Privacy Preserving Physical Layer Authentication Scheme for LBS based Wireless Networks

With the fast development in services related to localisation, location-based service (LBS) gains more importance amongst all the mobile wireless services. To avail the service in the LBS system, information about the location and identity of the user has to be provided to the service provider. The service provider authenticates the user based on their identity and location before providing services. In general, sharing location information and preserving the user’s privacy is a highly challenging task in conventional authentication techniques. To resolve these challenges in authenticating the users, retaining users’ privacy, a new SVD (singular value decomposition) based Privacy Preserved Location Authentication Scheme (SPPLAS) has been proposed. In this proposed method, physical layer signatures such as channel state information (CSI) and carrier frequency offset (CFO) are used for generating secret key required for encrypting the user’s location and identity information, and thus encrypted user’s information is sent to service provider for authentication. Secret key is generated by applying SVD on CSI vector. The proposed scheme aids in authenticating the user through location information while protecting the user’s privacy. The performance of the proposed method is evaluated in terms of bit mismatch, leakage and bit error rate performance of receiver and adversary. The simulation results show that the proposed scheme achieves better robustness and security than the existing location-based authentication techniques

6-Meth­oxy-2,3,4,9-tetra­hydro-1H-carbazol-1-one

The carbazole unit of the title mol­ecule, C13H13NO2, is not planar. The dihedral angle between the benzene ring and the pyrrole ring is 1.69 (6)°. The cyclo­hexene ring adopts an envelope conformation. Inter­molecular C—H⋯O and N—H⋯O hydrogen bonds are present in the crystal structure. A C—H⋯π inter­action, involving the benzene ring, is also found in the crystal structure

Quality of service analysis for hybrid-ARQ

Data intensive applications, requiring reliability and strict delay constraints, have emerged recently and they necessitate a different approach to analyzing system performance. In my work, I establish a framework that relates physical channel parameters to the queueing performance for a single-user wireless system. I then seek to assess the potential benefits of multirate techniques, such as hybrid-ARQ (Automatic Repeat reQuest), in the context of delay-sensitive communications. Present methods of analysis in an information theoretic paradigm define capacity assuming that long codewords can be used to take advantage of the ergodic properties of the fading wireless channel. This definition provides only a limited characterization of the channel in the light of delay constraints. The assumption of independent and identically distributed channel realizations tends to over-estimate the system performance by not considering the inherent time correlation. A finite-state continuous time Markov channel model that I formulate enables me to partition the instantaneous data-rate received at the destination into a finite number of states, representing layers in a hybrid-ARQ scheme. The correlation of channel has been incorporated through level crossing rates as transition rates in the Markov model. The large deviation principle governing the buffer overflow of the Markov model, is very sensitive to channel memory, is tractable, and gives a good estimate of the system performance. Metrics such as effective capacity and probability of buffer overflow, that are obtained through large deviations have been related to the wireless physical layer parameters through the model. Using the above metrics under QoS constraints, I establish the quantitative performance advantage of using hybrid-ARQ over traditional systems. I conduct this inquiry by restricting attention to the case where the expected transmit power is fixed at the transmitter. The results show that hybrid-ARQ helps us in obtaining higher effective capacity, but it is very difficult to support delay sensitive communication over wireless channel in the absence of channel knowledge and dynamic power allocation strategies

Primary vaginal Ewing’s sarcoma/primitive neuroectodermal tumour: diagnostic and treatment challenges

Extra osseous Ewing’s sarcoma/primitive neuroectodermal tumour (PNET) of the genital tract of women is scarcely\ud described in the literature and involvement of the vagina is even rarer with a very few cases reported so far. We present\ud 50-year-old-woman who presented with a vaginal mass that was diagnosed to be a malignant round cell tumour which\ud later was confirmed to be primary vaginal Ewing’s sarcoma/ PNET on light microscopy and immunohistochemical\ud staining. She was then treated with induction chemotherapy followed by local radiotherapy and further maintenance\ud chemotherapy. This rare case of primary vaginal Ewing’s sarcoma/PNET emphasizes the need for combining\ud morphological features with immunohistochemistry with a panel of antibodies in establishing the diagnosis of Ewing’s\ud sarcoma/PNET at an uncommon site. Further, the case also highlights the use of induction chemotherapy followed by\ud radiation therapy and subsequent maintenance chemotherapy as a treatment modality

3-Methyl-3,4-dihydro-9H-carbazol-1(2H)-one

In the title mol­ecule, C13H13NO, the dihedral angle between the benzene ring and the fused pyrrole ring is 2.03 (5)°. The methyl group at the 3-position has an equatorial orientation. The cyclo­hexene ring adopts an envelope conformation. Three C atoms of the cyclo­hexene ring, with their attached H atoms, and all atoms of the methyl group are disordered over two positions, the site-occupancy factors being 0.883 (2) and 0.117 (2). In the crystal structure, mol­ecules are stabilized by inter­molecular N—H⋯O hydrogen bonds. A C—H⋯π inter­action, involving the benzene ring, is also found

7,8,9,10-Tetra­hydro­cyclo­hepta­[b]indol-6(5H)-one

In the title mol­ecule, C13H13NO, the dihedral angle between the benzene and pyrrole rings is 1.05 (5)°. The cyclo­heptene ring adopts a slightly distorted boat conformation. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds form centrosymmetric dimers. A C—H⋯π inter­action, involving the benzene ring, is also found in the structure

4-Methyl-7,8,9,10-tetra­hydro­cyclo­hepta­[b]indol-6(5H)-one

In the title compound, C14H15NO, the seven-membered ring exhibits a slightly distorted twist-boat conformation. The pyrrole ring forms a dihedral angle of 1.44 (10)° with the fused benzene ring. N—H⋯O hydrogen bonds form a centrosymmetric dimer and weak C—H⋯π inter­actions are also found in the crystal structure

6-Chloro-3,4-di­hydro-9H-carbazol-1(2H)-one

The carbazole unit of the title mol­ecule, C12H10ClNO, is not planar. The dihedral angle between the benzene and pyrrole rings is 1.35 (10)°. The cyclo­hexene ring adopts an envelope conformation. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds form centrosymmetric dimers

4,8-Dimethyl­pyrano[2,3-a]carbazol-2(11H)-one

The mol­ecule of the title compound, C17H13NO2, is nearly planar, the r.m.s. deviation for all non-H atoms excluding the two methyl C atoms being 0.089 Å. Inter­molecular N—H⋯O and C—H⋯O hydrogen bonds are found in the crystal structure. C—H⋯π inter­actions are also found. The H atoms of the methyl group attached to the benzene ring are disordered equally over two positions