International Journal of Computer Applications (0975 – 8887) Volume 8– No.12, October 2010
Handover management in GSM cellular system
School of computer science PAF-KIET, Pakistan Air Force Base korangi Creek Karachi 75190 Pakistan
Handover mechanism is extremely important in cellular network because of the cellular architecture employed to maximize spectrum utilization. Handover is the procedure that transfers an ongoing call from one cell to another as the user’s moves through the coverage area of cellular system. One way to improve the cellular network performance is to use efficient handover prioritization schemes when user is switching between the cells. ...view middle of the document...
The main reason of this growth is newly concept of mobile terminal and user mobility. The main characteristics of cellular communication system offer user maximum freedom of moment while using cell phones (mobiles). A cellular network is made up of numbers of cells (or radio cells). Each cell is allocated a band of frequencies and served by base station consisting of transmitter, receiver and control unit. Adjacent cells are assigned different frequencies to avoid interference or cross talk . As more customers use the cellular network with single base station traffic may be build up so there are not enough frequency bands assigned to a cell to handle its calls. An approach can be used to cope with this situation to use the same radio frequency can be
reused in different area for a completely different transmission . The degree of reuse determined by how apart cells must be reuse the same frequency is depending upon the actual implementation of the radio link. The reuse of frequencies in different cells is a form of space division multiple access and it requires that location of each mobile agent to be known this is provided through a service known location management or mobility management. The obstruction in cellular network involves the problem when a mobile user travels from one cell to another during a call. As adjacent cell do not use the same radio channels, a call must be transferred from one radio channel to another when a user crosses the line between the adjacent cells. The process of handover takes place that transfer an ongoing call from one cell to another cell as the user moves through the coverage area of a cellular network. In handover process cellular network automatically transfer a call from one radio channel to another radio channel while maintaining quality of services (QoS) of a call . Handover mechanism is extremely important in mobile network because of the cellular architecture employed to maximize spectrum utilization. The number of cell boundaries increases because smaller cells are deployed in order to meet the demand of increased capacity. Each handover require network resources to route the call to next base station. If handover does not occur at right time the QoS may be drop below an adequate level and connection will be dropped . There are several different reasons needed to be known to determine whether a handover is required. The signal strength of the base station, along signal strengths of the surrounding stations. In addition the availability of the channels also needed to be known. The mobile monitors the strength of the base stations, but only the cellular network knows the status of channel availability and the network make the decision about the handover. The main goal of this research is to investigate the GSM handover research issues and developing schemes which can handle handovers traffic in order to support on-going calls when mobile users are switching between base stations. The...