CTIS 487: Lecture Notes 1

Transcription

1 CTIS 487: Lecture Notes 1 Mobile phones got their name due to the fact that they allow users to make phone calls while being mobile. The communication architecture was dominated by base stations communicating with the mobile phones. Base stations were needed to enter the existing telephone networks and allowed users to communicate with fixed line communication partners. Furthermore, the base stations and the connected backbone allowed customers to communicate with other mobile users in different cells. The early mobile networks were analog systems and were referred to as first generation (1G) networks. They were only capable of providing voice services to its users. With the second generation (2G), changing from analog mobile systems to digital ones, enhanced services were introduced such as the short message service (SMS) and limited data connections to the Internet. Due to an increase in demand for high data rate applications there was a need to move to faster and efficient networks. The 3G system evolved which promises to provide wide area wireless voice telephone, video calls, Mobile TV and wireless data, all in a mobile environment. Today's 3G systems can in practice offer up to 14.0 Mbit/s on the downlink and 5.8 Mbit/s on the uplink. Now we are talking about beyond 3G networks. These networks aim to provide even higher data rates with improved quality of service (QoS) with high speed mobility. DATA SERVICES General packet radio service (GPRS) is a packet oriented mobile data service available to users of the 2G cellular communication systems global system for mobile communications (GSM), as well as in the 3G systems. In 2G systems, GPRS provides data rates of kbit/s. GPRS data transfer is typically charged per megabyte of traffic transferred, while data communication via traditional circuit switching is billed per minute of connection time, independent of whether the user actually is using the capacity or is in an idle state. GPRS is a best effort packet switched service, as opposed to circuit switching, where a certain QoS is guaranteed during the connection. Enhanced Data rates for GSM Evolution (EDGE) (also known as Enhanced GPRS (EGPRS), is a backward compatible digital mobile phone technology that 1

2 allows improved data transmission rates, as an extension on top of standard GSM. EDGE is considered a 3G radio technology. EDGE provides more than three fold increase in both the capacity and performance of GSM/GPRS networks. It does this by introducing sophisticated methods of coding and transmitting data, delivering higher bit rates per radio channel. EDGE can be used for any packet switched application, such as an internet connection. EDGE delivered data services create a broadband internet like experience for the mobile phone user. High bandwidth data applications such as video services and other multimedia benefit from EGPRS' increased data capacity. MOBILE MARKET The mobile market can be divided into four different players, namely the customer as the main target of the business, the network providers enabling to convey bits toward the customer, the service provider, and the mobile phone manufacturer. The most dominating one is the relationship between network providers and mobile phone manufacturers. To attract customers, the network providers bundle their contracts with a mobile phone, both being renewed within a given period. This ensures the mobile phone manufacturers sell a huge number of mobile phones. On the other side, the network operators also pull strings as to which services and applications are available on the mobile phone. Furthermore the network operator also controls which services are going over their network and makes the service provider dependent on the network operators decision. Please note that this relationship should be taken into account while making novel applications for mobile phones. The dominating position of the network provider is getting weaker as the monopoly of the cellular communication link is destroyed by wireless technologies such as wireless local area network (WLAN) and Bluetooth. These types of communication enable the creation of new type of services without tight coupling with the network operator. Mobile phone manufacturers are forced by the operators to keep this new freedom under control. Third party developers seem to have a lot of freedom in the programming. But sometimes when it comes to the sensitive parts of the network operator, the mobile phone is not that flexible anymore (e.g., VOIP services). Another example for a possible restriction is the strict coupling of the IP protocol with the GPRS module. IP over Bluetooth or WLAN is either not supported or very difficult to use in some mobile phones. But these restrictions should not stop us from making interesting services, they cost only time. 2

3 SERVICE TYPES Personal services encompass all services, which are used by the customer on the phone with limited or no interaction with other customers. The community services are different in the interaction with other customers. These services are those made to interact with other people. Both, the personal and the community services, are separated into services with and without wireless network support. The figure shown below provides a graphical representation. 3

4 MOBILE DEVICE ARCHITECTURE The mobile phone platform has become more and more flexible for third party developers. The first programming language on the mobile phone was JAVA and now there are several ways to implement an application on the phone. As given in the above figure the applications run in the application suite. The user interface framework hosts all functionalities that let us operate the mobile device. The mobile phone manufacturer offers access to their platforms (with some restriction) using their kernel and hardware drivers (e.g., Symbian OS) to access the hardware platform. So nearly anything that is in software can be changed on the mobile. The only static part of the phone is the hardware platform. Beside the programming capabilities of the mobile phone, there are even more different capabilities and functionalities on a mobile device. We can group them in a smart mobile phone into three classes, namely user interfaces, communication interfaces, and built in resources. The user interfaces comprise typically the speaker, microphone, camera, display, built in sensors, and keyboard capabilities. 4

5 The built in terminal resources include the battery, the central processing unit, and the data storage. The communication interfaces typically include cellular and short range capabilities. SMARTPHONE MARKET SHARE A smartphone is a mobile phone that offers more advanced computing ability and connectivity than basic features. A smart cell phone may have a microphone, a numeric keypad and or touch screen, a display, a camera, sensors, a transmitter and receiver, a battery with a certain lifetime, a processor, some memory and wireless network capabilities. 5

6 According to a recent survey the market share of 2010 Q1 smartphone shipments by operating system is as follows: Figure taken from Wikipedia ( 6