A Survey on harnessing the Applications of Mobile Computing in Healthcare during the COVID-19 Pandemic: Challenges and Solutions

The COVID-19 pandemic ravaged almost every walk of life but it triggered many challenges for the healthcare system, globally. Different cutting-edge technologies such as Internet of things (IoT), machine learning, Virtual Reality (VR), Big data, Blockchain etc. have been adopted to cope with this menace. In this regard, various surveys have been conducted to highlight the importance of these technologies. However, among these technologies, the role of mobile computing is of paramount importance which is not found in the existing literature. Hence, this survey in mainly targeted to highlight the significant role of mobile computing in alleviating the impacts of COVID-19 in healthcare sector. The major applications of mobile computing such as software-based solutions, hardware-based solutions and wireless communication-based support for diagnosis, prevention, self-symptom reporting, contact tracing, social distancing, telemedicine and treatment related to coronavirus are discussed in detailed and comprehensive fashion. A state-of-the-art work is presented to identify the challenges along with possible solutions in adoption of mobile computing with respect to COVID-19 pandemic. Hopefully, this research will help the researchers, policymakers and healthcare professionals to understand the current research gaps and future research directions in this domain. To the best level of our knowledge, this is the first survey of its type to address the COVID-19 pandemic by exploring the holistic contribution of mobile computing technologies in healthcare area.


Introduction
The current COVID-19 outbreak has drastically affected all domains of life such as education, business, trade, transportation, global economy, movement and more importantly the routine activities of people. However, the most affected area is healthcare where it brought many challenges to the existing health infrastructure. The healthcare system of even advanced countries faced severe issues in dealing with this pandemic and they responded differently through the application of different technological solutions. However, during the pandemic to cope with this deadly virus, the widespread adoption of digital technologies has been escalated especially in healthcare area. In this regard, the role of machine learning, artificial intelligence, sensors, cameras, robots, virtual reality, information systems, electronic health records and global positioning systems (GPS) is very substantial and evident. However, among the emerging technologies, the application of mobile computing and Internet of Things (IoT) technology is of paramount importance. Mobile computing has noteworthy contributions to counter the adverse impacts of this pandemic. It is a vast field and has many applications in diverse domains but its role in healthcare systems in the context of handling coronavirus is praiseworthy. Mobile computing components such as mobile applications, hardware and communication technologies have been leveraged for the eradication of COVID-19 in the healthcare area. Mobile computing standalone or with the support of other technologies provided numerous healthcare services to tackle the emerging situation of COVID-19. For example, mobile computing in support with the artificial intelligence has been applied for the easy detection and analyzing COVID-19 symptoms [1]. Similarly, IoT based mobile computing accompanied by other technologies such as cloud, machine learning, and artificial intelligence provided an easy way to handle large-scale masses for monitoring, diagnosing, self-isolation and treatment purposes related to the COVID-19 outbreak in the healthcare ☆ This work is supported by Qatar National Library, 2021-010.
• The major objective of this research work is to enable the healthcare professionals and experts to leverage the mobile computing in holistic fashion during the pandemic of COVID-19 • To understand and analayze the emerging role of mobile computing in context of dealing with the current pandemic in healthcare area. As, the prior researches made in this domain are not adequate enough to explain the role of mobile computing comprehensively. • To discuss and highlight the application of all components of mobile computig such as hardware, software and communications technologies with respect to to provide healthcare services during the COVID-19 pandemic. • To explore COVID-19 mobile app technologies with respect to highlighting the various healthcare services in context of dealing with current pandemic. • To address the challenges emerging during the implementation of mobile computing and providing solutions to take full advantages of mobile computing applicability.
Following are the major contributions of proposed survey.
• This survey article is novel in comparison to previous studies for many reasons such as the application of mobile computing to combat this pandemic is comprehensively highlighted for the first time in healthcare setup. A theoretical framework based on mobile computing i.e. highlighting the application of these three major components such as hardware based support, software based support and communication technologies in the healthcare environment is presented to provide a deep level of understanding. • We analyzed and highlighted the software-based solutions of mobile computing such as the roles of various apps in the context of COVID-19. The software-based solution furnished by mobile computing for COVID-19 using the various apps alone and supported by data-driven with other technologies such as artificial intelligence and machine learning are analyzed, categorized, and thoroughly discussed. Mobile health applications have been extensively discussed for testing, isolation and diagnosis. The role of M-health apps has also been utilized to mitigate the effects of COVID-19. • The hardware-based solutions of mobile computing like mobile devices wearable gadgets, smartphones, handheld devices, acoustic sensors and smart gadgets in the context of COVID-19 surveillance, patient health monitoring and telemedicine are comprehensively analysed and illustrated. • The role and capabilities of communication technologies such as 5G, beyond 5G, Wi-Fi, Bluetooth, ZigBee, RFID, Global Navigation Satellite System (GNSS) are articulated in a comprehensive fashion to deal with COVID-19 combat. • We highlighted the various issues involved in the deployment of mobile computing technologies to address the COVID-19 disease. We also provided the possible solutions towards the existing issues and challenges based on our comprehensive literature study.
The remaining paper is divided into 6 major sections. Section 2 presents the related work. Section 3 discusses the research method of this survey. Section 4 explains the results and overview of selected studies. Section 5 highlights the challenges along with solutions faced by mobile communication technologies in the mitigation of coronavirus. Section 6 concludes the paper.

Related work
In the existing literature, the role of mobile technology is highlighted in narrow sense. Therefore, the proposed survey is focused on discussing Y. Ali and H.U. Khan the role of mobile computing in broader fashion in comparison to the previously presented research articles. Although, there are many research works available in the literature that are focusing on highlighting the role of different cutting-edge technologies with respect to dealing with the COVID-19 disease in healthcare domain but there is not a single work available focusing on discussing the role of mobile computing to deal with the COVID-19 outbreak. Similarly, there are few research articles that are only focusing on the communication or hardware aspects of mobile computing; and providing different solutions in healthcare environment. But, this research article is using holistic approach in highlighingt the role of mobile computing in medical care system during the pandemic.
BasheeruddinAsdaq et al. [10] presented a review highlighting the role of wireless technologies to provide healthcare services during the COVID-19 pandemic. The proposed work only presents an overview of the application of wireless technologies and their related challenges. Our survey provides a more comprehensive picture of the wireless communication technologies in comparison to their study. We have provided a broad discussion regarding the application of these technologies during the pandemic.
Ueafuea et al. [11] also presented a review on discussing the potential applications of mobile devices towards the remote psychological support during the COVID-19. Authors discussed the role of wearable devices and mobile technology to address the mental health issues such as anxiety, depression and insomnia. In comparison to our survey, this article only discusses the hardware aspects of mobile technology. Communication technological support and softwares based support of mobile technology are not highlighted in their work. A similar study is also conducted by Connolly et al. [12] provide an overview of smartphone apps use-cases to provide remote mental healthcare services during the current pandemic. Zhou et al. [13] also conducted a survey to study the role of mobile apps in China during the pandemic.
Iyengar et al. [14] review is aimed to highlight the application and role of smartphone technology for the diagnosis and surveillance. They also discussed the side effects and limitations of SMT.
Toquero et al. [15] presented the role of mobile health technology such as Mhealth app for the old aged and people with disabilities. Their's study is limited to discuss only few mobile phone app that are used by the different categories of disabled people during the pandemic.
Siriwardhana et al. [16] presented a comprehensive review related to highlighting the use cases of 5g technologies to battle against the COVID-19. The major focus of this study to understand the use cases of 5G and IoT technologies in telemedicine and contracting tracing. They also identified various issues and provided solutions. In comparison to our work it is only discussing the communication aspects of mobile computing.
The study presented by Singh et al. [17] is more related to our proposed survey as it discusses the different applications of mobile technology for healthcare services during the pandemic. The significant role of mobile technology is discussed for the surveillance, diagnosis, treatment, prevention and telehealth purposes. Authors did not highlight the major limitations. They also did not discuss the overall healthcare applications of mobile computing towards the pandemic.
Chow et al. [18] presented a review focusing on utilizing the mobile technology to address the healthcare issues by providing remote health access using mobile apps and communication services. They discussed the various technologies as language translator based on human interpretation and without their involvement. This is very limited study as it only discusses few mobile apps to provide solutions towards remote health access.
Kassab et al. [19] performed a detailed analysis of mobile apps targeted towards COVID-19 surveillance. They discussed digital tracing based in mobile and non-mobile technologies, comparatively. They also performed analysis of COVID-19 mobile apps based on four major parameters such as availability of source code, development sector, platform and technology support. But, it lacks detail about limitations and challenges and the surveillance apps are not enough as well in comparison to our work.
Grantz et al. [20] put forward their perspective on analyzing the mobile phone data to understand the user behaviour during the pandemic. They discussed the use mobile phone for contact tracing and monitoring of COVID-19.
The detailed summary of all related works in comparison to the proposed work is given in Table 1.

Research method
This study follows an organized and proper systematic search procedure for collecting different studies related to the topic. Initially, the main focus was to identify the target journals and then to perform search based on forming some suitable keywords. The following keywords were formed and applied on various online databases.
"Mobile computing" OR "Pervasive computing" AND "COVID-19" OR "Coronavirus" OR "SARS-CoV-2" AND "Healthcare" OR "Medical care" After completing the search processes, more than 503 papers were collected from well reputed journals in area of mobile computing and healthcare. Finally, every paper was checked for titles and abstract and full reading for the inclusion in our study. Finally over 200 papers were selected in this survey.
The selected papers were divided into three categories such as research studies relevant to the hardware component, software and communication component related to mobile computing were separated. The collected research papers were thoroughly checked for the contents and every component of mobile computing was noted. and discussed in the relevant sections.

Results and overview of selected studies
In this section, our major focus is to analyze and categorize the selected studies in three different components of mobile computing. Then, we are highlighting and discussing every component of mobile computing towards the pandemic in healthcare environment.
The term mobile computing can be well-described by three different major components i.e. hardware, software and communication technologies. In hardware concept of mobile computing all the portable devices come such as smartphones, PDAs, sensors, actuators, dedicated onboard Graphical Processing Unit (GPUs). Software components means the various applications running on the mobile devices. The examples of such apps can be different browsers, games or antivirus programs. The communication section of mobile computing deals with the different kind networking and communication infrastructures like cellular technologies and other wireless technologies and communication protocols. Mobile computing empowers its users to use features like flexibility, portability, efficient utilization of energy and context aware computation. The complete detail of different components of mobile computing is given in Fig 1. In the current pandemic different technologies have been adopted for healthcare services. Among the technologies, mobile computing cannot be neglected as it provides numerous healthcare services and solutions based on its three major components. For complete understanding the role of mobile computing in healthcare environment a conceptual framework is presented that demonstrates how mobile computing is proven to be effective to deal with healthcare problems in the current pandemic. The visual diagram of mobile computing is given in Fig 2. In this research, we conducted in depth analysis of different studies from different perspectives to understand the current adoption of mobile computing in healthcare for COVID-19. Initially, we identified those research studies that are focusing on utilizing the hardware component such as smartphone technology for healthcare domain in pandemic. The application detail of mobile phone technology for different healthcare activities is given in Fig 3. It was also observed in the literature study that mobile phone solitary cannot be used for healthcare purpose as it must be integrated with other technologies like virtual reality or machine learning or some other technology. We also analysed the various studies and extracted different technologies that have been adopted with smartphone for different healthcare purposes as given in Fig 4.Among these technologies, machine learning has been widely used by many smartphone based approaches during the pandemic.
Similarly from the software components of perspective, we also collected some mobile apps and searched for the various mobile platform supported by these collected apps. The detail of platform or operating system supported by the presented COVID-19 mobile apps in this study are given in Fig 5. The majority apps were Android and web based.
The complete discussion of application of mobile computing in terms of three components towards the COVID-19 pandemic for healthcare purposes is given in the following sections.

A. Hardware based solutions of mobile computing for COVID-19
The main outline of this section is to highlight and discuss the role of major component of mobile computing such as hardware based solutions in the COVID-19 crisis in healthcare industry. The changing role of mobile computing in terms of the different hardware-based equipment or components such as smartphones, tablets, drones, sensors, thermal cameras, microphones and notebooks is discussed in the healthcare environment.
In the hardware components, the role of mobile phones or smartphones is significant to handle COVID-19. As we know, the healthcare system was heavily overloaded in the current pandemic due to the number of people hit by this virus. This plight has led to many challenges in the healthcare system such as in the current pandemic the thousands of people have been waiting outside the hospitals due to limited health infrastructure; thus, frequent testing becomes an issue and more importantly, it led to cross infection. Similarly, the kit available for COVID-19 testing is costy and the number of radiologists are scarce.
There was a dire need for such a technology which can be quickly and easily used for testing. The proposed solution could be self-testing that is free from laboratory testing. The smartphone can be proven as gamerchanger in this situation. Mobile computing played a dominant and holistic role in testing or detecting the coronavirus through the implications of smartphones, smartwatches, wearable devices, built-in cameras and microphones. However, the role of smartphones is more dominant and prominent in testing or diagnosis. Several technologies have been proposed for detecting coronaviruses but smartphone-based testing has been introduced for instant COVID-19 testing. It played a prominent role because of their storage, processing, camera, screen and multi-sensor supporting options in COVID-19 testing. Owing to its low cost, high resolution, rapid GPS, processing abilities and point-of-care features make it a good choice for regions with limited resources [26]. Similarly, smartphones have the ability to capture a large amount of data and provide data analysis. The smartphone is applicable to a variety of tasks related to COVID-19 in the healthcare environment. It can be utilised as standalone or integrated with other technologies such as machine learning an artificial intelligence. It can be used for testing/diagnosis, self-isolation, treatment or telemedicine as well. The wide application of smartphones is frequently observed in cough testing for COVID-19. In this method, the cough voice of patients is recorded on a smartphone app and is provided as input to the model that is built on machine learning, signal processing or artificial intelligence techniques. These techniques decide whether the patients will undergo RT-PCR   testing or not. The general procedure for detecting COVID-19 through a cough test using a smartphone app is shown in Fig 6. In literature, various studies have focused on the use of smartphonebased cough testing for COVID-19 [27][28][29][30]. Smartphone is quick and easy to use procedure for testing of COVID-19. Recently, a research was conducted by the University of Arizona for COVID-19 home testing which uses saliva and delivers the results within 10 min using smartphone apps [31]. Based on its ubiquitous application, the smartphone-based home testing is also helpful in providing information pertaining to the virus load [32]. The Food and Drug Administration (FDA) also issued its authorisation for emergency situations during home testing [33]. In this regard, Maghded et al. [34] proposed a framework based on smartphone sensors in collaboration with machine learning techniques to detect COVID-19 or pneumonia. This method uses three sensors: inertial, microphone and temperature sensors. The role of sensors is to provide input to machine learning-based algorithms known as convolutional neural networks (CNNs) and recurrent neural networks (RNNs). These two algorithms have been combined to predict the presence and absence of the virus. Similarly, the work presented by Faezipour et al. [35] is also related to self-testing and is focused on leveraging the smartphone applications. This work is based on checking the breathing sound for pattern analysis using signal processing and machine learning techniques to investigate the oxygen level and lung volume. A smartphone or tablet integrated with microfluidics can also be used detecting COVID-19 by using saliva specimens [36]. The research work conducted by Fozouni et al. [37] used a mobile phone camera as a fluorescent detection microscope to detect swab COVID-19. In this research work, the mobile phone provides a basis for the research and it eliminates the use of laboratory equipment to provide quantitative results within a few minutes. The complete role of smartphone with respect to responding to COVID-19 has been given in Fig 7. Similarly, mobile phones also have been applied in numerous ways such as to extract viral genetic material from the respiratory tract which can also be used to detect antibodies developed in the blood against the virus [38]. The role of smartphone is also significant in developing a new technology such as "Integrated Quantum Dot Barcode" that works based on smartphone camera. This will provide a portable, easy-to-use, point-of-care and low-cost testing [39]. It is also applied for live video monitoring is connected to a smartphone, where drone with virtual reality technology scans the body temperature and sends it to a smartphone. The Global positioning System (GPS) installed on a phone provides the specific location information of individuals [40]. Smartphones have been adopted for symptom reporting related to COVID-19, where it uses different apps to report symptoms and symptoms related to COVID-19 on routine bases [41,42]. The ubiquitous nature of smartphones makes it a good option to allow citizens to download apps and register themselves for vaccinations without physically attending hospitals. The citizens can also register themselves by sending the required particulars to the centralised hospitals where the nearby hospital is allotted to them for vaccination. These apps also have features such as video-based appointments and live chatting. It also helps in reporting serious reactions in response to the doses of vaccinating jab. Smartphones have become the most important tools in this pandemic to collect data related to people. After proper analysis, it helps them identify the   reason for the spread of pandemics in certain regions. During the lockdown, it was not feasible for patients suffering from diseases such as hypertension, diabetes, asthma, cardiovascular diseases or other chronic diseases to visit hospitals/pharmacies to receive the prescribed medicine or treatment. In this way, smartphones and other wearable devices contributing with other technologies helped patients via telehealth or telemedicine technology [43]. Telemedicine is the procedure of obtaining information or healthcare services through remote distance from medical experts in emergency situations [44]. It empowers health professionals to monitor and diagnose their patients via remote clinic through video conferencing over the phone or laptop with the help of wireless technologies such as Wi-Fi, global system for mobile communication (GSM), 4G, 5G, and GPS. It also provides services such as health advice, proper counselling, health solutions and discussing mental  health issues in a cost-effective and easy-to-access manner. The identification and isolation of infected people have become a serious issue during the pandemic due to the limited resources of testing facilities available in the third world countries. For this purpose, a manual contract strategy is adopted by healthcare professionals. Manual contact tracing is performed via interviews or telephone to identify contagious people. However, many shortcomings are associated with this approach such as laborious effort, slow, time consuming, scarcity of staff, misconduct by government and lack of cooperation shown by contacts [45,46]. To stop the rapid spread of this deadly virus, it is important to apply the technology in breaking the chain of infection and identifying the infected people. Smartphone-based apps can be adopted to determine the proximity of individuals, who install apps on their smartphones. Google also provides an application programming interface (APIs) for contract tracing for different national apps [46]. For the purpose of contact tracing different smartphone-based schemes have been proposed [30,47,48,49,50,[51][52][53][54]. The complete details of all approaches, techniques and models related to combat the COVID-19 in terms of contact tracing, diagnosis, telemedicine and self-symptom reporting using smartphone technology/mobile computing based technologies are given in Table 2.
In the modern world, bio-sensing systems using bio-patches, cloth embedded sensors and wrist-based trackers are available in the market. These devices can perform a variety of tasks such as measuring heart rate, blood pressure, oxygen saturation, glucose level and temperature measurement. These sensors can play an important role in recording data related to coughing, sneezing, temperature or other measurements related to diseases. The use of skin patches and biosensors has become more vital because of the low contact between the patient and doctor in case of coronavirus. Besides, providing a list of functions such a sensors have some limitations such as covering less part of the body and suffering from privacy and security issues, data sharing and accessibility issues. These devices also play a significant role in contact-tracing, selfsymptom reporting, diagnosis and making appointments [74]. The wearable sensors have good applications in mitigating the effects of the COVID-19 pandemic [43,49].
Similarly, the role played by Acoustic sensing or Ultrasonic technology cannot be ignored during this pandemic. Acoustic sensing can be applied in testing, disinfection and maintaining social distance. Acoustic sensing offers variety of sensors for the diagnosis and monitoring of COVID-19 disease. These sensors can be used to measure the human airways. In this procedure, acoustic sensing technology is integrated with smartphones to provide cost effective and easier way to detect the COVID-19 infected people at home [75]. Similarly, Acoustic sensing brings ultrasonic sensors which are capable of detecting an infected person at a distance of 6 feet. Ultrasonic sensors have the abilities to transmit signals. Whenever the signal strikes anyone at a distance of around 6 feet, then a beep sound is made to alert the user and the other people to keep themselves isolated from that person [76]. Acoustic sensors can also be applied for measuring the respiration rate. These sensors use a highly sensitive microphone which can be placed on neck and still provides high accuracy than chest sensors [77]. The ultrasonic sensing technology can also be applied for sanitizing or disinfection. In this regard, the study presented by Pandya et al. [78] is leveraging acoustic sensing for the disinfection of COVID-19. The proposed model has been adopted in building for disinfecting a suspicious person of COVID-19.
The application of acoustic sensing technology can be profitable but still there are certain challenges associated with it that are required to be addressed i.e. building a robust model based on acoustic techniques that can extract the right acoustic features in the available datasets can be quite challenging. Similarly, the collection of sample data related to cough is also challenging job. Therefore, it must be filtered before adding it to the dataset [79]. However, some data mining and machine learning techniques can be effectively applied to address these challenges [80].

B. Software based support of mobile computing for COVID-19
Mobile computing also plays a major role by providing softwarebased support for handling the COVID-19 pandemics. In softwarebased support, the operating system, mobile platforms and different application softwares have been discussed with respect to control COVID-19 in the existing situations. The role of mobile computing to deal with rapidly spreading viruses is highlighted in a comprehensive manner in this section.

i. Operating systems support
Google and Apple are the two different companies but they were seen in rare joint ventures in this pandemic. During the COVID-19 pandemic, both Google and Apple combined to provide good application services to mobile users who are using Google Android and Apple iOS devices. In their collaborative efforts, the apps supported by both operating systems have also been introduced and yet they are also working on future projects to provide Bluetooth-based, energy-efficient and effective solutions for COVID-19 where different applications can tap into [81]. Similarly, the future focus is to introduce a Bluetooth-based operating system without installing apps. Unlike GPS-based contact tracing, this operating system is advantageous because of preserving the privacy. These two big giants are also working on to introduce Application Programming Interfaces (APIs) that will be able to provide application building platforms for app developers to build coronavirus tracking apps and interoperability between Android and iOS equipments. They are also introducing Bluetooth contact tracing platforms (more than just API) for the healthcare system. It will support apps which use Bluetooth by providing a range of 30 feet and energy efficiency. These apps will help to harness the power technology to mitigate the effect of COVID-19 by providing digital contact tracing in a privacy-preserving manner for healthcare systems. If a person comes closer to the person tested as COVID-19 positive then it will alert the owner of the phone to get isolated or separated from the infected person in the vicinity.
Similarly, Android and iOS operating systems have added features of COVID-19 tracing apps in their app phone settings that are available on update to the mobile phone users. Although, initially it was reckoned as mobile app but later on it was cleared by Alan Woodward that it is an extra feature added to the smartphone operating system [82]. Bluetooth tracing in COVID-19 is strongly recommended in the tracing and identification of infected people. However, there are some mobile apps which are using Quick Response (QR) code as well. For example, well-known app NZ Covid tracer app uses QR code feature that allows mobile users to maintain their privacy. It has many advantages over other communication technologies such as privacy preservation, supporting features of both Google and Android, minimum battery life and no mobile data usage [83]. It does not compromise the identity of users. It sends notifications when another app user tests positive in nearby places.

ii. Mobile platforms support
Mobile health platforms have also been presented to address COVID-19 challenges. Different platforms are provided by mobile computing to build healthcare-based solutions or to adopt the existing applications on top of these platforms. These platforms provide storage, processing, communication support and middleware between the communication devices operating in the healthcare environment. A multi-purpose platform for COVID-19 was presented by Petrellis et al. [72]. The proposed platform includes desktop and mobile applications, cloud services and sensor-based structures. This platform with support of other platforms such as Microsoft Azure, AWS and Google Cloud provides storage options by minimising the dependency on the cloud. This platform can be adopted by researchers, healthcare professionals and patients during or before hospitalisation. It is used for the classification of cough sounds during a pandemic. It furnishes a great deal of security services such as privacy, data related to patients are deleted from the cloud after using authentication and the encryption schemes are applied during the input of data. Similarly, different mobile health platforms have been proposed during the peak time of this contagious disease. Mobile health platforms are also introduced for COVID-19 at children hospitals in Geneva [84]. This platform is dedicated to providing up-to-date information and validation of information to healthcare professionals in a time-saving and effective fashion. This platform has been introduced as a channel of communication and dissemination of information in the children hospital related to local procedures, planning for treatment and general awareness. A similar approach/platform is also presented Wong et al. [73] to provide a sensor-based method using artificial intelligence for detecting COVID-19 symptoms and health surveillance. The main intention of this health based platform is to detect infected people early and quarantine them to break the chain of infection of the coronavirus outbreak. This platform has the capability of reporting physiological parameters such as oxygen saturation level, skin temperature and pulse rate by using wearable sensors. The mobile platform developed by Oslo University [85] for health information systems has specific COVID-19 functions based on the installation of COVID-19 related packages. These meta-data packages can be installed separately or together on Android-based devices. This system is used in more than 70 countries for health monitoring and analysis of health data. It has the following main features or functions related to coronavirus. The different apps supporting the relevant platforms for running are listed in Table 3.

iii. Mobile application support
In this section, our focus is to discuss the different applications in the context of dealing with COVID-19 and highlighting the major role and uses of different application software. Many studies have been conducted on the role of mobile applications (apps) to address the challenges of COVID-19.
Mobile apps have contributed to all aspects related to coronavirus; however, in this review the apps were investigated based on contact tracing, telemedicine, diagnosis and self-symptom reporting. Digital contact tracing is helpful in reducing the transmission level of COVID-19 as it provides preventive measures to control the epidemic. It was also used to control Ebola pandemics in 2014 but this is the first time that mobile app-based contact tracing has been used for COVID-19 [86]. Before, contact tracing was performed in a manual fashion but it was time-consuming, slow [46] and laborious task [87] as compared to digital contact tracing based on apps. Contact tracing performed via mobile apps is more accurate [88], fast [89] and has promising output [90]. However, the main issues with app-based tracing is privacy preservation which made people unwilling to install such apps for social distancing in lockdown. Ultimately, it led to the less using of contact-tracing-apps-based technologies. But its advantages can be ignored. According to the report of Zastrow [91], if 60% of the population uses these apps then the outbreak can be controlled. But, still there are some reservation by the mobile users. Among the countries, Australia is the leading in terms of using contact tracing apps. The COVID-19 mobile apps have different working and privacy mechanisms for contact tracing but there are two most common app-based contact-tracing architectures as given below as: • Centralized Contact Tracing Architecture (CCTA) All the activities and data storage are done through the central server in the centralized app contact tracing model. The data are controlled by central authorities such as government or private agencies; and are likely to be shared with third parties as well [92,93]. Health authorities have control over data in this structure which allow them to check the previous contacts and notify contacts about the exposure [94]. The main shortcoming of this approach is the one-point failure. Similarly, because of privacy and functionality issues many app users are shifting from centralised to decentralised app schemes. The Trace Together app is an example of a centralised architecture used for contact tracing employed in Singapore. Similarly, COVID SAFE mobile apps adopted in in Australia is also using centralization-based approach.
• Decentralized contact tracing architecture In contrast to centralised architecture, decentralised architecture provides control to the user related to sharing of data with the central server based on the conditions. The decentralised approach is more privacy-preserving than the centralised contact-tracing approach. It keeps the identity of the mobile or user hidden from other users or servers. Processing and notification exposure is performed through devices. This approach does not require prior registration. But, the decentralised approach is more prone to attacks on a large scale owing to data [95]. Recently, Apple and Google implemented Bluetooth-based decentralised approach for contact tracing [96]. The working procedure and structures of two architectures suggested for contact tracing i.e. centralized and decentralized approaches a graphical form demonstrated for easy understanding in Fig 8. In the literature, many research works and surveys are available for the interest of researchers and readers to understand the applications of the COVID-19 apps in COVID-19 situations [94,[97][98][99][100][101][102].
Smartphone apps have also played a significant role in symptom reporting and diagnosis related to COVID-19. In this pandemic, it was the most difficult task to visit physically especially for elderly patients or patients suffering from chronic diseases. As, coronavirus virus is highly contagious and can worsen their health more. Therefore, it is imperative to monitor these patients remotely by healthcare professionals to provide continuous check-ups using mobile applications. Symptom monitoring applications have also been widely used to combat the pandemic. The major function of such apps is to collect information from the patients based on the questions asked about the identification of symptoms such as fever, cough type, travelling history and contacts with the infected individuals etc. In this regard, the best symptoms monitoring app is "COVID-19 Screening Tool" developed by Apple [103], which is supported by web and iOS platforms. This apps has other features such as self-isolation and social distancing.
Similarly, the CoV-SCR app presented by Yap et al. [104] is a web-based app, in which a patient can record his symptom severity based on a five-point scale. It allows patients to record his\her 14 days visiting history and daily information related to their symptoms and information related to contact tracing; and symptom tracking is sent via email. This app is intended to remove false negative and false positives arising from Bluetooth-and GPS-based tracking apps. The "COVID-19

Y. Ali and H.U. Khan
Symptom Tracker " app introduced in the UK and US is also significant to be mentioned as it was downloaded by 3 million mobile users [42]. Another app which is used by both countries using syndromic study known as the COVID Symptom Stud. It allows registered users to provide filling of daily questions related to medical history and to provide information related to COVID-19. The main purpose of this study was to understand the symptoms of coronavirus [105]. Similarly, the COVID RADAR symptom Tracker applies data collection to detect loss of smell and taste [106]. The AarogyaSetu app was developed in India is providing health services to people in the situation of coronavirus. It also has the potential to provide self-assessment [107].
Telemedicine is an important component of the modern healthcare system as it provides healthcare solutions by using digital technologies such as software or other infrastructures to diagnose, monitor, consult, manage, prescribe medication, and treat patient from remote distance via audio or video calls or messages in real time. Sometimes, people also call telemedicine as "telehealth" but there is a difference between the two terms. Telehealth is used in a broader sense while telemedicine is narrow and specific in nature; and it can be reckoned as its service [108]. Mobile applications have also played a central role in providing remote healthcare or telemedicine services to patient with COVID-19. Telemedicine leverages different apps to provide healthcare services. The virtual visits of patients have increased from 257% to 700 %. The most vital apps used in providing mental health services during COVID-19 employed are Virtual Hope Box, Calm, Headspace and Breathe-to-Relax, Chatbots and Woebot [109]. Similarly, video conferencing apps also played a central role in reducing the spreading of COVID-19. These apps provided face-to-face and real-time communication with high-quality audio and video quality. The most popular video conferencing apps are Zoom, Google Meet, WhatsApp, Skype and Google Duo [110]. Virtual software is used in telemedicine for remote patient monitoring of elderly patients and pregnant women in an effective, attractive and affordable way. In this pandemic, such a software programs provided good options against the spreading of COVID-19 in social distancing and quarantine. These software programs along with telemedicine support furnished healthcare services to outpatients from 8 PM to 6 AM. Like in Canada, virtual clinics have been established using software-based technologies to provide virtual visits to patients by minimising virus exposure during the COVID-19 pandemic [111]. The most common virtual software platforms i.e. Apple Siri, Google Voice and Amazon Alexa were adopted at home for treatment [112]. Similarly, MyChart, Google Duo, Facetime, Doximity and Skype were used by remote patient monitoring in the coronavirus pandemic. Although, there were some limitations or factors that affected the adoptions of virtual softwares. These limitation include funding factors [113,114], training [115], security issues [2], practitioners or patients willingness [116] and policy making issues [117].

C. Wireless communication technological support for COVID-19
Wireless networking and communication technologies constitute the backbone of mobile computing. Mobile computing leverages different wireless technologies in preventing the spread of COVID-19. Leading wireless communication technologies such as Bluetooth, Bluetooth Low Energy (BLE), Wi-Fi, ZigBee, RFID, QR codes, GPS, and 5G/5G+ have remained as catalysts in preventing the spread and alleviating the impacts of COVID-19 in the healthcare industry. These technologies have revolutionised the healthcare system by contributing to COVID-19 in different ways such as social distancing, quarantine, health monitoring and diagnosis, telemedicine, prevention of spread, contact tracing and health conferencing. In the following section, the significant role of various wireless communication technologies in the context of fighting against COVID-19 is briefly discussed.

i. BLE or Bluetooth technology
The ubiquitous nature, low cost and less energy consumption, make Bluetooth an ideal protocol for communication and data transmission during the pandemic. This is the major reason that medical practitioners and researchers embraced Bluetooth technology to monitor, diagnose, trace contacts and minimise the exposures related to Coronavirus. Bluetooth technology enables healthcare devices or gadgets to provide healthcare services and facilities but during the COVID-19 pandemic a sharp hike is seen in the adoption of Bluetooth-enabled wearable devices. It is also expected Bluetooth-based wearable gadgets or devices annual shipments in 2025 will be 104 million [118]. These medical devices include blood pressure monitors, pulse oximeters, glucose monitors, pulse oximeters and asthma inhalers which are used to transmit critical information to medical professionals for diagnosis and treatment. Bluetooth-based medical devices are helpful in maintaining a proper distance between physicians and nursing staff to strictly avoid the cross-infection The most significant roles played by Bluetooth are contact tracing, location and proximity. Bluetooth-based contact tracing is considered the best choice because of its low power, accuracy and minimum false positive rate [119]. According to a survey report presented by Guo et al. [120], Bluetooth accounts for 57% of contact tracing technologies in geopolitical and technical features [120].
The Bluetooth protocol has enormous applications in different architectures presented to combat COVID-19. Since 2014, Chinese engineers and healthcare professionals have been working on the development of a system known as deep brain simulation (DBS) to provide healthcare solutions to more than 20,000 patients. In this system, notes or vital parameters are sent or updated using Bluetooth technology [121]. Similarly, the majority of apps use Bluetooth technology for contact tracing, social distancing and quarantine purposes. The usability of Bluetooth and GPS-based contract tracing apps has impacted the scale at which the COVID-19 virus spread. These apps keep a catalogue of all visits, people and timestamp details. This leads to building a contact neighbourhood in identifying the potential risky contact, sending alerts and isolation. Similarly, BLE apps have unique IDs that are shared with other devices using this app. This ID is also known as contact, which is stored in local devices. If anyone is tested positive then the contacts are uploaded to the central repository and are altered. This ultimately saves time in contact tracing and thus reduces the spread of the virus [122]. Similarly, the study presented by Gorji et al. [123] is also related to the use of Bluetooth technology for contact tracing. The main focus of this study is to apply Bluetooth protocol for the identification and isolation of infected people in a particular region. The BLE technology has been used in the detector for detecting the contact within 6 feet proximity for 15 minutes. In the proposed work, BLE signal is used for evaluation and decision making regarding the "too close" or not. The strength of the signal determines the contact tracing of the devices [124]. The BLE technology has been applied by many researchers owing to its low power consumption, fast within a short range and being ideal for indoor environments [125]. To avoid social distancing and spreading of COVID-19, a framework for conditional risk assessment on personal area networks using Bluetooth has been proposed by Munir et al. [126]. Similarly, the Bluetooth technology has contributed towards the "digital handshake" that allows many apps in different counties such as Austria (Stopp-Corona), France (StopCovid), Poland (ProteGo) and app being developed in UK are leveraging the Bluetooth technology. Android and Apple in a joint venture are speculating to build a system which will enable Google and iOS devices and apps to use Bluetooth for contact tracing and to alert the user in case of nearby contact with COVID-19 patient [6,127]. The app presented by Hekmati et al. [128] known as CONTAIN, also uses Bluetooth technology for contact tracing with more focus on privacy preservation. Keeping the advantages of Bluetooth in mind, majority of COVID-19 mobile applications are leveraging it for contact tracing [129][130][131][132][133][134].
Although, the contact tracing performed via Bluetooth is cost effective, flexible, simple, efficient and supporting standard infrastructure [96]. However, there are still some privacy and security concerns with its application [47]. Some other limitations are related to very short range and can be obstructed by walls, buildings or other material obstacles which lead to a low adaptation rate. Bluetooth consumes a large amount of smartphone battery power as well [135]. It also requires a compatible app for others to record the exposure. If, mobile app is not used then it has limited potential utility [136]. The security and privacy is major concern, however, there is potential solution related to security problem known as building a privacy model for Bluetooth-based tracing based on five suggestions [137].

ii. Global Navigation Satellite System (GNSS)
Global Navigation Satellite System is constellation of satellites that provides global navigation and positioning. In GNSS, GPS is an important technology for addressing the impacts of COVID-19. It can be reckoned as a good option for contact tracing and vaccination rollout in order to tackle situations awakened due to COVID-19. It supports the analysis of people's moments, locations and their visited places. GPSbased contact tracing does not need app to be downloaded for its effectiveness. It also does not exchange any information by using some hardware as in case of Bluetooth [138]. GPS is a useful technology for identifying COVID-19 hotspots and tracking outbreaks. The geographical information system (GIS) and GPS provide real-time mapping and tracking through the analysis of the relationship of location coordinates [139]. It helps in tracking the COVID-19 positive person. It is also helpful in collecting and importing historical and redacted data to public health to reduce the spread of the epidemic [136]. For COVID-19 contact tracing, this technology has been used by drones to locate people [109]. GPS is used by different applications for isolation and alert notifications [140]. The use of smartphones for proximity tracing becomes practically useless but it can be used for geofencing in lockdown such that when a particular device leaves a certain area, an alert is sent via apps. GPS technology is also adopted by majority of COVID-19 mobile apps [129-131, 135, 141].
GPS technology suffers from security and vulnerability issues, such as spoofing attacks [135,142]. The GPS navigation system changes from satellite to satellite. So, satellite navigation system can also affected by interference and noise factors. GPS on a smartphone has an accuracy of approximately 5m [143]. Therefore, this feature makes it more ideal choice of contact tracing.

iii. QR code
Quick Response (QR) code is a machine-readable code where information is encoded in a two-dimensional matrix. Like, Bluetooth and GPS, it can be used for contact tracing in COVID-19 pandemics. The QR code is scanned by a mobile phone camera to trigger a particular action such as to direct to a website or open application, checking location, or connecting to a wireless network. These codes have good applications in healthcare environment especially in COVID-19 where smart phone after scanning the QR code, the users submit information related to basic health, living places and information related to whether they have come across infected person or suspected COVID-19 person in past 14 days [131]. QR code is also used by many countries for reducing the spread of the COVID-19 in the current pandemic. Asian countries such as China, Korea and Singapore have become the first group to use and track the spread of COVID-19. QR codes have been adopted in China to prevent the spread of COVID-19 and self-isolation. In Taiwan, the QR code is scanned by a traveller after filling the health declaration form. In Israel, QR codes are used in the four main testing stationary centres and eight driving testing centres of metropolitan cities to identify infected people [144]. Singapore is one of the first countries to use QR codes for contact tracing based on the SafeEntry application [145]. The Zwaai app [145] also uses a QR code for contact tracing, provides an alternative for GPS and Bluetooth. Similarly, app proposed by Biswas et al. [146] also uses QR codes and GPS for location finding and assists health workers in avoiding the entry into hotspot regions of symptomatic and asymptomatic people. In particular, a privacy-preserving app was presented by Yasaka et al. [147] is also using QR codes for contact tracing. A framework based on the QR code [148] implemented in Fujan was presented to contain the spread of coronavirus. This framework is working on the principle of without identifying the location of users. It also helps in risk exposure, healthcare appointments, health updates with the features of interoperability, traceability, quick and credibility to combat COVID-19. The most common COVID-19 mobile apps such as Zwaai, SafeEntry, TrackCOVID, LeaveHomeSafe [ and NZ COVID Tracer are using QR code technology for contact tracing [129,130,145].
Although, QR code is regarded as a convenient and prompt way of contact tracing COVID-19 but still there are some limitations associated with its usability. First, it has proximity and accuracy issues such that it can be scanned by any person by obtaining the code; and system scanning the QR code may produce incomplete and inaccurate data. Second, QR codes are normally intended for both check in and check out, normally check-in detail is obtained at the entry by scanning; however, this activity is not performed by people to check out, which leads to serious risk and incomplete data. Sometimes, QR codes listed in restaurants and bars do not work which leads to incomplete scanning [149]. QR codes are also susceptible to QR spoofing issues. These codes also have adaptation issues that many users do not use because their data will be misused by the government or other agencies.
In this study, we also examined and analyzed the literature to figure out the adoption of communication technologies for contact tracing. The detail of number of COVID-19 mobile apps using different technologies for contact tracing is given in Fig 9. In Fig 9, it is clear that Bluetooth has been used by widely as communication infrastructure by apps. Similarly, the details of all apps using different technologies like Bluetooth, QR code, GPS and Bluetooth are shown in Fig 10.

iv. Fifth Generation (5G)
5G networking with the features of software-defined networks, network function virtualisation and network slicing becomes an ideal network for providing healthcare services in the current COVID-19 pandemic. The role of 5G technologies in the context of fighting against the COVID-19 is of paramount importance. Among the list of top technologies such as artificial intelligence, IoT, Bigdata, cloud computing, 5G etc has proven to be more effective weapon against the COVID-19 pandemic [150]. 5G technologies span almost every dimension and field of life but in recent times, it has contributed to the healthcare domain, significantly. It enables video conferencing based on live interactions between physicians and patients. The physicians help their patients via video conferencing who are unable to visit hospitals. Especially in rural areas, where good medical specialists are not available [151]. China has introduced a 5G +-based remote consultation system in different hospitals that allows doctors to examine patients through video links [6]. According to a survey, 22 Chinese cities and provinces have adopted 5G technology to tackle COVID-19 [152]. Telemedicine powered by 5G, remote ultrasound and CT scanning were applied in order to tackle the dearth of medical staff in the most affected areas and to maintain social distancing to avoid transmission. 5G enabled platforms have been used for remote diagnosis and treatment without any significant cost [152].
The supply chain management of medicines and other medical equipments have been affected by the rapidly spreading coronavirus worldwide. The demand for drugs, ventilators, personal protective equipment, masks, hand sanitizers and vaccines have increased drastically. However, the production companies were unable to deliver the supply due to the restrictions imposed by law enforcement agencies. The delivery of such items to final consumers was negatively affected by the coronavirus disease. To address these issues, IoT-based supply chain management has been applied to track the product from the manufacturer to the final consumers. Unmanned aerial vehicle (UAV)-based delivery provided by 5G, helped the products to be dispatched to the final customers without any physical contact [7]. These UAVs with telemedicine support by utilising 5G technologies provide a low-latency, data analytics and efficient system for detecting the crowd, identifying infected people and treating them without human intervention [153]. In China, UAV technologies are used for the transportation of healthcare samples from one city to another city during the COVID-19 pandemic. These technologies can also be utilized for vaccination and blood transfer [154]. In China's Yunnan province, 5G enabled drones were used to instruct people to avoid gathering, furnishing hot meals and disinfecting from the sky [152]. 5G allowed the Chinese doctors to diagnosis the COVID-19 patients in Chengdu city for the first time by doing remote CT scanning. It enabled them to diagnose the patients at a distance of 700 KM. 5G technology-based robots are also helpful in healthcare automation during the COVID-19. These robots have been used for a variety of tasks such as checking temperature, disinfecting hospital rooms and minimising the exposure of hospital personnel to the virus. These robots can not only be used for collecting data but can also be used to send data to remote servers with value-added efficiency, reliability and low latency. Robots powered by 5G have also been deployed in Thailand to resist the coronavirus. They deployed 5G robots in 20 hospitals to amplify telemedicine services in COVID-19. These robots are communication methods and have the ability to perform thermal scanning [153]. Similarly, the Chinese government also installed intelligent and smart robots in the cities of Shangai and Wuhan  cities, respectively. They also introduced 5G enabled patrol robots to check the temperature in multiple cities in China. These robots used cameras and thermal sensors to identify people, who are not wearing masks and measuring the temperature. If anyone is found, then the target person is reported to the authorities [153]. During the pandemic, connectivity has become more crucial for awareness and the latest news about COVID-19. 5G technologies provide a high-speed broadband internet to upload data collected from various sensors and wearable devices to the servers.

v. ZigBee
Contribution provided by other short-range wireless technologies such as Wi-Fi, Zigbee and RFID has also been phenomenal with respect to handling the effects of COVID-19. Zigbee is an ideal wireless communication standard for social distancing and contact tracing owing to its low cost and low power capabilities [130]. In this regard, a work proposed by Bian et al. [155] presented a Field based Proximity Sensing and monitoring system for social distancing of ranging from 0 to 2.0 m in COVID-19 using ZigBee network infrastructure. To address the COVID-19 issues related to monitoring, testing and online healthcare services in COVID-19, a cognitive IoMT system [156] was introduced, where ZigBee technology has been used for collecting patient data from various sensors installed on the human body. A similar IoT-based framework is also presented by Roy et al. [157]. This framework is related to monitoring and contact tracing of COVID-19. In this proposed framework, a device which is unable to establish a D-2-D communication link with the phone server, then they use the Zigbee communication infrastructure to send data to the mobile phones.

vi. RFID
Radio frequency identification (RFID) is a wireless communication technology that uses electromagnetic fields to tag objects and transfer data. RFID system is comprising of RFID tags and scanners provide costeffective and efficient mechanism for matching or tracking objects. It has many applications in medical care systems such as patient monitoring [158,159], healthcare asset tracking/supply chain management [160], drug administration [161] and authentication security [162] [163]. However, in this pandemic, the application and demand for RFID has been significantly seen in the supply chain process. It provides transparent and improved traceability [164]. It can be used as an alternative to QR codes for contact tracing in workplaces and sporting events because of its low power consumption and readers with high power support [165]. The complete detail of adoption of RFID with respect to COVID-19 in terms of alleviating its impact is given in Table 4.
Although RFID technology has vast applications in the healthcare domain with respect to COVID-19, but it still has privacy and security threats. These threats target the tags, the channel of communication and ultimately the entire RFID system as well [177]. Likewise, RFID equipment may also interfere with other hospital equipments so it must be tested vigorously before deployment [167].

vii. Wi-Fi
Wi-Fi plays an important role because of its ability to maintain social distance in indoor environments. Social distancing in indoor environments is a challenging task owing to the unavailability of GPS signals. According to the survey, the usage of Wi-Fi significantly increased from 70% to 94%. Wi-Fi has become an important component of self-testing at home [178]. The Vcontact approach presented by Li et al. [179] is also based on IoT-based Wi-Fi signals for contact tracing.

Challenges and solutions
Although, mobile computing has provided many benefits in dealing with COVID-19 pandemic but still there are some challenges [180,181] in its adoption. These challenges are required to be addressed before making mobile computing as technological choice for addressing the healthcare issues during the pandemic. In this regard, we searched the literature thoroughly and identified challenges along with some practical solutions. As, we know that healthcare professionals are unaware about the risk-benefit analysis due to lack of technical knowledge in this area. In this study, we covered all the latest problems/challenges that may hinder the implementation of mobile computing. We provided comprehensive and pragmatic solution towards these challenges based on our extensive literature study. According to our literature study, the healthcare personnel might be facing some serious challenges related to adoption of mobile computing for COVID-19 pandemic. Such a challenges are related to availability, power and battery, network security and privacy, performance and compatibility, and adaptability. This study provides comprehensive solutions towards these challenges before making mobile computing a technological option for clinical applications in healthcare department. The detail of challenges along with solutions is given as.

A. Power and battery issues
The modern phones and mobile devices are no longer the devices that providing only phone calling services or restricted to single task but they have bigger screen, smart sensors and more computational hardware installed. However, such a technological advancement has also led to the battery consumption or drainage. The battery issue is considered as the biggest hindrance for smartphone. The wireless connection and mobile devices relay on power source. The depletion of battery has remained a major issues over the last few years in the field of mobile computing but during the COVID-19 smartphone apps related to contact tracing have exaggerated this issue. These apps are working to use different technologies such as GPS, QR-code and Bluetooth. The contact tracing COVID-19 apps working on GPS and Bluetooth, which may drain the batteries when they remain opened for long time on phones [145]. During the peak hours of pandemic, the well-known COVID Irish app Wearable band using RFID reciever Temprature sensing of contacted lists Silveira et al. [170] RFID tag-tatoo Human temprature sensing Abuelkhail et al. [171] IoT health monitirong system using RFID

Health monitoring system
Garg et al. [172] Blockchain and IoT model using RFID Transciever Contact tracing Sending exposure notification Isolation Oliveira et al. [173] Six-minute walk automation testing using RFID Health monitoring and testing post-Covid for cardiopulmonary patients Safkhani et al. [174] Lighweight security protocol using RFID based system Covid Tracker received a lot of complaints about the battery drainage and ultimately, it was uninstalled by many smartphone users.

i. Possible solutions
This issues related to the adoption of mobile computing in context of dealing with COVID-19 can be solved in three ways: (i) Building and using smart app (ii) Adoption of BLE technology for contact tracing and (iii) User awareness about battery charging and saving. The same issue can also be resolved by developing well-designed smart apps that conserve less power of smartphone or mobile device battery. Only those smartphone apps should be used that require BLE technology for contact tracing purposes. The less power consumption of BLE enable the contact tracing apps to for hours without depleting the batteries, secondly, BLE is more ideal for indoor environment and works well for limited distance contact tracing [125]. Another way of controlling power of Android devices through the context aware battery management. The user behaviour is also important for controlling the battery life and its efficiency [182]. The battery drainage problem comes as a result of smartphone users' behaviour as they are unaware of charging and saving of their smartphone batteries. Similarly, they should utilize the available battery saving setting and develop habits that save battery on the devices.

B. Security and privacy issues
Security and Privacy are another serious issues with adoption of mobile computing technologies by healthcare stakeholders during the pandemic. As, we know that the wireless communication is more vulnerable to risks than wired communication. The application of mobile computing technology during the COVID-19 pandemic can be suffered from issues like data leakage, security standard, connection interference, lack of encryption, outdated operating system security and poor mobile health apps security and privacy preserving issues.
The COVID-19 mobile health apps also ask the mobile users to grant access to the mobile devices. It results in giving invitation to the data leakage problem and vulnerabilities like data manipulation, theft and failure of single point. Furthermore, the collection of personal data by these apps becomes a major concern. Besides, the mobile apps also ask for permission to get access to the media, contacts, files, storage, files, location, phone ID, etc. Since, these apps are continuously gathering data so the privacy and security becomes a major concern and it needs to be solved [183]. Before installing these apps the reassurance is given but despite of it, cyber-attacks may be a serious concern due to the centralized storage of data. It makes them vulnerable to get access the sensitive data and disseminate it. The mobile apps which are using Bluetooth, are extremely susceptible to cyber-attack; and the security is dependent on the quality of mobile phone [184]. Similarly, the verification mechanism is missing to ensure that a particular person is really infected or not as it is more likely that there is malicious information is embedded in the app to create panic in the other users. This situation leads to reliability and trust issues related to the COVID-19 specific apps. The COVID-19 contact tracing apps are normally built by third parties with the support of government. These apps can get access to the real time location of users and user moments as well. There are also other concerns like excessive data collection, data usage policies and lack of user control [185]. The existing schemes employed in COVID-19 mobile health apps are not conforming the HIPAA (Health Insurance Portability and Accountability Act) and they are not providing enough end-to-end security [186] which make these mobile health apps vulnerable to many cyber risks.
The secure communication done through insecure communication link can be achieved by the encryption which is done in the software. The managing of encryption key is also a difficult task [187]. The mobile connected to the public network used by healthcare department can also be compromised. The virtual private network (VPN) is an option; but it can be attacked by the bulky list of networks connected with each other [188]. The public Wi-Fi network are also the entry point of hackers to get into the network and ultimately, accessing the network device. The hackers can also target the operating system through security patches. The sensitive data collected by mobile devices such as IoT sensors and drone is vulnerable to different security risks such as Denial of Service (DosS) attacks [189].

i. Possible solutions
To solve these issues related to security and privacy of mobile computing in context of COVID-19, the smartphone manufacturers will have to play a better role to overcome the vulnerabilities related to mobile operating system and firmware. For example, the Bluetooth vulnerabilities such as 'BlueFrag' CVE-2020-0022 affected the old versions of Android operating system for serval months. The Android version 8 are vulnerable, if they are using Bluetooth-based data exchange applications or contact tracing application. Therefore, it is necessary for smartphone vendors to release the critical system updates through the life cycle of smartphone devices [190].
Similarly, before installing the COVID-19 app it is imperative to check whether the app is offered by legitimate developer or not. Downloading of the apps from trusted apps store can also handle the security issues to much extent [191]. The mobile computing devices manufacturers and designers must be proactive regarding the releasing of security patches and operating system. All these apps need to be tested by different testing procedures before making them available for customers. OWASP is considered as best solution or tool to check the privacy and security requirement of apps [192]. The problems rising due to the technological advancement in mobile computing can also be avoided by cryptographic techniques [193]. The network infrastructures like s5G architectures should be focusing on the privacy-by-design. Similarly, hybrid approach should be adopted by the mobile operators for securing storing the sensitive data in cloud.
According to the study conducted by Ramirez [192] a mobile security analyst at NowSecure company (a software testing company) suggested some solutions and best practices for building the COVID-19 mobile apps. According to them for secure sending of data over network, all app developers should be encouraged to use hypertext transfer protocol(HTTPs) rather than HTTP. For anonymous authentication APIs like Firebase are recommended. Similarly, to differentiate between real and fake API request, API like reCAPTCHA can be used as add-on to avoid the cyberattacks. For the third party components, OWASP Dependency Check can also be used to identify the vulnerability components. The IoMT devices operating in healthcare domain can be protected by lightweight and scalable security mechanisms. Similarly, Big data, machine learning and artificial intelligence can be integrated to develop advanced security algorithms for detecting of vulnerabilities in 5G system.

C. Hesitancy in adoption of mobile technologies
As, 5G networking technologies contributed significantly during the pandemic by providing stream of connectivity services to the healthcare staff. But, one of the major issues and event that took place during the early stage of COVID-19 during the adoption of 5G mobile technologies was the misbelief and conspiracy theory. Although, 5G network infrastructure plays a pivotal role in healthcare automation, however, still there are some conspiracy theories attached in the adoption of 5G technology for COVID-19 outbreak. These theories were disseminated through social media platforms like Facebook and Twitter [194,195]. There are two theories as pointed out by the work presented by Meese et al. [196]. The first one is about lowering of the immune system due to the radiation caused by 5G, which ultimately, makes people more vulnerable to virus. The second theory states that 5G causes COVID-19 with multiple variations. These conspiracy theories hampered many people to adopt 5G as networking and communication infrastructure option, especially in countries like Australia, United Kingdom and United States.

i. Possible solutions
To address these conspiracy theories, study conducted by Jolley et al. [197] provided empirical background and solution to explain these conspiracy theories in light of anger and violent response. This misbelief was promoted on social media but later on it was reckoned as myth. The other solutions will be that 5G solutions require technical knowledge on the part of users.

D. Connectivity and network issues
With the rise of COVID-19 many hospitals and clinics adopted the online mode of treatment. This is why a sudden shift in paradigm has been witnessed during the COVID-19 by healthcare sector to adopt 5G or 6G technologies for fast, constant and unified services [198]. Similarly, during the COVID-19 lockdown network traffic has drastically increased due to social media usage, gaming, online treatment etc. [199]. Ultimately, it led to bandwidth issues and network congestion due to the high flow of traffic. Currently, more than 0.5% of the world's total energy is consumed by the mobile networks According to the reporting of Mitra et al. [200], the mobile networks are responsible for consuming the 0.5% of the world's energy. However, the commercial deployment of 5G is at the early stage of beginning [201]. The installation of the emerging technology infrastructure will take some time to reach out the remote and rural areas. During the COVID-19, the online medical and surgeries were delivered by the ophthalmologists with the support of virtual reality (VR) technology. The VR technology use cases enable them to use language translation services and play ultra HD videos. However, the average bandwidth required is below even in the developed countries [202]. Similarly, the existing hardware such as laptops, mobile computers and other devices are not enough to meet the network requirements. The mobile computers have fewer resources such as bandwidth, computational power and less battery power than the wired computer [187]. Thus, the legacy hardware will not be able to support the new emerging applications related to security and cloud-based technologies.

i. Possible solutions
The issues in the mobile network can be solved with the deployment of 5G technologies. In this regard, the network operators, 5G devices and government should come up with plans related to deployment. The device manufacturing companies should come forward to design affordable and cost effective devices. Furthermore, the deployment of 5G network should also be encouraged at small scale or local level like hospital, universities and factories to address the local and specific demands by sponsoring local spectrum licensing [16].

E. Performance and compatibility issues
The existing mobile technologies are not equipped with secure and efficient mechanisms of COVID-19 testing and vaccination process. During the testing and vaccination of COVID-19 in the hospitals a lot of entries are made by the frontline health workers and administrative staff such as it can lead to inaccurate data through the existing mobile devices such as laptop or smartphone. It can lead to the chance of contacting and delay due to lab processing. A smart solution is required to avoid the close contacts of patients and practitioners. Similarly, mMIMO antenna positioning is responsible for determining the beamforming gain/loss and beam management in the 5G mobile devices. It directly affects the device coverage and mobility performance [203]. Majority of the application employed in healthcare industry are not compatible with other application such as standalone apps. The data generated for the monitoring devices in standard format that allows the information to be managed and stored by different kinds of data stores. During the COVID-19 majority of users faced problems with contact tracing apps such as incompatibility with operating system and frequent crashes [204]. Similarly, there are certain COVID-19 apps that are incompatible devices like NHP app can be installed on different Android devices but it does not guarantee to provide the best experience [205].

i. Possible solution
The Zebra mobile devices provide reasonable solutions to deal with the health related issues such as avoiding manual entries for registration, collecting patient's data through car window, safe and efficient testing in the current COVID-19 scenario [206]. These devices can be used as valuable tools in vaccination distribution to manage the assets and patients. The smartphone app's developers should focus on building such a mobile apps that are compatible with mobile devices and operating systems after passing them through mobile app compatibility testing. Some of well-known mobile app compatibility testing methods that can be used to check the mobile apps compatibility with devices [207][208][209].

F. Availability issues
The deployment of 5G technology depends upon the availability of 5G devices. The limited availability and scarcity of 5G devices is also a challenging because of multiband support and heating issues [203]. The testing of 5G devices is complex process as it take into account many parameters such as quantifying the device performance and its interaction with network.

i. Possible solution
5G and IoT devices should be designed and deployed to provide faster speed, quality of service and bandwidth support. 5G-enabled devices and sensors should be introduced to keep the patients and practitioner connected by catering improved life quality, better and efficient healthcare solutions and reduced operational costs.
The issues faced by the mobile computing during the COVID-19 pandemic in healthcare department are given in Fig 11.

Conclusion
The COVID-19 has proven to be a serious threat for all countries due to its fast spreading nature around the globe. It has ravaged many fields of life but healthcare has been badly affected by this pandemic. Different strategies for its prevention have been adopted to reduce the impact and spread of this deadly virus. The technological supports are provided a diverse range of solutions such as IoT, augmented reality, virtual reality, block chain, artificial intelligence, machine learning and Big data. Among the leading technologies, the mobile computing role is also noteworthy. Mobile computing has contributed towards mitigating the effects and spread of the virus directly or indirectly. In this study, a comprehensive survey is presented to highlight the importance of mobile computing related to the coronavirus pandemic.
A state-of-the-art work is presented to highlight the significant role of mobile computing in tackling the impacts of COVID-19 from the healthcare perspective. Mobile computing is composed of three major components: (i) software (ii) hardware and (iii) wireless technological support. The individual roles of each component is explained briefly. In hardware-based support, the role of wearable devices such as smart sensors, smartphones, handheld devices etc. is discussed with respect to handling COVID-19 pandemics. The smartphone role is especially discussed in different areas of healthcare such as testing, health monitoring, contact tracing, telehealth, and social distancing related to handling the coronavirus. Various approaches using the support of smartphones are explained in the context of COVID-19 disease. The software-based solutions provided by mobile computing such as various applications, operating systems, mobile application platforms and APIs are discussed for contact tracing, telemedicine, social distancing, health monitoring and diagnosis. Different contact-tracing approaches using mobile applications are discussed. All the applications along with operating system support for contact tracing and social distancing are identified. Storing wireless mobile technologies such as GPS, Bluetooth, QR code, 5G, RFID and Wi-Fi are highlighted to cope with COVID-19 pandemics. The limitations and challenges faced in adopting the mobile computing technologies to curtail the spread of the deadly virus are discussed along with the proposed solution based on our literature study.

Declaration of Competing Interest
We declare that this article has not been published previously and is not simultaneously submitted for publication in another journal or conference. We have no conflicts of interests to disclose.

Data availability
Data will be made available on request. Yasir Ali receives his MPHIL degree with distinction in Computer Science from the University of Swabi, KP Pakistan. He completed his M.Sc. degree in computer science from Department of Computer Science, University of Peshawar, KPK, Pakistan, in 2011. He has three years of research experience and ten years of teaching experience in government and private institutions. He is currently working as a Lecturer in the Government Degree College, Kotha Swabi. He was nominated for Culture Exchange Scholarship in 2017. His research interests include the Internet of Things, Mobile Computing, Augmented Reality, Network Security and Evaluation. He has published many research articles in well reputed journals and some are under review.
Habib Ullah Khan received a Ph.D. degree in management information systems from Leeds Beckett University, U.K. He is working as a Professor of Management Information Systems with the Department of Accounting and Information Systems, College of Business and Economics, Qatar University, Qatar. He has nearly 20 years of industry, teaching, and research experience. His research interests include IT adoption, social media, Internet addiction, mobile commerce, computer mediated communication, IT outsourcing, big data, and IT security.