MCA Articles - Page 78 of 94

Fourth Generation (4G) mobile phones provides broadband cellular network services and is successor to 3G mobile networks. It provides an all IP based cellular communications. The capabilities provided adhere to IMT-Advanced specifications as laid down by International Telecommunication Union (ITU).FeaturesIt provides an all IP packet switched network for transmission of voice, data, signals and multimedia.It aims to provide high quality uninterrupted services to any location at any time.As laid down in IMT-Advanced specifications, 4G networks should have peak data rates of 100Mbps for highly mobile stations like train, car etc., and 1Gbps for low mobility stations like residence etc.It also ... Read More

CDMA2000 is a code division multiple access (CDMA) version of IMT-2000 specifications developed by International Telecommunication Union (ITU). It includes a group of standards for voice and data services − Voice − CDMA2000 1xRTT, 1X Advanced Data − CDMA2000 1xEV-DO (Evolution-Data Optimized) Features CDMA2000 is a family of technology for 3G mobile cellular communications for transmission of voice, data and signals. It supports mobile communications at speeds between 144Kbps and 2Mbps. It has packet core network (PCN) for high speed secured delivery of data packets. It applies multicarrier modulation techniques to 3G networks. This gives higher ... Read More

Enhanced Data-rates for GSM Evolution (EDGE) is an improved version of GSM providing higher data transmission rate than GSM, while being compatible with the older systems. Features It was standardized by 3GPP as a part of GSM family and was deployed in GSM networks in 2003. The other names for EDGE are Enhanced GPRS (EGPRS) and IMT-Single Carrier (IMT-SC). It is compatible with any packet – switched application. It is also backward – compatible, i.e. compatible with existing or older versions. It enables data to be sent over a GSM TDMA systems at speeds of 384Kbps. GSM uses the ... Read More

Third generation mobile phones, or “3G Internet” mobile phones, is a set of standards for wireless mobile communication systems, that promises to deliver quality multimedia services along with high quality voice transmission.Features3G systems comply with the International Mobile Telecommunications-2000 (IMT-2000)specifications by the International Telecommunication Union (ITU).The first 3G services were available in 1998.It provides high speed transmission having data transfer rate more than 0.2Mbps.Global roaming services are available for both voice and data.It offers advanced multimedia access like playing music, viewing videos, television services etc.It provides access to all advanced Internet services, for example surfing webpages with audio and video.It ... Read More

Definition In cellular communications, the handoff is the process of transferring an active call or data session from one cell in a cellular network or from one channel to another. In satellite communications, it is the process of transferring control from one earth station to another. Handoff is necessary for preventing loss of interruption of service to a caller or a data session user. Handoff is also called handover. Situations for triggering Handoff Handoffs are triggered in any of the following situations − If a subscriber who is in a call or a data session moves out of ... Read More

The dining philosophers problem states that there are 5 philosophers sharing a circular table and they eat and think alternatively. There is a bowl of rice for each of the philosophers and 5 chopsticks. A philosopher needs both their right and left chopstick to eat. A hungry philosopher may only eat if there are both chopsticks available.Otherwise a philosopher puts down their chopstick and begin thinking again.The dining philosopher is a classic synchronization problem as it demonstrates a large class of concurrency control problems.Solution of Dining Philosophers ProblemA solution of the Dining Philosophers Problem is to use a semaphore to ... Read More

The readers-writers problem relates to an object such as a file that is shared between multiple processes. Some of these processes are readers i.e. they only want to read the data from the object and some of the processes are writers i.e. they want to write into the object.The readers-writers problem is used to manage synchronization so that there are no problems with the object data. For example - If two readers access the object at the same time there is no problem. However if two writers or a reader and writer access the object at the same time, there ... Read More

Client/Server communication involves two components, namely a client and a server. They are usually multiple clients in communication with a single server. The clients send requests to the server and the server responds to the client requests.There are three main methods to client/server communication. These are given as follows −SocketsSockets facilitate communication between two processes on the same machine or different machines. They are used in a client/server framework and consist of the IP address and port number. Many application protocols use sockets for data connection and data transfer between a client and a server.Socket communication is quite low-level as ... Read More

Multithreaded programs allow the execution of multiple parts of a program at the same time. These parts are known as threads and are lightweight processes available within the process.Threads improve the application performance using parallelism. They share information like data segment, code segment files etc. with their peer threads while they contain their own registers, stack, counter etc.Some of the issues with multithreaded programs are as follows −Let us see them one by one −Increased Complexity − Multithreaded processes are quite complicated. Coding for these can only be handled by expert programmers.Complications due to Concurrency − It is difficult to ... Read More

Priority inversion is a operating system scenario in which a higher priority process is preempted by a lower priority process. This implies the inversion of the priorities of the two processes.Problems due to Priority InversionSome of the problems that occur due to priority inversion are given as follows −A system malfunction may occur if a high priority process is not provided the required resources.Priority inversion may also lead to implementation of corrective measures. These may include the resetting of the entire system.The performance of the system can be reduces due to priority inversion. This may happen because it is imperative ... Read More