The millimeter wave (mmWave) frequency band spanning from 30 to 300 GHz constitutes a substantial portion of the unused frequency spectrum, which is an important resource for future wireless communication systems in order to fulfill the escalating capacity demand. Given the improvements in integrated components and enhanced power efficiency at high frequencies, wireless systems can operate in the mmWave frequency band. In this paper, we present a survey of the mmWave propagation characteristics, channel modeling, and design guidelines, such as system and antenna design considerations for mmWave, including the link budget of the network, which are essential for mmWave communication systems. We commence by introducing the main channel propagation characteristics of mmWaves followed by channel modeling and design guidelines. Then, we report on the main measurement and modeling campaigns conducted in order to understand the mmWave band’s properties and present the associated channel models. We survey the different channel models focusing on the channel models available for the 28, 38, 60, and 73 GHz frequency bands. Finally, we present the mmWave channel model and its challenges in the context of mmWave communication systems design.

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Millimeter-Wave Communications: Physical Channel Models, Design Considerations, Antenna Constructions, and Link-Budget

Fifth-generation (5G) cellular networks will almost certainly operate in the high-bandwidth, underutilized millimeter-wave (mmWave) frequency spectrum, which offers the potentiality of high-capacity wireless transmission of multi-gigabit-per-second (Gbps) data rates. Despite the enormous available bandwidth potential, mmWave signal transmissions suffer from fundamental technical challenges like severe path loss, sensitivity to blockage, directivity, and narrow beamwidth, due to its short wavelengths. To effectively support system design and deployment, accurate channel modeling comprising several 5G technologies and scenarios is essential. This survey provides a comprehensive overview of several emerging technologies for 5G systems, such as massive multiple-input multiple-output (MIMO) technologies, multiple access technologies, hybrid analog-digital precoding and combining, non-orthogonal multiple access (NOMA), cell-free massive MIMO, and simultaneous wireless information and power transfer (SWIPT) technologies. These technologies induce distinct propagation characteristics and establish specific requirements on 5G channel modeling. To tackle these challenges, we first provide a survey of existing solutions and standards and discuss the radio-frequency (RF) spectrum and regulatory issues for mmWave communications. Second, we compared existing wireless communication techniques like sub-6-GHz WiFi and sub-6 GHz 4G LTE over mmWave communications which come with benefits comprising narrow beam, high signal quality, large capacity data transmission, and strong detection potential. Third, we describe the fundamental propagation characteristics of the mmWave band and survey the existing channel models for mmWave communications. Fourth, we track evolution and advancements in hybrid beamforming for massive MIMO systems in terms of system models of hybrid precoding architectures, hybrid analog and digital precoding/combining matrices, with the potential antenna configuration scenarios and mmWave channel estimation (CE) techniques. Fifth, we extend the scope of the discussion by including multiple access technologies for mmWave systems such as non-orthogonal multiple access (NOMA) and space-division multiple access (SDMA), with limited RF chains at the base station. Lastly, we explore the integration of SWIPT in mmWave massive MIMO systems, with limited RF chains, to realize spectrally and energy-efficient communications.

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A Comprehensive Survey on Millimeter Wave Communications for Fifth-Generation Wireless Networks: Feasibility and Challenges

The rain attenuation in the 12-GHz band and one-minute- rain rate were measured at four satellite beacons located in South East Asia countries over a three-year period (2002-2004). The cumulative distribution of rain rate obtained as well as cumulative distribution of rain attenuation obtained are presented and compared with the rain prediction models. Most of the rain prediction models showed noticeable deviation to the measured values above the existence of the breakpoint (the point at which the slope changes). The results can be employed to guide the design and application of slant-path communication systems, especially in South East Asia countries.

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Rain attenuation predictions at ku-band in south east asia countries

The conversion of rain-rate cumulative distributions from any integration time, T, to one minute is a viable option whenever local one-minute data (time series or cumulative distribution functions) are not available for microwave system design. This paper reviews some of the most common rain-rate cumulative-distribution conversion methods. For selected models, it provides a complementary set of coefficients for regional and global application by performing regression to a measurements database. The performance of each model is analyzed, together with its adaptability to various climatic regions. Finally, recommendations with regard to the global applicability of models are given.

Analysis and Parameterization of Methodologies for the Conversion of Rain-Rate Cumulative Distributions from Various Integration Times to One Minute

This paper proposes a model for predicting rain attenuation in the tropical region. Slant path rain attenuation measurements were carried out in Singapore by analyzing the beacon signals from two satellites, namely WINDS and GE23, operating at frequencies of 18.9 and 12.75 GHz, respectively. Rainfall rates at the location of the beacon receivers were recorded. The cumulative distributions of the rainfall rate and the corresponding rain attenuation are presented and analyzed. It is found that the cumulative distribution of the measured rainfall rate is close to that predicted by the ITU-R model. Measurement data from a total of nine countries are compared with four existing rain attenuation prediction models, namely the Yamada, DAH, Karasawa, and Ramachandran models. Results show that although three of these models have relatively good prediction capability for the tropical region, they could be improved. Therefore, in this paper, a slant path rain attenuation model suitable for the tropical region is proposed. This is done by using the complementary cumulative distributions of rain attenuation for satellite links measured in Singapore and five other tropical countries. The proposed model is found to outperform exisitng models.

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Rain attenuation prediction model for satellite communications in tropical regions

A model for predicting rain attenuation on Earth-to-space is developed by using the measured data obtained from tropical and equatorial regions that was revised from the ITU model. The proposed rain attenuation model uses the complete rainfall rate cumulative distribution as input data. It is shown that significant improvements in terms of prediction error over existing attenuation models are obtained.

Rain attenuation model for south east asia countries

This paper presents the results of a study on tropospheric scintillation on satellite link that has been performed at University Sains Malaysia (USM) to obtain statistics of scintillation from the 12.255 GHz Superbird C satellite with an elevation angle of 40.10. The objective of this analysis was to determine whether the long-term scintillation follows the log normal or gamma distribution. It was found that the long term probability distribution follows the log-normal distribution. The short term probability distribution also follows the log-normal model for the driest and the wettest month. It has been proven that the log-normal model is also suitable for prediction at moderate angles.

Analysis of Tropospheric Scintillation Intensity on Earth to Space in Malaysia

In this study, several methods to convert rain rate data for various time intervals to one-minute rates are compared. High-resolution tipping bucket precipitation records for seven locations in a tropical region are analyzed and compared using these conversion models. The Segal, Chebil, and Burgueno methods give the smallest average errors below 10% at different integration times.

Conversion of 60-, 30-, 10-, and 5-Minute Rain Rates to 1-Minute Rates in Tropical Rain Rate Measurement

Summary This paper presents the results of beacon measurements on a moderate elevation satellite link at 12.255 GHz during the present of scintillation were analyzed. The spectra of the beacon signal were extracted from the raw beacon data using high pass filter with suitable cutoff frequency where the scintillation here are characterized by standard deviation of the amplitude fluctuations and by the distribution of amplitude deviations from their mean. The mean of the power spectra that’s been displayed by two asymptotic with the values was found to be close to the slope of the Kolmogorov spectra.

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Measurement of Tropospheric Scintillation from Satellite Beacon at Ku-Band In South East Asia

A model for predicting rain attenuation on earth-to-space was developed by using the measurement data obtained from tropical and equatorial region. The proposed rain attenuation model uses the complete rainfall rate cumulative distribution as input data. It was shown that significant improvements in terms of prediction error over existing attenuation model obtained.

Mitsuyoshi Iida

Papers

Rain attenuation model for south east asia countries

Analysis of Tropospheric Scintillation Intensity on Earth to Space in Malaysia

Conversion of 60-, 30-, 10-, and 5-Minute Rain Rates to 1-Minute Rates in Tropical Rain Rate Measurement

Measurement of Tropospheric Scintillation from Satellite Beacon at Ku-Band In South East Asia

Earth-To-Space Improved Model for Rain Attenuation Prediction at Ku-Band