Shubhajeet Chatterjee

An improved mobility management technique for IEEE 802.11 based WLAN by predicting the direction of the mobile node

In wireless local area network (WLAN), mobility management becomes a sophisticated issue of research due to the limited coverage of the Access Points (AP). For the successful communication between the mobile nodes (MN), every node should be connected with an access point (AP) during their operating mode, irrespective of their mobility. When a MN travels into the coverage area of its current AP, no special technique is required to maintain the connectivity. But when a MN travels out of the coverage area of its current AP and tries to associate with another AP, a delay occurs during the handover of connection which leads to a failure of connection. Throughout the last few years plenty of researches had been done to reduce this handover delay by reducing the scanning delay as the scanning process causes 90% of the total handover delay. In this paper, we propose a new scanning technique where the most potential AP is chosen according to the direction of the MN. First, we fit a polynomial equation along the trajectory of its motion and then to predict the direction of motion, we analyze the slope of the trajectory. Our simulation results show the effectiveness and accuracy of our proposed scheme in practical field.

Minimization of Handoff Latency by Cell Sectoring Method using GPS

Presently, IEEE 802.11 based wireless local area networks (WLAN) have been widely deployed for business and personal applications. The main issue regarding wireless network technology is handoff or hand over management. When a mobile station (MS) moves outside the range of its current access point (AP) it needs to perform a link layer handover. This causes data loss and interruption in communication. According to IEEE 802.11 link layer2 (L2) handoff performed in three phases – scanning, authentication and re-association. Scanning process causes 90% of the total handoff delay. Throughout the last few years so many researches had been done to reduce the hand off delay.Here we propose a new scanning technique in which we divide a cell in three sectors and thus reducing the number of APs to be scanned by fixing the neighbour APs with respect to each sector. This process effectively reduces the handoff latency.

Reducing handover failure probability by repetitive scanning process

In wireless communication, handoff has become an important topic of research. A mobile station (MS) requires handoff when it travels out of the coverage area of its current access point (AP) and tries to associate with another AP. But handoff failure probability provides a serious barrier for such services to be made available to mobile platforms. Throughout the last few years plenty of research had been done to reduce handoff failure probability, whereas very few of them can be applied for an irregular (haphazard) motion of MS. In this paper, we are going to implement a new handoff scheme which is applicable for both regular and irregular motion of MS. We will find the minimum time interval (T) that the MS should stay within the handoff region (the particular area within a cell where the handoff is initiated and performed). We will repeat the scanning process number of times at different points of MS trajectory within the handoff region until the total scanning time exceeds the fixed time interval (T) and by doing so we can find out the most significant AP. Our simulation results show the effectiveness of our proposed scheme in practical field.

A fast scanning technique for mobility management by optimized angular segmentation method

In wireless & mobile communication the mobility management technique is an important issue of research. To fulfill the criteria of the all time connectivity, the mobile station (MS) should be connected with a base station (BS) during its operating mode, irrespective of its mobility. When a MS travels within the cell, no special technique is required to maintain its connectivity. But when a MS travels out of the coverage area of its current BS and tries to associate with another BS, a delay occurs during the handover of connection which leads to a failure of connection. Throughout the last few years plenty of researches had been done to reduce this handover delay by reducing the scanning delay as the scanning process causes ninety percent of the total handover delay. In this paper, we propose a new scanning technique where the hexagonal cell is divided in three angular segments and for each segment two neighbour BSs are reserved for handover. MS will measure its distance from the reserved BSs at fixed time intervals and the handover of connection will be performed to the nearest BS when the handover will be required. Our simulation results show the effectiveness of our proposed scheme in practical field.

Minimization of Handoff Latency by Directional Tangent Method using GPS based Map

Handoff has become an essential criterion in mobile communication system, specially in urban areas, owing to the limited coverage area of Access Points (AP). Handover of calls between two Base Stations (BSs) is encountered frequently and it is essentially required to minimize the delay of the process. Many solutions attempting to improve this process have been proposed but only a few use geo-location systems in the management of the handover. Here we propose to minimize the handoff latency by minimizing the number of APs scanned by the Mobile Node (MN) during each handoff procedure. We consider the whole topographical area as a two dimensional plane. By GPS, we can note down the co-ordinates of the MN at any instant. The average rate of change of its latitudinal distance and longitudinal distance with a specific time period is evaluated at the end of the given time period. With the knowledge of the given parameter, it is possible to determine the latitude and longitude of the MN after a particular instant of time. Hence, the direction of motion of the MN can be determined, which in turns gives the AP towards which the MN is headings. This reduces the number of APs to be scanned. Thus, on an overall basis, the handoff latency can be reduced by almost half to one third of its value.