Fairness in message delivery in delay tolerant networks

Wireless Networks - Rare existence of the end-to-end path and intermittent connectivity among the nodes are the key characteristics of delay tolerant networks (DTNs). Such networks are potentially...     

Challenges of computing in mobile cellular environment—a survey

Advances in cellular mobile technology have engendered a new paradigm of computing, called mobile computing. The frequency spectrum allocated to this service is not sufficient with respect to enormous growth of mobile communication users. Tracking down a mobile user in a cellular network which is a collection of geometric areas called cells each serviced by a base station is the other concern to the designer. This service also needs another problem to be solved, that is the access of common information by mobile users. Other than the issues in existing technology, many other issues on developing technology need to be addressed.

The survey is done in two phases. In the first phase a survey of three fundamental problems in mobile computing on existing technology is done. The issues discussed arise from three essential requirements: the efficient management and sharing of the spectrum among the users; to locate a mobile user in the cellular mobile environments; and processing of queries on location dependent data. The second phase highlights on research on different issues such as security, routing etc. in third generation wireless network in developing technology.     

LoWaNA: low overhead watermark based node authentication in WSN

Nodes in a wireless sensor network (WSN) are generally deployed in unattended environments making them susceptible to attacks. Therefore, the need of defending such attacks is of utmost importance. The challenge in providing security in this network is that the securing mechanism must be lightweight to make it implementable for such resource-constrained nodes. A robust security solution for such networks must facilitate authentication of sensor nodes. So far, only data authentication has drawn much attention from the research community. In this paper, a digital watermark based low-overhead solution (LoWaNA) is proposed for node authentication. The proposed watermarking technique consists of three modules viz. watermark generation, embedding and detection. The robustness of the algorithm is measured in terms of cracking probability and cracking time. This robustness analysis helps us to set the design guideline regarding size of watermark. Performance of the scheme is analyzed in terms of storage, computation and communication overhead. The analytical results are compared with two of the existing schemes and that show significant reduction of all such overheads. Thus it proves the suitability of the proposed scheme for resource-constrained networks like WSN. Finally the entire scheme is simulated in Cooja, the Contiki network simulator to make it readily implementable in real life mote e.g. MICAz.

     

A dynamic TDMA based scheme for securing query processing in WSN

Nodes in a wireless sensor network (WSN) are generally deployed in unattended environments making the nodes susceptible to attacks. Therefore, the need of defending such attacks becomes a big challenge. We propose a scheme to build a security mechanism in a query-processing paradigm within WSN. The scheme is capable of protecting replay attack while preserving essential properties of security such as authentication, data integrity and data freshness. The solution is made lightweight using symmetric key cryptography with very short-length key. Further, the key used in our scheme is neither pre-deployed nor is transmitted directly. The key information is established among nodes through an efficient use of one variant of dynamic TDMA mechanism which ensures security of key. Another variant of dynamic TDMA is used to make the scheme bandwidth saving, an essential quality of WSN. Performance of the scheme is analyzed in terms of storage, computation and communication overhead. Finally the analytical results are compared with two of the existing schemes including the previous version of the present scheme that show significant reduction of all such overheads thereby proving the suitability of the proposed scheme for a resource-constrained network like WSN.