Anand Srinivasan

Efficient resource allocation for device-to-device communication underlaying LTE network

Device-to-device (D2D) communication as an underlaying cellular network empowers user-driven rich multimedia applications and also has proven to be network efficient offloading eNodeB traffic. However, D2D transmitters may cause significant amount of interference to the primary cellular network when radio resources are shared between them. During the downlink (DL) phase, primary cell UE (user equipment) may suffer from interference by the D2D transmitter. On the other hand, the immobile eNodeB is the victim of interference by the D2D transmitter during the uplink (UL) phase when radio resources are allocated randomly. Such interference can be avoided otherwise diminish if radio resource allocated intelligently with the coordination from the eNodeB. In this paper, we formulate the problem of radio resource allocation to the D2D communications as a mixed integer nonlinear programming (MINLP). Such an optimization problem is notoriously hard to solve within fast scheduling period of the Long Term Evolution (LTE) network. We therefore propose an alternative greedy heuristic algorithm that can lessen interference to the primary cellular network utilizing channel gain information. We also perform extensive simulation to prove the efficacy of the proposed algorithm.

Analysis on mobile WiMAX security

Security support is mandatory for any communication networks. For wireless systems, security support is even more important to protect the users as well as the network. Since wireless medium is available to all, the attackers can easily access the network and the network becomes more vulnerable for the user and the network service provider. In the existing research, there is lack of integrated presentation of solutions to all the security issues of mobile WiMAX network, which is important for researchers and practitioners. This paper discusses all the security issues in both point-to-multipoint and mesh network and discusses their solutions. In addition, a new recommendation is also proposed for one of the security issues.

Intelligent Weather Aware Scheme for Satellite Systems

Rain, snow, gaseous, cloud, fog, scintillation and other atmospheric properties can have a distorting effect on signal fidelity of Ku and Ka bands, thus resulting in excessive digital transmission error. This loss of signal is commonly referred to as signal attenuation. Signal attenuation impacts the QoS in wireless and satellite networks. Accurately predicting channel attenuation due to atmospheric conditions can enable mitigation planning by adaptively selecting appropriate modulation, coding, transmitted power level, transmission rate and configured frame size. The aim of this paper is to estimate different attenuations using predicted signal-weather correlated database in collaboration with ITU-R propagation models combined with interpolation methods, gateway, and ground terminal characteristics. A three dimensional relationship is proposed among these attenuations with respect to propagation angle and rainfall rate [l]-[8]. The outcome is key factor in diagnosing, adjusting and improving satellite signal power, modulation and coding schemes, monitored and controlled altogether by a powerful and efficient intelligent-based attenuation countermeasure system. These results will lead to an enhanced back propagation-learning algorithm that is used to iteratively tune the IS with returned SNR values to activate the weighted Modulation/Codepoint to its optimal values, depending on actual or predicted weather conditions, configuration settings and tolerance/safety margins for SLA commitment.

Performance optimization of big data in mobile networks

Smart phones are ubiquitous nowadays and have taken over the bulk data transfers in mobile networks. The next generation phones are even more powerful to handle voice, video and data catering real time multimedia experience. Unfortunately, the increase in service provider capacity has not kept up with the user demand for more bandwidth. It is becoming very expensive for service providers to cater higher bandwidth without investing on new technology or expansion. In this paper we propose a bandwidth optimization algorithm based on cache coherency where the user data transfer is optimized without compromising the user expectation or the need for service providers to expand their capacity. The proposed algorithm is compared with existing data transfer techniques (such as GIT [9]) and we show the efficiency of the proposed method through simulation. We validate the simulation results through two year measured result.

Performance Improvement in Satellite Networks Based on Markovian Weather Prediction

Prediction of channel characteristics can be of immense value in improving the quality of signals in high frequency satellite systems. Making prediction of rainfall rate (RR) using Markov theory and using that prediction in an intelligent system (IS) to maintain the quality of service (QoS) in channels impacted by attenuation due to weather is the object of this paper. The paper describes the method of prediction rainfall rate using weather collected by environment agencies and applying the predictions to gateway and ground terminal for optimal control of channel characteristics. This novel method of predicting weather characteristics using Markov theory supplies valuable data to develop an enhanced back propagation-learning algorithm to iteratively tune the IS to adapt to changing weather conditions. The effectiveness of the algorithm was tested on a simulated model for activating the weighted modulation and codepoint control. It demonstrated marked improvements in channel parameter tuning and signal quality.

A cost-effective protection and restoration mechanism for Ethernet based networks: an experiment report

Protection and restoration at the physical layer is fast, but may require dedicated hardware. On the other hand, IP, although it does not rely on specific topology, is slow. Protection based on MPLS is effective for rerouting traffic to a pre-established backup LSP in the case of failures. Failure detection plays a dominant role in protection and restoration. This research presents an approach for addressing MPLS link and node protection by making use of auto-negotiation for Ethernet. The method is efficient in detecting failures in an Ethernet-based network and can be easily adopted to support MPLS protection with low overhead. The experimental results show that traffic recovery can be achieved in sub-30ms.

Co-located Physical-Layer Network Coding to mitigate passive eavesdropping

Physical-Layer Network Coding (PLNC) has recently emerged as a promising new communications paradigm that has the ability to greatly increase the capacity of wireless networks. Current research has also demonstrated that PLNC can decrease the eavesdropping region of an external entity. In this paper we show how it is possible to mitigate passive eavesdropping in the presence of co-located nodes in a PLNC environment.

Favorable Peer Supported Throughput Optimization in Wireless Mesh Network

Peer selection strategy is one of the major challenges towards efficient peer-to-peer (P2P) system in wireless mesh networks (WMNs). When peers choose their own utility-maximizing strategies for coalition and peer formation, the solution is always sub-optimal. Peer formation, based on only application layer information, also results in inefficient use of network bandwidth. When multiple recipient-peers try to access the same file from same source-peer simultaneously, contention may occur on the shared wireless channel. On the discovery of multiple source-peers, corresponding recipient-peer may choose optimal source-peer in favor of increased network throughput. Here, we propose a novel optimization method to calculate the upper bound of the aggregate throughput for P2P over WMNs utilizing the underlying physical network information and optimal peer selection strategy. The results show that our favorable-peer selection strategy, results in higher aggregate throughput by selecting optimum source-peers with better load distribution and minimum interference.

Cache Coherency Algorithm to Optimize Bandwidth in Mobile Networks

Mobile networks are becoming popular in catering to Internet through smart phones. The next generation phones provide ubiquitous communication of voice, video and data through the hand held devices. Unfortunately, the increase in service provider capacity has not kept up with the user demand for more bandwidth. It is becoming very expensive for service providers to cater higher bandwidth without investing on new technology or expansion. In this paper we propose a bandwidth optimization algorithm based on cache coherency where the user data transfer is optimized without compromising the user expectation or the need for service providers to expand their capacity. The proposed algorithm is compared with existing data transfer techniques and we show through representative analysis the efficiency of the algorithm to keep the same level of communication with less transfer. To emphasize the practicality of the algorithm, we also provide some insights into how it is implemented.

Securing RSVP and RSVP-TE signaling protocols and their performance study

RSVP and RSVP-TE are signaling protocols used to set up paths and/or support quality of service (QoS) requirements in IP and MPLS-based networks, respectively. This paper analyzes an authentication mechanism for securing the RSVP and RSVP-TE control messages, and studies their performance. This design and implementation of the authentication mechanism, which is based on RFC2747, using four commonly adopted hash algorithms - MD5, RIPEMD160, SHA-1, and SHA-256, not only improves security, but also provides useful information from the performance aspect. The time for authenticating the signaling messages depends on the algorithm used, and increases slightly in the order of MD5, SHA-1, RIPEMD160 and SHA-256. The performance of the RSVP-TE with multiple sessions was measured.