A Review and Research towards Mobile Cloud Computing

Dipayan Dev1 Krishna Lal Baishnab2

M.Tech, Computer Science and Engineering 1 Assistant Professor 2 National Institute of Technology, Silchar1 National Institute of Technology, Silchar2 dev.dipayan16@gmail.com1 klbaishnab@gmail.com2

Abstract: With an explosive growth of the mobile applications and emerging of cloud computing concept, the Mobile Cloud Computing (MCC) has become a potential technology for the mobile service users. MCC integrates the technology of cloud computing with mobile environment and has taken part of major discussion thread in the IT world since 2009. The ABI Research predicts that the number of mobile cloud computing subscribers is expected to grow from 42.8 million (1.1% of total mobile users) in 2008 to 998 million (19% of total mobile users) in 2014. Despite of this hype achieved by mobile cloud computing, the growth of mobile cloud computing subscribers is still below expectations. According to the recent survey conducted by the International Data Corporation, most IT Executives and CEOs are not interested in adopting such services due to the drawbacks associated with this (e.g., battery life, storage, and bandwidth), environment (e.g., heterogeneity, scalability, and availability), and security (e.g., reliability and privacy). In spite of various efforts to overcome these, there are a number of loopholes and challenges that still exist in the security policies of mobile cloud computing. This paper will give a review of various challenges in this field and measures to overcome such.

Keywords-Cloud computing; Mobile computing; Virtualization; Offloading

I. INTRODUCTION Mobile devices (e.g., Smartphone, tablet pcs,

etc) are increasingly becoming an essential part of human life as the most effective and convenient communication tools not bounded by time and place. Mobile users accumulate rich experience of various services from mobile applications, which run on the devices and/or on remote servers via wireless networks. The rapid progress of mobile computing (MC) [1] becomes a powerful trend in the development of IT technology as well as commerce and industry fields. However, the mobile devices are facing many challenges in their resources (e.g., battery life, storage, and bandwidth) and communications (e.g., mobility and security) [2]. The limited resources significantly impede the improvement of service qualities. On the other hand, advances in the field of network based computing and applications on demand have led to an explosive growth of application models such as cloud computing, software as a service,

community network, web store, and so on. As a major application model in the era of the Internet, the term, Cloud Computing (CC) has become a significant research topic of the scientific and industrial communities since 2007. Commonly, cloud computing is described as a range of services which are provided by an Internet-based cluster system. Such cluster systems consist of a group of low-cost servers or Personal Computers (PCs), organizing the various resources of the computers according to a certain management strategy, and offering safe, reliable, fast, convenient and transparent services such as data storage, accessing and computing to clients. According to the top ten strategic technology trends for 2012 [3] provided by Gartner (a famous global analytical and consulting company), cloud computing has been on the top of the list. So, with the explosion of mobile applications and the taking support of CC for a variety of services for mobile users, mobile cloud computing (MCC) is introduced as an integration of cloud computing into the mobile environment. Mobile cloud computing brings new types of services and facilities for mobile users to take full advantages of cloud computing. As the development of cloud computing is going too fast, resources in mobile cloud computing networks are virtualized and assigned in a group of numerous distributed computers rather than in traditional local computers or servers, and are provided to mobile devices such as smartphones, portable terminal, and so on.

Figure1. Mobile Cloud Computing

2014 2nd IEEE International Conference on Mobile Cloud Computing, Services, and Engineering

978-1-4799-4425-5/14 $31.00 © 2014 IEEE

DOI 10.1109/MobileCloud.2014.41

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II. HOW MOBILE CLOUD COMPUTING WORKS

A. Architecture for Mobile Applications in Cloud Environment: We start our MCC with an open source project for mobile cloud platform called openmobster [4]. Its architecture is as given in the Figure 2.

Figure 2: [4] The openmobster architecture for MCC

B. Typical services needed by a mobile cloud client:The most essential services include:

� Sync: This service synchronizes all state changes made to the mobile or its applications back with the Cloud Server.

� Push: It manages any state updates being sent as a notification from the cloud server. This improves the user’s

experience as it does not require the user to pro-actively check for new information.

� OfflineApp: It is a service which carries the management capabilities to create smart coordination between low-level services like Sync and Push. It frees the programmer from the burden of writing code to actually perform synchronization as it is this service which decides synchronization management and mechanism which is best for the current state. The moment the data channel for any mobile application is established, all synchronizations and push notifications are automatically handled by OfflineApp service.

� Network: It manages the communication channel needed to receive Push notifications from the server. It carries the ability to establish proper connections automatically. It is a very low-level service and it shields any low-level connection establishment, security protocol details by providing a high level interfacing framework.

� Database: It manages the local data storage for the mo-bile applications.

Depending on the platform it uses the corresponding storage facilities. It must support storage among the various mobile applications and must ensure thread safe concurrent access. Just like Network service it is also a low-level service.

� InterApp Bus: This service provides low-level coordination/communication between the suites of applications installed on the device.

Figure 3 shows the client cloud stack.

Figure 3: [4] Client cloud stack

C. Typical services needed by a mobile cloud server:

These are the essential services that must be provided to the mobile apps by the server.

� Sync: Server Sync service synchronizes device side App state changes with the backend services where the data actually originates. It also must provide a plug-inframework to mobilize the backend data.

� Push: Server Push service monitors data channels (from backend) for updates. The moment updates are detected, corresponding notifications are sent back to the device. If the device is out of coverage or disconnected for some reason, it waits in a queue, and delivers the push the moment the device connects back to the network.

� Secure Socket-Based Data Service:Depending on the security requirements of the Apps this server side service must provide plain socket server or a SSL-based socket server or both.

� Security: Security component provides authentication and authorization services to make sure mobile devices connecting to the Cloud Server are in fact allowed to access the system. Every device must be first securely provisioned with the system before it can be used. After the device is registered, it is challenged for proper credentials when the device itself needs to be activated. Once the device is activated, all Cloud requests are properly

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authenticated/authorized going. � Management Console: Every instance of a

Cloud Server must have a Command Line application such as the Management Console as it provides user and device provisioning functionalities. In the future, this same component will have more device management features like remote data wipe, remote locking, remote tracking, etc.

Figure 4 shows the mobile server cloud stack.

Figure 4: [4] Mobile server cloud stack

III. ADVANTAGE OF MOBILE CLOUD COMPUTING

Cloud computing is known to be a promising solution for mobile computing due to many reasons (e.g., mobility, communication, and portability [5]). In the following, it describes how the cloud can be used to overcome obstacles in mobile computing, thereby pointing out advantages of MCC.

A. Extending battery lifetime Battery is one of the main concerns for mobile devices. Several solutions have been proposed to enhance the CPU performance [6] and to manage the disk an intelligent manner [7] to reduce power consumption. However, these solutions require changes in the structure of mobile devices, or they require a new hardware that results in an increase of cost and may not be feasible for all mobile devices. Computation offloading technique is proposed with the objective to migrate the large computations and complex processing from resource-limited devices (i.e., mobile devices) to resourceful machines (i.e., servers in clouds). This avoids taking a long application execution time on mobile devices which results in large amount of power consumption. [8] evaluates the effectiveness of offloading techniques through several experiments. The results demonstrate that the

remote application execution can save energy significantly. In addition, many mobile applications take advantages from task migration and remote processing. For example, using memory arithmetic unit and interface (MAUI) to migrate mobile game components [9] to servers in the cloud can save 27% of energy consumption for computer games and 45% for the chess game.

B. Improving data storage capacity and processing power: Storage capacity is also a constraint for mobile devices. MCC is developed to enable mobile users to store/access the large data on the cloud through wireless networks. First example is the Amazon Simple Storage Service (Amazon S3) [10] which supports file storage service. Mobile photo sharing service enables mobile users to upload images to the clouds immediately after capturing. Users may access all images from any devices. With cloud, the users can save considerable amount of energy andstorage space on their mobile devices since all images are sent and processed on the clouds. Facebook is the most successful social network application today, and it is also a typical example of using cloud in sharing images. Cloud computing can efficiently support various tasks for data warehousing, managing and synchronizing multiple documents online. Mobile applications also are not constrained by storage capacity on the devices because their data now is stored on the cloud). C. Improving reliability Storing data or running applications on clouds is an effective way to improve the reliability since the data and application are stored and backed up on a number of computers. This reduces the chance of data and application lost on the mobile devices. In addition, MCC can be designed as a comprehensive data security model for both service providers and users. For example, the cloud can be used to protect copyrighted digital contents (e.g., video, clip, and music) from being abused and unauthorized distribution [11]. Also, the cloud can remotely provide to mobile users with security services such as virus scanning, malicious code detection, and authentication [12]. Also, such cloud-based security services can make efficient use of the collected record from different users to improve the effectiveness of the services. In addition, MCC also inherits some advantages of clouds for mobile services as follows:

a) Dynamic provisioning: Dynamic on-demand provisioning of resources on a fine-grained, self-service basis is a flexible way for service providers and mobile users to run their applications without advanced reservation of resources.

b) Scalability: The deployment of mobile applications can be performed and scaled to meet the unpredictable user demands due to flexible

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resource provisioning. Service providers can easily add and expand an application and service without or with little constraint on the resource usage.

c) Multi-tenancy: Service providers (e.g., network operator and data centre owner) can share the resources and costs to support a variety of applications and large number of users.

d) Ease of Integration: Multiple services from different service providers can be integrated easily through the cloud and the Internet to meet the user’s demands.

IV. CHALLENGES IN MOBILE CLOUD COMPUTING

The main objective of mobile cloud computing is to provide a convenient and rapid method for users to access and receive data from the cloud, such convenient and rapid method means accessing cloud computing resources effectively by using mobile devices. The major challenge of mobile cloud computing comes from the characters of mobile devices and wireless networks, as well as their own restriction and limitation, and such challenge makes application designing,programming and deploying on mobile and distributed devices more complicated than on the fixed cloud device. In mobile cloud computing environment, the limitations of mobile devices, quality of wireless communication, types of application, and support from cloud computing to mobile are all important factors that affect assessing from cloud computing. Table 1 gives an overview of proposed challenges and some solutions about mobile cloud computing. A. Limitations of mobile devices While discussing mobile devices in cloud the first

thing is resource-constrain. Though smartphones have been improved obviously in various aspects such as capability of CPU and memory, storage, size of screen, wireless communication, sensing technology, and operation systems, still have serious limitations such as limited computing capability and energy resource, to deploy complicated applications. By contrast with PCs and Laptops in a given condition, these smartphones like iPhone 4S, Android serials, Windows Mobile serials decrease 3 times in processing capacity, 8 times in memory, 5 to 10 times in storage capacityand 10 times in network bandwidth. Normally, smart phone needs to be charged everyday as dialling calls, sending messages, surfing the Internet, community accessing, and other internet applications. According to past development trends, the increased mobile computing ability and rapid development of screen technology will lead to more and more complicated applications deployed in smartphones. If the battery technology cannot be improved in a short time, then how to

effectively save battery power in smart phone is a major issue we meet today. The processing capacity, storage, battery time, and communication of those smartphones should be improved consistently with the development of mobile computing. However, such enormous variations will persist as one of major challenges in mobile cloud computing.

TABLE I CHALLENGES AND SOLUTIONS OFMOBILE CLOUD COMPUTING

B. Quality of communication In contrast with wired network uses physical

connection to ensure bandwidth consistency, the data transfer rate in mobile cloud computing environment is constantly changing and the connection is discontinuous due to the existing clearance in network overlay. Furthermore, data centre in large enterprise and resource in Internet service provider normally is far away to end users, especially to mobile device users. In wireless network, the network latency delay may 200 ms in ’last mile’ but only 50 ms in traditional wired network. Some other issues such as dynamic changing of application throughput, mobility of users, and even weather will lead to changes in bandwidth and network overlay. Therefore, the handover delay in mobile network is higher than in wired network

C. Division of Application Services In order to dynamically shift the computation

between mobile device and cloud, applications needed to be split in loosely coupled modules interacting with each other. The modules are dynamically shifted between mobile devices and cloud depending on the several metric parameters modelled in cost model [15] .These parameters can include the module execution time, resource consumption, battery level, monetary costs, security or network bandwidth. User waiting time, which is a key aspect here i.e. the time a user, waits from invoking some actions on the device’s

Challenges Solutions

Limitations of mobile devicesImprovement of processing

capacity, storage, battery time of mobile devices

Quality of communication Bandwidth upgrading, Data delivery time reducing

Division of applications services

Fast optimization algorithm techniques based on which tasks to be shifted onto the

remote servers

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interface until a desired output or exception are returned to the user.

Figure 5: Cost model of elastic mobile cloud applications Cost Model: The cost model takes inputs from both device and cloud, and runs optimization algorithms to decide execution configuration of applications(Fig. 5). Zhang et al. [13] use Na¨ıve Bayesian

Learning classifiers to find the optimal execution configuration from all possible configurations with given CPU, memory and network consumption, user preferences, and log data from the application. Guirgiu et al. [14] model the application behaviour through a resource consumption graph. Every bundle or module composing the application has memory consumption, generated input and output traffic, and code size. Application’s distribution

between the server and phone is then optimized. The server is assumed to have infinite resources and the client has several resource constraints. The partitioning problem seeks to find an optimal solution in the graph satisfying an objective function and device’s constraints. The objective

function tries to minimize the interactions between the phone and the server, while taking into account the overhead of acquiring and installing the necessary bundles. However, optimization involving many interrelated parameters in the cost model can be time or computation consuming, and even can override the cost savings. Therefore, approximate and fast optimization techniques involving prediction are needed. The model could predict costs of different partitioning configurations before running the application and deciding on the best one.

V. CONCLUSION

Mobile cloud computing is one of major mobile technology trends in the future since it combines the advantages of both mobile computing and cloud computing, thereby providing optimal services for mobile users. The concept of cloud computing provides a brand new opportunity for the development of mobile applications since it allows the mobile devices to maintain a very thin layer for user applications and shift the computation and processing overhead to the virtual environment.This paper covered several representative mobile

cloud approaches. Much other related works exist,but the purpose of this paper is to give an overview of the wide spectrum of mobile cloud computing possibilities. None of the existing approaches meets completely the requirements of mobile clouds. Mobile cloud computing will be a source of challenging research problems in information and communication technology for many years to come. Solving these problems will require interdisciplinary research from systems and networks.

REFERENCES [1] M. Satyanarayanan, “Mobile computing: the next decade,” in Proceedings of the 1st ACM Workshop on Mobile Cloud Computing & Services: Social Networks and Beyond (MCS), June 2010. [2] M. Satyanarayanan, “Fundamental challenges in mobile

computing,” in Proceedings of the 5th annual ACM symposium on Principles of distributed computing, pp. 1-7, May 1996. [3]M. Cooney. (2011, Oct) Gartner: The top 10 strategic technology trends for 2012. [Online]. Available:http://www.networkworld.com/news/2011/101811-gartner-technology-trends-252100.html [4]https://code.google.com/p/openmobster/w/list [5]G. H. Forman and J. Zahorjan,“The Challenges of Mobile Computing,” IEEE Computer Society Magazine, April 1994.

[6]R. Kakerow, “Low power design methodologies for mobile

communication,” in proceedings of IEEE International Conference on Computer Design: VLSI in Computers and Processors, pp. 8, January 2003. [7]R. N. Mayo and P. Ranganathan, “Energy Consumption in Mobile Devices: Why Future systems Need Requirements Aware Energy Scale-Down,” in Proceedings of the Workshop on Power-Aware Computing Systems, October 2003. [8]A. Rudenko, P. Reiher, G. J. Popek, and G. H. Kuenning, “Saving portable computer battery power through remote process execution,” Journal of ACM SIGMOBILE on Mobile Computing and Communications Review, vol. 2, no. 1, January 1998. [9]E. Cuervo, A. Balasubramanian, Dae-ki Cho, A. Wolman, S. Saroiu, R. Chandra, and P. Bahl, “MAUI: Making Smartphones

Last Longer with Code offload,” in Proceedings of the 8th

International Conference on Mobile systems, applications, and services, pp. 49-62, June 2010. [10]http://aws.amazon.com/s3/ [11]P. Zou, C. Wang, Z. Liu, and D. Bao, “Phosphor: A Cloud Based DRM Scheme with Sim Card,” in Proceedings of the

12th International Asia-Pacific on Web Conference (APWEB),pp. 459, June 2010. [12]J. Oberheide, K. Veeraraghavan, E. Cooke, J. Flinn, and F. Jahanian. “Virtualized in-cloud security services for mobile devices,” in Proceedings of the 1st Workshop on virtualization in Mobile Computing (MobiVirt), pp. 31-35, June 2008. [13]X. Zhang, S. Jeong, A. Kunjithapatham, and Simon Gibbs, “Towards an Elastic Application Model for Augmenting Computing Capabilities of Mobile Platforms,” in The Third

International ICST Conference on MOBILe Wireless MiddleWARE, Operating Systems, and Applications, Chicago, IL, USA, 2010. [14]I. Giurgiu, O. Riva, D. Juric, I. Krivulev, and G. Alonso, “Calling the Cloud: Enabling Mobile Phones as Interfaces to Cloud Applications,” in

Proceedings of the 10th ACM/IFIP/USENIX International Conference on Middleware (Middleware ’09). Urbana

Champaign, IL, USA: Springer, Nov. 2009, pp. 1–20. [15] Mobile Cloud Computing: A Comparison of Application Models.Dejan Kovachev, Yiwei Cao and Ralf Klamma

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