about 40% is rich in trace elements (REE) and organic matter, which was deposited in a suboxic to anoxic section on the shelf, showing a high productivity and hydrocarbon-generation potential.

The ultra-dense network is a promising technology to increase the network capacity in the forthcoming fifth-generation (5G) mobile communication networks by deploying lots of low power Small Base Stations (SBSs) which overlap with Macro Base Stations (MBSs). The interference and energy consumption increase rapidly with the number of SBSs although each SBS transmits with small power. In this paper, we model a downlink heterogeneous ultra-dense network where a lot of SBSs are randomly deployed with MBSs based on the Poisson point process. We derive the coverage probability and its variance, and analyze the area spectral efficiency and energy efficiency of the network considering three Fractional Power Control (FPC) strategies. The numerical results and Monte Carlo simulation results show that power control can mitigate the interference and balance the performances of inner-user and edge-user equipments. Especially, a great improvement of energy efficiency is archived with a little loss of area spectral efficiency when FPC is adopted. Finally, we analyze the effect of base stations’ (BSs’) sleeping on the performance of the network when it is partially loaded.

Abstract Background In this study we aimed to identify a prognostic signature in BRCA1/2 mutations to predict disease progression and the efficiency of chemotherapy ovarian cancer (OV), the second most common cause of death from gynecologic cancer in women worldwide. Methods Univariate Cox proportional-hazards and multivariate Cox regression analyses were used to identifying prognostic factors from data obtained from The Cancer Genome Atlas (TCGA) database. The area under the curve of the receiver operating characteristic curve was assessed, and the sensitivity and specificity of the prediction model were determined. Results A signature consisting of two long noncoding RNAs(lncRNAs), Z98885.2 and AC011601.1, was selected as the basis for classifying patients into high and low-risk groups (median survival: 7.2 years vs. 2.3 years). The three-year overall survival (OS) rates for the high- and low-risk group were approximately 38 and 100%, respectively. Chemotherapy treatment survival rates indicated that the high-risk group had significantly lower OS rates with adjuvant chemotherapy than the low-risk group. The one-, three-, and five-year OS were 100, 40, and 15% respectively in the high-risk group. The survival rate of the high-risk group declined rapidly after 2 years of OV chemotherapy treatment. Multivariate Cox regression associated with other traditional clinical factors showed that the 2-lncRNA model could be used as an independent OV prognostic factor. Analyses of data from the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) indicated that these signatures are pivotal to cancer development. Conclusion In conclusion, Z98885.2 and AC011601.1 comprise a novel prognostic signature for OV patients with BRCA1/2 mutations, and can be used to predict prognosis and the efficiency of chemotherapy.

Due to the broadcast nature of millimeter wave (mmWave) communications, physical layer security has always been a fundamental but challenging concern. Fortunately, the recent advance of intelligent reflecting surface (IRS) introduces another dimension for mmWave secure communications by reconfiguring the transmission environments. In this article, we investigate the physical layer security issue for IRS-aided mmWave communications. Specifically, two scenarios are considered, i.e., with and without the knowledge of the eavesdropper's channel. When the eavesdropper's channel is known, under the unit modulus constraints at the IRS and the transmit power constraint at the access point (AP), the secrecy rate is maximized by jointly designing the beamforming vector of the AP and the phase shifts of the IRS. We propose an alternating optimization algorithm for improving the secrecy rate to solve the non-convex optimization problem. In particular, the phase shift matrix of the IRS is firstly optimized based on the manifold optimization algorithm. Under the given phase shift matrix of the IRS, the original problem is transformed into a difference of convex (DC) programming problem. To solve this problem, we use the successive convex approximation (SCA)-based method to transform the original problem into a convex approximation problem, and the transmit beamforming vector is obtained by solving the convex approximation problem. In addition, when the eavesdropper's channel is unknown, under the transmit power constraint and the minimum user rate constraint, an artificial-noise (AN)-aided scheme is proposed to jam the eavesdropper by maximizing the AN power. Numerical results evaluate that the performance of our proposed schemes is better than that of the conventional scheme in terms of secrecy rate. Moreover, simulations also demonstrate that the secrecy behaviors of the IRS-aided mmWave communication system are superior to the mmWave communications without IRS.

The optimization of the secrecy rate of the distributed intelligent reflecting surfaces (IRSs)-assisted millimeter wave (mmWave) communication system is studied in this paper. In this system, the users are served by multiple IRSs, and by adjusting the switch state of each IRS and optimizing the phase shift of the IRS to maximize the secrecy rate of the system. The problem is described as a joint IRS control, transmit beamforming design problem. Our objective is to maximize the secrecy rate of the distributed IRSs-aided system under the transmit power constraint of the access point (AP). Since the problem is non-convex, one alternating optimization algorithm is proposed for solving this problem. We use the successive convex approximation (SCA) algorithm to solve it, and the solution that is obtained by the SCA algorithm guarantees to converge to a stable point that satisfies the Karush-Kuhn-Tucker (KKT) conditions. Moreover, by using the dual method, we obtain the IRS switch. For the IRS phase shifts optimization problem, a low-complexity majorization-minimization (MM) algorithm is used to solve this problem. Numerical results show that the proposed scheme can achieve higher secrecy rate compared with the single IRS-aided scheme.

In this paper, we consider a reconfigurable intelligent surface (RIS) aided millimeter wave (mmWave) multiple-input multiple-output (MIMO) system. The system can obtain the huge gain via joint active beamforming at the base station (BS) and passive beamforming at the RIS. However, due to weather and atmospheric effects, outdoor RIS antenna elements are subject to full or partial blockages from a plethora of particles like dirt, salt, ice, and water droplets. These blockages can cause an approximate squared power/SNR loss for the system. Different from the conventional array diagnosis, the RIS has no signal processing capability. Thus, we propose the joint array diagnosis and channel estimation techniques containing two stages to solve the problem. At the first stage the channel parameters at user equipment (UE) and BS are estimated using an iterative reweighted (IR) method. At the second stage, the array blockage coefficient vector and the effective sparse channel parameters at RIS are jointly estimated via solving a two-timescale non-convex optimization problem. We propose two algorithms, i.e., a batch algorithm (BA) and a two-timescale online joint array diagnosis and channel estimation (TOJADCE) algorithm to solve the problem and compare the performance of these two algorithms. Finally, to speed up the convergence of long-term variable and improve estimation performance, we propose a noise reduction (NR) algorithm. The simulations verify the effectiveness of our proposed algorithms.

Initial cell search and selection is one of the first few essential steps that a mobile device must perform to access a mobile network. The traditional maximum received power based initial cell selection may result in unbalanced loads across the cells in multi-tier heterogeneous 5G networks with millimeter wave. The objective of this work is to improve the initial cell search and selection scheme to achieve a more balanced load distribution in 5G networks. We propose to augment the existing pure maximum received power based scheme with a new load factor broadcast as part of system information. To study the theoretical performance of the proposed initial cell search and selection scheme, we formulate a throughput optimization problem and solve it by using optimal stopping theory. We characterize the throughput optimal stopping strategy and the attained maximum throughput. We prove that the proposed initial cell search and selection scheme is throughput optimal with a carefully optimized connection threshold. The optimal connection threshold and maximum throughput can be found by solving a fixed point equation. We further develop an iterative algorithm to compute the solution to the fixed point equation and prove the convergence of the proposed iterative algorithm. We also provide simulation results to demonstrate the analytical results and obtain insights. Our analysis and results show that the proposed initial cell search and selection scheme can help achieve a more balanced load distribution in 5G networks.

In this paper, we study secure cooperative transmission for the multiple-input-single-output multiple-eavesdropper (MISOME) systems, where a source (Alice) aims to send confidential messages to a legitimate user (Bob) with the aid of an unmanned aerial vehicle (UAV) enabled friendly jammer (Charlie) in the presence of multiple eavesdroppers (Eves). To further guarantee the secrecy performance, artificial noise (AN) beamforming together with cooperative Jamming (CJ) has been utilized in this considered system with only location and statistical channel state information of the Eves. Specifically, taking imperfect channel state information (CSI) between Charlie and Bob into account, we derive the exact closed-form expression of the secrecy outage probability (SOP) and develop an efficient scheme to solve the secrecy rate maximization (SRM) problem which has been verified as a convex one under certain SOP. Moreover, we propose an optimal UAV placement strategy to further enhance secrecy performance. The numerical results are provided to validate that the system security would seriously degenerate with channel uncertainty. Besides, the proposed scheme is verified to outperform the terrestrial CJ scheme in improving the secrecy rate and secure energy efficiency (EE) performance under perfect CSI or tolerable channel estimation errors. Finally, the effectiveness of the proposed UAV placement strategy in enhancing transmission security and the applicability of the proposed scheme has also been demonstrated.

Millimeter-wave (mm-wave) communication has been widely applied in the small cellular networks, and it is not difficult to find that mm-wave plays an important role in improving the capacity and data transmission rate of the 5G network systems. Nevertheless, mm-waves also have some disadvantages, such as large propagation loss and weak penetration blockage. Although the extremely high direction of the mm-wave can compensate for the propagation loss, highly directional transmissions of the mm-wave result in conventional omnidirectional transmission cell discovery schemes may fail in mm-waves; thus, we need to redesign the cell discovery scheme of mm-wave. In addition, the overhead of mm-wave cell discovery is also large. In order to reduce the overhead and provide a reasonable solution for the mm-wave base station (BS) discovery, we propose an analysis framework that utilizes out-of-band (OOB) information assistance. First, we consider the BS discovery problem as a hypothesis test problem. We analyze the statistical properties of the generalized logarithm likelihood ratio detector and study the detection performance of the detector. Through analysis and calculation, we are able to find that the OOB scheme can not only improve the detection performance but also reduce the system overhead. Then, we also analyze the performance of the OOB scheme in the case of multiple UEs. Finally, we use the angle information provided by the OOB information to predesign the mm-wave codebooks to achieve the optimal expected mode. Analysis of the simulation results demonstrates the effectiveness of the OOB information-assisted scheme.

To acquire precise channel state information in the forthcoming 5G frequency division duplexing (FDD) communication system, we study the virtual angular domain channel common sparsity in the massive multiple-input multiple-output orthogonal frequency division multiplexing downlink transmission system. Here, we propose an off-line learning algorithm, which is based on expectation maximization and generalized approximate message passing (GAMP) algorithms. Besides, the learning algorithm utilizes the common sparsity to obtain the support information of the sparse channel vectors. This process is defined as zero partition. With this learned information, the sparse channel vectors are estimated using GAMP again. We prove that when the learned support information is correct, the zero partition-enhanced GAMP algorithm will achieve better sparsity and indeterminacy trade-off performance when compared with the original GAMP algorithm. Based on these results, our proposed channel estimation (CE) solution has two stages. In the first stage, because of the practical propagation characteristics, the zero partition learning algorithm is amended to ensure the correctness of the learned result. In the second stage, channel vectors on the virtual angular domain are estimated with the proposed zero partition-enhanced GAMP algorithm. Analysis and numerical results prove that our CE solution will consume less pilots to ensure the estimation accuracy, when compared with other existed FDD downlink CE solution.

Most research on stochastic geometry has uniformly treated all users in cellular networks. In reality, the performance of a user depends strongly on the distances from a user to the tagged base station and other interfering base stations. Meanwhile, the throughput of a network is decided by the number of base stations and the number of users that can be served in the cell. This paper aims to investigate the achievable performance of users located at different positions in the Voronoi cell. First, we proposed a near formula of distribution of distances from users to their tagged base stations. Then, we deduce the coverage probabilities and ergodic rates of different users in the cell when the network is fully loaded or partially loaded. Finally, we proposed a novel definition of network throughput to respond to the networks' throughput in real time. We compare all our derivations to the Monte Carlo simulation. The numerical results are very close to the simulation results.

Millimeter-wave (mm-wave) communication is a practicable scheme for big data communication, such as next-generation cellular communication. However, because mm-wave frequencies have an extremely large path loss, in order to mitigate the mm-wave path loss, a large number of antennas are packed for beamforming. Conventional multiple-input multiple-output (MIMO) beamforming uses digital processing, which leads to needing extremely giant energy. Hybrid analog/digital beamforming could serve as an awesome technique to reduce the cost. It is essential for achieving high beamfroming gain that accurate mm-wave channel information should be attained at the transmitter. This paper concentrates on the channel state information (CSI) acquirement problem in mm-wave communication systems with massive MIMO arrays. Because of the CSI acquirement, a method of significant overhead, we consider an accurate channel estimation scheme with low overhead. Not only do we in this paper propose using support information extracted at Sub-6GHz to aid the mm-wave CSI acquirement but also introduce a strategy used in the mm-wave channel estimation. We, in particular, formulate mm-wave CSI acquirement as a compressive sensing problem and obtain the CSI by using Bernoulli-Gaussian generalized approximate message passing (BG-GAMP) algorithm. We also extend the BG-GAMP algorithm with support distribution information from sub-6-GHz channel. Furthermore, based on the K nearest neighbor idea, we redesign the BG-GAMP algorithm depending on sub-6-GHz support distribution information. Details of BG-GAMP with the nearest neighbor learning algorithm that is built on support distribution information from sub-6-GHz channel would also be revealed. Simulation results show the out-of-band information aided mm-wave channel estimation is capable of reducing the pilot overhead greatly and channel estimation accuracy improved as well.

In this paper, two techniques to compensate inphase/quadrature-phase imbalance (IQI) are investigated in the uplink-quantized massive multiple-input and multiple-output (MIMO) systems for different models of randomized IQI parameters. One is referred to as combined-signal-based channel estimation and compensation (CCEC) and the other is denoted by effective channel estimation and compensation (ECEC). First, an independent automatic gain control (AGC) scheme is proposed to calibrate the dynamic range of both the I branch and the Q branch. By doing that, different quantization steps are used for analog-to-digital converters following the AGCs in these two branches at each receive antenna. Second, considering the impacts of both quantization and IQI, we give the details of channel estimation and IQI compensation for both the CCEC and the ECEC using bilinear generalized approximate message passing (Bi-GAMP). Moreover, to exploit the Bi-GAMP for ECEC reasonably, we theoretically derive the probability density function PDF of the elements in the effective channel for the case where only RX IQI is considered. Furthermore, we extend the ECEC to the case where both RX IQI and TX IQI are incorporated into the systems and derive the similar pdf as well. Finally, we use the numerical results to testify the validity of our theoretical analysis and the fact that the analytic PDF can be approximated by a Gaussian distribution when the IQI parameters are relatively small. Compared with other classical methods, the proposed methods can obtain better performance based on the Monte Carlo simulation results.

Wideband sensing-based cognitive radio with simultaneous wireless information and power transfer can be designed for efficient spectrum and energy usage. We first aim to maximize the sum energy harvested by all the energy harvesters subject to constraints on rate, transmit power, interference, and subchannel assignment. Due to the non-convexity of the formulated problem, we relax the integer variable and introduce an auxiliary variable to transform the original problem into a convex problem. Then, the Lagrangian and subgradient methods are adopted to obtain the optimal solutions. However, this scheme may lead to a severe fairness issue among different links. In view of this fact, we further propose an energyharvesting scheme for max-min fairness. In particular, we aim to maximize the energy harvested by the worst case individual link. We show that this problem can be solved in a similar manner to the problem of sum harvested energy maximization. Simulation results are presented to verify the convergence and fairness performance of the proposed algorithm, and to reveal a novel tradeoff between the network harvested energy and sensing time.