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Novel simple forms for the probability density function (PDF) and the cumulative distribution function (CDF) of two correlated Rician random variables (RVs) are derived. The new representations for the bivariate Rician PDF and CDF are given in the form of single integral solutions in terms of well known functions that are available in common mathematical software packages. The general case of non-identically...
In this paper, we propose a channel estimation scheme in orthogonal frequency-division multiplexing (OFDM) systems based on the recent methodology of distributed compressed sensing (DCS). The joint sparsity model 2 (JSM-2) in DCS theory and simultaneous orthogonal matching pursuit (SOMP) are both introduced to improve the estimation performance and increase the spectral efficiency. Simulation results...
This paper analyzes the performance of space-time block coded orthogonal frequency division multiplexing (OFDM) systems. In our analysis, we abandon the usually made assumption of quasi-static channel conditions. Instead of this, we consider the more general and realistic case that the channel envelope changes during two consecutive transmission time slots. In addition, we take the spatial correlation...
In cognitive radio networks (CRN), underlay spectrum sharing allows secondary users (SUs) to utilize the spectrum on which the primary users (PUs) in primary radio networks (PRN) are working at the same time, without introducing intolerant interferences. In this paper, we study the joint transmission power and time allocation in CRN with underlay spectrum sharing technology. To maximize the total...
In this paper, a distributed compressive spectrum sensing scheme in wideband cognitive radio networks is discussed. An AIC RF front-end sampling structure is proposed requiring only low rate ADCs and few storage units for spectrum sampling. Multiple CRs collect compressed samples through AICs and recover spectrum jointly. A novel joint sparsity model is defined in this scenario, along with a universal...
In this paper, a joint blind synchronization and demodulation scheme is developed for ultra-wideband (UWB) impulse radio systems. Based on the prior knowledge of the direct-sequence (DS) spread codes, the proposed approach can achieve frame-level synchronization with the help of frame-rate samples. Taking advantage of the periodicity of the DS spread codes, the frame-level synchronization can be carried...
In this paper, we investigate joint sensing and power allocation schemes for OFDM-based cognitive radio (CR) systems. A CR system employing cooperative sensing based on energy detection is considered. Each primary user (PU) band is assigned a subset of sensors and equal gain combining is used at the access point to detect the presence of PU in that particular band. For such a system, we propose algorithms...
In this paper, we will study the joint problem of power allocation, relay selection and subchannel pairing in OFDM based amplify-and-forward multiple relays system. The optimization problem of maximizing system capacity under joint power constraint at source and relays is firstly formulated. Then, based on Lagrangian dual method, an optimal algorithm to the problem is derived with high SNR assumption...
Novel single integral representations for the multivariate probability density function (PDF) and cumulative distribution function (CDF) of the Nakagami-m distribution with integer and identical fading severity parameter m are derived. A generalized correlation structure is used in this model. The single integral solutions for the PDF and the CDF are given in terms of well known mathematical functions...
In this paper, we study the problem of joint carrier frequency offset (CFO) and channel estimation for two-way relay network (TWRN). We consider the frequency selective fading channels and adopt the zero padding (ZP) based orthogonal frequency division multiplexing (OFDM) as the modulation of the transmission. Due to the mixture of the first and the second transmission phases, the joint estimation...
We study the problem of optimizing the symbol error probability (SEP) performance of cluster-based cooperative wireless sensor networks (WSNs). It is shown in the literature that an efficient relay selection protocol based on simple geographical information of the nodes to execute the cooperative diversity transmission, can significantly improve the SEP performance at the destination of such networks...
With the increasing popularity of wireless mesh networks (WMNs), broadcasting traffic (e.g. IP-TV) will contribute a large portion of network load. In this paper, we consider a multi-channel multi-interface WMN with real time broadcast call arrivals. Aiming at maximizing the call acceptance rate of the network, an efficient broadcast tree construction algorithm, called Schedule-based Greedy Expansion...
As one of the key technologies in TD-LTE-Advanced downlink system, MIMO-OFDMA (Multi-Input and Multi-Output Orthogonal Frequency Division Multiplexing Access) achieves high system throughput by using multiple antennas at both the transmitter and receiver while eliminating intra-cell interference by utilizing closely-spaced orthogonal sub-carriers. Nonetheless, the inter-cell interference among several...
This paper considers a joint subcarrier and power allocation in an orthogonal frequency division multiple access (OFDMA) cellular system with base station (BS) cooperation. The problem is formulated as an average utility maximization subject to the per-antenna power constraint. Existing algorithms to solve similar problem in a single-sell system are shown not so efficient in the cooperative multi-cell...
In recent years, wireless mesh networks (WMNs) have been widely deployed to provide wireless access to the Internet. However, due to inter-link interference, the aggregated capacity of WMNs is limited, even with multiple channels. As a result, many links in WMNs are suppressed since interfering links cannot be active (i.e., transmitting packets) simultaneously. In this paper, we propose a joint design...
The paper addresses wireless the 2-Way Relay Channel (2-WRC) system with a Hierarchical Decode and Forward strategy. This strategy uses a Hierarchical eXclusive Code (HXC) that allows full decoding of the hierarchical symbols at the relay. The HXC represents two data sources only through the exclusive law and requires side information on the complementary data at the destination (which naturally holds...
The deployment of relay stations in OFDMA cellular networks is a promising solution to provide ubiquitous high-data-rate coverage. However, it makes the resource allocation a more crucial and challenging task. In OFDMA relay-enhanced cellular networks, we formulate the optimal instantaneous resource allocation problem including path selection, power allocation and subchannel scheduling to achieve...
We propose the self-organization based sensor collaboration scheme for the Mobile Multi-Target Tracking (MMTT) in our developed Decentralized Wireless Sensor Networks (DWSN). Our developed DWSN has three-tier hierarchical structure. At each time step, the Cluster Heads (CH) having the more information on the tracked targets are activated. The activated CHs receive the measurement-sets from their own...
Performance and reliability of content access in mobile networks is conditioned jointly by the number and location of content replicas deployed at the network nodes. The endeavour of this work is to address such an optimization problem with a distributed, lightweight solution that handles network dynamics. We devise a mechanism that lets nodes share the burden of storing and providing content, so...
In ad hoc networks, reducing energy consumption and improving throughput are both important for high network performance. This paper presents a joint power and rate control adaptive algorithm to optimize the trade-off between power consumption and throughput in ad hoc networks. Each node chooses its own transmission power and rate based on limited environment information in order to achieve optimal...
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