With the help of architecture give the overview of mobile cloud.
From the concept of MCC, the general architecture of MCC can be shown in Figure 1. In Figure 1, mobile devices are connected to the mobile networks via base stations (e.g., base transceiver station, access point, or satellite) that establish and control the connections (air links) and functional interfaces between the networks and mobile devices. Mobile users' requests and information (e.g., ID and location) are transmitted to the central processors that are connected to servers providing mobile network services. Here, mobile network operators can provide services to mobile users as authentication, authorization, and accounting based on the home agent and subscribers' data stored in databases. After that, the subscribers' requests are delivered to a cloud through the Internet. In the cloud, cloud controllers process the requests to provide mobile users with the corresponding cloud services. These services are developed with the concepts of utility computing, virtualization, and service‐oriented architecture (e.g., web, application, and database servers).
Figure 1:-Mobile cloud computing architecture.
The details of cloud architecture could be different in different contexts. For example, a four‐layer architecture is explained in 8 to compare cloud computing with grid computing. Alternatively, a service‐oriented architecture, called Aneka, is introduced to enable developers to build. Microsoft.NET applications with the supports of application programming interfaces (APIs) and multiple programming models . presents an architecture for creating market‐oriented clouds and proposes an architecture for web‐delivered business services. In this paper, we focus on a layered architecture of CC (Figure 2). This architecture is commonly used to demonstrate the effectiveness of the CC model in terms of meeting the user's requirements .
Figure 2 :- Service‐oriented cloud computing architecture.
Generally, a CC is a large‐scale distributed network system implemented based on a number of servers in data centers. The cloud services are generally classified based on a layer concept (Figure 2). In the upper layers of this paradigm, Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) are stacked.
- Data centers layer. This layer provides the hardware facility and infrastructure for clouds. In data center layer, a number of servers are linked with high‐speed networks to provide services for customers. Typically, data centers are built in less populated places, with a high power supply stability and a low risk of disaster.
- IaaS. Infrastructure as a Service is built on top of the data center layer. IaaS enables the provision of storage, hardware, servers, and networking The client typically pays on a per‐use basis. Thus, clients can save cost as the payment is only based on how much resource they really use. Infrastructure can be expanded or shrunk dynamically as needed. The examples of IaaS are Amazon Elastic Cloud Computing and Simple Storage Service (S3).
- PaaS. Platform as a Service offers an advanced integrated environment for building, testing, and deploying custom applications. The examples of PaaS are Google App Engine, Microsoft Azure, and Amazon Map Reduce/Simple Storage Service.
- SaaS. Software as a Service supports a software distribution with specific requirements. In this layer, the users can access an application and information remotely via the Internet and pay only for that they use. Salesforce is one of the pioneers in providing this service model. Microsoft's Live Mesh also allows sharing files and folders across multiple devices simultaneously.
Although the CC architecture can be divided into four layers as shown in Figure 2, it does not mean that the top layer must be built on the layer directly below it. For example, the SaaS application can be deployed directly on IaaS, instead of PaaS. Also, some services can be considered as a part of more than one layer. For example, data storage service can be viewed as either in IaaS or PaaS. Given this architectural model, the users can use the services flexibly and efficiently.
Advantages of mobile cloud computing
Cloud computing is known to be a promising solution for MC because of many reasons (e.g., mobility, communication, and portability ). In the following, we describe how the cloud can be used to overcome obstacles in MC, thereby pointing out advantages of MCC.
- Extending battery lifetime. Battery is one of the main concerns for mobile devices. Several solutions have been proposed to enhance the CPU performance and to manage the disk and screen in an intelligent manner 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.
- Improving data storage capacity and processing power. Storage capacity is also a constraint for mobile 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 which supports file storage service. Another example is Image Exchange which utilizes the large storage space in clouds for mobile users. This 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 the cloud, the users can save considerable amount of energy and storage space on their mobile devices because all images are sent and processed on the clouds. Mobile cloud computing also helps in reducing the running cost for compute‐intensive applications that take long time and large amount of energy when performed on the limited‐resource devices. CC can efficiently support various tasks for data warehousing, managing and synchronizing multiple documents online. For example, clouds can be used for transcoding , playing chess , or broadcasting multimedia services to mobile devices. In these cases, all the complex calculations for transcoding or offering an optimal chess move that take a long time when perform on mobile devices will be processed efficiently on the cloud. Mobile applications also are not constrained by storage capacity on the devices because their data now is stored on the cloud.
- Improving reliability. Storing data or running applications on clouds is an effective way to improve the reliability because 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 . Also, the cloud can remotely provide to mobile users with security services such as virus scanning, malicious code detection, and 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:
- 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.
- Scalability. The deployment of mobile applications can be performed and scaled to meet the unpredictable user demands due to flexible resource provisioning. Service providers can easily add and expand an application and service without or with little constraint on the resource usage.
- Multitenancy. Service providers (e.g., network operator and data center owner) can share the resources and costs to support a variety of applications and large number of users.
- Ease of integration. Multiple services from different service providers can be integrated easily through the cloud and Internet to meet the user demand.
APPLICATIONS OF MOBILE CLOUD COMPUTING
Mobile applications gain increasing share in a global mobile market. Various mobile applications have taken the advantages of MCC. In this section, some typical MCC applications are introduced.
