In this letter, we investigate the outage probability (OP) performance of a multirelay multiuser hybrid satellite-terrestrial relay network operating at millimeter wave (mmWave) bands. Considering the dominant fading factor of the mmWave band is rain attenuation, we combine the long-term rain attenuation model with the statistical channel model to describe the mmWave channel. Then we utilize expected rain attenuation value of satellite links to select the desired relay node to improve the OP performance of the considered system, and the exact closed-form expressions of OP for both variable and fixed gain relaying protocols are derived. Finally, numerical and simulation results are provided to validate our analytical results.

Outage Analysis of Multirelay Multiuser Hybrid Satellite-Terrestrial Millimeter-Wave Networks

The integration of high throughput satellite into Internet of Things (IoT) is regarded as an effective strategy to provide ubiquitous broadband access in a seamless, cost-efficient manner. Meanwhile, due to the demand of machine-to-machine (M2M) high throughput services, millimeter-wave (mmWave) IoT networks arouses huge interest. In this paper, we investigate the performance of an amplify-and-forward (AF) mmWave hybrid satellite-terrestrial relay networks (HSTRN) for IoT broadband communications, where we assume source-relay link undergos Shadowed-Rician fading and the relay-destination link undergos Rayleigh fading. Considering rain attenuation is the main factor at mmWave bands, we utilize the multidimensional rain attenuation model to analyze the effect of rain attenuation on system performance. Then we derive the closed-form expression of outage probability and tight approximation of ergodic capacity. Finally, numerical and simulation results are provided to validate our analytical results and show the effect of rain attenuation on the system performance.

Performance Analysis of Millimeter-Wave Hybrid Satellite-Terrestrial Relay Networks Over Rain Fading Channel

This paper describes the design of a broadband, fixed-IF single balanced subharmonic mixer at entire Ka-band The co-simulation between HFSS and ADS was applied to the modeling of the mixer In order to improve the accuracy of simulation, an accurate diode nonlinear equivalent circuit is established and verified by testing data The circuit of the presented mixer printed on the substrate of Rogers RT/Duroid 3003 with permittivity of 3 and thickness of 254 µm is mounted in a waveguide block When the IF frequency is fixed at 15 GHz, the measured results show that the conversion loss of the mixer is less than 9 dB in most bandwidth from 25 GHz to 40 GHz The minimum conversion loss of 69 dB is measured at 36 GHz The measured isolation of LO to RF and LO to IF is more than 28 dB The RF to IF isolation is more than 20 dB The good isolation has been achieved

A 26–40 GHz Broadband Fixed IF Sub-harmonic mixer Based on Schottky Diode

This paper presents a novel method for constructing high performance unequal error protection (UEP) quasicyclic low-density parity-check (QC-LDPC) codes. These codes are highly efficient and designed with flexible rates, lengths and number of protection levels. The given QC-LDPC codes are based on the combinatorial design. Each circulant constituting the parity check matrix of the UEP code is determined from subsets with the distinct difference between elements. Simulation results indicate that proposed UEP codes have equivalent performance to UEP codes constructed with the higher girth and lower rate, while achieving superior performance than the codes constructed by conventional equal error protection (EEP) techniques.

An Unequal Error Protection of Quasi-Cyclic Low Density Parity Check (QC-LDPC) Codes Based on Combinatorial Designs

2-D CS SAR imaging endures great computational complexity since it has to deal with a large measurement matrix when processing the raw data. The skew-view SAR signal features large range walk and small range curvature, which enable the raw data be processed in range and azimuth separately. In this paper, a two-dimension-separated compressive sensing method of is skew-view SAR presented. It can reduce the computational complexity from the square order to the linear logarithm order compared with the conventional CS imaging algorithm while preserving the equivalent imaging quality. Experiment results are presented to verify the method.

A compressive sensing approach for skew-view SAR imaging

In satellite communication system, rain attenuation is one of the most important reasons for the signal fading transmitted at Ka band (30/20GHz). In this paper, based on the ITU recommendation rainfall attenuation prediction model, we obtain the rainfall attenuation value of one specific area in satellite communication systems at Ka band, in premise of knowing that rain attenuation value of a certain area follows lognormal distribution, then statistical distribution parameters are derived in detail by a method of the least squares curve fitting. After QPSK modulation, signal is polluted by additive noise in AWGN channel. We analyze and simulate the effect of light rain and heavy rain on signal propagation. The simulation results indicate that rain attenuation makes the signal-to-noise ratio and the bit error rate worse.

Distribution characteristics and performance simulations of rain attenuation at Ka band for satellite communications

16APSK and 32APSK, which are adopted by DVB-S2, can improve spectral efficiency. In order to reduce BER, the receiver will use demodulation method with good performance and low computation complexity. Based on the existing several demodulation methods, this paper presents a new demodulation method with practical value, and compares BER performance with several other existing demodulation methods through simulations. The simulation results verify the validity of the proposed methods of demodulation.

A new method of demodulation for 16APSK/32APSK

Puncturing is an effective method to achieve rate compatible. However, the existing puncturing algorithms are complex and difficult to implement by hardware. This article researches on puncturing algorithm for QC-LDPC codes with dual-diagonal structure. Taking LDPC codes under IEEE802.16e standard as an example, this paper proposes a simple puncturing algorithm to achieve bit-rate compatible. Based on dual-diagonal structure, the puncturing algorithm chooses variable nodes with low degree for deletion and follows the rule that the deleted variable nodes should not be in the same calibration equation as far as possible. The simulation shows that the proposed puncturing algorithm is simple and effective, and the sub-codes obtained through the puncturing have better BER performance than that of random puncturing and order puncturing. In addition, because the puncturing matrix does not need to send to the receiver, it reduces a lot of overhead. Overall, the proposed puncturing algorithm is very practical to achieve rate compatible.

An effective puncturing algorithm for QC-LDPC codes with dual-diagonal structure

To reduce the data transmission load of spaceborne SAR, this paper proposes a 2D imaging scheme based on compressive sensing (CS). First the sparse characteristics of spaceborne SAR echoes are analyzed, and then the echoes' sparse model and the targets' restore matrix are established. The minimum l 1 norm algorithm is used to reconstruct the compressed data in distance and azimuth dimensions, and at last the low-load, high-resolution image is got. The simulation results prove the validity of the algorithm.

2D Imaging algorithm of spaceborne SAR based on compressive sensing

Improving the spectral efficiency as far as possible while guaranteeing communication quality by channel coding becomes the development direction of the communication system. This paper studies the application of Low-Density Parity-Check Codes under high-order modulation, which not only considers improving the reliability of communication through the LDPC channel coding, but also taking the effectiveness of communication by using high-order modulation. A detailed analysis is given for two methods of the calculation of initialization information for the LLR-BP algorithm under high-order modulation: component calculation and Euclidean distance calculation. The first method is deduced in detail by taking 16APSK modulation as an example. Finally, simulations are done to verify the decoding performance of LDPC code under high-order modulation. We do the simulations combining with QPSK, 8PSK, and 16APSK. The simulation results demonstrate the feasibility of the first method. The performance of two methods is similar.

Yantao Guo

Papers

Distribution characteristics and performance simulations of rain attenuation at Ka band for satellite communications

A new method of demodulation for 16APSK/32APSK

An effective puncturing algorithm for QC-LDPC codes with dual-diagonal structure

2D Imaging algorithm of spaceborne SAR based on compressive sensing

Simulations of Low-Density Parity-Check Codes under high-order modulation