Towards a reconfigurable hardware architecture for implementing a LDPC module suitable for software radio systems

Forward Error Correction is a key piece in modern digital communications. When a signal is transmitted over a noisy channel, multiple errors are generated. FEC techniques are directed towards the recovery of such errors. In last years, LDPC (Low Density Parity Check) codes have attracted attention of researchers because of their excellent error correction capabilities, but for actual radios high performance is not enough since they require to communicate with other multiple radios too. In general, communication between multiple radios requires the use of different standards. In this sense, Software Defined Radio (SDR) approach allows building multi standard radios based on reconfigurability abilities which means that base components including recovery errors block must provide reconfigurable options. In this paper, some open problems in designing and implementing reconfigurable LDPC components are presented and discussed. Some features of works in the state of the art are commented and possible research lines proposed

Cognitive Spectrum Sensing Techniques: A Brief Review

The radio wireless network is meant as a sophisticated technology integration atmosphere with specialise in building adjustive, spectrum-efficient systems with rising programmable radios. The rising radio state of affairs is of current interest to each policy manufacturers and technologists owing to the potential for order-of-magnitude gains in spectral and network performance. the concept of a cognitive radio extends the concepts of a haredware radio and a software defined radio (SDR) from a straightforward, single operate device to a radio that senses and reacts to its operational atmosphere DOI: 10.17762/ijritcc2321-8169.15075

Mark-aided distributed filtering by using neural network for DDoS defense

Currently Distributed Denial of Service (DDoS) attacks have been identified as one of the most serious problems on the Internet. The aim of DDoS attacks is to prevent legitimate users from accessing desired resources, such as network bandwidth. Hence the immediate task of DDoS defense is to provide as much resources as possible to legitimate users when there is an attack. Unfortunately most current defense approaches can not efficiently detect and filter out attack traffic. Our approach is to find the network anomalies by using neural network, deploy the system at distributed routers, identify the attack packets, and then filter them. The marks in the IP header that are generated by a group of IP traceback schemes, Deterministic Packet Marking (DPM)/Flexible Deterministic Packet Marking (FDPM), assist this process of identifying attack packets. The experimental results show that this approach can be used to defend against both intensive and subtle DDoS attacks, and can catch DDoS attacks&rsquo; characteristic of starting from multiple sources to a single victim. According to results, we find the marks in IP headers can enhance the sensitivity and accuracy of detection, thus improve the legitimate traffic throughput and reduce attack traffic throughput. Therefore, it can perform well in filtering DDoS attack traffic precisely and effectively.<br /

A peer to peer approach to large scale information monitoring

Issued as final reportNational Science Foundation (U.S.

On detection algorithms for spurious retransmissions in TCP

In TCP, a spurious packet retransmission can be caused by either spurious timeout (STO) or spurious fast retransmit (SFR). The "lost" packets are unnecessarily retransmitted and the evoked congestion control process causes network underutilization. In this paper, we focus on spurious retransmission detection. We first present a survey on some important and interesting spurious retransmission detection algorithms. Based on the insights obtained, we propose a novel yet simple detection algorithm called split-and-retransmit (SnR). SnR only requires a minor modification to the TCP sender while leaving the receiver intact. The key idea is to split the retransmitted packet into two smaller ones before retransmitting them. As the packet size is different, the ACK triggered will carry different ACK numbers. This allows the sender to easily distinguish between the original transmission and the retransmission of a packet without relying on, e.g., TCP options. We then compare our SnR with STODER, F-RTO and Newreno under both loss-free and lossy network environments. We show that our SnR is resilient to packet loss and yields good performance under various simulation settings. ©2010 IEEE.published_or_final_versionThe 2010 IEEE Wireless Communications and Networking Conference (WCNC), Sydney, Australia, 18-21 April 2010. In Proceedings of WCNC, 2010, p. 1-

Partial Program Admission by Path Enumeration

Real-time systems on non-preemptive platforms require a means of bounding the execution time of programs for admission purposes. Worst-Case Execution Time (WCET) is most commonly used to bound program execution time. While bounding a program\u27s WCET statically is possible, computing its true WCET is difficult without significant semantic knowledge. We present an algorithm for partial program admission, suited for non-preemptive platforms, using dynamic programming to perform explicit enumeration of program paths. Paths - possible or not - are bounded by the available execution time and admitted on a path-by-path basis without requiring semantic knowledge of the program beyond its Control Flow Graph (CFG)