Modelling 3D blockage effects for millimetre-wave communication systems

The millimetre wave (mmWave) band, which has a frequency range of 30-300 GHz, can provide the desired requirements for future communication systems, such as wide bandwidth and high data-rate with very low latency. However, these advantages entail several consequences and challenges: compared with the microwave band, below 6 GHz, the mmWave band not only suffers from increased path loss but also higher sensitivity to blockage effects due to very short wavelengths. Considering the mmWave band, a human blockage, for example, could severely affect the transmitted signal by causing attenuation of 20 dB or more. With motion, the attenuation problem becomes even more serious. The rapid changes of dynamic blockages surrounding a moving transceiver can cause a significant and sudden impact on channel attenuation, which affects the overall quality of service for mmWave systems. The main scope of this thesis is to develop new mathematical models that accurately capture the dynamics of blockers affecting a moving transceiver in order to compute the resulting channel attenuation accurately. The first Markov chain model studied in this work follows a simple approach by assigning a fixed-attenuation value to each blocker and using a geometric model to generate the transition probability matrices. The transition probabilities are calculated both analytically and via a geometric simulation, where the results are found to match well. The proposed model successfully captures the dynamics of the channel caused by blockers surrounding a moving transceiver. The model works well for stationary scenarios, and the proposed technique of switching between several Markov chains makes the model applicable to a non-stationary average number of blockers as well. The adaptive sum of Markov chains (sum of MC) is another proposed model, which can model the dynamics of blockage effects more accurately than the simpler Markov Chain model. It is adaptive to non-stationary scenarios in any given environment, and it efficiently captures the dynamics of blockages arising from a moving transceiver. The sum of Markov chains model can integrate any desired attenuation function, including the third-generation partnership project (3GPP) blockage model and any lab measurement attenuation profile. The sum of MC model could be a very useful tool for communication engineers, allowing them to perform an initial mmWave coverage analysis for a given environment in the presence of time-varying blockage effects. Unlike human blockage, which has been widely studied in the literature, the impact of other small objects on signal strength, such as metal road signs, is not so well understood. This thesis has carried out a measurement campaign for these small blockers, which induce measured loss in the range of 15- 30 dB, depending on the type and size of the blocker. The thesis also compares those results with existing simulation blockage models for these small objects. These blockage models include the 3GPP model, the multiple knife-edge (MKE) model, and the mmMAGIC model, where the latter two models show a better fit to the measured attenuation of relatively small blockers than the 3GPP model. Finally, the thesis evaluates the impact of blockers on the overall performance of mmWave multiple-input multiple-output (MIMO) wireless systems, where a ray-tracing tool is used to establish all possible propagation paths for a moving transceiver in an outdoor scenario. The performance impact of the measured attenuation profiles for road signs are evaluated for an outdoor scenario using the sum of MC model

Dual-band MIMO antenna with low mutual coupling for 2.4/5.8 GHz communication and wearable technologies.

To satisfy the requirements of modern communication systems and wearables using 2.4/5.8 GHz band this paper presents a simple, compact, and dual-band solution. The antenna is extracted from a circular monopole by inserting various patches and stubs. The genetic algorithm is utilized to optimize the parameters and achieve the best possible results regarding bandwidth and gain. Afterward, a 2-port multiple-input-multiple-output (MIMO) configuration is created by positioning an identical second single element perpendicularly to the first one. The electrical size of the suggested MIMO configuration is 0.26 λL × 0.53 λL, where λL represents the free space wavelength at lower resonance of 2.45 GHz. The common ground technique is adopted to further reduce and achieve the accepted level of mutual coupling of the MIMO configuration. The presented MIMO antenna offers a low mutual coupling of < -27 dB with 0.2 envelope correlation coefficient (ECC). The antenna has a gain of around 6.2 dBi and 6.5 dBi at resonating frequencies of 2.45 GHz and 5.4 GHz. Furthermore, the specific absorption rate (SAR) analysis of the MIMO antenna offers a range inside of the standard values, showing its potential for On/Off body communications. The comparison with already published works shows that the proposed antenna achieves better results in either compact size or wide operational bandwidth along with low mutual coupling

Adaptive Sum of Markov Chains for Modelling 3D Blockage in mmWave V2I Communications

This data set contains the MATLAB software used to reproduce results in the paper entitled "Adaptive Sum of Markov Chains for Modelling 3D Blockage in mmWave V2I Communications". It has been accepted for publication by IEEE Transactions on Vehicular Technology in May 2020.Alsaleem, Fahd. (2020). Adaptive Sum of Markov Chains for Modelling 3D Blockage in mmWave V2I Communications, [dataset]. University of Edinburgh. School of Engineering. Institute for Digital Communications. https://doi.org/10.7488/ds/2845

Mutual Coupling Reduction in Compact MIMO Antenna Operating on 28 GHz by Using Novel Decoupling Structure

This article presents an antenna with compact and simple geometry and a low profile. Roger RT6002, with a 10 mm × 10 mm dimension, is utilized to engineer this work, offering a wideband and high gain. The antenna structure contains a patch of circular-shaped stubs and a circular stub and slot. These insertions are performed to improve the impedance bandwidth of the antenna. The antenna is investigated, and the results are analyzed in the commercially accessible electromagnetic (EM) software tool High Frequency Structure Simulator (HFSS). Afterwards, a two-port multiple–input–multiple–output (MIMO) antenna is engineered by orthogonalizing the second element to the first element. The antenna offers good value for mutual coupling of less than −20 dB. The decoupling structure or parasitic patch is placed between two MIMO elements for more refined mutual coupling of the proposed MIMO antenna. The resultant antenna offers mutual coupling of less than −32 dB. Moreover, other MIMO parameters like envelop correlation coefficient (ECC), mean effective gain (MEG), diversity gain (DG), and channel capacity loss (CCL) are also studied to recommend antennas for future applications. The hardware model is fabricated and tested to validate the results, which resembles software-generated results. Moreover, the comparison of outcomes and other important parameters is performed using published work. The outcome of this proposed work is performed using already published work. The outcomes and comparison make the presented design the best option for future 5G devices

Analyzing the Performance of Millimeter Wave MIMO Antenna under Different Orientation of Unit Element

In this paper, a compact and simplified geometry monopole antenna with high gain and wideband is introduced. The presented antenna incorporates a microstrip feedline and a circular patch with two circular rings of stubs, which are inserted into the reference circular patch antenna to enhance the bandwidth and return loss. Roger RT/Duroid 6002 is used as the material for the antenna, and has overall dimensions of WS × LS = 12 mm × 9 mm. Three designs of two-port MIMO configurations are derived from the reference unit element antenna. In the first design, the antenna element is placed parallel to the reference antenna, while in the second design, the element is placed orthogonal to the reference element of the antenna. In the third design, the antenna elements are adjusted to be opposite each other. In this study, we analyze the isolation between the MIMO elements with different arrangements of the elements. The MIMO configurations have dimensions of 15 mm × 26 mm for two of the cases and 15 mm × 28.75 mm for the third case. All three MIMO antennas are made using similar materials and have the same specifications as the single element antenna. Other significant MIMO parameters, including the envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and mean effective gain (MEG), are also researched. Additionally, the paper includes a table summarizing the assessment of this work in comparison to relevant literature. The results of this study indicate that the proposed antenna is well-suited for future millimeter wave applications operating at 28 GHz

Compact MIMO UWB antenna integration with Ku band for advanced wireless communication applications

This paper introduces a compact Multiple Input Multiple Output (MIMO) Ultrawideband (UWB) antenna seamlessly integrated with the Ku band, tailored for wireless communication applications. The MIMO antenna employs octagonal radiators, crafted from a tapered microstrip line-fed rectangular patch, etched on an economically efficient FR4 substrate measuring 40 × 23 mm2. The octagonal configuration is achieved by introducing a rectangular patch to the central radiator, while parasitic stubs are strategically employed to mitigate coupling among MIMO elements. The antenna demonstrates an extensive operational bandwidth spanning 3.28–17.8 GHz, covering UWB, extended UWB, and Ku-band spectrums globally allocated for heterogeneous applications. With a peak gain of 4.93 dBi and an efficiency of 95.34%, the proposed MIMO antenna showcases superior performance. Key performance parameters, including a low envelope correlation coefficient (ECC) of 0.003 and a substantial diversity gain (DG) of 9.997 dB, are thoroughly analyzed. Comparative assessments against recent works validate the novelty and potential of the proposed antenna for integration into compact wireless systems. This study underscores the success of the antenna design in achieving a harmonious balance of compactness, wide operational bandwidth, and high performance, positioning it as a promising candidate for diverse wireless communication applications

Predicated and hardware tested transmission coefficient of recommended two port MIMO antenna with decoupling structure.

Predicated and hardware tested transmission coefficient of recommended two port MIMO antenna with decoupling structure.</p

|S12/21| of proposed MIMO antenna against with and without decoupling structure.

|S12/21| of proposed MIMO antenna against with and without decoupling structure.</p