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In this paper, a novel general small-scale fading model for wireless communications, that describes the nonhomogeneous nature of the propagation medium, is introduced. Its probability density function (PDF) is given by a simple, exact, and closed-form expression. Namely, the η - λ - μ includes the λ - μ, the η - μ, the gamma, the exponential, the Hoyt, the Nakagami-m, the Rayleigh, and the one-sided...
AWG-based optical switching fabrics are affected by coherent crosstalk, that can significantly impair system operation when the same wavelength is used simultaneously on several input ports to forward data to output ports. To permit large port counts in a N x N AWG, the scheduling of transmissions across the AWG must therefore prevent switch configurations that generate large crosstalk. We study the...
In this paper, a new opportunistic feedback and user selection protocol is proposed for the multiple antenna downlink. The proposed scheme uses the structure of zero-forcing dirty paper coding (DPC) at the transmitter and selects users using a contention-based feedback channel. The user selection procedure is divided into stages and within each stage, a user is selected for one spatial channel (defined...
In this paper we propose a transmission range reduction scheme for a clustered wireless sensor network (WSN), in order to reduce power consumption while maintaining the network connectivity, particularly in scenarios where consecutive reporting of sensing values is inherent in the network. The platform WSN is based on a multi-hop clustering algorithm, where clusterheads send information to the sink...
The knapsack scheme is expected to be not only a light-weight public-key cryptosystem but also a post quantum cryptosystem. In this paper, we propose a new method for constructing knapsack PKC by using a random sequence. We also give two concrete knapsack schemes based on the proposed method. The scheme constructed the proposed method can be secure against the low-density attack because the density...
Ethernet networks are evolving from the enterprise to the carrier thus facing new demands and requirements. Therefore, a set of new control approaches are being defined for Ethernet. Amongst these, IEEE 802.1aq Shortest Path Bridging (SPB) aims to assure the transmission of unicast and multicast frames on the shortest path in a bridged network. Three protocols have been proposed for the control of...
The Voice over IP (VoIP) application utilizes the Internet to provide voice service; thus it is susceptible to various security issues common on the IP networks, such as the flooding attack. Moreover, VoIP uses the Session Initiation Protocol (SIP) for session control and management. The transactional nature of SIP makes flooding attack an even severer threat, which can consequentially lead to denial...
Frequently appeared sensor faults greatly reduce the usability and reliability of sensor networks. Distributed automatous faulty sensor detection is critical for self-managed and sustainable sensor networks. A number of detection methods have been proposed for specific fault types. In this paper, we propose a general approach for detecting arbitrary types of faults. The approach includes a new general...
Proxy mobile IPv6 (PMIPv6), a network-based IP mobility solution, is a promising approach for mobility management in all-IP wireless networks. How to enhance its handoff-related performance, such as handoff delay and signaling cost, is an important issue. Current solutions rely on approaches such as fast handoff, routing optimization and paging extension. However, the case of many correlated mobile...
It is known that there exist Triangle Inequality Violations (TIVs) with respect to network Quality of Service (QoS) metrics such as latency between nodes in the Internet. This motivates the exploitation of QoS-aware routing overlays. To find an optimal overlay route, we would usually need to examine all the possible overlay routes. However, this requires both measuring QoS between all node pairs and...
The performance of prevalent MAC protocols in MANETs relies on the level of contention in networks. While contention-based MAC protocols such as CSMA suffer from inefficiency under high contention, slot-based MAC protocols such as TDMA perform in the opposite way. In this paper, we propose a hybrid protocol to which we refer as Load-Adaptive MAC (LA-MAC) protocol for MANETs. By adaptively switching...
In this paper, we propose a novel routing metric, namely biased delivery probability (BDP), for measuring the wireless node's capacity of forwarding data packet to the destination. BDP essentially assigns different weights to the multi-paths information associated with different hop counts. An theoretical theory is established to compute the weights for different scenarios. Using BDP routing metric,...
PAPR reduction is an important issue in wireless OFDM transmission. Partial transmit sequence (PTS) is one of the distortionless methods. However, PTS requires side information on the phase rotation. This impacts not only the transmit efficiency but also the standardization process. Thus, blind detection without side information is expected as a solution to implement PTS. In the paper, simple blind...
The capacity of rate adaptive, power nonadaptive, multibranch, multihop, decode-and-forward relaying networks is analyzed for ergodically fading channels. Different cases of superimposed, selection, and orthogonal relaying are investigated. Parallel channel coding and repetition coding are considered for each case. Closed-form expressions for the maximum instantaneous achievable rates are obtained...
Optical Packet/Burst Switching (OPS/OBS) has emerged as a promising candidate for the next-generation all-optical network scenario. A crucial issue in OPS/OBS networks is how to provide packet loss rate (PLR) differentiation at the network layer. In this paper we propose a novel PLR differentiation scheme that utilizes network layer packet redundancy in order to isolate service classes in an OPS/OBS...
IPTV (Internet protocol television) terminals have a large receiving buffer for IP networks with large delay jitter. However the large buffer for jitter would cause large delay in playout. In this paper, we propose novel methods to achieve low-delay playout for IPTV terminals even in large-jitter networks. To minimize buffering time of received data in an IPTV terminal, the buffering time should be...
Maximum distance separable (MDS) array codes are XOR-based optimal erasure codes that are particularly suitable for use in disk arrays. This paper develops an innovative method to build MDS array codes from an elegant class of nested graphs, termed complete-graph-of-rings (CGR). We discuss a systematic and concrete way to transfer these graphs to array codes, unveil an interesting relation between...
This work presents a theoretical framework for determining the optimal clipping level for a multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) system. We start by modeling of the clipping noise, and propose a maximum likelihood (ML) receiver for the resulting signal. The bit error rate (BER) for this ML receiver is then derived for MIMO spatial multiplexing, space...
Energy harvesting sensors (EHS), which harvest energy from the environment in order to sense and then communicate their measurements over a wireless link, provide the tantalizing possibility of perpetual lifetime operation of a sensor network. The wireless communication link design problem needs to be revisited for these sensors as the energy harvested can be random and small and not available when...
In this paper, we derive the maximum likelihood (ML) channel estimate in the presence of phase noise (PHN) and I/Q imbalance for OFDM systems. Since it is estimated jointly with I/Q and PHN, the channel estimate is more robust to these RF impairments compared to the conventional schemes. The complexity of the joint estimator is reduced using an approximate cost functions for both PHN and I/Q imbalance...
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