Informatics Publishing Limited

Debabrata Sarddar ¹, Shubhajeet Chatterjee ², Papri Mani ³, Pulak Mazumder ⁴, Sandip kr. Bala ¹, Utpal Biswas ¹, M. K. Naskar ¹

Affiliations
1 Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata – 700032, IN
2 Department of Electronics and Communication Engineering, Institute of Engg. & Managment College, saltlake, Kolkata-700091, IN
3 Department of Information Technology, West Bengal University of Technology, Kolkata-700064, IN
4 Department of Electronics and Telecommunication Engineering, Regent Education & Research Foundation, Barracpore, IN

Abstract

Due to rapid growth in IEEE 802.11 based Wireless Local Area Networks (WLAN), handoff has become a burning issue. A mobile node (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 delays provide a serious barrier for such services to be made available to mobile platforms. Throughout the last few years there has been plenty of research aimed towards reducing the handoff delay incurred in the various levels of wireless communication. In this paper, we propose to reduce handoff latency for IEEE 802.11 wireless networks with map based on GPS. IEEE 802.11 uses 14 possible channels of which only the channels 1, 6 and 11 do not mutually overlap. As they are non-overlapping, the channels are expected to have a lower carrier-to-interference ratio (CI) compared to the other channels present under the same base station, which increases the channel‟s availability during handoff. Based on the GPS, when handoff criterions have been met, we design an algorithm to first scan the channels 1, 6 and 11, if present under the next Access Point (AP), to reduce the scanning delay. We also introduce pre-authentication mechanism, which will effectively reduce the message processing delay.

Keywords

Next Generation Wireless Systems (NGWS), Handoff, BS (Base Station), MS (Mobile Node), RSS (Received Signal Strength), IEEE802.11, CI Ratio.

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Debabrata Sarddar ¹, Shubhajeet Chatterjee ², Ramesh Jana ¹, Shaik Sahil Babu ¹, Utpal Biswas ³, M. K. Naskar ⁴

Affiliations
1 Department of Electronics and Telecommunication Engg, Jadavpur University, Kolkata – 700032, IN
2 Department of Electronics and Communication Engg, Institute of Engg. & Managment College, Saltlake, Kolkata-70009, IN
3 Jadavpur University, IN
4 E&ECE Department, IIT Kharagpur, IN

Abstract

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.

Keywords

IEEE 802.11, Handoff Latency, GPS (Global Positioning System), Regression, Neighbor APs.

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Debabrata Sarddar ¹, Shubhajeet Chatterjee ², Arnab Raha ¹, Mustque Ahmed ¹, Pulak Mazumder ³, Utpal Biswas ¹, M. K. Naskar ¹

Affiliations
1 Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata – 700032, IN
2 Department of Electronics and Communication Engineering, Institute of Engg. & Managment College, Saltlake, Kolkata-700091, IN
3 Department of Electronics and Telecommunication Engg, Regent Education & Research Foundation, Barracpore, IN

Abstract

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, especially in urban areas, due to the limited coverage of access points (APs) or base stations (BS). When a mobile station (MS) moves outside the range of its current access point (AP) it needs to perform a link layer handover. 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 works had been done to reduce the hand off failure probability. Whereas, some of them have applied efficient channel allocation techniques, keeping the total number of channels constant. In this paper we also propose a method to minimize the handoff failure probability by increasing the total number of channel with help of Mother cell Child cell concept. Here we consider a larger hexagonal cell which almost covers up the whole region of a seven cell cluster. We will say this larger cell as the Mother cell and the smaller cells are the Child cells. The mother cell AP has a higher signal range than that of child cell as it covers larger area than the child cell. The Mother cell AP will only perform the handoff job whereas the child cell AP will perform both the originating and the handoff calls. Thus the total number of channel increases without any channel interference. This in turn, reduces the handoff failure probability. Simulation results yield that the proposed mechanism outperforms the usual channel allocation technique.

Keywords

IEEE 802.11, Handoff Failure, GPS (Global Positioning System), Channel Allocation, Neighbor APs.

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Debabrata Sarddar ¹, Shubhajeet Chatterjee ², Arnab Raha ³, Karmajyoti Panigrahi ⁴, Pulak Mazumder ⁵, Utpal Biswas ⁶, M. K. Naskar ⁷

Affiliations
1 Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata – 700032, IN
2 Department of Electronics and Communication Engineering, Institute of Engineering. & Managment College, Saltlake, Kolkata-700091, IN
3 Jadavpur University at the Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata–700032, IN
4 Techno India College of Technology at the Department of EIE, IN
5 Department of Electronics and Telecommunication Engineering, Regent Education & Research Foundation, Barracpore, IN
6 Kalyani University at the Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata – 700032, IN
7 Jadavpur University at the Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata – 700032, IN

Abstract

Due to rapid growth in IEEE 802.11 based Wireless Local Area Networks (WLAN), handoff has become a burning issue. A mobile node (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 delays provide a serious barrier for such services to be made available to mobile platforms. Throughout the last few years there has been plenty of research aimed towards reducing the handoff delay incurred in the various levels of wireless communication. In this article we propose to minimize the handoff latency by minimizing the number of APs scanned by the mobile station (MS) during each handoff procedure. We assume hexagonal coverage area of an AP with the AP situated at the center. By GPS, we can note down the co-ordinates of the MS at any instant. Segmenting the hexagon into 6 segments with 600 coverage area for each, we determine the trajectory of the MS by GPS. Hence the direction of motion of the MS can be determined, which in turns gives the AP towards which the MS is heading towards. 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.

Keywords

IEEE 802.11, Handoff Failure, GPS (Global Positioning System), Channel Allocation, Neighbor APs.

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Debabrata Sarddar ¹, Shubhajeet Chatterjee ², Ramesh Jana ³, Mandovi Mukherjee ³, Sreya Mallik ³, Utpal Biswas ⁴, M. K. Naskar ³

Affiliations
1 Jadavpur University, Department of Electronics & Telecommunication Engineering, IN
2 Institute of Engineering & Management, Department of Electronics & Telecommunication, IN
3 jadavpur University, Department of Electronics & Telecommunication, IN
4 Jadavpur University, Department of Electronics & Telecommunication, IN
5 Kalyani University, Department of Electronics & Telecommunication, IN

Abstract

Presently IEEE 802.11b based wireless networks are being widely used in various fields like personal as well as business applications. Handoff is a critical issue in IEEE 802.11b based wireless networks. When a mobile node (MN) moves away from the range of its current access point (AP) it needs to perform a link layer handoff. This causes data loss and interruption in communication. According to IEEE 802.11b link layer2 (L2) handoff consists of three phases – scanning, authentication and re-association. Scanning process delay is 90% of the total handoff delay. So in this paper we propose a better scanning mechanism to reduce handoff latency. Using GPS we determine the direction of velocity of the MN as well as position. It reduces the time to find the closest and best AP among all neighbor APs. This process effectively reduces the handoff latency.

Keywords

IEEE 802.11b, Handoff Latency, GPS (Global Positioning System), Direction of Velocity of MN, Neighbor APs, Mobile Node (MN).

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M. K. Naskar ¹

Affiliations
1 Department of Electronics Engineering, R.I.T., Jamshedpur - 831 014, IN

Abstract

The purpose of including laboratory classes in the engineering curriculum is to supplement as well as to verify and extend the knowledge obtained from the theory classes. Engineering students must have confidence and skill to develop engineering products which cannot be built up without laboratory classes and hence laboratory classes have some added importance compared to the theory classes.

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