Sustainable Non-Cooperative User Detection Techniques in 5G Communications for Smart City Users

Round 1

Reviewer 1 Report

The manuscript discusses a timely topic and presents some interesting results and discussions. However, this authors feels that the literature review is very short and misses some important and highly relevant discussions. For instance, you mention that "Intelligent Transporting System (ITS) is one of the many smart city applications that can be realized via 5G technology" but this wasn't elaborated; check this relevant work "LSTM-Based Distributed Conditional Generative Adversarial Network for Data-Driven 5G-Enabled Maritime UAV Communications" and discuss it herein. Other relevant works that can be used to enrich the literature review in the introduction section include "Efficient Algorithms for Cache-Throughput Analysis in Cellular-D2D 5G Networks", "Multidimensional Generalized Quadrature Index Modulation for 5G Wireless Communications", "Performance Analysis of Massive MIMO-OFDM System Incorporated with Various Transforms for Image Communication in 5G Systems", "Power allocation scheme for maximizing spectral efficiency and energy efficiency tradeoff for uplink NOMA systems in B5G/6G", etc.  

 

 

 

Author Response

Reviewer 1:

However, this authors feels that the literature review is very short and misses some important and highly relevant discussions. For instance, you mention that "Intelligent Transporting System (ITS) is one of the many smart city applications that can be realized via 5G technology" but this wasn't elaborated; check this relevant work "LSTM-Based Distributed Conditional Generative Adversarial Network for Data-Driven 5G-Enabled Maritime UAV Communications" and discuss it herein. Other relevant works that can be used to enrich the literature review in the introduction section include "Efficient Algorithms for Cache-Throughput Analysis in Cellular-D2D 5G Networks", "Multidimensional Generalized Quadrature Index Modulation for 5G Wireless Communications", "Performance Analysis of Massive MIMO-OFDM System Incorporated with Various Transforms for Image Communication in 5G Systems", "Power allocation scheme for maximizing spectral efficiency and energy efficiency tradeoff for uplink NOMA systems in B5G/6G", etc.  

Response:

As per the reviewer suggestion, the literature review is updated with the suggested research papers and cited.

smart city is an urban area wherein various electronic devices and sensors are in-stalled to facilitate the collection and sharing of information. Most contemporary smart cities rely on 5G technology to share information between networks. 5G ultra-dense wireless networks can reduce load on converged cell-less communications. Vertically converged architectures are used at access points to enable 5G converged communication. Soft-ware-defined radio access networks are used to manage traffic in 5G [1]. 5G technology can profoundly impact economies and societies because it can provide the communication infrastructure required for various smart city applications. Intelligent transporting system (ITS) is one of the many smart city applications that can be realized via 5G technology. Various studies have investigated the impact and implications of 5G on ITS. Sensors and electronic devices are used for data collection from smart cities. Information and communication technologies (ICT) can be adopted to ensure sustain-able installations and provide comfort and high-quality services to smart city users. To connect everyone and everything in a smart city, a new paradigm of 5G wireless communication is highly recommended. 5G-enabled ITSs can be used for implement-ing several smart city applications. Various studies have explored the benefits of 5G-enabled ITS for smart city users in applications such as manufacturing, entertainment, healthcare, and public transport. To enable better performance for these applications, herein, the following technologies are suggested: enhanced mobile broad-band (eMBB), ultra-reliable and low latency communication (uRLLC), and vehicle-to-everything (V2X) communication [2]. 5G thus becomes the real enabler of internet of things (IoT) applications in smart cities. As an intelligent and economical means of transport, 5G plays a vital role for smart city users [3]. Millimeter wave (mmWave) technology can help achieve high data rates in 5G application, which can increase the data transmission speed for smart city users by using advanced ICT infra-structure. In [4], pre-coded orthogonal frequency division multiplexing (OFDM) tech-niques were proposed to achieve high data rates for smart city and smart home users.

 

5G-Enabled maritime unmanned aerial vehicles (UAVs) are highly recommended to operate mission critical applications with minimum latency and high reliability. High data rates with lossless transmission are crucial requirements for contemporary wire-less communication systems. Lossless transmission depends on channel conditions, and it can be implemented using 5G with mmWave and air-to-surface linking. In [21], long short term memory (LSTM)-distributed conditional generative adversarial network (DCGAN) with channel state information (CSI) was used for channel estimation. Afterward, the channel models were trained in the spatial domain for all distributions. From the trained models, most favorable LSTM-DCGAN channels were considered for high-speed data transmission. The proposed model was compared with the existing CGAN network in the simulation environment. In [22], to reduce playback and start-up in cellular networks for video on demand (VoD) users, a two-tier seg-ment-based de-vice-to-device (S-D2D) method was proposed. Cache memory in a 5G-enabled device was split into two blocks by using the S-D2D caching approach. A video is divided into fixed-sized fragments and stored in the cache memory, which are known as segments. For the most popular video files, the first cache segment is reserved for the starting portion of the video and another segment is reserved for the latter portion. To improve the performance and throughput of the videos in cache memory, three cache control algorithms are proposed. D2D segmentation cache memory architecture and video segment protocols have been proposed, and the optimal cache probability and beginning segment size for throughput improvement have also been formulated. In [22], an iterative algorithm was derived to minimize the non-convex cache-throughout maximization problem. Radio frequency (RF) mirrors, time indices, and space parameters were used to represent extra-digital information using multidimensional generalized quadrature index modulation. By merging media-based modulation (MBM) transmission principle with time-indexed generalized quadrature spatial modulation (TI-GQSM) system, a hybrid model was designed, labeled as TI-GQSM-MBM scheme. The performance of the proposed scheme was estimated using bit error rate (BER), which can provide excellent performance at high data rates. Compared with multidimensional generalized spatial modulation (GSM) techniques, channel estimation errors (CEEs) exhibited better performance in a simulation environment. This technique was recommended for 5G and beyond wireless networks for error-free transmission [23]. To enable fast and efficient transmission of multimedia information, the latest communication technologies such as 5G and 6G are needed. A hybrid technique was developed by combining OFDM and massive multiple input multiple output (mMIMO) technologies, and it was used for 5G and 6G applications. This hybrid technique, OFDM-mMIMO, was used for transmission of images, and it was tested using fast Fourier transform (FFT), fractional Fourier transform (FrFT), and discrete wavelet transform (DWT). The simulation results were analyzed for the following parameters: signal-to-noise ratio (SNR), peak SNR (PSNR), and structural similarity index measure (SSIM) under Rayleigh fading channels with M-ary phase-shift keying (M-PSK) modulation. FrFt and DWT demonstrated better performance than the FFT-based technique for PSNR and SSIM [24]. Key technologies such as non-orthogonal multiple access (NOMA) are required for advanced 6G cellular networks. For NOMA uplink systems, the problems of energy and power allocation for spectral efficiency still need to be ad-dressed. In [25], a survey was conducted to determine how to maximize the energy and power allocation for mul-ti-cluster-user applications. First, they formulated a power allocation problem with a power budget for each user. Thereafter, they decomposed the optimization problem in the cluster as sub-problems, and then, these sub-problems were solved by monotonicity and bisection methods. In this study, a highly accurate channel is provided to smart city users. Smart city users face a frequent handoff due to small cell areas. Thus, providing continuous 5G signal services in smart cities and for smart home users is crucial. Due to the continuous signal transmission, only 5G technology shows sustainable results. We considered nonadaptive spectrum sensing techniques of MFDI, CFDI, and HFDI for providing a highly accurate spectrum slot to smart mobility users at low SNR. Throughput is a key parameter for data transmission in channels assigned to smart mobility users. Herein, it was analyzed as the parameter for the three detection techniques, with respect to P_D, P_fa and P_md, with the detection criteria of the Neyman Pearson (NP) Observer. If the throughput was low and a channel was assigned, it was considered useless for the user and the 5G operator.

 

Reviewer 2 Report

'Due to this, the researchers desire the future of charging EV batteries with 5G technology to be fulfilled at low power levels.'

It is not clear where this statement comes form

While the conclusion claims that HFDINP is better, the results show only marginal differences with MFDINP; even the gain in performance over CFDINP is limited

'The existing 4G network did not meet the satisfactory level to achieve high data rates for 12 smart city users.'

This statement is not backed-up with facts

'5G is expected to unlock to meet the high data rates for the smart city users and overcome other issues also.'

this is wishful thinking, while in addition it seems to ignore that 5G is being rolled-out already . . . 

It would be helpful if Abstract and Introduction would limit themselves to talk about what the research covers; and not enter into a kind of promotion of 5G on applications that are not related to the research.

The Research by itself is useful, and is considered a contribution, even if the interpretation of the results could be that differences between HFDINP, MFDINP and CFDINP would be limited: that is still a valualbe scientific result 

Author Response

Reviewer 2:

1.'Due to this, the researchers desire the future of charging EV batteries with 5G technology to be fulfilled at low power levels.' It is not clear where this statement comes form

Response:

As per the reviewer suggestion, the statement is updated in the revised manuscript. 

2. While the conclusion claims that HFDINP is better, the results show only marginal differences with MFDINP; even the gain in performance over CFDINP is limited. 'The existing 4G network did not meet the satisfactory level to achieve high data rates for 12 smart city users.' This statement is not backed-up with facts

Response: As per the reviewer suggestion, the conclusion section is revised in the revised manuscript.

3. '5G is expected to unlock to meet the high data rates for the smart city users and overcome other issues also.' this is wishful thinking, while in addition it seems to ignore that 5G is being rolled-out already . . . 

Response: As per the reviewer suggestion, the meaning of the sentence is updated correctly in the revised manuscript.

4. It would be helpful if Abstract and Introduction would limit themselves to talk about what the research covers; and not enter into a kind of promotion of 5G on applications that are not related to the research.

Response: As per the reviewer suggestion, the abstract and introduction sections are updated in the revised manuscript.

Abstract:

The 4G network is not sufficient for achieving the high data requirements of smart city users. 5G networks can meet these requirements and overcome other application issues, such as fast data transmission, video buffering and coverage issues, providing excellent mobile data services to smart city users. To allocate a channel or spectrum to a smart city user for error-free transmission with low latency, the accurate information of the spectrum should be detected. In this study, we determined the range of non-cooperative detection techniques, such as matched filter detection with inverse covariance approach (MFDI), cyclostationary feature detection with inverse covariance approach (CFDI), and hybrid filter detection with inverse covariance approach (HFDI); based on the results of these methods, we provided highly accurate spectrum information for smart city users, enabling sustainable development. To evaluate the performance of the proposed detection techniques, the following parameters are used: probability of detection (P_D), probability of false alarms (P_fa), probability of miss detection (P_md), sensing time, and throughput. The simulation results revealed that the HFDI detection method provided sustainable results at low signal-to-noise ratio ranges and improved channel detection and throughput of approximately 17% and 10%, respectively.

5. The Research by itself is useful, and is considered a contribution, even if the interpretation of the results could be that differences between HFDINP, MFDINP and CFDINP would be limited: that is still a valualbe scientific result 

Response: As per the reviewer suggestion, the results are extended by compare with probability of Detection, probability of false alarm with sensing time and throughput with justification in the revised manuscript.

 

Reviewer 3 Report

Journal: SUSTAINABILITY

Article title: Sustainable Non-Cooperative User Detection Techniques in 5G Communications for Smart City Users.

General Comments:

The subject of the article is very interesting and topical. It is unfortunately not adequate to the journal theme and scope in present form. It needs major improvements. The authors focused on assessing techniques to provide continuous signal transmission with high accuracy for the smart city users. It is not clear how it concerns the topic “sustainability”. The authors used such concept as: “sustainable (…) techniques”, “sustainable improvement in the detection…”. It is not clear how the authors understand the relationship between the main topic and these concepts.

The paper is very interesting; but in my view, it needs to be major improved to reach the standard required for publication in this journal.

I hope this paper will be published. However, I suggest considering following specific comments:

1.      Introduction/abstract needs to be improved considering general and subsequent specific comments.

2.      Literature review: the review literature chapter is missing. Lack of development of topics linking the research done with journal subject areas.

3.      Results – there is no discussion of the results obtained. Appropriate comment or adding a discussion is required.

4.      Conclusions: Too concise. Content must be expanded. There is no description of the limitations of the conducted research. Appropriate comment and adding limitations of the research is required.

5.      References: The number of references is low. This indicates too little literature research. Even though the article focuses on the technical aspects, some important concepts appearing in the title and abstract that relate to the topic of the Sustainability journal are not adequately researched. Including the links between the research and the concept of "sustainability" are unclear, and the concept of "non-cooperative user detection techniques" has not been explained. I also encourage the authors to review the subject of "smart and sustainable cities". Perhaps it will inspire them to look for connections between the research done and the topic of the Sustainability journal.

There are serious linguistic errors in the content, for example (Certainly there are others that I have not been able to notice):

-          “Now a days” line 33;

-          Lines 43-44 – should be included in one sentence.

Editorial errors:

-          Lines 12-18 - "smart city user / s" was used five times.

-          not all abbreviations are explained when used for the first time – e.g.: internet of things IoT, PD, Pfa and Pmd.

-          Some abbreviations are expanded multiple times, for example: Intelligent Transporting System (ITS).

-          Figures 1-3 – figures 1-3 are not properly formatted/design and numbered.

-          Incorrect titles of chapters 3.1, 3.2, 3.3 - required expansion.

I would like to thank the authors for their work in preparing this article and see this manuscript published but considering at least the above suggestions.

 

Author Response

Reviewer 3:

1. Introduction/abstract needs to be improved considering general and subsequent specific comments.

Response: As per the reviewer suggestion, the Introduction section is improved and updated in the revised manuscript.

smart city is an urban area wherein various electronic devices and sensors are in-stalled to facilitate the collection and sharing of information. Most contemporary smart cities rely on 5G technology to share information between networks. 5G ultra-dense wireless networks can reduce load on converged cell-less communications. Vertically converged architectures are used at access points to enable 5G converged communication. Soft-ware-defined radio access networks are used to manage traffic in 5G [1]. 5G technology can profoundly impact economies and societies because it can provide the communication infrastructure required for various smart city applications. Intelligent transporting system (ITS) is one of the many smart city applications that can be realized via 5G technology. Various studies have investigated the impact and implications of 5G on ITS. Sensors and electronic devices are used for data collection from smart cities. Information and communication technologies (ICT) can be adopted to ensure sustain-able installations and provide comfort and high-quality services to smart city users. To connect everyone and everything in a smart city, a new paradigm of 5G wireless communication is highly recommended. 5G-enabled ITSs can be used for implement-ing several smart city applications. Various studies have explored the benefits of 5G-enabled ITS for smart city users in applications such as manufacturing, entertainment, healthcare, and public transport. To enable better performance for these applications, herein, the following technologies are suggested: enhanced mobile broad-band (eMBB), ultra-reliable and low latency communication (uRLLC), and vehicle-to-everything (V2X) communication [2]. 5G thus becomes the real enabler of internet of things (IoT) applications in smart cities. As an intelligent and economical means of transport, 5G plays a vital role for smart city users [3]. Millimeter wave (mmWave) technology can help achieve high data rates in 5G application, which can increase the data transmission speed for smart city users by using advanced ICT infra-structure. In [4], pre-coded orthogonal frequency division multiplexing (OFDM) tech-niques were proposed to achieve high data rates for smart city and smart home users.

 

5G-Enabled maritime unmanned aerial vehicles (UAVs) are highly recommended to operate mission critical applications with minimum latency and high reliability. High data rates with lossless transmission are crucial requirements for contemporary wire-less communication systems. Lossless transmission depends on channel conditions, and it can be implemented using 5G with mmWave and air-to-surface linking. In [21], long short term memory (LSTM)-distributed conditional generative adversarial network (DCGAN) with channel state information (CSI) was used for channel estimation. Afterward, the channel models were trained in the spatial domain for all distributions. From the trained models, most favorable LSTM-DCGAN channels were considered for high-speed data transmission. The proposed model was compared with the existing CGAN network in the simulation environment. In [22], to reduce playback and start-up in cellular networks for video on demand (VoD) users, a two-tier seg-ment based de-vice-to-device (S-D2D) method was proposed. Cache memory in a 5G-enabled device was split into two blocks by using the S-D2D caching approach. A video is divided into fixed-sized fragments and stored in the cache memory, which are known as segments. For the most popular video files, the first cache segment is reserved for the starting portion of the video and another segment is reserved for the latter portion. To improve the performance and throughput of the videos in cache memory, three cache control algorithms are proposed. D2D segmentation cache memory architecture and video segment protocols have been proposed, and the optimal cache probability and beginning segment size for throughput improvement have also been formulated. In [22], an iterative algorithm was derived to minimize the non-convex cache-throughout maximization problem. Radio frequency (RF) mirrors, time indices, and space parameters were used to represent extra-digital information using multidimensional generalized quadrature index modulation. By merging media-based modulation (MBM) transmission principle with time-indexed generalized quadrature spatial modulation (TI-GQSM) system, a hybrid model was designed, labeled as TI-GQSM-MBM scheme. The performance of the proposed scheme was estimated using bit error rate (BER), which can provide excellent performance at high data rates. Compared with multidimensional generalized spatial modulation (GSM) techniques, channel estimation errors (CEEs) exhibited better performance in a simulation environment. This technique was recommended for 5G and beyond wireless networks for error-free transmission [23]. To enable fast and efficient transmission of multimedia information, the latest communication technologies such as 5G and 6G are needed. A hybrid technique was developed by combining OFDM and massive multiple input multiple output (mMIMO) technologies, and it was used for 5G and 6G applications. This hybrid technique, OFDM-mMIMO, was used for transmission of images, and it was tested using fast Fourier transform (FFT), fractional Fourier transform (FrFT), and discrete wavelet transform (DWT). The simulation results were analyzed for the following parameters: signal-to-noise ratio (SNR), peak SNR (PSNR), and structural similarity index measure (SSIM) under Rayleigh fading channels with M-ary phase-shift keying (M-PSK) modulation. FrFt and DWT demonstrated better performance than the FFT-based technique for PSNR and SSIM [24]. Key technologies such as non-orthogonal multiple access (NOMA) are required for advanced 6G cellular networks. For NOMA uplink systems, the problems of energy and power allocation for spectral efficiency still need to be ad-dressed. In [25], a survey was conducted to determine how to maximize the energy and power allocation for mul-ti-cluster-user applications. First, they formulated a power allocation problem with a power budget for each user. Thereafter, they decomposed the optimization problem in the cluster as sub-problems, and then, these sub-problems were solved by monotonicity and bisection methods. In this study, a highly accurate channel is provided to smart city users. Smart city users face a frequent handoff due to small cell areas. Thus, providing continuous 5G signal services in smart cities and for smart home users is crucial. Due to the continuous signal transmission, only 5G technology shows sustainable results. We considered nonadaptive spectrum sensing techniques of MFDI, CFDI, and HFDI for providing a highly accurate spectrum slot to smart mobility users at low SNR. Throughput is a key parameter for data transmission in channels assigned to smart mobility users. Herein, it was analyzed as the parameter for the three detection techniques, with respect to P_D, P_fa and P_md, with the detection criteria of the Neyman Pearson (NP) Observer. If the throughput was low and a channel was assigned, it was considered useless for the user and the 5G operator.

2. Literature review: the review literature chapter is missing. Lack of development of topics linking the research done with journal subject areas.

Response:

 

To identify spectrum availability in the CR, spectrum sensing (SS) techniques are used. Various studies have investigated different SS techniques in half and full duplex para-digms. In full duplex mode, throughput and collision point of view are investigated. The sensing data are most useful for IoT applications and wireless sensor networks. There are two types of sensing techniques, cooperative and non-cooperative detection. Spectrum utilization for 5G and beyond communications has also been discussed in detail. Additional features are identified using SS with available channels and free space transmission information [26]. Unused frequency bands/slots in the RF spectrum can be identified by SS only. SS can detect and identify whether the primary users (PU)/licensed users or secondary users (SU)/unlicensed users are utilizing these bands. Compressive sensing frameworks and sparse structures are useful for improving the efficiency of RF spectrum detection in CR. Cooperative detection techniques contain fusion centers to collect sensing data and make decisions about spectrum slot availability based on the threshold value. In case of non-cooperative detection, there is no fusion center, and the spectrum decision is taken care by itself. Studies have provided examples of how SS can be used with IoT for smart city applications, and they have presented the associated challenges and investigated compressive spectrum sensing techniques [27]. The issues and challenges faced by smart city users include transferring information using wireless devices and networks. CR networks provide solutions for some of the challenges in frequency envelope modulation (FEM) and adhoc networks. Smart cities need advanced control and excellent networks with latest infrastructure to provide efficient network services. Challenges in radio spectrum assigning for smart city users in CR networks have also been discussed. Apart from SS, spectrum sharing, decision, and mobility issues have also been discussed with physical and medium access control [28]. In cognitive wireless networks (CWNs), SS was used for efficient multi-node cooperative spectrum sensing (CSS) for applications in smart cities. To improve the reliability and energy efficiency of the spectrum, high computation costs are re-quired for CSS. To ensure efficient utilization of SS, node interpretation should be enhanced and the associated challenges should be addressed. Energy detection (ED) techniques are useful for minimizing the complexity and optimizing the energy for sensor selection for SS applications. Blockchain encryption is used for storing information in the FC. It is compared with existing approaches, and it was shown that the efficiency improved by 10% by varying the nodes [29]. To develop the city as smart city spectrum is a scarce resource and critical task to identify the frequency availability. Frequency spectrum availability in latest 5G networks can be determined using SS techniques. Various detection techniques have been proposed to improve PU detection in CR networks. The detection performance is estimated by using ED along with various detection criteria. The authors identified PU instead of fast-moving users in the spectrum. The performance of the detection technique was estimated basis parameters such as SNR, PD, number of samples, and fading techniques [30]. There are several issues in wireless communication; computational speed has been improved by adopting artificial intelligence (AI) in wireless communication. There have been several technological advances in 5G supported gadgets, and to meet the networking standards, emerging AI technology is needed. CR is the backbone technology for 5G intelligent radio. Radio spectrum management is required to balance the usage of 5G gadgets in the spectrum. Researchers have focused on various energy efficient SS schemes to identify the frequency spectrum slots available by using cooperative and non-cooperative detection methods [31].

A smart sustainable city is an innovative city that uses various ICTs to improve quality of life, efficiency of urban operations and services, and competitiveness, while ensuring that it meets the needs of present and future generations considering various economic, social, environmental, and cultural aspects. The methods proposed herein can increase the quality of life for smart city users by providing efficient, reliable, and high data transmission spectrum in 5G networks. To provide this service, a sustainable (the ability to be maintained at a certain rate or level) spectrum sensing detection algorithm is needed to determine whether the spectrum is free or occupied. In existing research, three non-cooperative detection algorithms (MFDI, CFDI, and HFDI) have been pro-posed that exhibit excellent performance and use GLRT and NP observer detection criteria. However, no contemporary studies have focused on the level of sustainability of these detection methods. In this study, we investigated the range of these three detection methods for producing sustainable results. In addition to the three parameters P_D, P_fa, and P_md, we estimated sensing time and throughput for estimation of sustainability of these detection methods. In Section 3, the three detection methods are presented and the dynamic threshold is formulated, and the equations for the sensing time and throughput are further formulated.

 

3. Results – there is no discussion of the results obtained. Appropriate comment or adding a discussion is required.

Response: As per the reviewer suggestions, the results section is updated in the revised manuscript.

 

4. Conclusions: Too concise. Content must be expanded. There is no description of the limitations of the conducted research. Appropriate comment and adding limitations of the research is required.

Response: As per the reviewer suggestions, the conclusion section is revised and the limitation of the research work is also added in the revised manuscript.

 

Sustainable performance analysis is carried out between the three non-cooperative de-tection methods of HFDINP, MFDINP, and CFDINP based on the parameters P_D, P_fa, P_md, local sensing time, and throughput. HFDINP provided better sensing performance than the remaining two detection criteria in terms of P_D, P_fa, and P_md. From these results, HFDINP was identified as the better detection method. To identify SNR values for which HFDINP provided sustainable results, local sensing time and throughput were measured. Under any robust environment, the detection performance should provide sustainable results; thus, to estimate the sustainable performance of HFDINP, sensing time and throughput parameters were considered. HFDINP required less sensing time to scan the spectrum and identify the vacated slots. It required approximately 15% and 12% less time compared to CFDINP and MFDINP at PD = 1. Throughput was high when the value of β was 500 ms compared with that at 450 ms and 400 ms. The three detection methods thus provided sustainable results up to the SNR of −20 dB only.

 

5. References: The number of references is low. This indicates too little literature research. Even though the article focuses on the technical aspects, some important concepts appearing in the title and abstract that relate to the topic of the Sustainability journal are not adequately researched. Including the links between the research and the concept of "sustainability" are unclear, and the concept of "non-cooperative user detection techniques" has not been explained. I also encourage the authors to review the subject of "smart and sustainable cities". Perhaps it will inspire them to look for connections between the research done and the topic of the Sustainability journal

Response: As per the reviewer suggestions, the number of references are increased and cited in the text. Literature review also elaborated.

 

A smart sustainable city is an innovative city that uses ICTs and other means to improve quality of life, efficiency of urban operation and services, and competitiveness, while ensuring that it meets the needs of present and future generations with respect to economic, social, environmental as well as cultural aspects. In this paper the authors proposed their research work to increase the quality of life for smart city users by providing the efficient, reliable and high data transmission spectrum in the 5G. To provide this service it is needed a sustainable (the ability to be maintained at a certain rate or level) spectrum sensing detection algorithms to find the spectrum is free or busy. The existing research work shows the three non-cooperative detection algorithms (MFDI, CFDI and HFDI) gives better performance by using GLRT and NP observer detection criteria’s. But the existing authors doesn’t focus on the level of sustainability produced by these detection methods. In this paper, the authors done their research for how much of range these three detection methods produce sustainable results. Apart from the three parameters of P_D, P_fa and P_md the authors estimated sensing time and throughput for estimation of sustainability of these detection methods.

 

6. There are serious linguistic errors in the content, for example (Certainly there are others that I have not been able to notice):

             “Now a days” line 33;

       Lines 43-44 – should be included in one sentence.

Response:  As per the reviewer comment, the linguistic errors are eliminated in the revised manuscript.

7. Editorial errors:

-          Lines 12-18 - "smart city user / s" was used five times.

-          not all abbreviations are explained when used for the first time – e.g.: internet of things IoT, PD, Pfa and Pmd.

-          Some abbreviations are expanded multiple times, for example: Intelligent Transporting System (ITS).

-          Figures 1-3 – figures 1-3 are not properly formatted/design and numbered.

-          Incorrect titles of chapters 3.1, 3.2, 3.3 - required expansion.

Response:  As per the reviewer suggestion, the paper is proof read by English native speakers and the multiple abbreviations are eliminated. 

 

 

 

 

 

 

 

 

 

 

 

 

Reviewer 4 Report

Abstract: The justification is not well address. Try to provide a more comprehensive abstract

 

In general, the paper doesn’t provide a clear evaluation of the state of the art. A more in deep analysis is needed providing reasons to carry on the evaluation of the three techniques for detection of 5G spectrum signal. It is recommended to extend this part to put a real value of the research proposal.

Figures should be improved to avoid text cuts (figure 1, 2 and 3) and reference in the text (fig 5, 7, 8, etc)  In the text figure 6.4 is refer which doesn’t correspond to any figure??

English should be checked in deep avoiding abstract sentences with no clear meaning and solving typos like: “Now a days”,…

There are a set of references not included in the text like [5], [7] and from [12] till [20]. This should be justified and as recommended an extension of the state of the art should be provided. [12]. There is a great number of autoreference included without no justification ( [14], [15], [16], [18], [19], [20]

My recommendation is to extend the explanation of the section 2 with more justification of the parameters and relation to section 3. Seems that section 2 and 3 are not well connected. A clear description on how the evaluation is done is needed: simulation? which scenario?

A conclusion section needs to address a clear output of the evaluation research. Current version gives to HFDINP the best performances in any scenario. Sentences like the reference to the EV mobility users seems to be out of context as well as final remark “the researchers desire the future of charging EV batteries with 314 5G technology to be fulfilled at low power levels”.

 

To summarize, I suggest to provide a more elaborated paper considering a clear justification based on a solid state of the art to perform the research as well as improve the description of research with as more detail explanation of the relevant parameters and how you perform the evaluation

Author Response

Reviewer 4:

1. Abstract: The justification is not well address. Try to provide a more comprehensive abstract

Response:  As per the reviewer suggestion, the abstract is rewritten and incorporated in the revised manuscript.

 

2. In general, the paper doesn’t provide a clear evaluation of the state of the art. A more in deep analysis is needed providing reasons to carry on the evaluation of the three techniques for detection of 5G spectrum signal. It is recommended to extend this part to put a real value of the research proposal.

Response:  As per the reviewer suggestion, the abstract is rewritten and incorporated in the revised manuscript.

 

In this paper, the authors focused on providing a channel to smart city users with high accuracy. Smart city users face a frequent handoff due to the small cell area. So, provide continuous 5G signal service to the smart city or smart home users is a vital task. Due to the continuous signal transmission only the 5G technology is shows sustainable results.

 

A smart sustainable city is an innovative city that uses ICTs and other means to improve quality of life, efficiency of urban operation and services, and competitiveness, while ensuring that it meets the needs of present and future generations with respect to economic, social, environmental as well as cultural aspects. In this paper the authors proposed their research work to increase the quality of life for smart city users by providing the efficient, reliable and high data transmission spectrum in the 5G. To provide this service it is needed a sustainable (the ability to be maintained at a certain rate or level) spectrum sensing detection algorithms to find the spectrum is free or busy. The existing research work shows the three non-cooperative detection algorithms (MFDI, CFDI and HFDI) gives better performance by using GLRT and NP observer detection criteria’s. But the existing authors doesn’t focus on the level of sustainability produced by these detection methods. In this paper, the authors done their research for how much of range these three detection methods produce sustainable results. Apart from the three parameters of P_D, P_fa and P_md the authors estimated sensing time and throughput for estimation of sustainability of these detection methods.

 

 

3. Figures should be improved to avoid text cuts (figure 1, 2 and 3) and reference in the text (fig 5, 7, 8, etc) In the text figure 6.4 is refer which doesn’t correspond to any figure??

Response:  As per the reviewer suggestion, the text cuts in the Figures 1,2 and 3 are updated and the reference in the text of all figures are updated in the revised manuscript.

 

4. English should be checked in deep avoiding abstract sentences with no clear meaning and solving typos like: “Now a days”,…

Response: As per the reviewer suggestion, the paper is proof read by English native speakers. 

5. There are a set of references not included in the text like [5], [7] and from [12] till [20]. This should be justified and as recommended an extension of the state of the art should be provided. [12]. There is a great number of autoreference included without no justification ( [14], [15], [16], [18], [19], [20]

Response: As per the reviewer suggestion, the references are cited in the revised manuscript.  

 

6. My recommendation is to extend the explanation of the section 2 with more justification of the parameters and relation to section 3. Seems that section 2 and 3 are not well connected. A clear description on how the evaluation is done is needed: simulation? which scenario?

Response: As per the reviewer suggestion, section 2 and 3 are extended in the revised manuscript.

 

7. A conclusion section needs to address a clear output of the evaluation research. Current version gives to HFDINP the best performances in any scenario. Sentences like the reference to the EV mobility users seems to be out of context as well as final remark “the researchers desire the future of charging EV batteries with 314 5G technology to be fulfilled at low power levels”.

Response: As per the reviewer suggestion, the conclusion section is revised in the revised manuscript.  

 

8. To summarize, I suggest to provide a more elaborated paper considering a clear justification based on a solid state of the art to perform the research as well as improve the description of research with as more detail explanation of the relevant parameters and how you perform the evaluation.

Response: As per the reviewer suggestion, the paper is elaborated with clear justifications in the revised manuscript.

 

Round 2

Reviewer 2 Report

The paper is still selling 5G, and too little the research it intends to present: if if 5G was so fantastic, then this research would be a waste of time! 

You undermine the value of your research by repeating wishful thinking on 5G and 5G applications that is really unscientific and little credible . . . 

So please make the following modifications:

Conclusions: 

Please remove the word SUSTAINABLE: it has no meaning; if you mean stable or reproducible, then use that, not a misused and misleading term as sustainable

Abstract:

The 4G network is not sufficient for achieving the high data requirements of smart city 12 users. 5G networks INTENDS TO meet these requirements and overcome other application issues, such as fast 13 data transmission, video buffering and coverage issues, providing excellent mobile data services to 14 smart city users.

Introduction

STOP (OVER)SELLING 5G, AND STOP making yourself believe that IoT is only high datarates and that 5G can make autonomous (?!) vehicles possible.

Limit your introduction on 5G to maximum 3 times the length in the abstract (see above) and please stay with what 5G INTENDS to do and stay reasonable with your examples of applications that should be in line with the objectives of your research

For example  . . . . . . .  5G-Enabled maritime unmanned aerial vehicles (UAVs) are highly recommended to op-56 erate mission critical applications with minimum latency and high reliability. High data 57 rates with lossless transmission are crucial requirements for contemporary wire-less com-58 munication systems.

>>>> start a new paragraph AND ONLY TALK ABOUT YOUR RESEARCH FROM HERE
Lossless transmission depends on channel conditions, . . . . 

Author Response

Dear Reviewer,

Thank you for positive critics on my research work, which are prone to increase the quality of the research paper.

Thank you

Regards,

Dr.Budati Anil Kumar

Author Response File: Author Response.pdf

Reviewer 3 Report

I accept the changes made by the authors. The final layout of the content, the form of presentation, description and inference reflect the formal requirements, but also the individual approach of the authors and they may differ slightly from the opinions of others. In my opinion, the literature review is not conducted reliably. However, the article meets the requirements and can be published in its current version. I thank the authors for their work in developing the article and I wish them good luck.

Author Response

Dear Reviewer,

Thank you for considering the paper for publication and your positive critic. As per your suggestion I have updated the literature work and incorporated in the revised manuscript.

Thank you

Regards,

Dr.Budati Anil Kumar

Author Response File: Author Response.pdf

Reviewer 4 Report

The authors provided the requested modifications. Congratulations.

Author Response

Dear Reviewer,

Thank you for your positive critic on my research paper and accepted for publication.

Thank you

Regards,

Dr.Budati Anil Kumar

Round 3

Reviewer 2 Report

Dear Authors, I think we are almost there, and still need to give more visibility to your research!

I suggest to make the following change in your introduction text (comments are in Italic); I count on you making this change in the right spirit, and check your English (which is pretty good already), and do not think there is a need for another review (other than by the editor) for publlication; Success!

Hereafter text with suggested change:

-----------------------------------------------------

A smart city is an urban area wherein various electronic devices and sensors are in-stalled 30 to facilitate the collection and sharing of information. Most contemporary smart cities rely 31 on 5G technology to share information between networks. 5G ultra-dense wireless net-32 works can reduce load on converged cell-less communications. Vertically converged ar-33 chitectures are used at access points to enable 5G converged communication. Software-34 defined radio access networks are used to manage traffic in 5G [1].

[separate paragraph: explain in one or two sentences the contribution of your research to the effective operation of 5G (and possibly 6G) networks to the benefit of the users] 

[new paragraph] To estimate the prob-35 ability of sensing time and channel workload, the authors used window-based and sam-36 ple-based sensing mechanisms in the CR spectrum . . . . 

Author Response

Dear Reviewer,

Thank you for your positive critics, which help us to improve the quality of our paper.

Thank you

Regards,

Dr.Budati Anil Kumar

Author Response File: Author Response.pdf